* [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-02 19:15 [PATCH 0/5] Linux: Fall back to mmap if early sbrk fails Florian Weimer
@ 2022-05-02 19:15 ` Florian Weimer
2022-05-02 19:45 ` H.J. Lu
2022-05-02 19:15 ` [PATCH 2/5] Linux: Define MMAP_CALL_INTERNAL Florian Weimer
` (3 subsequent siblings)
4 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-02 19:15 UTC (permalink / raw)
To: libc-alpha
---
sysdeps/unix/sysv/linux/i386/startup.h | 17 ++----------
sysdeps/unix/sysv/linux/startup.h | 38 ++++++++++++++++++++++++++
2 files changed, 40 insertions(+), 15 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/startup.h
diff --git a/sysdeps/unix/sysv/linux/i386/startup.h b/sysdeps/unix/sysv/linux/i386/startup.h
index 67c9310f3a..694d6cf4e7 100644
--- a/sysdeps/unix/sysv/linux/i386/startup.h
+++ b/sysdeps/unix/sysv/linux/i386/startup.h
@@ -19,19 +19,6 @@
#if BUILD_PIE_DEFAULT
/* Can't use "call *%gs:SYSINFO_OFFSET" during statup in static PIE. */
# define I386_USE_SYSENTER 0
-
-# include <sysdep.h>
-# include <abort-instr.h>
-
-__attribute__ ((__noreturn__))
-static inline void
-_startup_fatal (const char *message __attribute__ ((unused)))
-{
- /* This is only called very early during startup in static PIE.
- FIXME: How can it be improved? */
- ABORT_INSTRUCTION;
- __builtin_unreachable ();
-}
-#else
-# include_next <startup.h>
#endif
+
+#include_next <startup.h>
diff --git a/sysdeps/unix/sysv/linux/startup.h b/sysdeps/unix/sysv/linux/startup.h
new file mode 100644
index 0000000000..a5de941759
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/startup.h
@@ -0,0 +1,38 @@
+/* Linux definitions of functions used by static libc main startup.
+ Copyright (C) 2017-2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifdef SHARED
+# include_next <startup.h>
+#else
+# include <sysdep.h>
+
+/* Avoid a run-time invocation of strlen. */
+#define _startup_fatal(message) \
+ do \
+ { \
+ size_t message_length = __builtin_strlen (message); \
+ if (! __builtin_constant_p (message_length)) \
+ { \
+ extern void _startup_fatal_not_constant (void); \
+ _startup_fatal_not_constant (); \
+ } \
+ INTERNAL_SYSCALL_CALL (write, STDERR_FILENO, message, message_length); \
+ INTERNAL_SYSCALL_CALL (exit_group, 127); \
+ } \
+ while (0)
+#endif /* !SHARED */
--
2.35.1
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-02 19:15 ` [PATCH 1/5] Linux: Implement a useful version of _startup_fatal Florian Weimer
@ 2022-05-02 19:45 ` H.J. Lu
2022-05-02 19:52 ` Florian Weimer
0 siblings, 1 reply; 23+ messages in thread
From: H.J. Lu @ 2022-05-02 19:45 UTC (permalink / raw)
To: Florian Weimer; +Cc: GNU C Library
On Mon, May 2, 2022 at 12:16 PM Florian Weimer via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> ---
> sysdeps/unix/sysv/linux/i386/startup.h | 17 ++----------
> sysdeps/unix/sysv/linux/startup.h | 38 ++++++++++++++++++++++++++
> 2 files changed, 40 insertions(+), 15 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/startup.h
>
> diff --git a/sysdeps/unix/sysv/linux/i386/startup.h b/sysdeps/unix/sysv/linux/i386/startup.h
> index 67c9310f3a..694d6cf4e7 100644
> --- a/sysdeps/unix/sysv/linux/i386/startup.h
> +++ b/sysdeps/unix/sysv/linux/i386/startup.h
> @@ -19,19 +19,6 @@
> #if BUILD_PIE_DEFAULT
> /* Can't use "call *%gs:SYSINFO_OFFSET" during statup in static PIE. */
> # define I386_USE_SYSENTER 0
> -
> -# include <sysdep.h>
> -# include <abort-instr.h>
> -
> -__attribute__ ((__noreturn__))
> -static inline void
> -_startup_fatal (const char *message __attribute__ ((unused)))
> -{
> - /* This is only called very early during startup in static PIE.
> - FIXME: How can it be improved? */
> - ABORT_INSTRUCTION;
> - __builtin_unreachable ();
> -}
> -#else
> -# include_next <startup.h>
> #endif
> +
> +#include_next <startup.h>
> diff --git a/sysdeps/unix/sysv/linux/startup.h b/sysdeps/unix/sysv/linux/startup.h
> new file mode 100644
> index 0000000000..a5de941759
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/startup.h
> @@ -0,0 +1,38 @@
> +/* Linux definitions of functions used by static libc main startup.
> + Copyright (C) 2017-2022 Free Software Foundation, Inc.
Shouldn't it just be 2022?
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#ifdef SHARED
> +# include_next <startup.h>
> +#else
> +# include <sysdep.h>
> +
> +/* Avoid a run-time invocation of strlen. */
> +#define _startup_fatal(message) \
Is this needed only for static PIE?
> + do \
> + { \
> + size_t message_length = __builtin_strlen (message); \
> + if (! __builtin_constant_p (message_length)) \
> + { \
> + extern void _startup_fatal_not_constant (void); \
> + _startup_fatal_not_constant (); \
> + } \
> + INTERNAL_SYSCALL_CALL (write, STDERR_FILENO, message, message_length); \
> + INTERNAL_SYSCALL_CALL (exit_group, 127); \
> + } \
> + while (0)
> +#endif /* !SHARED */
> --
> 2.35.1
>
>
--
H.J.
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-02 19:45 ` H.J. Lu
@ 2022-05-02 19:52 ` Florian Weimer
2022-05-02 20:06 ` H.J. Lu
0 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-02 19:52 UTC (permalink / raw)
To: H.J. Lu; +Cc: GNU C Library
* H. J. Lu:
>> +#include_next <startup.h>
>> diff --git a/sysdeps/unix/sysv/linux/startup.h b/sysdeps/unix/sysv/linux/startup.h
>> new file mode 100644
>> index 0000000000..a5de941759
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/startup.h
>> @@ -0,0 +1,38 @@
>> +/* Linux definitions of functions used by static libc main startup.
>> + Copyright (C) 2017-2022 Free Software Foundation, Inc.
> Shouldn't it just be 2022?
>> + This file is part of the GNU C Library.
>> +
>> + The GNU C Library is free software; you can redistribute it and/or
>> + modify it under the terms of the GNU Lesser General Public
>> + License as published by the Free Software Foundation; either
>> + version 2.1 of the License, or (at your option) any later version.
>> +
>> + The GNU C Library is distributed in the hope that it will be useful,
>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>> + Lesser General Public License for more details.
>> +
>> + You should have received a copy of the GNU Lesser General Public
>> + License along with the GNU C Library; if not, see
>> + <https://www.gnu.org/licenses/>. */
>> +
>> +#ifdef SHARED
>> +# include_next <startup.h>
>> +#else
>> +# include <sysdep.h>
>> +
>> +/* Avoid a run-time invocation of strlen. */
>> +#define _startup_fatal(message) \
>
> Is this needed only for static PIE?
I don't know. It's used from csu/libc-tls.c, some targets may need it
for ET_EXEC static linking, too. I haven't checked. The additional
code size is minimal.
Thanks,
Florian
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-02 19:52 ` Florian Weimer
@ 2022-05-02 20:06 ` H.J. Lu
2022-05-02 20:37 ` Florian Weimer
0 siblings, 1 reply; 23+ messages in thread
From: H.J. Lu @ 2022-05-02 20:06 UTC (permalink / raw)
To: Florian Weimer; +Cc: GNU C Library
On Mon, May 2, 2022 at 12:53 PM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu:
>
> >> +#include_next <startup.h>
> >> diff --git a/sysdeps/unix/sysv/linux/startup.h b/sysdeps/unix/sysv/linux/startup.h
> >> new file mode 100644
> >> index 0000000000..a5de941759
> >> --- /dev/null
> >> +++ b/sysdeps/unix/sysv/linux/startup.h
> >> @@ -0,0 +1,38 @@
> >> +/* Linux definitions of functions used by static libc main startup.
> >> + Copyright (C) 2017-2022 Free Software Foundation, Inc.
> > Shouldn't it just be 2022?
> >> + This file is part of the GNU C Library.
> >> +
> >> + The GNU C Library is free software; you can redistribute it and/or
> >> + modify it under the terms of the GNU Lesser General Public
> >> + License as published by the Free Software Foundation; either
> >> + version 2.1 of the License, or (at your option) any later version.
> >> +
> >> + The GNU C Library is distributed in the hope that it will be useful,
> >> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> >> + Lesser General Public License for more details.
> >> +
> >> + You should have received a copy of the GNU Lesser General Public
> >> + License along with the GNU C Library; if not, see
> >> + <https://www.gnu.org/licenses/>. */
> >> +
> >> +#ifdef SHARED
> >> +# include_next <startup.h>
> >> +#else
> >> +# include <sysdep.h>
> >> +
> >> +/* Avoid a run-time invocation of strlen. */
> >> +#define _startup_fatal(message) \
> >
> > Is this needed only for static PIE?
>
> I don't know. It's used from csu/libc-tls.c, some targets may need it
> for ET_EXEC static linking, too. I haven't checked. The additional
> code size is minimal.
_startup_fatal was added for i386 static PIE. I don't think it is
needed for normal static executables.
--
H.J.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-02 20:06 ` H.J. Lu
@ 2022-05-02 20:37 ` Florian Weimer
2022-05-03 5:18 ` Florian Weimer
0 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-02 20:37 UTC (permalink / raw)
To: H.J. Lu; +Cc: GNU C Library
* H. J. Lu:
> On Mon, May 2, 2022 at 12:53 PM Florian Weimer <fweimer@redhat.com> wrote:
>>
>> * H. J. Lu:
>>
>> >> +#include_next <startup.h>
>> >> diff --git a/sysdeps/unix/sysv/linux/startup.h b/sysdeps/unix/sysv/linux/startup.h
>> >> new file mode 100644
>> >> index 0000000000..a5de941759
>> >> --- /dev/null
>> >> +++ b/sysdeps/unix/sysv/linux/startup.h
>> >> @@ -0,0 +1,38 @@
>> >> +/* Linux definitions of functions used by static libc main startup.
>> >> + Copyright (C) 2017-2022 Free Software Foundation, Inc.
>> > Shouldn't it just be 2022?
>> >> + This file is part of the GNU C Library.
>> >> +
>> >> + The GNU C Library is free software; you can redistribute it and/or
>> >> + modify it under the terms of the GNU Lesser General Public
>> >> + License as published by the Free Software Foundation; either
>> >> + version 2.1 of the License, or (at your option) any later version.
>> >> +
>> >> + The GNU C Library is distributed in the hope that it will be useful,
>> >> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>> >> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>> >> + Lesser General Public License for more details.
>> >> +
>> >> + You should have received a copy of the GNU Lesser General Public
>> >> + License along with the GNU C Library; if not, see
>> >> + <https://www.gnu.org/licenses/>. */
>> >> +
>> >> +#ifdef SHARED
>> >> +# include_next <startup.h>
>> >> +#else
>> >> +# include <sysdep.h>
>> >> +
>> >> +/* Avoid a run-time invocation of strlen. */
>> >> +#define _startup_fatal(message) \
>> >
>> > Is this needed only for static PIE?
>>
>> I don't know. It's used from csu/libc-tls.c, some targets may need it
>> for ET_EXEC static linking, too. I haven't checked. The additional
>> code size is minimal.
>
> _startup_fatal was added for i386 static PIE. I don't think it is
> needed for normal static executables.
Based on the current initialization ordering, it seems to me that we
need it for non-PIE static programs, too. Maybe I should check this
tomorrow.
Thanks,
Florian
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-02 20:37 ` Florian Weimer
@ 2022-05-03 5:18 ` Florian Weimer
2022-05-03 15:54 ` H.J. Lu
0 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-03 5:18 UTC (permalink / raw)
To: H.J. Lu; +Cc: GNU C Library
* Florian Weimer:
> * H. J. Lu:
>
>> On Mon, May 2, 2022 at 12:53 PM Florian Weimer <fweimer@redhat.com> wrote:
>>>
>>> * H. J. Lu:
>>>
>>> >> +#include_next <startup.h>
>>> >> diff --git a/sysdeps/unix/sysv/linux/startup.h b/sysdeps/unix/sysv/linux/startup.h
>>> >> new file mode 100644
>>> >> index 0000000000..a5de941759
>>> >> --- /dev/null
>>> >> +++ b/sysdeps/unix/sysv/linux/startup.h
>>> >> @@ -0,0 +1,38 @@
>>> >> +/* Linux definitions of functions used by static libc main startup.
>>> >> + Copyright (C) 2017-2022 Free Software Foundation, Inc.
>>> > Shouldn't it just be 2022?
>>> >> + This file is part of the GNU C Library.
>>> >> +
>>> >> + The GNU C Library is free software; you can redistribute it and/or
>>> >> + modify it under the terms of the GNU Lesser General Public
>>> >> + License as published by the Free Software Foundation; either
>>> >> + version 2.1 of the License, or (at your option) any later version.
>>> >> +
>>> >> + The GNU C Library is distributed in the hope that it will be useful,
>>> >> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> >> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>>> >> + Lesser General Public License for more details.
>>> >> +
>>> >> + You should have received a copy of the GNU Lesser General Public
>>> >> + License along with the GNU C Library; if not, see
>>> >> + <https://www.gnu.org/licenses/>. */
>>> >> +
>>> >> +#ifdef SHARED
>>> >> +# include_next <startup.h>
>>> >> +#else
>>> >> +# include <sysdep.h>
>>> >> +
>>> >> +/* Avoid a run-time invocation of strlen. */
>>> >> +#define _startup_fatal(message) \
>>> >
>>> > Is this needed only for static PIE?
>>>
>>> I don't know. It's used from csu/libc-tls.c, some targets may need it
>>> for ET_EXEC static linking, too. I haven't checked. The additional
>>> code size is minimal.
>>
>> _startup_fatal was added for i386 static PIE. I don't think it is
>> needed for normal static executables.
>
> Based on the current initialization ordering, it seems to me that we
> need it for non-PIE static programs, too. Maybe I should check this
> tomorrow.
It does not work on x86-64 because cancellation handling needs the TCB:
Breakpoint 1, _dl_early_allocate (size=size@entry=3520) at ../sysdeps/unix/sysv/linux/dl-early_allocate.c:41
41 if (__curbrk != NULL)
(gdb) finish
Run till exit from #0 _dl_early_allocate (size=size@entry=3520)
at ../sysdeps/unix/sysv/linux/dl-early_allocate.c:41
__libc_setup_tls () at libc-tls.c:149
149 if (tlsblock == NULL)
Value returned is $1 = (void *) 0x4eb000
(gdb) set $rax = 0
(gdb) c
Continuing.
Program received signal SIGSEGV, Segmentation fault.
__writev (fd=fd@entry=2, iov=iov@entry=0x7fffffffddb0, iovcnt=iovcnt@entry=1) at ../sysdeps/unix/sysv/linux/writev.c:26
26 return SYSCALL_CANCEL (writev, fd, iov, iovcnt);
(gdb) disas
Dump of assembler code for function __writev:
=> 0x000000000044e3c0 <+0>: mov %fs:0x18,%eax
0x000000000044e3c8 <+8>: test %eax,%eax
0x000000000044e3ca <+10>: jne 0x44e3e0 <__writev+32>
0x000000000044e3cc <+12>: mov $0x14,%eax
0x000000000044e3d1 <+17>: syscall
0x000000000044e3d3 <+19>: cmp $0xfffffffffffff000,%rax
0x000000000044e3d9 <+25>: ja 0x44e430 <__writev+112>
0x000000000044e3db <+27>: ret
0x000000000044e3dc <+28>: nopl 0x0(%rax)
0x000000000044e3e0 <+32>: sub $0x28,%rsp
0x000000000044e3e4 <+36>: mov %edx,0x1c(%rsp)
0x000000000044e3e8 <+40>: mov %rsi,0x10(%rsp)
0x000000000044e3ed <+45>: mov %edi,0x8(%rsp)
0x000000000044e3f1 <+49>: call 0x46d2b0 <__pthread_enable_asynccancel>
0x000000000044e3f6 <+54>: mov 0x1c(%rsp),%edx
0x000000000044e3fa <+58>: mov 0x10(%rsp),%rsi
0x000000000044e3ff <+63>: mov %eax,%r8d
0x000000000044e402 <+66>: mov 0x8(%rsp),%edi
0x000000000044e406 <+70>: mov $0x14,%eax
0x000000000044e40b <+75>: syscall
0x000000000044e40d <+77>: cmp $0xfffffffffffff000,%rax
0x000000000044e413 <+83>: ja 0x44e448 <__writev+136>
0x000000000044e415 <+85>: mov %r8d,%edi
0x000000000044e418 <+88>: mov %rax,0x8(%rsp)
0x000000000044e41d <+93>: call 0x46d330 <__pthread_disable_asynccancel>
0x000000000044e422 <+98>: mov 0x8(%rsp),%rax
0x000000000044e427 <+103>: add $0x28,%rsp
0x000000000044e42b <+107>: ret
0x000000000044e42c <+108>: nopl 0x0(%rax)
0x000000000044e430 <+112>: mov $0xffffffffffffffa8,%rdx
0x000000000044e437 <+119>: neg %eax
0x000000000044e439 <+121>: mov %eax,%fs:(%rdx)
0x000000000044e43c <+124>: mov $0xffffffffffffffff,%rax
0x000000000044e443 <+131>: ret
0x000000000044e444 <+132>: nopl 0x0(%rax)
0x000000000044e448 <+136>: mov $0xffffffffffffffa8,%rdx
0x000000000044e44f <+143>: neg %eax
0x000000000044e451 <+145>: mov %eax,%fs:(%rdx)
0x000000000044e454 <+148>: mov $0xffffffffffffffff,%rax
0x000000000044e45b <+155>: jmp 0x44e415 <__writev+85>
End of assembler dump.
(gdb) bt
#0 __writev (fd=fd@entry=2, iov=iov@entry=0x7fffffffddb0,
iovcnt=iovcnt@entry=1) at ../sysdeps/unix/sysv/linux/writev.c:26
#1 0x00000000004077aa in writev_for_fatal (fd=<optimized out>,
total=<optimized out>, niov=<optimized out>, iov=<optimized out>)
at ../sysdeps/posix/libc_fatal.c:44
#2 __libc_message (action=action@entry=do_abort, fmt=fmt@entry=0x4c70ad "%s")
at ../sysdeps/posix/libc_fatal.c:124
#3 0x000000000040789c in __libc_fatal (
message=message@entry=0x4adb60 "Fatal glibc error: Cannot allocate TLS block\n") at ../sysdeps/posix/libc_fatal.c:164
#4 0x000000000040a3c0 in __libc_setup_tls () at libc-tls.c:150
#5 0x0000000000409709 in __libc_start_main_impl (main=0x401740 <main>,
argc=1, argv=0x7fffffffe008, init=<optimized out>, fini=<optimized out>,
rtld_fini=0x0, stack_end=0x7fffffffdff8) at ../csu/libc-start.c:301
#6 0x0000000000401da1 in _start () at ../sysdeps/x86_64/start.S:115
(gdb)
That might be a different bug.
Thanks,
Florian
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-03 5:18 ` Florian Weimer
@ 2022-05-03 15:54 ` H.J. Lu
2022-05-03 16:00 ` Florian Weimer
0 siblings, 1 reply; 23+ messages in thread
From: H.J. Lu @ 2022-05-03 15:54 UTC (permalink / raw)
To: Florian Weimer; +Cc: GNU C Library
On Mon, May 2, 2022 at 10:18 PM Florian Weimer <fweimer@redhat.com> wrote:
>
> * Florian Weimer:
>
> > * H. J. Lu:
> >
> >> On Mon, May 2, 2022 at 12:53 PM Florian Weimer <fweimer@redhat.com> wrote:
> >>>
> >>> * H. J. Lu:
> >>>
> >>> >> +#include_next <startup.h>
> >>> >> diff --git a/sysdeps/unix/sysv/linux/startup.h b/sysdeps/unix/sysv/linux/startup.h
> >>> >> new file mode 100644
> >>> >> index 0000000000..a5de941759
> >>> >> --- /dev/null
> >>> >> +++ b/sysdeps/unix/sysv/linux/startup.h
> >>> >> @@ -0,0 +1,38 @@
> >>> >> +/* Linux definitions of functions used by static libc main startup.
> >>> >> + Copyright (C) 2017-2022 Free Software Foundation, Inc.
> >>> > Shouldn't it just be 2022?
> >>> >> + This file is part of the GNU C Library.
> >>> >> +
> >>> >> + The GNU C Library is free software; you can redistribute it and/or
> >>> >> + modify it under the terms of the GNU Lesser General Public
> >>> >> + License as published by the Free Software Foundation; either
> >>> >> + version 2.1 of the License, or (at your option) any later version.
> >>> >> +
> >>> >> + The GNU C Library is distributed in the hope that it will be useful,
> >>> >> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> >>> >> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> >>> >> + Lesser General Public License for more details.
> >>> >> +
> >>> >> + You should have received a copy of the GNU Lesser General Public
> >>> >> + License along with the GNU C Library; if not, see
> >>> >> + <https://www.gnu.org/licenses/>. */
> >>> >> +
> >>> >> +#ifdef SHARED
> >>> >> +# include_next <startup.h>
> >>> >> +#else
> >>> >> +# include <sysdep.h>
> >>> >> +
> >>> >> +/* Avoid a run-time invocation of strlen. */
> >>> >> +#define _startup_fatal(message) \
> >>> >
> >>> > Is this needed only for static PIE?
> >>>
> >>> I don't know. It's used from csu/libc-tls.c, some targets may need it
> >>> for ET_EXEC static linking, too. I haven't checked. The additional
> >>> code size is minimal.
> >>
> >> _startup_fatal was added for i386 static PIE. I don't think it is
> >> needed for normal static executables.
> >
> > Based on the current initialization ordering, it seems to me that we
> > need it for non-PIE static programs, too. Maybe I should check this
> > tomorrow.
>
> It does not work on x86-64 because cancellation handling needs the TCB:
>
> Breakpoint 1, _dl_early_allocate (size=size@entry=3520) at ../sysdeps/unix/sysv/linux/dl-early_allocate.c:41
> 41 if (__curbrk != NULL)
> (gdb) finish
> Run till exit from #0 _dl_early_allocate (size=size@entry=3520)
> at ../sysdeps/unix/sysv/linux/dl-early_allocate.c:41
> __libc_setup_tls () at libc-tls.c:149
> 149 if (tlsblock == NULL)
> Value returned is $1 = (void *) 0x4eb000
> (gdb) set $rax = 0
> (gdb) c
> Continuing.
>
> Program received signal SIGSEGV, Segmentation fault.
> __writev (fd=fd@entry=2, iov=iov@entry=0x7fffffffddb0, iovcnt=iovcnt@entry=1) at ../sysdeps/unix/sysv/linux/writev.c:26
> 26 return SYSCALL_CANCEL (writev, fd, iov, iovcnt);
> (gdb) disas
> Dump of assembler code for function __writev:
> => 0x000000000044e3c0 <+0>: mov %fs:0x18,%eax
> 0x000000000044e3c8 <+8>: test %eax,%eax
> 0x000000000044e3ca <+10>: jne 0x44e3e0 <__writev+32>
> 0x000000000044e3cc <+12>: mov $0x14,%eax
> 0x000000000044e3d1 <+17>: syscall
> 0x000000000044e3d3 <+19>: cmp $0xfffffffffffff000,%rax
> 0x000000000044e3d9 <+25>: ja 0x44e430 <__writev+112>
> 0x000000000044e3db <+27>: ret
> 0x000000000044e3dc <+28>: nopl 0x0(%rax)
> 0x000000000044e3e0 <+32>: sub $0x28,%rsp
> 0x000000000044e3e4 <+36>: mov %edx,0x1c(%rsp)
> 0x000000000044e3e8 <+40>: mov %rsi,0x10(%rsp)
> 0x000000000044e3ed <+45>: mov %edi,0x8(%rsp)
> 0x000000000044e3f1 <+49>: call 0x46d2b0 <__pthread_enable_asynccancel>
> 0x000000000044e3f6 <+54>: mov 0x1c(%rsp),%edx
> 0x000000000044e3fa <+58>: mov 0x10(%rsp),%rsi
> 0x000000000044e3ff <+63>: mov %eax,%r8d
> 0x000000000044e402 <+66>: mov 0x8(%rsp),%edi
> 0x000000000044e406 <+70>: mov $0x14,%eax
> 0x000000000044e40b <+75>: syscall
> 0x000000000044e40d <+77>: cmp $0xfffffffffffff000,%rax
> 0x000000000044e413 <+83>: ja 0x44e448 <__writev+136>
> 0x000000000044e415 <+85>: mov %r8d,%edi
> 0x000000000044e418 <+88>: mov %rax,0x8(%rsp)
> 0x000000000044e41d <+93>: call 0x46d330 <__pthread_disable_asynccancel>
> 0x000000000044e422 <+98>: mov 0x8(%rsp),%rax
> 0x000000000044e427 <+103>: add $0x28,%rsp
> 0x000000000044e42b <+107>: ret
> 0x000000000044e42c <+108>: nopl 0x0(%rax)
> 0x000000000044e430 <+112>: mov $0xffffffffffffffa8,%rdx
> 0x000000000044e437 <+119>: neg %eax
> 0x000000000044e439 <+121>: mov %eax,%fs:(%rdx)
> 0x000000000044e43c <+124>: mov $0xffffffffffffffff,%rax
> 0x000000000044e443 <+131>: ret
> 0x000000000044e444 <+132>: nopl 0x0(%rax)
> 0x000000000044e448 <+136>: mov $0xffffffffffffffa8,%rdx
> 0x000000000044e44f <+143>: neg %eax
> 0x000000000044e451 <+145>: mov %eax,%fs:(%rdx)
> 0x000000000044e454 <+148>: mov $0xffffffffffffffff,%rax
> 0x000000000044e45b <+155>: jmp 0x44e415 <__writev+85>
> End of assembler dump.
> (gdb) bt
> #0 __writev (fd=fd@entry=2, iov=iov@entry=0x7fffffffddb0,
> iovcnt=iovcnt@entry=1) at ../sysdeps/unix/sysv/linux/writev.c:26
> #1 0x00000000004077aa in writev_for_fatal (fd=<optimized out>,
> total=<optimized out>, niov=<optimized out>, iov=<optimized out>)
> at ../sysdeps/posix/libc_fatal.c:44
> #2 __libc_message (action=action@entry=do_abort, fmt=fmt@entry=0x4c70ad "%s")
> at ../sysdeps/posix/libc_fatal.c:124
> #3 0x000000000040789c in __libc_fatal (
> message=message@entry=0x4adb60 "Fatal glibc error: Cannot allocate TLS block\n") at ../sysdeps/posix/libc_fatal.c:164
> #4 0x000000000040a3c0 in __libc_setup_tls () at libc-tls.c:150
> #5 0x0000000000409709 in __libc_start_main_impl (main=0x401740 <main>,
> argc=1, argv=0x7fffffffe008, init=<optimized out>, fini=<optimized out>,
> rtld_fini=0x0, stack_end=0x7fffffffdff8) at ../csu/libc-start.c:301
> #6 0x0000000000401da1 in _start () at ../sysdeps/x86_64/start.S:115
> (gdb)
>
> That might be a different bug.
The startup codes can't use cancellation before it is ready. Do we need to
check SHARED in this case?
--
H.J.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-03 15:54 ` H.J. Lu
@ 2022-05-03 16:00 ` Florian Weimer
2022-05-03 16:36 ` H.J. Lu
0 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-03 16:00 UTC (permalink / raw)
To: H.J. Lu; +Cc: GNU C Library
* H. J. Lu:
> The startup codes can't use cancellation before it is ready. Do we need to
> check SHARED in this case?
I think __libc_fatal shouldn't be a cancellation point. That's not
really related to SHARED.
We can reimplement __libc_fatal in terms of direct system calls (with
some caveats), so that it is guaranteed to be usable at this point. But
I think that would be a different patch series.
Thanks,
Florian
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-03 16:00 ` Florian Weimer
@ 2022-05-03 16:36 ` H.J. Lu
2022-05-03 16:43 ` Florian Weimer
0 siblings, 1 reply; 23+ messages in thread
From: H.J. Lu @ 2022-05-03 16:36 UTC (permalink / raw)
To: Florian Weimer; +Cc: GNU C Library
On Tue, May 3, 2022 at 9:01 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu:
>
> > The startup codes can't use cancellation before it is ready. Do we need to
> > check SHARED in this case?
>
> I think __libc_fatal shouldn't be a cancellation point. That's not
> really related to SHARED.
Should we define _startup_fatal unconditionally and always define
I386_USE_SYSENTER as 0 for i386 so that _startup_fatal can be
used safely during startup?
> We can reimplement __libc_fatal in terms of direct system calls (with
> some caveats), so that it is guaranteed to be usable at this point. But
> I think that would be a different patch series.
__libc_fatal shouldn't be used in csu/libc-tls.c.
--
H.J.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-03 16:36 ` H.J. Lu
@ 2022-05-03 16:43 ` Florian Weimer
2022-05-03 16:46 ` H.J. Lu
0 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-03 16:43 UTC (permalink / raw)
To: H.J. Lu; +Cc: GNU C Library
* H. J. Lu:
> On Tue, May 3, 2022 at 9:01 AM Florian Weimer <fweimer@redhat.com> wrote:
>>
>> * H. J. Lu:
>>
>> > The startup codes can't use cancellation before it is ready. Do we need to
>> > check SHARED in this case?
>>
>> I think __libc_fatal shouldn't be a cancellation point. That's not
>> really related to SHARED.
>
> Should we define _startup_fatal unconditionally and always define
> I386_USE_SYSENTER as 0 for i386 so that _startup_fatal can be
> used safely during startup?
Hmm. Isn't that what my patch does?
Thanks,
Florian
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-03 16:43 ` Florian Weimer
@ 2022-05-03 16:46 ` H.J. Lu
2022-05-03 16:57 ` Florian Weimer
0 siblings, 1 reply; 23+ messages in thread
From: H.J. Lu @ 2022-05-03 16:46 UTC (permalink / raw)
To: Florian Weimer; +Cc: GNU C Library
On Tue, May 3, 2022 at 9:44 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu:
>
> > On Tue, May 3, 2022 at 9:01 AM Florian Weimer <fweimer@redhat.com> wrote:
> >>
> >> * H. J. Lu:
> >>
> >> > The startup codes can't use cancellation before it is ready. Do we need to
> >> > check SHARED in this case?
> >>
> >> I think __libc_fatal shouldn't be a cancellation point. That's not
> >> really related to SHARED.
> >
> > Should we define _startup_fatal unconditionally and always define
> > I386_USE_SYSENTER as 0 for i386 so that _startup_fatal can be
> > used safely during startup?
>
> Hmm. Isn't that what my patch does?
>
Your patch still checks BUILD_PIE_DEFAULT and SHARED.
--
H.J.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-03 16:46 ` H.J. Lu
@ 2022-05-03 16:57 ` Florian Weimer
2022-05-03 17:01 ` Adhemerval Zanella
0 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-03 16:57 UTC (permalink / raw)
To: H.J. Lu; +Cc: GNU C Library
* H. J. Lu:
> On Tue, May 3, 2022 at 9:44 AM Florian Weimer <fweimer@redhat.com> wrote:
>>
>> * H. J. Lu:
>>
>> > On Tue, May 3, 2022 at 9:01 AM Florian Weimer <fweimer@redhat.com> wrote:
>> >>
>> >> * H. J. Lu:
>> >>
>> >> > The startup codes can't use cancellation before it is ready. Do we need to
>> >> > check SHARED in this case?
>> >>
>> >> I think __libc_fatal shouldn't be a cancellation point. That's not
>> >> really related to SHARED.
>> >
>> > Should we define _startup_fatal unconditionally and always define
>> > I386_USE_SYSENTER as 0 for i386 so that _startup_fatal can be
>> > used safely during startup?
>>
>> Hmm. Isn't that what my patch does?
>>
>
> Your patch still checks BUILD_PIE_DEFAULT and SHARED.
Ah, I see, thanks. You are right, the i386 version should define
I386_USE_SYSENTER unconditionally. Will fix.
Florian
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-03 16:57 ` Florian Weimer
@ 2022-05-03 17:01 ` Adhemerval Zanella
2022-05-03 20:16 ` Florian Weimer
0 siblings, 1 reply; 23+ messages in thread
From: Adhemerval Zanella @ 2022-05-03 17:01 UTC (permalink / raw)
To: libc-alpha
On 03/05/2022 13:57, Florian Weimer via Libc-alpha wrote:
> * H. J. Lu:
>
>> On Tue, May 3, 2022 at 9:44 AM Florian Weimer <fweimer@redhat.com> wrote:
>>>
>>> * H. J. Lu:
>>>
>>>> On Tue, May 3, 2022 at 9:01 AM Florian Weimer <fweimer@redhat.com> wrote:
>>>>>
>>>>> * H. J. Lu:
>>>>>
>>>>>> The startup codes can't use cancellation before it is ready. Do we need to
>>>>>> check SHARED in this case?
>>>>>
>>>>> I think __libc_fatal shouldn't be a cancellation point. That's not
>>>>> really related to SHARED.
>>>>
>>>> Should we define _startup_fatal unconditionally and always define
>>>> I386_USE_SYSENTER as 0 for i386 so that _startup_fatal can be
>>>> used safely during startup?
>>>
>>> Hmm. Isn't that what my patch does?
>>>
>>
>> Your patch still checks BUILD_PIE_DEFAULT and SHARED.
>
> Ah, I see, thanks. You are right, the i386 version should define
> I386_USE_SYSENTER unconditionally. Will fix.
I think you might want to check ia64 as well, since it uses a TCB variable
to call the syscall in some cases.
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal
2022-05-03 17:01 ` Adhemerval Zanella
@ 2022-05-03 20:16 ` Florian Weimer
0 siblings, 0 replies; 23+ messages in thread
From: Florian Weimer @ 2022-05-03 20:16 UTC (permalink / raw)
To: Adhemerval Zanella via Libc-alpha
* Adhemerval Zanella via Libc-alpha:
> On 03/05/2022 13:57, Florian Weimer via Libc-alpha wrote:
>> * H. J. Lu:
>>
>>> On Tue, May 3, 2022 at 9:44 AM Florian Weimer <fweimer@redhat.com> wrote:
>>>>
>>>> * H. J. Lu:
>>>>
>>>>> On Tue, May 3, 2022 at 9:01 AM Florian Weimer <fweimer@redhat.com> wrote:
>>>>>>
>>>>>> * H. J. Lu:
>>>>>>
>>>>>>> The startup codes can't use cancellation before it is ready. Do we need to
>>>>>>> check SHARED in this case?
>>>>>>
>>>>>> I think __libc_fatal shouldn't be a cancellation point. That's not
>>>>>> really related to SHARED.
>>>>>
>>>>> Should we define _startup_fatal unconditionally and always define
>>>>> I386_USE_SYSENTER as 0 for i386 so that _startup_fatal can be
>>>>> used safely during startup?
>>>>
>>>> Hmm. Isn't that what my patch does?
>>>>
>>>
>>> Your patch still checks BUILD_PIE_DEFAULT and SHARED.
>>
>> Ah, I see, thanks. You are right, the i386 version should define
>> I386_USE_SYSENTER unconditionally. Will fix.
>
> I think you might want to check ia64 as well, since it uses a TCB variable
> to call the syscall in some cases.
“might want to check“ isn't a phrase I would use in the context with
ia64, but yes, I can add a startup.h file for it, too. Thanks for the
suggestion.
Florian
^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 2/5] Linux: Define MMAP_CALL_INTERNAL
2022-05-02 19:15 [PATCH 0/5] Linux: Fall back to mmap if early sbrk fails Florian Weimer
2022-05-02 19:15 ` [PATCH 1/5] Linux: Implement a useful version of _startup_fatal Florian Weimer
@ 2022-05-02 19:15 ` Florian Weimer
2022-05-03 18:30 ` Florian Weimer
2022-05-02 19:15 ` [PATCH 3/5] i386: Remove OPTIMIZE_FOR_GCC_5 from Linux libc-do-syscall.S Florian Weimer
` (2 subsequent siblings)
4 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-02 19:15 UTC (permalink / raw)
To: libc-alpha
Unlike MMAP_CALL, this avoids a TCB dependency for an errno update
on failure.
<mmap_internal.h> cannot be included as is on several architectures
due to the definition of page_unit, so introduce a separate header
file for the definition of MMAP_CALL and MMAP_CALL_INTERNAL,
<mmap_call.h>.
---
sysdeps/unix/sysv/linux/mmap_call.h | 22 +++++++++++++++++++
sysdeps/unix/sysv/linux/mmap_internal.h | 6 +----
.../s390/{mmap_internal.h => mmap_call.h} | 14 ++++++------
3 files changed, 30 insertions(+), 12 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/mmap_call.h
rename sysdeps/unix/sysv/linux/s390/{mmap_internal.h => mmap_call.h} (78%)
diff --git a/sysdeps/unix/sysv/linux/mmap_call.h b/sysdeps/unix/sysv/linux/mmap_call.h
new file mode 100644
index 0000000000..3547c99e14
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mmap_call.h
@@ -0,0 +1,22 @@
+/* Generic definition of MMAP_CALL and MMAP_CALL_INTERNAL.
+ Copyright (C) 2017-2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
+ INLINE_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
+#define MMAP_CALL_INTERNAL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
+ INTERNAL_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
diff --git a/sysdeps/unix/sysv/linux/mmap_internal.h b/sysdeps/unix/sysv/linux/mmap_internal.h
index 841b731391..aebf97d064 100644
--- a/sysdeps/unix/sysv/linux/mmap_internal.h
+++ b/sysdeps/unix/sysv/linux/mmap_internal.h
@@ -42,10 +42,6 @@ static uint64_t page_unit;
/* Do not accept offset not multiple of page size. */
#define MMAP_OFF_LOW_MASK (MMAP2_PAGE_UNIT - 1)
-/* An architecture may override this. */
-#ifndef MMAP_CALL
-# define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
- INLINE_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
-#endif
+#include <mmap_call.h>
#endif /* MMAP_INTERNAL_LINUX_H */
diff --git a/sysdeps/unix/sysv/linux/s390/mmap_internal.h b/sysdeps/unix/sysv/linux/s390/mmap_call.h
similarity index 78%
rename from sysdeps/unix/sysv/linux/s390/mmap_internal.h
rename to sysdeps/unix/sysv/linux/s390/mmap_call.h
index cc76ac9735..f169b8bab9 100644
--- a/sysdeps/unix/sysv/linux/s390/mmap_internal.h
+++ b/sysdeps/unix/sysv/linux/s390/mmap_call.h
@@ -16,9 +16,6 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-#ifndef MMAP_S390_INTERNAL_H
-# define MMAP_S390_INTERNAL_H
-
#define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
({ \
long int __args[6] = { (long int) (__addr), (long int) (__len), \
@@ -26,7 +23,10 @@
(long int) (__fd), (long int) (__offset) }; \
INLINE_SYSCALL_CALL (__nr, __args); \
})
-
-#include_next <mmap_internal.h>
-
-#endif
+#define MMAP_CALL_INTERNAL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
+ ({ \
+ long int __args[6] = { (long int) (__addr), (long int) (__len), \
+ (long int) (__prot), (long int) (__flags), \
+ (long int) (__fd), (long int) (__offset) }; \
+ INTERNAL_SYSCALL_CALL (__nr, __args); \
+ })
--
2.35.1
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [PATCH 2/5] Linux: Define MMAP_CALL_INTERNAL
2022-05-02 19:15 ` [PATCH 2/5] Linux: Define MMAP_CALL_INTERNAL Florian Weimer
@ 2022-05-03 18:30 ` Florian Weimer
2022-05-04 13:10 ` Stefan Liebler
0 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-03 18:30 UTC (permalink / raw)
To: Stefan Liebler; +Cc: libc-alpha
* Florian Weimer via Libc-alpha:
> Unlike MMAP_CALL, this avoids a TCB dependency for an errno update
> on failure.
>
> <mmap_internal.h> cannot be included as is on several architectures
> due to the definition of page_unit, so introduce a separate header
> file for the definition of MMAP_CALL and MMAP_CALL_INTERNAL,
> <mmap_call.h>.
> ---
> sysdeps/unix/sysv/linux/mmap_call.h | 22 +++++++++++++++++++
> sysdeps/unix/sysv/linux/mmap_internal.h | 6 +----
> .../s390/{mmap_internal.h => mmap_call.h} | 14 ++++++------
> 3 files changed, 30 insertions(+), 12 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/mmap_call.h
> rename sysdeps/unix/sysv/linux/s390/{mmap_internal.h => mmap_call.h} (78%)
>
> diff --git a/sysdeps/unix/sysv/linux/mmap_call.h b/sysdeps/unix/sysv/linux/mmap_call.h
> new file mode 100644
> index 0000000000..3547c99e14
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/mmap_call.h
> @@ -0,0 +1,22 @@
> +/* Generic definition of MMAP_CALL and MMAP_CALL_INTERNAL.
> + Copyright (C) 2017-2022 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
> + INLINE_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
> +#define MMAP_CALL_INTERNAL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
> + INTERNAL_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
> diff --git a/sysdeps/unix/sysv/linux/mmap_internal.h b/sysdeps/unix/sysv/linux/mmap_internal.h
> index 841b731391..aebf97d064 100644
> --- a/sysdeps/unix/sysv/linux/mmap_internal.h
> +++ b/sysdeps/unix/sysv/linux/mmap_internal.h
> @@ -42,10 +42,6 @@ static uint64_t page_unit;
> /* Do not accept offset not multiple of page size. */
> #define MMAP_OFF_LOW_MASK (MMAP2_PAGE_UNIT - 1)
>
> -/* An architecture may override this. */
> -#ifndef MMAP_CALL
> -# define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
> - INLINE_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
> -#endif
> +#include <mmap_call.h>
>
> #endif /* MMAP_INTERNAL_LINUX_H */
> diff --git a/sysdeps/unix/sysv/linux/s390/mmap_internal.h b/sysdeps/unix/sysv/linux/s390/mmap_call.h
> similarity index 78%
> rename from sysdeps/unix/sysv/linux/s390/mmap_internal.h
> rename to sysdeps/unix/sysv/linux/s390/mmap_call.h
> index cc76ac9735..f169b8bab9 100644
> --- a/sysdeps/unix/sysv/linux/s390/mmap_internal.h
> +++ b/sysdeps/unix/sysv/linux/s390/mmap_call.h
> @@ -16,9 +16,6 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> -#ifndef MMAP_S390_INTERNAL_H
> -# define MMAP_S390_INTERNAL_H
> -
> #define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
> ({ \
> long int __args[6] = { (long int) (__addr), (long int) (__len), \
> @@ -26,7 +23,10 @@
> (long int) (__fd), (long int) (__offset) }; \
> INLINE_SYSCALL_CALL (__nr, __args); \
> })
> -
> -#include_next <mmap_internal.h>
> -
> -#endif
> +#define MMAP_CALL_INTERNAL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
> + ({ \
> + long int __args[6] = { (long int) (__addr), (long int) (__len), \
> + (long int) (__prot), (long int) (__flags), \
> + (long int) (__fd), (long int) (__offset) }; \
> + INTERNAL_SYSCALL_CALL (__nr, __args); \
> + })
Stefan, would you be able to review this patch? It's mostly an S390
change, after all.
Thanks,
Florian
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [PATCH 2/5] Linux: Define MMAP_CALL_INTERNAL
2022-05-03 18:30 ` Florian Weimer
@ 2022-05-04 13:10 ` Stefan Liebler
0 siblings, 0 replies; 23+ messages in thread
From: Stefan Liebler @ 2022-05-04 13:10 UTC (permalink / raw)
To: Florian Weimer; +Cc: libc-alpha
On 03/05/2022 20:30, Florian Weimer wrote:
> * Florian Weimer via Libc-alpha:
>
>> Unlike MMAP_CALL, this avoids a TCB dependency for an errno update
>> on failure.
>>
>> <mmap_internal.h> cannot be included as is on several architectures
>> due to the definition of page_unit, so introduce a separate header
>> file for the definition of MMAP_CALL and MMAP_CALL_INTERNAL,
>> <mmap_call.h>.
>> ---
>> sysdeps/unix/sysv/linux/mmap_call.h | 22 +++++++++++++++++++
>> sysdeps/unix/sysv/linux/mmap_internal.h | 6 +----
>> .../s390/{mmap_internal.h => mmap_call.h} | 14 ++++++------
>> 3 files changed, 30 insertions(+), 12 deletions(-)
>> create mode 100644 sysdeps/unix/sysv/linux/mmap_call.h
>> rename sysdeps/unix/sysv/linux/s390/{mmap_internal.h => mmap_call.h} (78%)
>>
>> diff --git a/sysdeps/unix/sysv/linux/mmap_call.h b/sysdeps/unix/sysv/linux/mmap_call.h
>> new file mode 100644
>> index 0000000000..3547c99e14
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/mmap_call.h
>> @@ -0,0 +1,22 @@
>> +/* Generic definition of MMAP_CALL and MMAP_CALL_INTERNAL.
>> + Copyright (C) 2017-2022 Free Software Foundation, Inc.
>> + This file is part of the GNU C Library.
>> +
>> + The GNU C Library is free software; you can redistribute it and/or
>> + modify it under the terms of the GNU Lesser General Public
>> + License as published by the Free Software Foundation; either
>> + version 2.1 of the License, or (at your option) any later version.
>> +
>> + The GNU C Library is distributed in the hope that it will be useful,
>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>> + Lesser General Public License for more details.
>> +
>> + You should have received a copy of the GNU Lesser General Public
>> + License along with the GNU C Library; if not, see
>> + <https://www.gnu.org/licenses/>. */
>> +
>> +#define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
>> + INLINE_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
>> +#define MMAP_CALL_INTERNAL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
>> + INTERNAL_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
>> diff --git a/sysdeps/unix/sysv/linux/mmap_internal.h b/sysdeps/unix/sysv/linux/mmap_internal.h
>> index 841b731391..aebf97d064 100644
>> --- a/sysdeps/unix/sysv/linux/mmap_internal.h
>> +++ b/sysdeps/unix/sysv/linux/mmap_internal.h
>> @@ -42,10 +42,6 @@ static uint64_t page_unit;
>> /* Do not accept offset not multiple of page size. */
>> #define MMAP_OFF_LOW_MASK (MMAP2_PAGE_UNIT - 1)
>>
>> -/* An architecture may override this. */
>> -#ifndef MMAP_CALL
>> -# define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
>> - INLINE_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
>> -#endif
>> +#include <mmap_call.h>
>>
>> #endif /* MMAP_INTERNAL_LINUX_H */
>> diff --git a/sysdeps/unix/sysv/linux/s390/mmap_internal.h b/sysdeps/unix/sysv/linux/s390/mmap_call.h
>> similarity index 78%
>> rename from sysdeps/unix/sysv/linux/s390/mmap_internal.h
>> rename to sysdeps/unix/sysv/linux/s390/mmap_call.h
>> index cc76ac9735..f169b8bab9 100644
>> --- a/sysdeps/unix/sysv/linux/s390/mmap_internal.h
>> +++ b/sysdeps/unix/sysv/linux/s390/mmap_call.h
>> @@ -16,9 +16,6 @@
>> License along with the GNU C Library; if not, see
>> <https://www.gnu.org/licenses/>. */
>>
>> -#ifndef MMAP_S390_INTERNAL_H
>> -# define MMAP_S390_INTERNAL_H
>> -
>> #define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
>> ({ \
>> long int __args[6] = { (long int) (__addr), (long int) (__len), \
>> @@ -26,7 +23,10 @@
>> (long int) (__fd), (long int) (__offset) }; \
>> INLINE_SYSCALL_CALL (__nr, __args); \
>> })
>> -
>> -#include_next <mmap_internal.h>
>> -
>> -#endif
>> +#define MMAP_CALL_INTERNAL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
>> + ({ \
>> + long int __args[6] = { (long int) (__addr), (long int) (__len), \
>> + (long int) (__prot), (long int) (__flags), \
>> + (long int) (__fd), (long int) (__offset) }; \
>> + INTERNAL_SYSCALL_CALL (__nr, __args); \
>> + })
>
> Stefan, would you be able to review this patch? It's mostly an S390
> change, after all.
>
> Thanks,
> Florian
>
Sure. The patch looks good to me.
Moving the definition of MMAP_CALL is just a mechanical change. The
definition of MMAP_CALL_INTERNAL is similar and no other architecture
than s390x has its own definition of MMAP_CALL.
Thanks.
Reviewed-by: Stefan Liebler <stli@linux.ibm.com>
^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 3/5] i386: Remove OPTIMIZE_FOR_GCC_5 from Linux libc-do-syscall.S
2022-05-02 19:15 [PATCH 0/5] Linux: Fall back to mmap if early sbrk fails Florian Weimer
2022-05-02 19:15 ` [PATCH 1/5] Linux: Implement a useful version of _startup_fatal Florian Weimer
2022-05-02 19:15 ` [PATCH 2/5] Linux: Define MMAP_CALL_INTERNAL Florian Weimer
@ 2022-05-02 19:15 ` Florian Weimer
2022-05-02 19:20 ` H.J. Lu
2022-05-02 19:15 ` [PATCH 4/5] i386: Honor I386_USE_SYSENTER for 6-argument Linux system calls Florian Weimer
2022-05-02 19:15 ` [PATCH 5/5] csu: Implement and use _dl_early_allocate during static startup Florian Weimer
4 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-02 19:15 UTC (permalink / raw)
To: libc-alpha
After commit a78e6a10d0b50d0ca80309775980fc99944b1727
("i386: Remove broken CAN_USE_REGISTER_ASM_EBP (bug 28771)"),
it is never defined.
---
sysdeps/unix/sysv/linux/i386/libc-do-syscall.S | 3 ---
1 file changed, 3 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/i386/libc-do-syscall.S b/sysdeps/unix/sysv/linux/i386/libc-do-syscall.S
index 04154f43e0..3eea5f3a5d 100644
--- a/sysdeps/unix/sysv/linux/i386/libc-do-syscall.S
+++ b/sysdeps/unix/sysv/linux/i386/libc-do-syscall.S
@@ -18,8 +18,6 @@
#include <sysdep.h>
-#ifndef OPTIMIZE_FOR_GCC_5
-
/* %eax, %ecx, %edx and %esi contain the values expected by the kernel.
%edi points to a structure with the values of %ebx, %edi and %ebp. */
@@ -50,4 +48,3 @@ ENTRY (__libc_do_syscall)
cfi_restore (ebx)
ret
END (__libc_do_syscall)
-#endif
--
2.35.1
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [PATCH 3/5] i386: Remove OPTIMIZE_FOR_GCC_5 from Linux libc-do-syscall.S
2022-05-02 19:15 ` [PATCH 3/5] i386: Remove OPTIMIZE_FOR_GCC_5 from Linux libc-do-syscall.S Florian Weimer
@ 2022-05-02 19:20 ` H.J. Lu
0 siblings, 0 replies; 23+ messages in thread
From: H.J. Lu @ 2022-05-02 19:20 UTC (permalink / raw)
To: Florian Weimer; +Cc: GNU C Library
On Mon, May 2, 2022 at 12:18 PM Florian Weimer via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> After commit a78e6a10d0b50d0ca80309775980fc99944b1727
> ("i386: Remove broken CAN_USE_REGISTER_ASM_EBP (bug 28771)"),
> it is never defined.
> ---
> sysdeps/unix/sysv/linux/i386/libc-do-syscall.S | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/i386/libc-do-syscall.S b/sysdeps/unix/sysv/linux/i386/libc-do-syscall.S
> index 04154f43e0..3eea5f3a5d 100644
> --- a/sysdeps/unix/sysv/linux/i386/libc-do-syscall.S
> +++ b/sysdeps/unix/sysv/linux/i386/libc-do-syscall.S
> @@ -18,8 +18,6 @@
>
> #include <sysdep.h>
>
> -#ifndef OPTIMIZE_FOR_GCC_5
> -
> /* %eax, %ecx, %edx and %esi contain the values expected by the kernel.
> %edi points to a structure with the values of %ebx, %edi and %ebp. */
>
> @@ -50,4 +48,3 @@ ENTRY (__libc_do_syscall)
> cfi_restore (ebx)
> ret
> END (__libc_do_syscall)
> -#endif
> --
> 2.35.1
>
>
LGTM.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Thanks.
--
H.J.
^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 4/5] i386: Honor I386_USE_SYSENTER for 6-argument Linux system calls
2022-05-02 19:15 [PATCH 0/5] Linux: Fall back to mmap if early sbrk fails Florian Weimer
` (2 preceding siblings ...)
2022-05-02 19:15 ` [PATCH 3/5] i386: Remove OPTIMIZE_FOR_GCC_5 from Linux libc-do-syscall.S Florian Weimer
@ 2022-05-02 19:15 ` Florian Weimer
2022-05-02 19:24 ` H.J. Lu
2022-05-02 19:15 ` [PATCH 5/5] csu: Implement and use _dl_early_allocate during static startup Florian Weimer
4 siblings, 1 reply; 23+ messages in thread
From: Florian Weimer @ 2022-05-02 19:15 UTC (permalink / raw)
To: libc-alpha
Introduce an int-80h-based version of __libc_do_syscall and use
it if I386_USE_SYSENTER is defined as 0.
---
sysdeps/unix/sysv/linux/i386/Makefile | 2 +-
.../sysv/linux/i386/libc-do-syscall-int80.S | 25 +++++++++++++++++++
sysdeps/unix/sysv/linux/i386/sysdep.h | 13 ++++++++--
3 files changed, 37 insertions(+), 3 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/i386/libc-do-syscall-int80.S
diff --git a/sysdeps/unix/sysv/linux/i386/Makefile b/sysdeps/unix/sysv/linux/i386/Makefile
index fcab129fc1..598e27dcda 100644
--- a/sysdeps/unix/sysv/linux/i386/Makefile
+++ b/sysdeps/unix/sysv/linux/i386/Makefile
@@ -13,7 +13,7 @@ install-bin += lddlibc4
endif
ifeq ($(subdir),io)
-sysdep_routines += libc-do-syscall
+sysdep_routines += libc-do-syscall libc-do-syscall-int80
endif
ifeq ($(subdir),stdlib)
diff --git a/sysdeps/unix/sysv/linux/i386/libc-do-syscall-int80.S b/sysdeps/unix/sysv/linux/i386/libc-do-syscall-int80.S
new file mode 100644
index 0000000000..2c472f2557
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/libc-do-syscall-int80.S
@@ -0,0 +1,25 @@
+/* Out-of-line syscall stub for six-argument syscalls from C. For static PIE.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#ifndef SHARED
+# define I386_USE_SYSENTER 0
+# include <sysdep.h>
+
+# define __libc_do_syscall __libc_do_syscall_int80
+# include "libc-do-syscall.S"
+#endif
diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h
index 4558ab66cb..7085f7e19a 100644
--- a/sysdeps/unix/sysv/linux/i386/sysdep.h
+++ b/sysdeps/unix/sysv/linux/i386/sysdep.h
@@ -42,6 +42,15 @@
# endif
#endif
+#if !I386_USE_SYSENTER && IS_IN (libc) && !defined SHARED
+/* Inside static libc, we have two versions. For compilation units
+ with !I386_USE_SYSENTER, the vDSO entry mechanism cannot be
+ used. */
+# define I386_DO_SYSCALL_STRING "__libc_do_syscall_int80"
+#else
+# define I386_DO_SYSCALL_STRING "__libc_do_syscall"
+#endif
+
#ifdef __ASSEMBLER__
/* Linux uses a negative return value to indicate syscall errors,
@@ -301,7 +310,7 @@ struct libc_do_syscall_args
}; \
asm volatile ( \
"movl %1, %%eax\n\t" \
- "call __libc_do_syscall" \
+ "call " I386_DO_SYSCALL_STRING \
: "=a" (resultvar) \
: "i" (__NR_##name), "c" (arg2), "d" (arg3), "S" (arg4), "D" (&_xv) \
: "memory", "cc")
@@ -315,7 +324,7 @@ struct libc_do_syscall_args
}; \
asm volatile ( \
"movl %1, %%eax\n\t" \
- "call __libc_do_syscall" \
+ "call " I386_DO_SYSCALL_STRING \
: "=a" (resultvar) \
: "a" (name), "c" (arg2), "d" (arg3), "S" (arg4), "D" (&_xv) \
: "memory", "cc")
--
2.35.1
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: [PATCH 4/5] i386: Honor I386_USE_SYSENTER for 6-argument Linux system calls
2022-05-02 19:15 ` [PATCH 4/5] i386: Honor I386_USE_SYSENTER for 6-argument Linux system calls Florian Weimer
@ 2022-05-02 19:24 ` H.J. Lu
0 siblings, 0 replies; 23+ messages in thread
From: H.J. Lu @ 2022-05-02 19:24 UTC (permalink / raw)
To: Florian Weimer; +Cc: GNU C Library
On Mon, May 2, 2022 at 12:18 PM Florian Weimer via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> Introduce an int-80h-based version of __libc_do_syscall and use
> it if I386_USE_SYSENTER is defined as 0.
> ---
> sysdeps/unix/sysv/linux/i386/Makefile | 2 +-
> .../sysv/linux/i386/libc-do-syscall-int80.S | 25 +++++++++++++++++++
> sysdeps/unix/sysv/linux/i386/sysdep.h | 13 ++++++++--
> 3 files changed, 37 insertions(+), 3 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/i386/libc-do-syscall-int80.S
>
> diff --git a/sysdeps/unix/sysv/linux/i386/Makefile b/sysdeps/unix/sysv/linux/i386/Makefile
> index fcab129fc1..598e27dcda 100644
> --- a/sysdeps/unix/sysv/linux/i386/Makefile
> +++ b/sysdeps/unix/sysv/linux/i386/Makefile
> @@ -13,7 +13,7 @@ install-bin += lddlibc4
> endif
>
> ifeq ($(subdir),io)
> -sysdep_routines += libc-do-syscall
> +sysdep_routines += libc-do-syscall libc-do-syscall-int80
> endif
>
> ifeq ($(subdir),stdlib)
> diff --git a/sysdeps/unix/sysv/linux/i386/libc-do-syscall-int80.S b/sysdeps/unix/sysv/linux/i386/libc-do-syscall-int80.S
> new file mode 100644
> index 0000000000..2c472f2557
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/i386/libc-do-syscall-int80.S
> @@ -0,0 +1,25 @@
> +/* Out-of-line syscall stub for six-argument syscalls from C. For static PIE.
> + Copyright (C) 2022 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#ifndef SHARED
> +# define I386_USE_SYSENTER 0
> +# include <sysdep.h>
> +
> +# define __libc_do_syscall __libc_do_syscall_int80
> +# include "libc-do-syscall.S"
> +#endif
> diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h
> index 4558ab66cb..7085f7e19a 100644
> --- a/sysdeps/unix/sysv/linux/i386/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h
> @@ -42,6 +42,15 @@
> # endif
> #endif
>
> +#if !I386_USE_SYSENTER && IS_IN (libc) && !defined SHARED
> +/* Inside static libc, we have two versions. For compilation units
> + with !I386_USE_SYSENTER, the vDSO entry mechanism cannot be
> + used. */
> +# define I386_DO_SYSCALL_STRING "__libc_do_syscall_int80"
> +#else
> +# define I386_DO_SYSCALL_STRING "__libc_do_syscall"
> +#endif
> +
> #ifdef __ASSEMBLER__
>
> /* Linux uses a negative return value to indicate syscall errors,
> @@ -301,7 +310,7 @@ struct libc_do_syscall_args
> }; \
> asm volatile ( \
> "movl %1, %%eax\n\t" \
> - "call __libc_do_syscall" \
> + "call " I386_DO_SYSCALL_STRING \
> : "=a" (resultvar) \
> : "i" (__NR_##name), "c" (arg2), "d" (arg3), "S" (arg4), "D" (&_xv) \
> : "memory", "cc")
> @@ -315,7 +324,7 @@ struct libc_do_syscall_args
> }; \
> asm volatile ( \
> "movl %1, %%eax\n\t" \
> - "call __libc_do_syscall" \
> + "call " I386_DO_SYSCALL_STRING \
> : "=a" (resultvar) \
> : "a" (name), "c" (arg2), "d" (arg3), "S" (arg4), "D" (&_xv) \
> : "memory", "cc")
> --
> 2.35.1
>
>
LGTM.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Thanks.
--
H.J.
^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 5/5] csu: Implement and use _dl_early_allocate during static startup
2022-05-02 19:15 [PATCH 0/5] Linux: Fall back to mmap if early sbrk fails Florian Weimer
` (3 preceding siblings ...)
2022-05-02 19:15 ` [PATCH 4/5] i386: Honor I386_USE_SYSENTER for 6-argument Linux system calls Florian Weimer
@ 2022-05-02 19:15 ` Florian Weimer
4 siblings, 0 replies; 23+ messages in thread
From: Florian Weimer @ 2022-05-02 19:15 UTC (permalink / raw)
To: libc-alpha
This implements mmap fallback for a brk failure during TLS
allocation.
scripts/tls-elf-edit.py is updated to support the new patching method.
The script no longer requires that in the input object is of ET_DYN
type.
---
csu/libc-tls.c | 12 ++-
elf/Makefile | 19 +++++
elf/dl-early_allocate.c | 30 ++++++++
elf/tst-tls-allocation-failure-static.c | 31 ++++++++
scripts/tst-elf-edit.py | 34 +++++++--
sysdeps/generic/ldsodefs.h | 5 ++
sysdeps/unix/sysv/linux/dl-early_allocate.c | 81 +++++++++++++++++++++
7 files changed, 202 insertions(+), 10 deletions(-)
create mode 100644 elf/dl-early_allocate.c
create mode 100644 elf/tst-tls-allocation-failure-static.c
create mode 100644 sysdeps/unix/sysv/linux/dl-early_allocate.c
diff --git a/csu/libc-tls.c b/csu/libc-tls.c
index bef92a7568..7d311056bc 100644
--- a/csu/libc-tls.c
+++ b/csu/libc-tls.c
@@ -145,11 +145,16 @@ __libc_setup_tls (void)
_dl_allocate_tls_storage (in elf/dl-tls.c) does using __libc_memalign
and dl_tls_static_align. */
tcb_offset = roundup (memsz + GLRO(dl_tls_static_surplus), max_align);
- tlsblock = __sbrk (tcb_offset + TLS_INIT_TCB_SIZE + max_align);
+ tlsblock = _dl_early_allocate (tcb_offset + TLS_INIT_TCB_SIZE + max_align);
+ if (tlsblock == NULL)
+ _startup_fatal ("Fatal glibc error: Cannot allocate TLS block\n");
#elif TLS_DTV_AT_TP
tcb_offset = roundup (TLS_INIT_TCB_SIZE, align ?: 1);
- tlsblock = __sbrk (tcb_offset + memsz + max_align
- + TLS_PRE_TCB_SIZE + GLRO(dl_tls_static_surplus));
+ tlsblock = _dl_early_allocate (tcb_offset + memsz + max_align
+ + TLS_PRE_TCB_SIZE
+ + GLRO(dl_tls_static_surplus));
+ if (tlsblock == NULL)
+ _startup_fatal ("Fatal glibc error: Cannot allocate TLS block\n");
tlsblock += TLS_PRE_TCB_SIZE;
#else
/* In case a model with a different layout for the TCB and DTV
@@ -157,6 +162,7 @@ __libc_setup_tls (void)
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
#endif
+
/* Align the TLS block. */
tlsblock = (void *) (((uintptr_t) tlsblock + max_align - 1)
& ~(max_align - 1));
diff --git a/elf/Makefile b/elf/Makefile
index fc9860edee..ce3345ed92 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -33,6 +33,7 @@ routines = \
$(all-dl-routines) \
dl-addr \
dl-addr-obj \
+ dl-early_allocate \
dl-error \
dl-iteratephdr \
dl-libc \
@@ -108,6 +109,7 @@ all-dl-routines = $(dl-routines) $(sysdep-dl-routines)
# But they are absent from the shared libc, because that code is in ld.so.
elide-routines.os = \
$(all-dl-routines) \
+ dl-early_allocate \
dl-exception \
dl-origin \
dl-reloc-static-pie \
@@ -276,6 +278,7 @@ tests-static-normal := \
tst-linkall-static \
tst-single_threaded-pthread-static \
tst-single_threaded-static \
+ tst-tls-allocation-failure-static \
tst-tlsalign-extern-static \
tst-tlsalign-static \
# tests-static-normal
@@ -1213,6 +1216,10 @@ $(objpfx)tst-glibcelf.out: tst-glibcelf.py elf.h $(..)/scripts/glibcelf.py \
--cc="$(CC) $(patsubst -DMODULE_NAME=%,-DMODULE_NAME=testsuite,$(CPPFLAGS))" \
< /dev/null > $@ 2>&1; $(evaluate-test)
+ifeq ($(run-built-tests),yes)
+tests-special += $(objpfx)tst-tls-allocation-failure-static-patched.out
+endif
+
# The test requires shared _and_ PIE because the executable
# unit test driver must be able to link with the shared object
# that is going to eventually go into an installed DSO.
@@ -2937,3 +2944,15 @@ $(eval $(call tst-trace-skeleton,4,\
$(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4))
$(eval $(call tst-trace-skeleton,5,\
$(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4:$(objpfx)libtracemod5))
+
+$(objpfx)tst-tls-allocation-failure-static-patched: \
+ $(objpfx)tst-tls-allocation-failure-static $(..)scripts/tst-elf-edit.py
+ cp $< $@
+ $(PYTHON) $(..)scripts/tst-elf-edit.py --maximize-tls-size $@
+
+$(objpfx)tst-tls-allocation-failure-static-patched.out: \
+ $(objpfx)tst-tls-allocation-failure-static-patched
+ $< > $@ 2>&1; echo "status: $$?" >> $@
+ grep -q '^Fatal glibc error: Cannot allocate TLS block$$' $@ \
+ && grep -q '^status: 127$$' $@; \
+ $(evaluate-test)
diff --git a/elf/dl-early_allocate.c b/elf/dl-early_allocate.c
new file mode 100644
index 0000000000..d7f59d41e5
--- /dev/null
+++ b/elf/dl-early_allocate.c
@@ -0,0 +1,30 @@
+/* Early memory allocation for the dynamic loader. Generic version.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <ldsodefs.h>
+#include <stddef.h>
+#include <unistd.h>
+
+void *
+_dl_early_allocate (size_t size)
+{
+ void *result = __sbrk (size);
+ if (result == (void *) -1)
+ _dl_fatal_printf ("Fatal glibc error: Early memory allocation failed\n");
+ return result;
+}
diff --git a/elf/tst-tls-allocation-failure-static.c b/elf/tst-tls-allocation-failure-static.c
new file mode 100644
index 0000000000..8de831b246
--- /dev/null
+++ b/elf/tst-tls-allocation-failure-static.c
@@ -0,0 +1,31 @@
+/* Base for test program with impossiblyh large PT_TLS segment.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+/* The test actual binary is patched using scripts/tst-elf-edit.py
+ --maximize-tls-size, and this introduces the expected test
+ allocation failure due to an excessive PT_LS p_memsz value.
+
+ Patching the binary is required because on some 64-bit targets, TLS
+ relocations can only cover a 32-bit range, and glibc-internal TLS
+ variables such as errno end up outside that range. */
+
+int
+main (void)
+{
+ return 0;
+}
diff --git a/scripts/tst-elf-edit.py b/scripts/tst-elf-edit.py
index a514179bbf..0e19ce1e73 100644
--- a/scripts/tst-elf-edit.py
+++ b/scripts/tst-elf-edit.py
@@ -43,9 +43,11 @@ EI_DATA=5
ELFDATA2LSB=b'\x01'
ELFDATA2MSB=b'\x02'
+ET_EXEC=2
ET_DYN=3
PT_LOAD=1
+PT_TLS=7
def elf_types_fmts(e_ident):
endian = '<' if e_ident[EI_DATA] == ELFDATA2LSB else '>'
@@ -146,8 +148,15 @@ def elf_edit_align(phdr, align):
else:
phdr.p_align = int(align)
+def elf_edit_maximize_tls_size(phdr, elfclass):
+ if elfclass == ELFCLASS32:
+ # It is possible that the kernel can allocate half of the
+ # address space, so use something larger.
+ phdr.p_memsz = 0xfff00000
+ else:
+ phdr.p_memsz = 1 << 63
-def elf_edit(f, align):
+def elf_edit(f, opts):
ei_nident_fmt = 'c' * EI_NIDENT
ei_nident_len = struct.calcsize(ei_nident_fmt)
@@ -172,24 +181,35 @@ def elf_edit(f, align):
ehdr = Elf_Ehdr(e_ident)
ehdr.read(f)
- if ehdr.e_type != ET_DYN:
- error('{}: not a shared library'.format(f.name))
+ if ehdr.e_type not in (ET_EXEC, ET_DYN):
+ error('{}: not an executable or shared library'.format(f.name))
phdr = Elf_Phdr(e_ident)
+ maximize_tls_size_done = False
for i in range(0, ehdr.e_phnum):
f.seek(ehdr.e_phoff + i * phdr.len)
phdr.read(f)
- if phdr.p_type == PT_LOAD:
- elf_edit_align(phdr, align)
+ if phdr.p_type == PT_LOAD and opts.align is not None:
+ elf_edit_align(phdr, opts.align)
+ f.seek(ehdr.e_phoff + i * phdr.len)
+ phdr.write(f)
+ break
+ if phdr.p_type == PT_TLS and opts.maximize_tls_size:
+ elf_edit_maximize_tls_size(phdr, e_ident[EI_CLASS])
f.seek(ehdr.e_phoff + i * phdr.len)
phdr.write(f)
+ maximize_tls_size_done = True
break
+ if opts.maximize_tls_size and not maximize_tls_size_done:
+ error('{}: TLS maximum size was not updated'.format(f.name))
def get_parser():
parser = argparse.ArgumentParser(description=__doc__)
- parser.add_argument('-a', dest='align', required=True,
+ parser.add_argument('-a', dest='align',
help='How to set the LOAD alignment')
+ parser.add_argument('--maximize-tls-size', action='store_true',
+ help='Set maximum PT_TLS size')
parser.add_argument('output',
help='ELF file to edit')
return parser
@@ -199,7 +219,7 @@ def main(argv):
parser = get_parser()
opts = parser.parse_args(argv)
with open(opts.output, 'r+b') as fout:
- elf_edit(fout, opts.align)
+ elf_edit(fout, opts)
if __name__ == '__main__':
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 4a5e698db2..5d0369358d 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -1211,6 +1211,11 @@ extern struct link_map * _dl_get_dl_main_map (void)
# endif
#endif
+/* Perform early memory allocation, avoding a TCB dependency.
+ Terminate the process if allocation fails. May attempt to use
+ brk. */
+void *_dl_early_allocate (size_t size) attribute_hidden;
+
/* Initialize the DSO sort algorithm to use. */
#if !HAVE_TUNABLES
static inline void
diff --git a/sysdeps/unix/sysv/linux/dl-early_allocate.c b/sysdeps/unix/sysv/linux/dl-early_allocate.c
new file mode 100644
index 0000000000..2c77b6e3ff
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/dl-early_allocate.c
@@ -0,0 +1,81 @@
+/* Early memory allocation for the dynamic loader. Generic version.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+/* Mark symbols hidden in static PIE for early self relocation to work. */
+#if BUILD_PIE_DEFAULT
+# pragma GCC visibility push(hidden)
+#endif
+#include <startup.h>
+
+#include <ldsodefs.h>
+#include <stddef.h>
+#include <string.h>
+#include <sysdep.h>
+#include <unistd.h>
+
+#include <mmap_call.h>
+
+/* Defined in brk.c. */
+extern void *__curbrk;
+
+void *
+_dl_early_allocate (size_t size)
+{
+ void *result;
+
+ if (__curbrk != NULL)
+ /* If the break has been initialized, brk must have run before,
+ so just call it once more. */
+ {
+ result = __sbrk (size);
+ if (result == (void *) -1)
+ result = NULL;
+ }
+ else
+ {
+ /* If brk has not been invoked, there is no need to update
+ __curbrk. The first call to brk will take care of that. */
+ void *previous = (void *) INTERNAL_SYSCALL_CALL (brk, 0);
+ result = (void *) INTERNAL_SYSCALL_CALL (brk, previous + size);
+ if (result == previous)
+ result = NULL;
+ else
+ result = previous;
+ }
+
+ /* If brk fails, fall back to mmap. This can happen due to
+ unfortunate ASLR layout decisions and kernel bugs, particularly
+ for static PIE. */
+ if (result == NULL)
+ {
+ long int ret;
+ int prot = PROT_READ | PROT_WRITE;
+ int flags = MAP_PRIVATE | MAP_ANONYMOUS;
+#ifdef __NR_mmap2
+ ret = MMAP_CALL_INTERNAL (mmap2, 0, size, prot, flags, -1, 0);
+#else
+ ret = MMAP_CALL_INTERNAL (mmap, 0, size, prot, flags, -1, 0);
+#endif
+ if (INTERNAL_SYSCALL_ERROR_P (ret))
+ result = NULL;
+ else
+ result = (void *) ret;
+ }
+
+ return result;
+}
--
2.35.1
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