* [PATCH v2 1/2] riscv: support GNU indirect function
2020-12-15 9:16 [PATCH v2 0/2] riscv: add support for GNU indirect function Vincent Chen
@ 2020-12-15 9:16 ` Vincent Chen
2020-12-15 9:16 ` [PATCH v2 2/2] riscv: Initialize $gp before resolving the IRELATIVE relocation Vincent Chen
2021-01-04 1:38 ` [PATCH v2 0/2] riscv: add support for GNU indirect function Vincent Chen
2 siblings, 0 replies; 10+ messages in thread
From: Vincent Chen @ 2020-12-15 9:16 UTC (permalink / raw)
To: libc-alpha, palmer, darius, dj
Cc: nelson.chu, jimw, paul.walmsley, Vincent Chen
Enable riscv glibc to support GNU indirect function
---
libc-abis | 1 +
sysdeps/riscv/dl-irel.h | 56 ++++++++++++++++++++++++++++++++++++++
sysdeps/riscv/dl-machine.h | 22 +++++++++++++++
3 files changed, 79 insertions(+)
create mode 100644 sysdeps/riscv/dl-irel.h
diff --git a/libc-abis b/libc-abis
index e702f6ae24..70b154de4b 100644
--- a/libc-abis
+++ b/libc-abis
@@ -48,3 +48,4 @@ IFUNC sparc64-*-linux*
IFUNC sparc-*-linux*
# Absolute (SHN_ABS) symbols working correctly.
ABSOLUTE
+IFUNC riscv*-linux*
diff --git a/sysdeps/riscv/dl-irel.h b/sysdeps/riscv/dl-irel.h
new file mode 100644
index 0000000000..cad9cc87b1
--- /dev/null
+++ b/sysdeps/riscv/dl-irel.h
@@ -0,0 +1,56 @@
+/* Machine-dependent ELF indirect relocation inline functions.
+ RISC-V version.
+ Copyright (C) 2020 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 _DL_IREL_H
+#define _DL_IREL_H
+
+#include <stdio.h>
+#include <unistd.h>
+#include <ldsodefs.h>
+#include <sysdep.h>
+
+#define ELF_MACHINE_IRELA 1
+
+static inline ElfW(Addr)
+__attribute ((always_inline))
+elf_ifunc_invoke (ElfW(Addr) addr)
+{
+ /* The second argument is a void pointer to preserve the extension
+ fexibility. */
+ return ((ElfW(Addr) (*) (uint64_t, void *)) (addr))
+ (GLRO(dl_hwcap), NULL);
+}
+
+static inline void
+__attribute ((always_inline))
+elf_irela (const ElfW(Rela) *reloc)
+{
+ ElfW(Addr) *const reloc_addr = (void *) reloc->r_offset;
+ const unsigned long int r_type = ELFW(R_TYPE) (reloc->r_info);
+
+ if (__glibc_likely (r_type == R_RISCV_IRELATIVE))
+ {
+ ElfW(Addr) value = elf_ifunc_invoke (reloc->r_addend);
+ *reloc_addr = value;
+ }
+ else
+ __libc_fatal ("Unexpected reloc type in static binary.\n");
+}
+
+#endif
diff --git a/sysdeps/riscv/dl-machine.h b/sysdeps/riscv/dl-machine.h
index 511140864e..0ae45dd0c3 100644
--- a/sysdeps/riscv/dl-machine.h
+++ b/sysdeps/riscv/dl-machine.h
@@ -25,6 +25,7 @@
#include <elf/elf.h>
#include <sys/asm.h>
#include <dl-tls.h>
+#include <dl-irel.h>
#ifndef _RTLD_PROLOGUE
# define _RTLD_PROLOGUE(entry) \
@@ -176,6 +177,13 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
if (sym_map != NULL)
value = SYMBOL_ADDRESS (sym_map, sym, true) + reloc->r_addend;
+ if (sym != NULL
+ && __glibc_unlikely (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC)
+ && __glibc_likely (sym->st_shndx != SHN_UNDEF)
+ && __glibc_likely (!skip_ifunc))
+ value = elf_ifunc_invoke (value);
+
+
switch (r_type)
{
#ifndef RTLD_BOOTSTRAP
@@ -251,6 +259,13 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
}
#endif
+ case R_RISCV_IRELATIVE:
+ value = map->l_addr + reloc->r_addend;
+ if (__glibc_likely (!skip_ifunc))
+ value = elf_ifunc_invoke (value);
+ *addr_field = value;
+ break;
+
case R_RISCV_JUMP_SLOT:
case __WORDSIZE == 64 ? R_RISCV_64 : R_RISCV_32:
*addr_field = value;
@@ -292,6 +307,13 @@ elf_machine_lazy_rel (struct link_map *map, ElfW(Addr) l_addr,
else
*reloc_addr = map->l_mach.plt;
}
+ else if (__glibc_unlikely (r_type == R_RISCV_IRELATIVE))
+ {
+ ElfW(Addr) value = map->l_addr + reloc->r_addend;
+ if (__glibc_likely (!skip_ifunc))
+ value = elf_ifunc_invoke (value);
+ *reloc_addr = value;
+ }
else
_dl_reloc_bad_type (map, r_type, 1);
}
--
2.29.2
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v2 2/2] riscv: Initialize $gp before resolving the IRELATIVE relocation
2020-12-15 9:16 [PATCH v2 0/2] riscv: add support for GNU indirect function Vincent Chen
2020-12-15 9:16 ` [PATCH v2 1/2] riscv: support " Vincent Chen
@ 2020-12-15 9:16 ` Vincent Chen
2021-01-04 1:38 ` [PATCH v2 0/2] riscv: add support for GNU indirect function Vincent Chen
2 siblings, 0 replies; 10+ messages in thread
From: Vincent Chen @ 2020-12-15 9:16 UTC (permalink / raw)
To: libc-alpha, palmer, darius, dj
Cc: nelson.chu, jimw, paul.walmsley, Vincent Chen
The $gp register may be used to access the global variable in
the PDE program, so the $gp register should be initialized before
executing the IFUNC resolver of PDE program to avoid unexpected
error occurs.
---
sysdeps/riscv/dl-machine.h | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/sysdeps/riscv/dl-machine.h b/sysdeps/riscv/dl-machine.h
index 0ae45dd0c3..211835f0e6 100644
--- a/sysdeps/riscv/dl-machine.h
+++ b/sysdeps/riscv/dl-machine.h
@@ -339,8 +339,28 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
gotplt[0] = (ElfW(Addr)) &_dl_runtime_resolve;
gotplt[1] = (ElfW(Addr)) l;
}
-#endif
+ if (l->l_type == lt_executable)
+ {
+ /* The __global_pointer$ may not be defined by the linker if the
+ $gp register does not be used to access the global variable
+ in the executable program. Therefore, the search symbol is
+ set to a weak symbol to avoid we error out if the
+ __global_pointer$ is not found. */
+ ElfW(Sym) gp_sym = { 0 };
+ gp_sym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
+
+ const ElfW(Sym) *ref = &gp_sym;
+ _dl_lookup_symbol_x ("__global_pointer$", l, &ref,
+ l->l_scope, NULL, 0, 0, NULL);
+ if (ref)
+ asm (
+ "mv gp, %0\n"
+ :
+ : "r" (ref->st_value)
+ );
+ }
+#endif
return lazy;
}
--
2.29.2
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/2] riscv: add support for GNU indirect function
2020-12-15 9:16 [PATCH v2 0/2] riscv: add support for GNU indirect function Vincent Chen
2020-12-15 9:16 ` [PATCH v2 1/2] riscv: support " Vincent Chen
2020-12-15 9:16 ` [PATCH v2 2/2] riscv: Initialize $gp before resolving the IRELATIVE relocation Vincent Chen
@ 2021-01-04 1:38 ` Vincent Chen
2021-01-05 1:53 ` Jim Wilson
2021-01-11 2:29 ` DJ Delorie
2 siblings, 2 replies; 10+ messages in thread
From: Vincent Chen @ 2021-01-04 1:38 UTC (permalink / raw)
To: GNU C Library, Palmer Dabbelt, Darius Rad, DJ Delorie
Cc: Nelson Chu, Jim Wilson, Paul Walmsley
On Tue, Dec 15, 2020 at 5:16 PM Vincent Chen <vincent.chen@sifive.com> wrote:
>
> The riscv Binutils supported GNU indirect function in the commit
> 02dd9d25. To make the entire mechanism work, these patches adds the
> required ports to enable Glibc to address the IRELATIVE relocation.
>
> Because the dynamic linker resolves the IRELATIVE relocation before
> jumping into the executable program, the $gp register is not initialized
> when executing the IFUNC resolver function. It may cause some unexpected
> error to occur when the dynamic loader resolves the IREALTIVE relocation
> of the position-dependent executable program. To solve this issue, the
> second patch enables dynamic linker to look for the __global_pointer$
> symbol and use it to initialize $gp before resolving the IREALTIVE
> relocation of the PDE program.
>
>
> Changes since v1:
> 1. Move the riscv entry to the end of libc-abis file
> 2. Add the second input argument to IFUNC resolver to preserve the
> extension flexibility
> 3. Enable ld.so to initilize $gp by __global_pointer$ symbol instead
> of the DT_RISCV_GP dynamic entry to avoid to modify the riscv ELF
> psABI specification.
>
Gentle ping on this series. Thanks and happy new year.
>
> Vincent Chen (2):
> riscv: support GNU indirect function
> riscv: Initialize $gp before resolving the IRELATIVE relocation
>
> libc-abis | 1 +
> sysdeps/riscv/dl-irel.h | 56 ++++++++++++++++++++++++++++++++++++++
> sysdeps/riscv/dl-machine.h | 44 +++++++++++++++++++++++++++++-
> 3 files changed, 100 insertions(+), 1 deletion(-)
> create mode 100644 sysdeps/riscv/dl-irel.h
>
> --
> 2.29.2
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/2] riscv: add support for GNU indirect function
2021-01-04 1:38 ` [PATCH v2 0/2] riscv: add support for GNU indirect function Vincent Chen
@ 2021-01-05 1:53 ` Jim Wilson
2021-01-05 3:13 ` Nelson Chu
2021-01-05 12:32 ` Carlos O'Donell
2021-01-11 2:29 ` DJ Delorie
1 sibling, 2 replies; 10+ messages in thread
From: Jim Wilson @ 2021-01-05 1:53 UTC (permalink / raw)
To: Vincent Chen
Cc: GNU C Library, Palmer Dabbelt, Darius Rad, DJ Delorie,
Nelson Chu, Paul Walmsley
On Sun, Jan 3, 2021 at 5:38 PM Vincent Chen <vincent.chen@sifive.com> wrote:
> Gentle ping on this series. Thanks and happy new year.
>
This is on the release blockers list at my request, so hopefully it will
get looked at before the release.
https://sourceware.org/glibc/wiki/Release/2.33#Release_blockers.3F
Jim
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/2] riscv: add support for GNU indirect function
2021-01-05 1:53 ` Jim Wilson
@ 2021-01-05 3:13 ` Nelson Chu
2021-01-05 12:32 ` Carlos O'Donell
1 sibling, 0 replies; 10+ messages in thread
From: Nelson Chu @ 2021-01-05 3:13 UTC (permalink / raw)
To: Jim Wilson
Cc: Vincent Chen, GNU C Library, Palmer Dabbelt, Darius Rad,
DJ Delorie, Paul Walmsley
On Tue, Jan 5, 2021 at 9:53 AM Jim Wilson <jimw@sifive.com> wrote:
> This is on the release blockers list at my request, so hopefully it will get looked at before the release.
> https://sourceware.org/glibc/wiki/Release/2.33#Release_blockers.3F
Thank you very much, Jim.
> 3. Enable ld.so to initilize $gp by __global_pointer$ symbol instead
> of the DT_RISCV_GP dynamic entry to avoid to modify the riscv ELF
The binutils commit 18b9872261b950a8d10a4ae6ccb8f2acdaebc3e6 is
committed, so this should work when updating the mainline binutils.
Thanks
Nelson
psABI specification.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/2] riscv: add support for GNU indirect function
2021-01-05 1:53 ` Jim Wilson
2021-01-05 3:13 ` Nelson Chu
@ 2021-01-05 12:32 ` Carlos O'Donell
2021-01-06 0:53 ` Vincent Chen
1 sibling, 1 reply; 10+ messages in thread
From: Carlos O'Donell @ 2021-01-05 12:32 UTC (permalink / raw)
To: Jim Wilson, Vincent Chen; +Cc: GNU C Library, Nelson Chu, Paul Walmsley
On 1/4/21 8:53 PM, Jim Wilson wrote:
> On Sun, Jan 3, 2021 at 5:38 PM Vincent Chen <vincent.chen@sifive.com> wrote:
>
>> Gentle ping on this series. Thanks and happy new year.
>>
>
> This is on the release blockers list at my request, so hopefully it will
> get looked at before the release.
> https://sourceware.org/glibc/wiki/Release/2.33#Release_blockers.3F
The patches were discussed on the Monday patch review meeting.
I've asked DJ to help move these along.
I have confidence that we will get to them before the release.
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/2] riscv: add support for GNU indirect function
2021-01-05 12:32 ` Carlos O'Donell
@ 2021-01-06 0:53 ` Vincent Chen
0 siblings, 0 replies; 10+ messages in thread
From: Vincent Chen @ 2021-01-06 0:53 UTC (permalink / raw)
To: Carlos O'Donell; +Cc: Jim Wilson, GNU C Library, Nelson Chu, Paul Walmsley
On Tue, Jan 5, 2021 at 8:32 PM Carlos O'Donell <carlos@redhat.com> wrote:
>
> On 1/4/21 8:53 PM, Jim Wilson wrote:
> > On Sun, Jan 3, 2021 at 5:38 PM Vincent Chen <vincent.chen@sifive.com> wrote:
> >
> >> Gentle ping on this series. Thanks and happy new year.
> >>
> >
> > This is on the release blockers list at my request, so hopefully it will
> > get looked at before the release.
> > https://sourceware.org/glibc/wiki/Release/2.33#Release_blockers.3F
>
> The patches were discussed on the Monday patch review meeting.
>
> I've asked DJ to help move these along.
>
> I have confidence that we will get to them before the release.
>
Glad to hear this information. Thanks to the people who have given me
help on this patch set.
Best Regards
Vincent Chen
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/2] riscv: add support for GNU indirect function
2021-01-04 1:38 ` [PATCH v2 0/2] riscv: add support for GNU indirect function Vincent Chen
2021-01-05 1:53 ` Jim Wilson
@ 2021-01-11 2:29 ` DJ Delorie
2021-01-11 7:34 ` Nelson Chu
1 sibling, 1 reply; 10+ messages in thread
From: DJ Delorie @ 2021-01-11 2:29 UTC (permalink / raw)
To: Vincent Chen; +Cc: libc-alpha, palmer, darius, nelson.chu, jimw, paul.walmsley
Vincent Chen <vincent.chen@sifive.com> writes:
> Gentle ping on this series. Thanks and happy new year.
Series committed. Thanks!
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 0/2] riscv: add support for GNU indirect function
2021-01-11 2:29 ` DJ Delorie
@ 2021-01-11 7:34 ` Nelson Chu
0 siblings, 0 replies; 10+ messages in thread
From: Nelson Chu @ 2021-01-11 7:34 UTC (permalink / raw)
To: DJ Delorie
Cc: Vincent Chen, GNU C Library, Palmer Dabbelt, Darius Rad,
Jim Wilson, Paul Walmsley
Thank you all !
Nelson
On Mon, Jan 11, 2021 at 10:29 AM DJ Delorie <dj@redhat.com> wrote:
>
> Vincent Chen <vincent.chen@sifive.com> writes:
> > Gentle ping on this series. Thanks and happy new year.
>
> Series committed. Thanks!
>
^ permalink raw reply [flat|nested] 10+ messages in thread