[RFC PATCH 0/9] More x86_64-gnu glibc work

[RFC PATCH 0/9] More x86_64-gnu glibc work

[Sergey Bugaev]

Hello,

here's some more work on the x86_64-gnu glibc port. Large parts of glibc
(almost all of it?) builds, in particular mach/subdir_lib builds cleanly.

Patch 6 is really unrelated to the rest of the changes, it's just a small thing
that I've noticed while single-stepping through glibc startup, trying to
understand which order things are getting called in, and from where.

Patch 8/9 adds i386_fsgs_base_state to Mach headers. Does this look reasonable?
I have not written an implementation. Any volunteers? :)

Then patch 9/9 adds a fairly complete implementation of tls.h based on that
API. It turned out that thread_state.h did not need large changes compared to
the i386 version after all, so consider applying Flavio's patch ("Define PC, SP
and SYSRETURN for hurd x86_64") instead of the version my patch adds (but keep
the rest of my patch).

I'm not super sure that the thing I've done with __libc_tls_initialized is
correct / makes sense; please do take a look!

Large parts remaining:
* ucontext / sigcontext
* intr_msg / signal trampoline

Sergey

[RFC PATCH 1/9] hurd: Move thread state manipulation into _hurd_tls_new ()

[Sergey Bugaev]

This is going to be done differently on x86_64.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 mach/setup-thread.c          | 18 ++----------------
 sysdeps/mach/hurd/i386/tls.h | 25 ++++++++++++++++++++-----
 2 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/mach/setup-thread.c b/mach/setup-thread.c
index 6ce5c13d..ae24a149 100644
--- a/mach/setup-thread.c
+++ b/mach/setup-thread.c
@@ -83,25 +83,11 @@ weak_alias (__mach_setup_thread, mach_setup_thread)
 kern_return_t
 __mach_setup_tls (thread_t thread)
 {
-  kern_return_t error;
-  struct machine_thread_state ts;
-  mach_msg_type_number_t tssize = MACHINE_THREAD_STATE_COUNT;
-  tcbhead_t *tcb;
-
-  tcb = _dl_allocate_tls (NULL);
+  tcbhead_t *tcb = _dl_allocate_tls (NULL);
   if (tcb == NULL)
     return KERN_RESOURCE_SHORTAGE;
 
-  if (error = __thread_get_state (thread, MACHINE_THREAD_STATE_FLAVOR,
-			     (natural_t *) &ts, &tssize))
-    return error;
-  assert (tssize == MACHINE_THREAD_STATE_COUNT);
-
-  _hurd_tls_new (thread, &ts, tcb);
-
-  error = __thread_set_state (thread, MACHINE_THREAD_STATE_FLAVOR,
-			      (natural_t *) &ts, tssize);
-  return error;
+  return _hurd_tls_new (thread, tcb);
 }
 
 weak_alias (__mach_setup_tls, mach_setup_tls)
diff --git a/sysdeps/mach/hurd/i386/tls.h b/sysdeps/mach/hurd/i386/tls.h
index 590abd47..0f8dd241 100644
--- a/sysdeps/mach/hurd/i386/tls.h
+++ b/sysdeps/mach/hurd/i386/tls.h
@@ -378,16 +378,25 @@ _hurd_tls_fork (thread_t child, thread_t orig, struct i386_thread_state *state)
 }
 
 static inline kern_return_t __attribute__ ((unused))
-_hurd_tls_new (thread_t child, struct i386_thread_state *state, tcbhead_t *tcb)
+_hurd_tls_new (thread_t child, tcbhead_t *tcb)
 {
+  error_t err;
+  /* Fetch the target thread's state.  */
+  struct i386_thread_state state;
+  mach_msg_type_number_t state_count = i386_THREAD_STATE_COUNT;
+  err = __thread_get_state (child, i386_REGS_SEGS_STATE,
+                            (thread_state_t) &state,
+                            &state_count);
+  if (err)
+    return err;
+  assert (state_count == i386_THREAD_STATE_COUNT);
   /* Fetch the selector set by _hurd_tls_init.  */
   int sel;
   asm ("mov %%gs, %w0" : "=q" (sel) : "0" (0));
-  if (sel == state->ds)		/* _hurd_tls_init was never called.  */
+  if (sel == state.ds)		/* _hurd_tls_init was never called.  */
     return 0;
 
   HURD_TLS_DESC_DECL (desc, tcb);
-  error_t err;
 
   tcb->tcb = tcb;
   tcb->self = child;
@@ -397,8 +406,14 @@ _hurd_tls_new (thread_t child, struct i386_thread_state *state, tcbhead_t *tcb)
   else
     err = __i386_set_gdt (child, &sel, desc);
 
-  state->gs = sel;
-  return err;
+  if (err)
+    return err;
+
+  /* Update gs to use the selector.  */
+  state.gs = sel;
+  return __thread_set_state (child, i386_REGS_SEGS_STATE,
+                             (thread_state_t) &state,
+                             state_count);
 }
 
 /* Global scope switch support.  */
-- 
2.39.2

[RFC PATCH 2/9] hurd: Use proper integer types

[Sergey Bugaev]

Fix a few more cases of build errors caused by mismatched types. This is a
continuation of f4315054b46d5e58b44a709a51943fb73f846afb.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 hurd/hurdsig.c                  | 6 +++---
 sysdeps/mach/hurd/getpriority.c | 6 +++---
 sysdeps/mach/hurd/if_index.c    | 2 +-
 sysdeps/mach/hurd/ifreq.c       | 2 +-
 sysdeps/mach/hurd/readdir64.c   | 4 +++-
 sysdeps/mach/hurd/readdir64_r.c | 4 +++-
 6 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c
index 56e8e614..ea79ffb5 100644
--- a/hurd/hurdsig.c
+++ b/hurd/hurdsig.c
@@ -430,8 +430,8 @@ _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread,
      receive completes immediately or aborts.  */
   abort_thread (ss, state, reply);
 
-  if (state->basic.PC >= (natural_t) &_hurd_intr_rpc_msg_about_to
-      && state->basic.PC < (natural_t) &_hurd_intr_rpc_msg_in_trap)
+  if (state->basic.PC >= (uintptr_t) &_hurd_intr_rpc_msg_about_to
+      && state->basic.PC < (uintptr_t) &_hurd_intr_rpc_msg_in_trap)
     {
       /* The thread is about to do the RPC, but hasn't yet entered
 	 mach_msg.  Mutate the thread's state so it knows not to try
@@ -442,7 +442,7 @@ _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread,
       state->basic.SYSRETURN = MACH_SEND_INTERRUPTED;
       *state_change = 1;
     }
-  else if (state->basic.PC == (natural_t) &_hurd_intr_rpc_msg_in_trap
+  else if (state->basic.PC == (uintptr_t) &_hurd_intr_rpc_msg_in_trap
 	   /* The thread was blocked in the system call.  After thread_abort,
 	      the return value register indicates what state the RPC was in
 	      when interrupted.  */
diff --git a/sysdeps/mach/hurd/getpriority.c b/sysdeps/mach/hurd/getpriority.c
index 9869c2f5..45b32215 100644
--- a/sysdeps/mach/hurd/getpriority.c
+++ b/sysdeps/mach/hurd/getpriority.c
@@ -30,7 +30,7 @@ __getpriority (enum __priority_which which, id_t who)
   int maxpri = INT_MIN;
   struct procinfo *pip;		/* Just for sizeof.  */
   int pibuf[sizeof *pip + 2 * sizeof (pip->threadinfos[0])], *pi = pibuf;
-  size_t pisize = sizeof pibuf / sizeof pibuf[0];
+  mach_msg_type_number_t pisize = sizeof pibuf / sizeof pibuf[0];
 
   error_t getonepriority (pid_t pid, struct procinfo *pip)
     {
@@ -39,9 +39,9 @@ __getpriority (enum __priority_which which, id_t who)
       else
 	{
 	  int *oldpi = pi;
-	  size_t oldpisize = pisize;
+	  mach_msg_type_number_t oldpisize = pisize;
 	  char *tw = 0;
-	  size_t twsz = 0;
+	  mach_msg_type_number_t twsz = 0;
 	  int flags = PI_FETCH_TASKINFO;
 	  onerr = __USEPORT (PROC, __proc_getprocinfo (port, pid, &flags,
 						       &pi, &pisize,
diff --git a/sysdeps/mach/hurd/if_index.c b/sysdeps/mach/hurd/if_index.c
index a4472269..c8ad7e72 100644
--- a/sysdeps/mach/hurd/if_index.c
+++ b/sysdeps/mach/hurd/if_index.c
@@ -99,7 +99,7 @@ __if_nameindex (void)
     nifs = 0;
   else
     {
-      size_t len = sizeof data;
+      mach_msg_type_number_t len = sizeof data;
       err = __pfinet_siocgifconf (server, -1, &ifc.ifc_buf, &len);
       if (err == MACH_SEND_INVALID_DEST || err == MIG_SERVER_DIED)
 	{
diff --git a/sysdeps/mach/hurd/ifreq.c b/sysdeps/mach/hurd/ifreq.c
index ef210c32..394d020c 100644
--- a/sysdeps/mach/hurd/ifreq.c
+++ b/sysdeps/mach/hurd/ifreq.c
@@ -37,7 +37,7 @@ __ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
   else
     {
       char *data = NULL;
-      size_t len = 0;
+      mach_msg_type_number_t len = 0;
       error_t err = __pfinet_siocgifconf (server, -1, &data, &len);
       if (err == MACH_SEND_INVALID_DEST || err == MIG_SERVER_DIED)
 	{
diff --git a/sysdeps/mach/hurd/readdir64.c b/sysdeps/mach/hurd/readdir64.c
index 47829d9e..cf98bbb1 100644
--- a/sysdeps/mach/hurd/readdir64.c
+++ b/sysdeps/mach/hurd/readdir64.c
@@ -43,12 +43,13 @@ __readdir64 (DIR *dirp)
 	  /* We've emptied out our buffer.  Refill it.  */
 
 	  char *data = dirp->__data;
+	  mach_msg_type_number_t data_size = dirp->__size;
 	  int nentries;
 	  error_t err;
 
 	  if (err = HURD_FD_PORT_USE (dirp->__fd,
 				      __dir_readdir (port,
-						     &data, &dirp->__size,
+						     &data, &data_size,
 						     dirp->__entry_ptr,
 						     -1, 0, &nentries)))
 	    {
@@ -57,6 +58,7 @@ __readdir64 (DIR *dirp)
 	      break;
 	    }
 
+          dirp->__size = data_size;
 	  /* DATA now corresponds to entry index DIRP->__entry_ptr.  */
 	  dirp->__entry_data = dirp->__entry_ptr;
 
diff --git a/sysdeps/mach/hurd/readdir64_r.c b/sysdeps/mach/hurd/readdir64_r.c
index 7e438aaf..4f4252c2 100644
--- a/sysdeps/mach/hurd/readdir64_r.c
+++ b/sysdeps/mach/hurd/readdir64_r.c
@@ -45,11 +45,12 @@ __readdir64_r (DIR *dirp, struct dirent64 *entry, struct dirent64 **result)
 	  /* We've emptied out our buffer.  Refill it.  */
 
 	  char *data = dirp->__data;
+	  mach_msg_type_number_t data_size = dirp->__size;
 	  int nentries;
 
 	  if (err = HURD_FD_PORT_USE (dirp->__fd,
 				      __dir_readdir (port,
-						     &data, &dirp->__size,
+						     &data, &data_size,
 						     dirp->__entry_ptr,
 						     -1, 0, &nentries)))
 	    {
@@ -58,6 +59,7 @@ __readdir64_r (DIR *dirp, struct dirent64 *entry, struct dirent64 **result)
 	      break;
 	    }
 
+	  dirp->__size = data_size;
 	  /* DATA now corresponds to entry index DIRP->__entry_ptr.  */
 	  dirp->__entry_data = dirp->__entry_ptr;
 
-- 
2.39.2

[RFC PATCH 3/9] hurd: Fix xattr function return type

[Sergey Bugaev]

They all return int, not size_t.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 sysdeps/mach/hurd/fsetxattr.c    | 2 +-
 sysdeps/mach/hurd/lremovexattr.c | 2 +-
 sysdeps/mach/hurd/lsetxattr.c    | 2 +-
 sysdeps/mach/hurd/removexattr.c  | 2 +-
 sysdeps/mach/hurd/setxattr.c     | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/sysdeps/mach/hurd/fsetxattr.c b/sysdeps/mach/hurd/fsetxattr.c
index 71ee7599..dcc48fa0 100644
--- a/sysdeps/mach/hurd/fsetxattr.c
+++ b/sysdeps/mach/hurd/fsetxattr.c
@@ -22,7 +22,7 @@
 #include <hurd/xattr.h>
 #include <hurd/fd.h>
 
-ssize_t
+int
 fsetxattr (int fd, const char *name, const void *value, size_t size, int flags)
 {
   error_t err;
diff --git a/sysdeps/mach/hurd/lremovexattr.c b/sysdeps/mach/hurd/lremovexattr.c
index 1d761e2d..cb6a1f8f 100644
--- a/sysdeps/mach/hurd/lremovexattr.c
+++ b/sysdeps/mach/hurd/lremovexattr.c
@@ -22,7 +22,7 @@
 #include <hurd/xattr.h>
 #include <fcntl.h>
 
-ssize_t
+int
 lremovexattr (const char *path, const char *name)
 {
   error_t err;
diff --git a/sysdeps/mach/hurd/lsetxattr.c b/sysdeps/mach/hurd/lsetxattr.c
index 56c138dc..4e1e2de2 100644
--- a/sysdeps/mach/hurd/lsetxattr.c
+++ b/sysdeps/mach/hurd/lsetxattr.c
@@ -22,7 +22,7 @@
 #include <hurd/xattr.h>
 #include <fcntl.h>
 
-ssize_t
+int
 lsetxattr (const char *path, const char *name, const void *value, size_t size,
 	   int flags)
 {
diff --git a/sysdeps/mach/hurd/removexattr.c b/sysdeps/mach/hurd/removexattr.c
index 128d0e01..fedc5370 100644
--- a/sysdeps/mach/hurd/removexattr.c
+++ b/sysdeps/mach/hurd/removexattr.c
@@ -21,7 +21,7 @@
 #include <hurd.h>
 #include <hurd/xattr.h>
 
-ssize_t
+int
 removexattr (const char *path, const char *name)
 {
   error_t err;
diff --git a/sysdeps/mach/hurd/setxattr.c b/sysdeps/mach/hurd/setxattr.c
index be3b172b..ba6047cd 100644
--- a/sysdeps/mach/hurd/setxattr.c
+++ b/sysdeps/mach/hurd/setxattr.c
@@ -21,7 +21,7 @@
 #include <hurd.h>
 #include <hurd/xattr.h>
 
-ssize_t
+int
 setxattr (const char *path, const char *name, const void *value, size_t size,
 	  int flags)
 {
-- 
2.39.2

[RFC PATCH 4/9] hurd: Make timer_t pointer-sized

[Sergey Bugaev]

This ensures that a timer_t value can be cast to struct timer_node *
and back.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 sysdeps/mach/hurd/bits/typesizes.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sysdeps/mach/hurd/bits/typesizes.h b/sysdeps/mach/hurd/bits/typesizes.h
index 725a0cb1..7b95bb0b 100644
--- a/sysdeps/mach/hurd/bits/typesizes.h
+++ b/sysdeps/mach/hurd/bits/typesizes.h
@@ -54,7 +54,7 @@
 #define __DADDR_T_TYPE		__S32_TYPE
 #define __KEY_T_TYPE		__S32_TYPE
 #define __CLOCKID_T_TYPE	__S32_TYPE
-#define __TIMER_T_TYPE		__S32_TYPE
+#define __TIMER_T_TYPE		__UWORD_TYPE
 #define __BLKSIZE_T_TYPE	__SLONGWORD_TYPE
 #define __FSID_T_TYPE		__UQUAD_TYPE
 #define __SSIZE_T_TYPE		__SWORD_TYPE
-- 
2.39.2

[RFC PATCH 5/9] hurd: Simplify init-first.c a bit

[Sergey Bugaev]

And make it a bit more 64-bit ready. This is in preparation to moving this
file into x86/

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 sysdeps/mach/hurd/i386/init-first.c | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/i386/init-first.c
index 94c94651..a558da16 100644
--- a/sysdeps/mach/hurd/i386/init-first.c
+++ b/sysdeps/mach/hurd/i386/init-first.c
@@ -195,7 +195,7 @@ init (int *data)
   /* Call `init1' (above) with the user code as the return address, and the
      argument data immediately above that on the stack.  */
 
-  int usercode;
+  void *usercode, **ret_address;
 
   void call_init1 (void);
 
@@ -206,10 +206,11 @@ init (int *data)
      recognize that this read operation may alias the following write
      operation, and thus is free to reorder the two, clobbering the
      original return address.  */
-  usercode = *((int *) __builtin_frame_address (0) + 1);
+  ret_address = (void **) __builtin_frame_address (0) + 1;
+  usercode = *ret_address;
   /* GCC 4.4.6 also wants us to force loading USERCODE already here.  */
   asm volatile ("# %0" : : "X" (usercode));
-  *((void **) __builtin_frame_address (0) + 1) = &call_init1;
+  *ret_address = &call_init1;
   /* Force USERCODE into %eax and &init1 into %ecx, which are not
      restored by function return.  */
   asm volatile ("# a %0 c %1" : : "a" (usercode), "c" (&init1));
@@ -223,19 +224,9 @@ init (int *data)
 /* The return address of `init' above, was redirected to here, so at
    this point our stack is unwound and callers' registers restored.
    Only %ecx and %eax are call-clobbered and thus still have the
-   values we set just above.  Fetch from there the new stack pointer
-   we will run on, and jmp to the run-time address of `init1'; when it
-   returns, it will run the user code with the argument data at the
-   top of the stack.  */
-asm ("switch_stacks:\n"
-     "	movl %eax, %esp\n"
-     "	jmp *%ecx");
-
-/* As in the stack-switching case, at this point our stack is unwound
-   and callers' registers restored, and only %ecx and %eax communicate
-   values from the lines above.  In this case we have stashed in %eax
-   the user code return address.  Push it on the top of the stack so
-   it acts as init1's return address, and then jump there.  */
+   values we set just above.  We have stashed in %eax the user code
+   return address.  Push it on the top of the stack so it acts as
+   init1's return address, and then jump there.  */
 asm ("call_init1:\n"
      "	push %eax\n"
      "	jmp *%ecx\n");
-- 
2.39.2

[RFC PATCH 6/9] mach: Use PAGE_SIZE

[Sergey Bugaev]

The PAGE_SIZE from the Mach headers statically defines the machine's
page size. There's no need to query it dynamically; furthermore, the
implementation of the vm_statistics () RPC unconditionally fills in

pagesize = PAGE_SIZE;

Not doing the extra RPC shaves off 2 RPCs from the start-up of every
process!

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 mach/mach_init.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/mach/mach_init.c b/mach/mach_init.c
index a0d9f7f5..42b9cacf 100644
--- a/mach/mach_init.c
+++ b/mach/mach_init.c
@@ -17,6 +17,7 @@
 
 #include <mach.h>
 #include <mach/mig_support.h>
+#include <mach/vm_param.h>
 #include <unistd.h>
 
 mach_port_t __mach_task_self_;
@@ -38,7 +39,10 @@ __mach_init (void)
   __mach_host_self_ = (__mach_host_self) ();
   __mig_init (0);
 
-#ifdef HAVE_HOST_PAGE_SIZE
+#ifdef PAGE_SIZE
+  __vm_page_size = PAGE_SIZE;
+  (void) err;
+#elif defined (HAVE_HOST_PAGE_SIZE)
   if (err = __host_page_size (__mach_host_self (), &__vm_page_size))
     _exit (err);
 #else
-- 
2.39.2

[RFC PATCH 7/9] hurd: Generalize init-first.c to support x86_64

[Sergey Bugaev]

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 sysdeps/mach/hurd/{i386 => x86}/init-first.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)
 rename sysdeps/mach/hurd/{i386 => x86}/init-first.c (96%)

diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/x86/init-first.c
similarity index 96%
rename from sysdeps/mach/hurd/i386/init-first.c
rename to sysdeps/mach/hurd/x86/init-first.c
index a558da16..75ac1ff2 100644
--- a/sysdeps/mach/hurd/i386/init-first.c
+++ b/sysdeps/mach/hurd/x86/init-first.c
@@ -227,10 +227,15 @@ init (int *data)
    values we set just above.  We have stashed in %eax the user code
    return address.  Push it on the top of the stack so it acts as
    init1's return address, and then jump there.  */
+#ifdef __x86_64__
+asm ("call_init1:\n"
+     "  push %rax\n"
+     "  jmp *%rcx\n");
+#else
 asm ("call_init1:\n"
      "	push %eax\n"
      "	jmp *%ecx\n");
-
+#endif
 
 /* Do the first essential initializations that must precede all else.  */
 static inline void
@@ -242,7 +247,7 @@ first_init (void)
 #ifndef SHARED
   /* In the static case, we need to set up TLS early so that the stack
      protection guard can be read at gs:0x14 by the gcc-generated snippets.  */
-  _hurd_tls_init(&__init1_tcbhead);
+  _hurd_tls_init (&__init1_tcbhead);
   asm ("movw %%gs,%w0" : "=m" (__init1_desc));
 #endif
 
@@ -300,7 +305,7 @@ _hurd_stack_setup (void)
 	{
 	  /* If we use ``__builtin_frame_address (0) + 2'' here, GCC gets
 	     confused.  */
-	  init ((int *) &argc);
+	  init (&argc);
 	}
 
       /* Push the user return address after the argument data, and then
@@ -308,9 +313,15 @@ _hurd_stack_setup (void)
 	 caller had called `doinit1' with the argument data already on the
 	 stack.  */
       *--data = caller;
+# ifdef __x86_64__
+      asm volatile ("movq %0, %%rsp\n" /* Switch to new outermost stack.  */
+                    "movq $0, %%rbp\n" /* Clear outermost frame pointer.  */
+                    "jmp *%1" : : "r" (data), "r" (&doinit1));
+# else
       asm volatile ("movl %0, %%esp\n" /* Switch to new outermost stack.  */
 		    "movl $0, %%ebp\n" /* Clear outermost frame pointer.  */
 		    "jmp *%1" : : "r" (data), "r" (&doinit1));
+# endif
       /* NOTREACHED */
     }
 
-- 
2.39.2

[RFC PATCH 8/9 gnumach] Add i386_fsgs_base_state

[Sergey Bugaev]

---
 i386/include/mach/i386/thread_status.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/i386/include/mach/i386/thread_status.h b/i386/include/mach/i386/thread_status.h
index 3de22ff3..32e40686 100644
--- a/i386/include/mach/i386/thread_status.h
+++ b/i386/include/mach/i386/thread_status.h
@@ -57,6 +57,7 @@
 #define	i386_V86_ASSIST_STATE	4
 #define	i386_REGS_SEGS_STATE	5
 #define	i386_DEBUG_STATE	6
+#define	i386_FSGS_BASE_STATE	7
 
 /*
  * This structure is used for both
@@ -179,4 +180,11 @@ struct i386_debug_state {
 #define	i386_DEBUG_STATE_COUNT \
 	    (sizeof(struct i386_debug_state)/sizeof(unsigned int))
 
+struct i386_fsgs_base_state {
+	unsigned long fs_base;
+	unsigned long gs_base;
+};
+#define i386_FSGS_BASE_STATE_COUNT \
+	    (sizeof(struct i386_fsgs_base_state)/sizeof(unsigned int))
+
 #endif	/* _MACH_I386_THREAD_STATUS_H_ */
-- 
2.39.2

[RFC PATCH 9/9] hurd, htl: Add some more x86_64-specific code

[Sergey Bugaev]

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 sysdeps/mach/hurd/x86/init-first.c          |  14 +-
 sysdeps/mach/hurd/x86_64/tls.h              | 257 ++++++++++++++++++++
 sysdeps/mach/x86_64/thread_state.h          |  51 ++++
 sysdeps/x86_64/htl/bits/pthreadtypes-arch.h |  36 +++
 sysdeps/x86_64/htl/pt-machdep.h             |  28 +++
 5 files changed, 385 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/mach/hurd/x86_64/tls.h
 create mode 100644 sysdeps/mach/x86_64/thread_state.h
 create mode 100644 sysdeps/x86_64/htl/bits/pthreadtypes-arch.h
 create mode 100644 sysdeps/x86_64/htl/pt-machdep.h

diff --git a/sysdeps/mach/hurd/x86/init-first.c b/sysdeps/mach/hurd/x86/init-first.c
index 75ac1ff2..d4e6a4d6 100644
--- a/sysdeps/mach/hurd/x86/init-first.c
+++ b/sysdeps/mach/hurd/x86/init-first.c
@@ -43,8 +43,14 @@ extern char **__libc_argv attribute_hidden;
 extern char **_dl_argv;
 
 #ifndef SHARED
-unsigned short __init1_desc;
 static tcbhead_t __init1_tcbhead;
+# ifndef __x86_64__
+unsigned short __init1_desc;
+# endif
+#endif
+
+#ifdef __x86_64__
+unsigned char __libc_tls_initialized;
 #endif
 
 /* Things that want to be run before _hurd_init or much anything else.
@@ -248,7 +254,13 @@ first_init (void)
   /* In the static case, we need to set up TLS early so that the stack
      protection guard can be read at gs:0x14 by the gcc-generated snippets.  */
   _hurd_tls_init (&__init1_tcbhead);
+
+  /* Make sure __LIBC_NO_TLS () keeps evaluating to 1.  */
+# ifdef __x86_64__
+  __libc_tls_initialized = 0;
+# else
   asm ("movw %%gs,%w0" : "=m" (__init1_desc));
+# endif
 #endif
 
   RUN_RELHOOK (_hurd_preinit_hook, ());
diff --git a/sysdeps/mach/hurd/x86_64/tls.h b/sysdeps/mach/hurd/x86_64/tls.h
new file mode 100644
index 00000000..644dcb1a
--- /dev/null
+++ b/sysdeps/mach/hurd/x86_64/tls.h
@@ -0,0 +1,257 @@
+/* Definitions for thread-local data handling.  Hurd/x86_64 version.
+   Copyright (C) 2003-2023 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 _X86_64_TLS_H
+#define _X86_64_TLS_H
+
+
+/* Some things really need not be machine-dependent.  */
+#include <sysdeps/mach/hurd/tls.h>
+
+
+#ifndef __ASSEMBLER__
+# include <dl-dtv.h>
+# include <mach/machine/thread_status.h>
+# include <errno.h>
+# include <assert.h>
+
+/* Type of the TCB.  */
+typedef struct
+{
+  void *tcb;			/* Points to this structure.  */
+  dtv_t *dtv;			/* Vector of pointers to TLS data.  */
+  thread_t self;		/* This thread's control port.  */
+  int __glibc_padding1;
+  int multiple_threads;
+  int gscope_flag;
+  uintptr_t sysinfo;
+  uintptr_t stack_guard;
+  uintptr_t pointer_guard;
+  long __glibc_padding2[2];
+  int private_futex;
+  int __glibc_padding3;
+  /* Reservation of some values for the TM ABI.  */
+  void *__private_tm[4];
+  /* GCC split stack support.  */
+  void *__private_ss;
+  /* The lowest address of shadow stack.  */
+  unsigned long long int ssp_base;
+
+  /* Keep these fields last, so offsets of fields above can continue being
+     compatible with the x86_64 NPTL version.  */
+  mach_port_t reply_port;      /* This thread's reply port.  */
+  struct hurd_sigstate *_hurd_sigstate;
+
+  /* Used by the exception handling implementation in the dynamic loader.  */
+  struct rtld_catch *rtld_catch;
+} tcbhead_t;
+
+/* GCC generates %fs:0x28 to access the stack guard.  */
+_Static_assert (offsetof (tcbhead_t, stack_guard) == 0x28,
+                "stack guard offset");
+/* libgcc uses %fs:0x70 to access the split stack pointer.  */
+_Static_assert (offsetof (tcbhead_t, __private_ss) == 0x70,
+                "split stack pointer offset");
+
+extern unsigned char __libc_tls_initialized;
+# define __LIBC_NO_TLS() __builtin_expect (!__libc_tls_initialized, 0)
+
+/* The TCB can have any size and the memory following the address the
+   thread pointer points to is unspecified.  Allocate the TCB there.  */
+# define TLS_TCB_AT_TP	1
+# define TLS_DTV_AT_TP	0
+
+# define TCB_ALIGNMENT	64
+
+
+# define TLS_INIT_TP(descr) _hurd_tls_init ((tcbhead_t *) (descr))
+
+# if __GNUC_PREREQ (6, 0)
+
+#  define THREAD_SELF							\
+  (*(tcbhead_t * __seg_fs *) offsetof (tcbhead_t, tcb))
+#  define THREAD_GETMEM(descr, member)					\
+  (*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member))
+#  define THREAD_SETMEM(descr, member, value)				\
+  (*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member) = value)
+
+# else
+
+#  define THREAD_SELF							\
+  ({ tcbhead_t *__tcb;							\
+     asm ("movq %%fs:%c1,%0" : "=r" (__tcb)				\
+          : "i" (offsetof (tcbhead_t, tcb)));				\
+     __tcb; })
+
+/* Read member of the thread descriptor directly.  */
+# define THREAD_GETMEM(descr, member) \
+  ({ __typeof (descr->member) __value;					\
+     _Static_assert (sizeof (__value) == 1				\
+                     || sizeof (__value) == 4				\
+                     || sizeof (__value) == 8,				\
+                     "size of per-thread data");			\
+     if (sizeof (__value) == 1)						\
+       asm volatile ("movb %%fs:%P2,%b0"				\
+                     : "=q" (__value)					\
+                     : "0" (0), "i" (offsetof (tcbhead_t, member)));	\
+     else if (sizeof (__value) == 4)					\
+       asm volatile ("movl %%fs:%P1,%0"					\
+                     : "=r" (__value)					\
+                     : "i" (offsetof (tcbhead_t, member)));		\
+     else /* 8 */							\
+       asm volatile ("movq %%fs:%P1,%0"					\
+                     : "=r" (__value)					\
+                     : "i" (offsetof (tcbhead_t, member)));		\
+     __value; })
+
+/* Write member of the thread descriptor directly.  */
+#  define THREAD_SETMEM(descr, member, value) \
+  ({									\
+     _Static_assert (sizeof (descr->member) == 1			\
+                     || sizeof (descr->member) == 4			\
+                     || sizeof (descr->member) == 8,			\
+                     "size of per-thread data");			\
+     if (sizeof (descr->member) == 1)					\
+       asm volatile ("movb %b0,%%fs:%P1" :				\
+                     : "iq" (value),					\
+                       "i" (offsetof (tcbhead_t, member)));		\
+     else if (sizeof (descr->member) == 4)				\
+       asm volatile ("movl %0,%%fs:%P1" :				\
+                     : "ir" (value),					\
+                       "i" (offsetof (tcbhead_t, member)));		\
+     else /* 8 */							\
+       asm volatile ("movq %0,%%fs:%P1" :				\
+                     : "ir" (value),					\
+                       "i" (offsetof (tcbhead_t, member)));		\
+     })
+# endif /* __GNUC_PREREQ (6, 0) */
+
+/* Return the TCB address of a thread given its state.
+   Note: this is expensive.  */
+static inline tcbhead_t * __attribute__ ((unused))
+THREAD_TCB (thread_t thread,
+            const void *all_state __attribute__ ((unused)))
+{
+  error_t err;
+  /* Fetch the target thread's state.  */
+  struct i386_fsgs_base_state state;
+  mach_msg_type_number_t state_count = i386_FSGS_BASE_STATE_COUNT;
+  err = __thread_get_state (thread, i386_FSGS_BASE_STATE,
+                            (thread_state_t) &state,
+                            &state_count);
+  assert_perror (err);
+  assert (state_count == i386_FSGS_BASE_STATE_COUNT);
+  return (tcbhead_t *) state.fs_base;
+}
+
+/* Set the stack guard field in TCB head.  */
+# define THREAD_SET_STACK_GUARD(value)					\
+  THREAD_SETMEM (THREAD_SELF, stack_guard, value)
+# define THREAD_COPY_STACK_GUARD(descr)					\
+  ((descr)->stack_guard							\
+   = THREAD_GETMEM (THREAD_SELF, stack_guard))
+
+/* Set the pointer guard field in the TCB head.  */
+# define THREAD_SET_POINTER_GUARD(value)				\
+  THREAD_SETMEM (THREAD_SELF, pointer_guard, value)
+# define THREAD_COPY_POINTER_GUARD(descr)				\
+  ((descr)->pointer_guard						\
+   = THREAD_GETMEM (THREAD_SELF, pointer_guard))
+
+/* Install new dtv for current thread.  */
+# define INSTALL_NEW_DTV(dtvp) THREAD_SETMEM (THREAD_SELF, dtv, dtvp)
+
+/* Return the address of the dtv for the current thread.  */
+# define THREAD_DTV() THREAD_GETMEM (THREAD_SELF, dtv)
+
+/* Set up TLS in the new thread of a fork child, copying from the original.  */
+static inline kern_return_t __attribute__ ((unused))
+_hurd_tls_fork (thread_t child, thread_t orig,
+                void *machine_state __attribute__ ((unused)))
+{
+  error_t err;
+  struct i386_fsgs_base_state state;
+  mach_msg_type_number_t state_count = i386_FSGS_BASE_STATE_COUNT;
+  err = __thread_get_state (orig, i386_FSGS_BASE_STATE,
+                            (thread_state_t) &state,
+                            &state_count);
+  if (err)
+    return err;
+  assert (state_count == i386_FSGS_BASE_STATE_COUNT);
+
+  return __thread_set_state (child, i386_FSGS_BASE_STATE,
+                             (thread_state_t) &state,
+                             state_count);
+}
+
+static inline kern_return_t __attribute__ ((unused))
+_hurd_tls_new (thread_t child, tcbhead_t *tcb)
+{
+  struct i386_fsgs_base_state state;
+
+  tcb->tcb = tcb;
+  tcb->self = child;
+
+  /* Install the TCB address into FS base.  */
+  state.fs_base = (uintptr_t) tcb;
+  state.gs_base = 0;
+  return __thread_set_state (child, i386_FSGS_BASE_STATE,
+                             (thread_state_t) &state,
+                             i386_FSGS_BASE_STATE_COUNT);
+}
+
+static inline bool __attribute__ ((unused))
+_hurd_tls_init (tcbhead_t *tcb)
+{
+  error_t err;
+  thread_t self = __mach_thread_self ();
+
+  /* We always at least start the sigthread anyway.  */
+  tcb->multiple_threads = 1;
+
+  err = _hurd_tls_new (self, tcb);
+  __mach_port_deallocate (__mach_task_self (), self);
+  __libc_tls_initialized = 1;
+  return err == 0;
+}
+
+
+/* Global scope switch support.  */
+# define THREAD_GSCOPE_FLAG_UNUSED 0
+# define THREAD_GSCOPE_FLAG_USED   1
+# define THREAD_GSCOPE_FLAG_WAIT   2
+
+# define THREAD_GSCOPE_SET_FLAG() \
+  THREAD_SETMEM (THREAD_SELF, gscope_flag, THREAD_GSCOPE_FLAG_USED)
+
+# define THREAD_GSCOPE_RESET_FLAG() \
+  ({									\
+    int __flag;								\
+    asm volatile ("xchgl %0, %%fs:%P1"					\
+                  : "=r" (__flag)					\
+                  : "i" (offsetof (tcbhead_t, gscope_flag)),		\
+                    "0" (THREAD_GSCOPE_FLAG_UNUSED));			\
+    if (__flag == THREAD_GSCOPE_FLAG_WAIT)				\
+      lll_wake (THREAD_SELF->gscope_flag, LLL_PRIVATE);			\
+  })
+
+
+
+#endif	/* __ASSEMBLER__ */
+#endif	/* x86_64/tls.h */
diff --git a/sysdeps/mach/x86_64/thread_state.h b/sysdeps/mach/x86_64/thread_state.h
new file mode 100644
index 00000000..d8c8889f
--- /dev/null
+++ b/sysdeps/mach/x86_64/thread_state.h
@@ -0,0 +1,51 @@
+/* Mach thread state definitions for machine-independent code.  x86_64 version.
+   Copyright (C) 1994-2023 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 _MACH_X86_64_THREAD_STATE_H
+#define _MACH_X86_64_THREAD_STATE_H 1
+
+#include <mach/machine/thread_status.h>
+
+#define MACHINE_NEW_THREAD_STATE_FLAVOR	i386_THREAD_STATE
+#define MACHINE_THREAD_STATE_FLAVOR	i386_THREAD_STATE
+#define MACHINE_THREAD_STATE_COUNT	i386_THREAD_STATE_COUNT
+
+#define machine_thread_state i386_thread_state
+
+#define PC rip
+#define SP ursp
+#define SYSRETURN rax
+
+#define MACHINE_THREAD_STATE_FIX_NEW(ts) do { \
+	asm ("mov %%cs, %w0" : "=q" ((ts)->cs)); \
+	asm ("mov %%ds, %w0" : "=q" ((ts)->ds)); \
+	asm ("mov %%es, %w0" : "=q" ((ts)->es)); \
+	asm ("mov %%fs, %w0" : "=q" ((ts)->fs)); \
+	asm ("mov %%gs, %w0" : "=q" ((ts)->gs)); \
+} while(0)
+
+struct machine_thread_all_state
+  {
+    int set;			/* Mask of bits (1 << FLAVOR).  */
+    struct i386_thread_state basic;
+    struct i386_float_state fpu;
+  };
+
+#include <sysdeps/mach/thread_state.h>
+
+#endif /* mach/x86_64/thread_state.h */
diff --git a/sysdeps/x86_64/htl/bits/pthreadtypes-arch.h b/sysdeps/x86_64/htl/bits/pthreadtypes-arch.h
new file mode 100644
index 00000000..1d402cc6
--- /dev/null
+++ b/sysdeps/x86_64/htl/bits/pthreadtypes-arch.h
@@ -0,0 +1,36 @@
+/* Machine-specific pthread type layouts.  Hurd x86_64 version.
+   Copyright (C) 2002-2023 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 _BITS_PTHREADTYPES_ARCH_H
+#define _BITS_PTHREADTYPES_ARCH_H	1
+
+#define __SIZEOF_PTHREAD_MUTEX_T 32
+#define __SIZEOF_PTHREAD_ATTR_T 48
+#define __SIZEOF_PTHREAD_RWLOCK_T 48
+#define __SIZEOF_PTHREAD_BARRIER_T 40
+#define __SIZEOF_PTHREAD_MUTEXATTR_T 16
+#define __SIZEOF_PTHREAD_COND_T 40
+#define __SIZEOF_PTHREAD_CONDATTR_T 8
+#define __SIZEOF_PTHREAD_RWLOCKATTR_T 4
+#define __SIZEOF_PTHREAD_BARRIERATTR_T 4
+#define __SIZEOF_PTHREAD_ONCE_T 8
+
+#define __LOCK_ALIGNMENT
+#define __ONCE_ALIGNMENT
+
+#endif /* bits/pthreadtypes.h */
diff --git a/sysdeps/x86_64/htl/pt-machdep.h b/sysdeps/x86_64/htl/pt-machdep.h
new file mode 100644
index 00000000..2e2846fa
--- /dev/null
+++ b/sysdeps/x86_64/htl/pt-machdep.h
@@ -0,0 +1,28 @@
+/* Machine dependent pthreads internal defenitions.  x86_64 version.
+   Copyright (C) 2000-2023 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 _PT_MACHDEP_H
+#define _PT_MACHDEP_H	1
+
+struct pthread_mcontext
+{
+  void *pc;
+  void *sp;
+};
+
+#endif /* pt-machdep.h */
-- 
2.39.2

Re: [RFC PATCH 1/9] hurd: Move thread state manipulation into _hurd_tls_new ()

[Samuel Thibault]

Applied, thanks!

Sergey Bugaev, le sam. 18 févr. 2023 23:37:09 +0300, a ecrit:
> This is going to be done differently on x86_64.
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  mach/setup-thread.c          | 18 ++----------------
>  sysdeps/mach/hurd/i386/tls.h | 25 ++++++++++++++++++++-----
>  2 files changed, 22 insertions(+), 21 deletions(-)
> 
> diff --git a/mach/setup-thread.c b/mach/setup-thread.c
> index 6ce5c13d..ae24a149 100644
> --- a/mach/setup-thread.c
> +++ b/mach/setup-thread.c
> @@ -83,25 +83,11 @@ weak_alias (__mach_setup_thread, mach_setup_thread)
>  kern_return_t
>  __mach_setup_tls (thread_t thread)
>  {
> -  kern_return_t error;
> -  struct machine_thread_state ts;
> -  mach_msg_type_number_t tssize = MACHINE_THREAD_STATE_COUNT;
> -  tcbhead_t *tcb;
> -
> -  tcb = _dl_allocate_tls (NULL);
> +  tcbhead_t *tcb = _dl_allocate_tls (NULL);
>    if (tcb == NULL)
>      return KERN_RESOURCE_SHORTAGE;
>  
> -  if (error = __thread_get_state (thread, MACHINE_THREAD_STATE_FLAVOR,
> -			     (natural_t *) &ts, &tssize))
> -    return error;
> -  assert (tssize == MACHINE_THREAD_STATE_COUNT);
> -
> -  _hurd_tls_new (thread, &ts, tcb);
> -
> -  error = __thread_set_state (thread, MACHINE_THREAD_STATE_FLAVOR,
> -			      (natural_t *) &ts, tssize);
> -  return error;
> +  return _hurd_tls_new (thread, tcb);
>  }
>  
>  weak_alias (__mach_setup_tls, mach_setup_tls)
> diff --git a/sysdeps/mach/hurd/i386/tls.h b/sysdeps/mach/hurd/i386/tls.h
> index 590abd47..0f8dd241 100644
> --- a/sysdeps/mach/hurd/i386/tls.h
> +++ b/sysdeps/mach/hurd/i386/tls.h
> @@ -378,16 +378,25 @@ _hurd_tls_fork (thread_t child, thread_t orig, struct i386_thread_state *state)
>  }
>  
>  static inline kern_return_t __attribute__ ((unused))
> -_hurd_tls_new (thread_t child, struct i386_thread_state *state, tcbhead_t *tcb)
> +_hurd_tls_new (thread_t child, tcbhead_t *tcb)
>  {
> +  error_t err;
> +  /* Fetch the target thread's state.  */
> +  struct i386_thread_state state;
> +  mach_msg_type_number_t state_count = i386_THREAD_STATE_COUNT;
> +  err = __thread_get_state (child, i386_REGS_SEGS_STATE,
> +                            (thread_state_t) &state,
> +                            &state_count);
> +  if (err)
> +    return err;
> +  assert (state_count == i386_THREAD_STATE_COUNT);
>    /* Fetch the selector set by _hurd_tls_init.  */
>    int sel;
>    asm ("mov %%gs, %w0" : "=q" (sel) : "0" (0));
> -  if (sel == state->ds)		/* _hurd_tls_init was never called.  */
> +  if (sel == state.ds)		/* _hurd_tls_init was never called.  */
>      return 0;
>  
>    HURD_TLS_DESC_DECL (desc, tcb);
> -  error_t err;
>  
>    tcb->tcb = tcb;
>    tcb->self = child;
> @@ -397,8 +406,14 @@ _hurd_tls_new (thread_t child, struct i386_thread_state *state, tcbhead_t *tcb)
>    else
>      err = __i386_set_gdt (child, &sel, desc);
>  
> -  state->gs = sel;
> -  return err;
> +  if (err)
> +    return err;
> +
> +  /* Update gs to use the selector.  */
> +  state.gs = sel;
> +  return __thread_set_state (child, i386_REGS_SEGS_STATE,
> +                             (thread_state_t) &state,
> +                             state_count);
>  }
>  
>  /* Global scope switch support.  */
> -- 
> 2.39.2
> 
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.

Re: [RFC PATCH 2/9] hurd: Use proper integer types

[Samuel Thibault]

Applied, thanks!

Sergey Bugaev, le sam. 18 févr. 2023 23:37:10 +0300, a ecrit:
> Fix a few more cases of build errors caused by mismatched types. This is a
> continuation of f4315054b46d5e58b44a709a51943fb73f846afb.
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  hurd/hurdsig.c                  | 6 +++---
>  sysdeps/mach/hurd/getpriority.c | 6 +++---
>  sysdeps/mach/hurd/if_index.c    | 2 +-
>  sysdeps/mach/hurd/ifreq.c       | 2 +-
>  sysdeps/mach/hurd/readdir64.c   | 4 +++-
>  sysdeps/mach/hurd/readdir64_r.c | 4 +++-
>  6 files changed, 14 insertions(+), 10 deletions(-)
> 
> diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c
> index 56e8e614..ea79ffb5 100644
> --- a/hurd/hurdsig.c
> +++ b/hurd/hurdsig.c
> @@ -430,8 +430,8 @@ _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread,
>       receive completes immediately or aborts.  */
>    abort_thread (ss, state, reply);
>  
> -  if (state->basic.PC >= (natural_t) &_hurd_intr_rpc_msg_about_to
> -      && state->basic.PC < (natural_t) &_hurd_intr_rpc_msg_in_trap)
> +  if (state->basic.PC >= (uintptr_t) &_hurd_intr_rpc_msg_about_to
> +      && state->basic.PC < (uintptr_t) &_hurd_intr_rpc_msg_in_trap)
>      {
>        /* The thread is about to do the RPC, but hasn't yet entered
>  	 mach_msg.  Mutate the thread's state so it knows not to try
> @@ -442,7 +442,7 @@ _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread,
>        state->basic.SYSRETURN = MACH_SEND_INTERRUPTED;
>        *state_change = 1;
>      }
> -  else if (state->basic.PC == (natural_t) &_hurd_intr_rpc_msg_in_trap
> +  else if (state->basic.PC == (uintptr_t) &_hurd_intr_rpc_msg_in_trap
>  	   /* The thread was blocked in the system call.  After thread_abort,
>  	      the return value register indicates what state the RPC was in
>  	      when interrupted.  */
> diff --git a/sysdeps/mach/hurd/getpriority.c b/sysdeps/mach/hurd/getpriority.c
> index 9869c2f5..45b32215 100644
> --- a/sysdeps/mach/hurd/getpriority.c
> +++ b/sysdeps/mach/hurd/getpriority.c
> @@ -30,7 +30,7 @@ __getpriority (enum __priority_which which, id_t who)
>    int maxpri = INT_MIN;
>    struct procinfo *pip;		/* Just for sizeof.  */
>    int pibuf[sizeof *pip + 2 * sizeof (pip->threadinfos[0])], *pi = pibuf;
> -  size_t pisize = sizeof pibuf / sizeof pibuf[0];
> +  mach_msg_type_number_t pisize = sizeof pibuf / sizeof pibuf[0];
>  
>    error_t getonepriority (pid_t pid, struct procinfo *pip)
>      {
> @@ -39,9 +39,9 @@ __getpriority (enum __priority_which which, id_t who)
>        else
>  	{
>  	  int *oldpi = pi;
> -	  size_t oldpisize = pisize;
> +	  mach_msg_type_number_t oldpisize = pisize;
>  	  char *tw = 0;
> -	  size_t twsz = 0;
> +	  mach_msg_type_number_t twsz = 0;
>  	  int flags = PI_FETCH_TASKINFO;
>  	  onerr = __USEPORT (PROC, __proc_getprocinfo (port, pid, &flags,
>  						       &pi, &pisize,
> diff --git a/sysdeps/mach/hurd/if_index.c b/sysdeps/mach/hurd/if_index.c
> index a4472269..c8ad7e72 100644
> --- a/sysdeps/mach/hurd/if_index.c
> +++ b/sysdeps/mach/hurd/if_index.c
> @@ -99,7 +99,7 @@ __if_nameindex (void)
>      nifs = 0;
>    else
>      {
> -      size_t len = sizeof data;
> +      mach_msg_type_number_t len = sizeof data;
>        err = __pfinet_siocgifconf (server, -1, &ifc.ifc_buf, &len);
>        if (err == MACH_SEND_INVALID_DEST || err == MIG_SERVER_DIED)
>  	{
> diff --git a/sysdeps/mach/hurd/ifreq.c b/sysdeps/mach/hurd/ifreq.c
> index ef210c32..394d020c 100644
> --- a/sysdeps/mach/hurd/ifreq.c
> +++ b/sysdeps/mach/hurd/ifreq.c
> @@ -37,7 +37,7 @@ __ifreq (struct ifreq **ifreqs, int *num_ifs, int sockfd)
>    else
>      {
>        char *data = NULL;
> -      size_t len = 0;
> +      mach_msg_type_number_t len = 0;
>        error_t err = __pfinet_siocgifconf (server, -1, &data, &len);
>        if (err == MACH_SEND_INVALID_DEST || err == MIG_SERVER_DIED)
>  	{
> diff --git a/sysdeps/mach/hurd/readdir64.c b/sysdeps/mach/hurd/readdir64.c
> index 47829d9e..cf98bbb1 100644
> --- a/sysdeps/mach/hurd/readdir64.c
> +++ b/sysdeps/mach/hurd/readdir64.c
> @@ -43,12 +43,13 @@ __readdir64 (DIR *dirp)
>  	  /* We've emptied out our buffer.  Refill it.  */
>  
>  	  char *data = dirp->__data;
> +	  mach_msg_type_number_t data_size = dirp->__size;
>  	  int nentries;
>  	  error_t err;
>  
>  	  if (err = HURD_FD_PORT_USE (dirp->__fd,
>  				      __dir_readdir (port,
> -						     &data, &dirp->__size,
> +						     &data, &data_size,
>  						     dirp->__entry_ptr,
>  						     -1, 0, &nentries)))
>  	    {
> @@ -57,6 +58,7 @@ __readdir64 (DIR *dirp)
>  	      break;
>  	    }
>  
> +          dirp->__size = data_size;
>  	  /* DATA now corresponds to entry index DIRP->__entry_ptr.  */
>  	  dirp->__entry_data = dirp->__entry_ptr;
>  
> diff --git a/sysdeps/mach/hurd/readdir64_r.c b/sysdeps/mach/hurd/readdir64_r.c
> index 7e438aaf..4f4252c2 100644
> --- a/sysdeps/mach/hurd/readdir64_r.c
> +++ b/sysdeps/mach/hurd/readdir64_r.c
> @@ -45,11 +45,12 @@ __readdir64_r (DIR *dirp, struct dirent64 *entry, struct dirent64 **result)
>  	  /* We've emptied out our buffer.  Refill it.  */
>  
>  	  char *data = dirp->__data;
> +	  mach_msg_type_number_t data_size = dirp->__size;
>  	  int nentries;
>  
>  	  if (err = HURD_FD_PORT_USE (dirp->__fd,
>  				      __dir_readdir (port,
> -						     &data, &dirp->__size,
> +						     &data, &data_size,
>  						     dirp->__entry_ptr,
>  						     -1, 0, &nentries)))
>  	    {
> @@ -58,6 +59,7 @@ __readdir64_r (DIR *dirp, struct dirent64 *entry, struct dirent64 **result)
>  	      break;
>  	    }
>  
> +	  dirp->__size = data_size;
>  	  /* DATA now corresponds to entry index DIRP->__entry_ptr.  */
>  	  dirp->__entry_data = dirp->__entry_ptr;
>  
> -- 
> 2.39.2
> 
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.

Re: [RFC PATCH 3/9] hurd: Fix xattr function return type

[Samuel Thibault]

Applied, thanks!

Sergey Bugaev, le sam. 18 févr. 2023 23:37:11 +0300, a ecrit:
> They all return int, not size_t.
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  sysdeps/mach/hurd/fsetxattr.c    | 2 +-
>  sysdeps/mach/hurd/lremovexattr.c | 2 +-
>  sysdeps/mach/hurd/lsetxattr.c    | 2 +-
>  sysdeps/mach/hurd/removexattr.c  | 2 +-
>  sysdeps/mach/hurd/setxattr.c     | 2 +-
>  5 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/sysdeps/mach/hurd/fsetxattr.c b/sysdeps/mach/hurd/fsetxattr.c
> index 71ee7599..dcc48fa0 100644
> --- a/sysdeps/mach/hurd/fsetxattr.c
> +++ b/sysdeps/mach/hurd/fsetxattr.c
> @@ -22,7 +22,7 @@
>  #include <hurd/xattr.h>
>  #include <hurd/fd.h>
>  
> -ssize_t
> +int
>  fsetxattr (int fd, const char *name, const void *value, size_t size, int flags)
>  {
>    error_t err;
> diff --git a/sysdeps/mach/hurd/lremovexattr.c b/sysdeps/mach/hurd/lremovexattr.c
> index 1d761e2d..cb6a1f8f 100644
> --- a/sysdeps/mach/hurd/lremovexattr.c
> +++ b/sysdeps/mach/hurd/lremovexattr.c
> @@ -22,7 +22,7 @@
>  #include <hurd/xattr.h>
>  #include <fcntl.h>
>  
> -ssize_t
> +int
>  lremovexattr (const char *path, const char *name)
>  {
>    error_t err;
> diff --git a/sysdeps/mach/hurd/lsetxattr.c b/sysdeps/mach/hurd/lsetxattr.c
> index 56c138dc..4e1e2de2 100644
> --- a/sysdeps/mach/hurd/lsetxattr.c
> +++ b/sysdeps/mach/hurd/lsetxattr.c
> @@ -22,7 +22,7 @@
>  #include <hurd/xattr.h>
>  #include <fcntl.h>
>  
> -ssize_t
> +int
>  lsetxattr (const char *path, const char *name, const void *value, size_t size,
>  	   int flags)
>  {
> diff --git a/sysdeps/mach/hurd/removexattr.c b/sysdeps/mach/hurd/removexattr.c
> index 128d0e01..fedc5370 100644
> --- a/sysdeps/mach/hurd/removexattr.c
> +++ b/sysdeps/mach/hurd/removexattr.c
> @@ -21,7 +21,7 @@
>  #include <hurd.h>
>  #include <hurd/xattr.h>
>  
> -ssize_t
> +int
>  removexattr (const char *path, const char *name)
>  {
>    error_t err;
> diff --git a/sysdeps/mach/hurd/setxattr.c b/sysdeps/mach/hurd/setxattr.c
> index be3b172b..ba6047cd 100644
> --- a/sysdeps/mach/hurd/setxattr.c
> +++ b/sysdeps/mach/hurd/setxattr.c
> @@ -21,7 +21,7 @@
>  #include <hurd.h>
>  #include <hurd/xattr.h>
>  
> -ssize_t
> +int
>  setxattr (const char *path, const char *name, const void *value, size_t size,
>  	  int flags)
>  {
> -- 
> 2.39.2
> 
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.

Re: [RFC PATCH 4/9] hurd: Make timer_t pointer-sized

[Samuel Thibault]

Applied, thanks!

Sergey Bugaev, le sam. 18 févr. 2023 23:37:12 +0300, a ecrit:
> This ensures that a timer_t value can be cast to struct timer_node *
> and back.
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  sysdeps/mach/hurd/bits/typesizes.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sysdeps/mach/hurd/bits/typesizes.h b/sysdeps/mach/hurd/bits/typesizes.h
> index 725a0cb1..7b95bb0b 100644
> --- a/sysdeps/mach/hurd/bits/typesizes.h
> +++ b/sysdeps/mach/hurd/bits/typesizes.h
> @@ -54,7 +54,7 @@
>  #define __DADDR_T_TYPE		__S32_TYPE
>  #define __KEY_T_TYPE		__S32_TYPE
>  #define __CLOCKID_T_TYPE	__S32_TYPE
> -#define __TIMER_T_TYPE		__S32_TYPE
> +#define __TIMER_T_TYPE		__UWORD_TYPE
>  #define __BLKSIZE_T_TYPE	__SLONGWORD_TYPE
>  #define __FSID_T_TYPE		__UQUAD_TYPE
>  #define __SSIZE_T_TYPE		__SWORD_TYPE
> -- 
> 2.39.2
> 
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.

Re: [RFC PATCH 5/9] hurd: Simplify init-first.c a bit

[Samuel Thibault]

Applied, thanks!

Sergey Bugaev, le sam. 18 févr. 2023 23:37:13 +0300, a ecrit:
> And make it a bit more 64-bit ready. This is in preparation to moving this
> file into x86/
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  sysdeps/mach/hurd/i386/init-first.c | 23 +++++++----------------
>  1 file changed, 7 insertions(+), 16 deletions(-)
> 
> diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/i386/init-first.c
> index 94c94651..a558da16 100644
> --- a/sysdeps/mach/hurd/i386/init-first.c
> +++ b/sysdeps/mach/hurd/i386/init-first.c
> @@ -195,7 +195,7 @@ init (int *data)
>    /* Call `init1' (above) with the user code as the return address, and the
>       argument data immediately above that on the stack.  */
>  
> -  int usercode;
> +  void *usercode, **ret_address;
>  
>    void call_init1 (void);
>  
> @@ -206,10 +206,11 @@ init (int *data)
>       recognize that this read operation may alias the following write
>       operation, and thus is free to reorder the two, clobbering the
>       original return address.  */
> -  usercode = *((int *) __builtin_frame_address (0) + 1);
> +  ret_address = (void **) __builtin_frame_address (0) + 1;
> +  usercode = *ret_address;
>    /* GCC 4.4.6 also wants us to force loading USERCODE already here.  */
>    asm volatile ("# %0" : : "X" (usercode));
> -  *((void **) __builtin_frame_address (0) + 1) = &call_init1;
> +  *ret_address = &call_init1;
>    /* Force USERCODE into %eax and &init1 into %ecx, which are not
>       restored by function return.  */
>    asm volatile ("# a %0 c %1" : : "a" (usercode), "c" (&init1));
> @@ -223,19 +224,9 @@ init (int *data)
>  /* The return address of `init' above, was redirected to here, so at
>     this point our stack is unwound and callers' registers restored.
>     Only %ecx and %eax are call-clobbered and thus still have the
> -   values we set just above.  Fetch from there the new stack pointer
> -   we will run on, and jmp to the run-time address of `init1'; when it
> -   returns, it will run the user code with the argument data at the
> -   top of the stack.  */
> -asm ("switch_stacks:\n"
> -     "	movl %eax, %esp\n"
> -     "	jmp *%ecx");
> -
> -/* As in the stack-switching case, at this point our stack is unwound
> -   and callers' registers restored, and only %ecx and %eax communicate
> -   values from the lines above.  In this case we have stashed in %eax
> -   the user code return address.  Push it on the top of the stack so
> -   it acts as init1's return address, and then jump there.  */
> +   values we set just above.  We have stashed in %eax the user code
> +   return address.  Push it on the top of the stack so it acts as
> +   init1's return address, and then jump there.  */
>  asm ("call_init1:\n"
>       "	push %eax\n"
>       "	jmp *%ecx\n");
> -- 
> 2.39.2
> 
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.

Re: [RFC PATCH 6/9] mach: Use PAGE_SIZE

[Samuel Thibault]

Applied, thanks!

Sergey Bugaev, le sam. 18 févr. 2023 23:37:14 +0300, a ecrit:
> The PAGE_SIZE from the Mach headers statically defines the machine's
> page size. There's no need to query it dynamically; furthermore, the
> implementation of the vm_statistics () RPC unconditionally fills in
> 
> pagesize = PAGE_SIZE;
> 
> Not doing the extra RPC shaves off 2 RPCs from the start-up of every
> process!
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  mach/mach_init.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/mach/mach_init.c b/mach/mach_init.c
> index a0d9f7f5..42b9cacf 100644
> --- a/mach/mach_init.c
> +++ b/mach/mach_init.c
> @@ -17,6 +17,7 @@
>  
>  #include <mach.h>
>  #include <mach/mig_support.h>
> +#include <mach/vm_param.h>
>  #include <unistd.h>
>  
>  mach_port_t __mach_task_self_;
> @@ -38,7 +39,10 @@ __mach_init (void)
>    __mach_host_self_ = (__mach_host_self) ();
>    __mig_init (0);
>  
> -#ifdef HAVE_HOST_PAGE_SIZE
> +#ifdef PAGE_SIZE
> +  __vm_page_size = PAGE_SIZE;
> +  (void) err;
> +#elif defined (HAVE_HOST_PAGE_SIZE)
>    if (err = __host_page_size (__mach_host_self (), &__vm_page_size))
>      _exit (err);
>  #else
> -- 
> 2.39.2
> 
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.

Re: [RFC PATCH 7/9] hurd: Generalize init-first.c to support x86_64

[Samuel Thibault]

Sergey Bugaev, le sam. 18 févr. 2023 23:37:15 +0300, a ecrit:
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  sysdeps/mach/hurd/{i386 => x86}/init-first.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
>  rename sysdeps/mach/hurd/{i386 => x86}/init-first.c (96%)
> 
> diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/x86/init-first.c
> similarity index 96%
> rename from sysdeps/mach/hurd/i386/init-first.c
> rename to sysdeps/mach/hurd/x86/init-first.c
> index a558da16..75ac1ff2 100644
> --- a/sysdeps/mach/hurd/i386/init-first.c
> +++ b/sysdeps/mach/hurd/x86/init-first.c
> @@ -227,10 +227,15 @@ init (int *data)
>     values we set just above.  We have stashed in %eax the user code
>     return address.  Push it on the top of the stack so it acts as
>     init1's return address, and then jump there.  */
> +#ifdef __x86_64__
> +asm ("call_init1:\n"
> +     "  push %rax\n"
> +     "  jmp *%rcx\n");
> +#else
>  asm ("call_init1:\n"
>       "	push %eax\n"
>       "	jmp *%ecx\n");
> -
> +#endif
>  
>  /* Do the first essential initializations that must precede all else.  */
>  static inline void
> @@ -242,7 +247,7 @@ first_init (void)
>  #ifndef SHARED
>    /* In the static case, we need to set up TLS early so that the stack
>       protection guard can be read at gs:0x14 by the gcc-generated snippets.  */
> -  _hurd_tls_init(&__init1_tcbhead);
> +  _hurd_tls_init (&__init1_tcbhead);
>    asm ("movw %%gs,%w0" : "=m" (__init1_desc));
>  #endif
>  
> @@ -300,7 +305,7 @@ _hurd_stack_setup (void)
>  	{
>  	  /* If we use ``__builtin_frame_address (0) + 2'' here, GCC gets
>  	     confused.  */
> -	  init ((int *) &argc);
> +	  init (&argc);

That won't work on x86_64: there, arguments are passed mostly through
registers, so &argc won't actually give you the address of arguments on
the stack. This can probably be checked on linux x86_64 to make sure how
arguments are passed.

>  	}
>  
>        /* Push the user return address after the argument data, and then
> @@ -308,9 +313,15 @@ _hurd_stack_setup (void)
>  	 caller had called `doinit1' with the argument data already on the
>  	 stack.  */
>        *--data = caller;
> +# ifdef __x86_64__
> +      asm volatile ("movq %0, %%rsp\n" /* Switch to new outermost stack.  */
> +                    "movq $0, %%rbp\n" /* Clear outermost frame pointer.  */
> +                    "jmp *%1" : : "r" (data), "r" (&doinit1));
> +# else
>        asm volatile ("movl %0, %%esp\n" /* Switch to new outermost stack.  */
>  		    "movl $0, %%ebp\n" /* Clear outermost frame pointer.  */
>  		    "jmp *%1" : : "r" (data), "r" (&doinit1));
> +# endif
>        /* NOTREACHED */
>      }
>  
> -- 
> 2.39.2
> 
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.

Re: [RFC PATCH 9/9] hurd, htl: Add some more x86_64-specific code

[Samuel Thibault]

Sergey Bugaev, le sam. 18 févr. 2023 23:37:17 +0300, a ecrit:
> diff --git a/sysdeps/mach/hurd/x86_64/tls.h b/sysdeps/mach/hurd/x86_64/tls.h
> new file mode 100644
> index 00000000..644dcb1a
> --- /dev/null
> +++ b/sysdeps/mach/hurd/x86_64/tls.h
> @@ -0,0 +1,257 @@
> +# define TCB_ALIGNMENT	64

Please copy the comment about the penalty of non-64-aligned accesses.

> +# define TLS_INIT_TP(descr) _hurd_tls_init ((tcbhead_t *) (descr))
> +
> +# if __GNUC_PREREQ (6, 0)
> +
> +#  define THREAD_SELF							\
> +  (*(tcbhead_t * __seg_fs *) offsetof (tcbhead_t, tcb))
> +#  define THREAD_GETMEM(descr, member)					\
> +  (*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member))
> +#  define THREAD_SETMEM(descr, member, value)				\
> +  (*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member) = value)
> +
> +# else

I'd say don't bother keeping the non-gcc-6 case, since x86_64-gnu got
added to gcc only recently.

> +/* Set the stack guard field in TCB head.  */
> +# define THREAD_SET_STACK_GUARD(value)					\
> +  THREAD_SETMEM (THREAD_SELF, stack_guard, value)
> +# define THREAD_COPY_STACK_GUARD(descr)					\
> +  ((descr)->stack_guard							\
> +   = THREAD_GETMEM (THREAD_SELF, stack_guard))
> +
> +/* Set the pointer guard field in the TCB head.  */
> +# define THREAD_SET_POINTER_GUARD(value)				\
> +  THREAD_SETMEM (THREAD_SELF, pointer_guard, value)
> +# define THREAD_COPY_POINTER_GUARD(descr)				\
> +  ((descr)->pointer_guard						\
> +   = THREAD_GETMEM (THREAD_SELF, pointer_guard))
> +
> +/* Install new dtv for current thread.  */
> +# define INSTALL_NEW_DTV(dtvp) THREAD_SETMEM (THREAD_SELF, dtv, dtvp)
> +
> +/* Return the address of the dtv for the current thread.  */
> +# define THREAD_DTV() THREAD_GETMEM (THREAD_SELF, dtv)

Please keep #define order coherent with i386/tls.h

> diff --git a/sysdeps/x86_64/htl/pt-machdep.h b/sysdeps/x86_64/htl/pt-machdep.h
> new file mode 100644
> index 00000000..2e2846fa
> --- /dev/null
> +++ b/sysdeps/x86_64/htl/pt-machdep.h

I don't think this is needed since we already have sysdeps/x86/htl/pt-machdep.h
?

Samuel

Re: [RFC PATCH 7/9] hurd: Generalize init-first.c to support x86_64

[Sergey Bugaev]

On Mon, Feb 20, 2023 at 3:01 AM Samuel Thibault <samuel.thibault@gnu.org> wrote:
> That won't work on x86_64: there, arguments are passed mostly through
> registers, so &argc won't actually give you the address of arguments on
> the stack.

Right, good point.

I wish I had a better understanding of just what's going on in this
file. Maybe a lot of the hacks can be rewritten in a nicer way. For
instance, do we really need to hijack the return addresses and jump to
init1 in this weird way, only to enable it to access argc/arg0? Since
we know where they are on our stack (__builtin_frame_address (0) + 2
or something like that), can't we just pass it a pointer?

Let me actually try just that...

Sergey

Re: [RFC PATCH 7/9] hurd: Generalize init-first.c to support x86_64

[Sergey Bugaev]

> I wish I had a better understanding of just what's going on in this
> file. Maybe a lot of the hacks can be rewritten in a nicer way. For
> instance, do we really need to hijack the return addresses and jump to
> init1 in this weird way, only to enable it to access argc/arg0? Since
> we know where they are on our stack (__builtin_frame_address (0) + 2
> or something like that), can't we just pass it a pointer?
>
> Let me actually try just that...

Eh, no, let's start even earlier than that. Please correct me if I
(inevitably) get things wrong.

_dl_init_first is Hurd-specific. It is called from the assembly code
in dl-machine.h, specifically there's a RTLD_START_SPECIAL_INIT macro
that's defined to call _dl_init_first on the Hurd, and to nothing
otherwise. This RTLD_START_SPECIAL_INIT is used ("invoked") in
i386/dl-machine.h, s390/s390-{32,64}/dl-machine.h, ia64/dl-machine.h,
and alpha/dl-machine.h (but notably not in x86_64/dl-machine.h). In
all cases, it's emphasized that "The special initializer gets called
with the stack just as the application's entry point will see it; it
can switch stacks if it moves these contents over."

But I conclude that:
- s390-gnu, ia64-gnu, and alpha-gnu ports are nonexistent, nor are
they realistically ever going to happen, so we can ignore them
completely
- the implementation does not seem to actually switch stacks (in fact,
I have removed the unused switch_stacks function in the last commit)
-- so the "gets called with the stack just as the application's entry
point will see it" property may not be important anymore?

The only thing it really needs, it seems, is a pointer to
argc/argv/envp & Hurd data block *somewhere*. It does not have to be
on the stack (though where else would it be), or immediately preceding
its call frame -- all that really matters is that there's a pointer.

So my thinking goes, why don't we just hook into _dl_start, which
already has this very pointer? And in fact, _dl_start calls
_dl_sysdep_start, for which there is already a Hurd version. Can't we
just call our logic from there, and not worry about the stack layout
and overwriting return addresses?

That would work for the SHARED case; we also need to do something for
the static case. In that case, we are invoked by static-start.S; do I
understand it right that the argc/argv/whatever is still located
on-stack even on x86_64 in this case, and not passed in registers
according to the calling convention? Then again, we should be able to
just use __builtin_frame_address (0) + 2 and avoid most of the hacks?

Please tell me if this makes any sense.

Sergey

Re: [RFC PATCH 7/9] hurd: Generalize init-first.c to support x86_64

[Noah Goldstein]

On Sat, Feb 18, 2023 at 2:40 PM Sergey Bugaev via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  sysdeps/mach/hurd/{i386 => x86}/init-first.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
>  rename sysdeps/mach/hurd/{i386 => x86}/init-first.c (96%)
>
> diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/x86/init-first.c
> similarity index 96%
> rename from sysdeps/mach/hurd/i386/init-first.c
> rename to sysdeps/mach/hurd/x86/init-first.c
> index a558da16..75ac1ff2 100644
> --- a/sysdeps/mach/hurd/i386/init-first.c
> +++ b/sysdeps/mach/hurd/x86/init-first.c
> @@ -227,10 +227,15 @@ init (int *data)
>     values we set just above.  We have stashed in %eax the user code
>     return address.  Push it on the top of the stack so it acts as
>     init1's return address, and then jump there.  */
> +#ifdef __x86_64__
> +asm ("call_init1:\n"
> +     "  push %rax\n"
> +     "  jmp *%rcx\n");
> +#else
>  asm ("call_init1:\n"
>       " push %eax\n"
>       " jmp *%ecx\n");
> -
> +#endif
>
>  /* Do the first essential initializations that must precede all else.  */
>  static inline void
> @@ -242,7 +247,7 @@ first_init (void)
>  #ifndef SHARED
>    /* In the static case, we need to set up TLS early so that the stack
>       protection guard can be read at gs:0x14 by the gcc-generated snippets.  */
> -  _hurd_tls_init(&__init1_tcbhead);
> +  _hurd_tls_init (&__init1_tcbhead);
>    asm ("movw %%gs,%w0" : "=m" (__init1_desc));
>  #endif
>
> @@ -300,7 +305,7 @@ _hurd_stack_setup (void)
>         {
>           /* If we use ``__builtin_frame_address (0) + 2'' here, GCC gets
>              confused.  */
> -         init ((int *) &argc);
> +         init (&argc);
>         }
>
>        /* Push the user return address after the argument data, and then
> @@ -308,9 +313,15 @@ _hurd_stack_setup (void)
>          caller had called `doinit1' with the argument data already on the
>          stack.  */
>        *--data = caller;
> +# ifdef __x86_64__
> +      asm volatile ("movq %0, %%rsp\n" /* Switch to new outermost stack.  */
> +                    "movq $0, %%rbp\n" /* Clear outermost frame pointer.  */
Unless you are intentionally preserving flags, `xorl %%ebp, %%ebp` is
better way to
zero a register.
> +                    "jmp *%1" : : "r" (data), "r" (&doinit1));
> +# else
>        asm volatile ("movl %0, %%esp\n" /* Switch to new outermost stack.  */
>                     "movl $0, %%ebp\n" /* Clear outermost frame pointer.  */
>                     "jmp *%1" : : "r" (data), "r" (&doinit1));
> +# endif
>        /* NOTREACHED */
>      }
>
> --
> 2.39.2
>

Re: [RFC PATCH 7/9] hurd: Generalize init-first.c to support x86_64

[Samuel Thibault]

Sergey Bugaev, le lun. 20 févr. 2023 20:10:29 +0300, a ecrit:
> - the implementation does not seem to actually switch stacks (in fact,
> I have removed the unused switch_stacks function in the last commit)
> -- so the "gets called with the stack just as the application's entry
> point will see it" property may not be important anymore?

That's possible, yes.

> So my thinking goes, why don't we just hook into _dl_start, which
> already has this very pointer? And in fact, _dl_start calls
> _dl_sysdep_start, for which there is already a Hurd version. Can't we
> just call our logic from there, and not worry about the stack layout
> and overwriting return addresses?

Possibly, yes.

> That would work for the SHARED case; we also need to do something for
> the static case. In that case, we are invoked by static-start.S; do I
> understand it right that the argc/argv/whatever is still located
> on-stack even on x86_64 in this case, and not passed in registers
> according to the calling convention?

I don't know. But you can check on Linux, we'll probably want to use the
same ABI.

Samuel