| Message ID | 20240103171502.1358371-8-bugaevc@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | aarch64-gnu port | expand |
Applied, thanks! Sergey Bugaev, le mer. 03 janv. 2024 20:14:40 +0300, a ecrit: > Instead of relying on the stack frame layout to figure out where the stack > pointer was prior to the _hurd_stack_setup () call, just pass the pointer > as an argument explicitly. This is less brittle and much more portable. > > Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> > --- > sysdeps/mach/hurd/i386/static-start.S | 3 +++ > sysdeps/mach/hurd/x86/init-first.c | 16 +++++++--------- > sysdeps/mach/hurd/x86_64/static-start.S | 1 + > 3 files changed, 11 insertions(+), 9 deletions(-) > > diff --git a/sysdeps/mach/hurd/i386/static-start.S b/sysdeps/mach/hurd/i386/static-start.S > index d83505b2..3ffcb47d 100644 > --- a/sysdeps/mach/hurd/i386/static-start.S > +++ b/sysdeps/mach/hurd/i386/static-start.S > @@ -19,7 +19,10 @@ > .text > .globl _start > _start: > + pushl %esp > call _hurd_stack_setup > + /* No need to "addl %4, %esp", since _hurd_stack_setup > + * returns with an already adjusted stack pointer. */ > xorl %edx, %edx > jmp _start1 > > diff --git a/sysdeps/mach/hurd/x86/init-first.c b/sysdeps/mach/hurd/x86/init-first.c > index bb051418..6f71d71b 100644 > --- a/sysdeps/mach/hurd/x86/init-first.c > +++ b/sysdeps/mach/hurd/x86/init-first.c > @@ -197,7 +197,7 @@ strong_alias (posixland_init, __libc_init_first); > which should not exist at all. */ > void > inhibit_stack_protector > -_hurd_stack_setup (void) > +_hurd_stack_setup (void **argptr) > { > /* This is the very first C code that runs in a statically linked > executable -- calling this function is the first thing that _start in > @@ -206,14 +206,12 @@ _hurd_stack_setup (void) > > _start1 expects the arguments, environment, and a Hurd data block to be > located at the top of the stack. The data may already be located there, > - or we may need to receive it from the exec server. */ > - void *caller = __builtin_extract_return_addr (__builtin_return_address (0)); > - /* If the arguments and environment are already located on the stack, this is > - where they are, just above our call frame. Note that this may not be a > - valid pointer in case we're supposed to receive the arguments from the exec > - server, so we can not dereference it yet. */ > - void **p = (void **) __builtin_frame_address (0) + 2; > + or we may need to receive it from the exec server. If the data is located > + on the stack (just above our call frame), argptr points to it. Note that > + this may not be a valid pointer in case we're supposed to receive the > + arguments from the exec server, so we can not dereference it yet. */ > > + void *caller = __builtin_extract_return_addr (__builtin_return_address (0)); > /* Init the essential things. */ > first_init (); > > @@ -245,7 +243,7 @@ _hurd_stack_setup (void) > the stack pointer to the data (which is somewhere on the current stack > anyway). This way, _start1 find the data on the top of the stack, just as > it expects to. */ > - _hurd_startup (p, &doinit); > + _hurd_startup (argptr, &doinit); > __builtin_unreachable (); > } > #endif > diff --git a/sysdeps/mach/hurd/x86_64/static-start.S b/sysdeps/mach/hurd/x86_64/static-start.S > index 9b9db937..0ec00905 100644 > --- a/sysdeps/mach/hurd/x86_64/static-start.S > +++ b/sysdeps/mach/hurd/x86_64/static-start.S > @@ -25,6 +25,7 @@ _start: > leaq __strlen_sse2(%rip), %rax > movq %rax, strlen@GOTPCREL(%rip) > > + movq %rsp, %rdi > call _hurd_stack_setup > xorq %rdx, %rdx > jmp _start1 > -- > 2.43.0 > >
diff --git a/sysdeps/mach/hurd/i386/static-start.S b/sysdeps/mach/hurd/i386/static-start.S index d83505b2..3ffcb47d 100644 --- a/sysdeps/mach/hurd/i386/static-start.S +++ b/sysdeps/mach/hurd/i386/static-start.S @@ -19,7 +19,10 @@ .text .globl _start _start: + pushl %esp call _hurd_stack_setup + /* No need to "addl %4, %esp", since _hurd_stack_setup + * returns with an already adjusted stack pointer. */ xorl %edx, %edx jmp _start1 diff --git a/sysdeps/mach/hurd/x86/init-first.c b/sysdeps/mach/hurd/x86/init-first.c index bb051418..6f71d71b 100644 --- a/sysdeps/mach/hurd/x86/init-first.c +++ b/sysdeps/mach/hurd/x86/init-first.c @@ -197,7 +197,7 @@ strong_alias (posixland_init, __libc_init_first); which should not exist at all. */ void inhibit_stack_protector -_hurd_stack_setup (void) +_hurd_stack_setup (void **argptr) { /* This is the very first C code that runs in a statically linked executable -- calling this function is the first thing that _start in @@ -206,14 +206,12 @@ _hurd_stack_setup (void) _start1 expects the arguments, environment, and a Hurd data block to be located at the top of the stack. The data may already be located there, - or we may need to receive it from the exec server. */ - void *caller = __builtin_extract_return_addr (__builtin_return_address (0)); - /* If the arguments and environment are already located on the stack, this is - where they are, just above our call frame. Note that this may not be a - valid pointer in case we're supposed to receive the arguments from the exec - server, so we can not dereference it yet. */ - void **p = (void **) __builtin_frame_address (0) + 2; + or we may need to receive it from the exec server. If the data is located + on the stack (just above our call frame), argptr points to it. Note that + this may not be a valid pointer in case we're supposed to receive the + arguments from the exec server, so we can not dereference it yet. */ + void *caller = __builtin_extract_return_addr (__builtin_return_address (0)); /* Init the essential things. */ first_init (); @@ -245,7 +243,7 @@ _hurd_stack_setup (void) the stack pointer to the data (which is somewhere on the current stack anyway). This way, _start1 find the data on the top of the stack, just as it expects to. */ - _hurd_startup (p, &doinit); + _hurd_startup (argptr, &doinit); __builtin_unreachable (); } #endif diff --git a/sysdeps/mach/hurd/x86_64/static-start.S b/sysdeps/mach/hurd/x86_64/static-start.S index 9b9db937..0ec00905 100644 --- a/sysdeps/mach/hurd/x86_64/static-start.S +++ b/sysdeps/mach/hurd/x86_64/static-start.S @@ -25,6 +25,7 @@ _start: leaq __strlen_sse2(%rip), %rax movq %rax, strlen@GOTPCREL(%rip) + movq %rsp, %rdi call _hurd_stack_setup xorq %rdx, %rdx jmp _start1
Instead of relying on the stack frame layout to figure out where the stack pointer was prior to the _hurd_stack_setup () call, just pass the pointer as an argument explicitly. This is less brittle and much more portable. Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> --- sysdeps/mach/hurd/i386/static-start.S | 3 +++ sysdeps/mach/hurd/x86/init-first.c | 16 +++++++--------- sysdeps/mach/hurd/x86_64/static-start.S | 1 + 3 files changed, 11 insertions(+), 9 deletions(-)