[AArch64] Fix libc internal asm profiling code
Commit Message
When glibc is built with --enable-profile, the ENTRY of
asm functions includes CALL_MCOUNT for profiling.
(matters for binaries static linked against libc_p.a.)
CALL_MCOUNT did not save/restore argument registers
around the _mcount call so it clobbered them.
(it is enough to only save/restore the arguments passed
to a given asm function, but that would be too many asm
changes so it is simpler to always save all argument
registers in this macro.)
float args are not saved: mcount does not clobber the
float regs and currently no asm function takes float
arguments anyway.
2016-01-15 Szabolcs Nagy <szabolcs.nagy@arm.com>
* sysdeps/aarch64/Makefile (CFLAGS-mcount.c): Add -mgeneral-regs-only.
* sysdeps/aarch64/sysdep.h (CALL_MCOUNT): Save argument registers.
Comments
If this fixes bug 18707, then include [BZ #18707] in the ChangeLog entry
and close the bug as fixed with the appropriate milestone set on commit.
On 15/01/16 15:46, Szabolcs Nagy wrote:
> When glibc is built with --enable-profile, the ENTRY of
> asm functions includes CALL_MCOUNT for profiling.
> (matters for binaries static linked against libc_p.a.)
>
> CALL_MCOUNT did not save/restore argument registers
> around the _mcount call so it clobbered them.
> (it is enough to only save/restore the arguments passed
> to a given asm function, but that would be too many asm
> changes so it is simpler to always save all argument
> registers in this macro.)
>
> float args are not saved: mcount does not clobber the
> float regs and currently no asm function takes float
> arguments anyway.
>
> 2016-01-15 Szabolcs Nagy <szabolcs.nagy@arm.com>
>
> * sysdeps/aarch64/Makefile (CFLAGS-mcount.c): Add -mgeneral-regs-only.
> * sysdeps/aarch64/sysdep.h (CALL_MCOUNT): Save argument registers.
ping.
with bz in changelog:
2016-07-08 Szabolcs Nagy <szabolcs.nagy@arm.com>
[BZ #18707]
* sysdeps/aarch64/Makefile (CFLAGS-mcount.c): Add -mgeneral-regs-only.
* sysdeps/aarch64/sysdep.h (CALL_MCOUNT): Save argument registers.
> On 8 Jul 2016, at 17:06, Szabolcs Nagy <Szabolcs.Nagy@arm.com> wrote:
>
> 2016-07-08 Szabolcs Nagy <szabolcs.nagy@arm.com>
>
> [BZ #18707]
> * sysdeps/aarch64/Makefile (CFLAGS-mcount.c): Add -mgeneral-regs-only.
> * sysdeps/aarch64/sysdep.h (CALL_MCOUNT): Save argument registers.
OK /Marcus
@@ -12,3 +12,7 @@ endif
ifeq ($(subdir),csu)
gen-as-const-headers += tlsdesc.sym
endif
+
+ifeq ($(subdir),gmon)
+CFLAGS-mcount.c += -mgeneral-regs-only
+endif
@@ -66,9 +66,38 @@
/* If compiled for profiling, call `mcount' at the start of each function. */
#ifdef PROF
# define CALL_MCOUNT \
- str x30, [sp, #-16]!; \
+ str x30, [sp, #-80]!; \
+ cfi_adjust_cfa_offset (80); \
+ cfi_rel_offset (x30, 0); \
+ stp x0, x1, [sp, #16]; \
+ cfi_rel_offset (x0, 16); \
+ cfi_rel_offset (x1, 24); \
+ stp x2, x3, [sp, #32]; \
+ cfi_rel_offset (x2, 32); \
+ cfi_rel_offset (x3, 40); \
+ stp x4, x5, [sp, #48]; \
+ cfi_rel_offset (x4, 48); \
+ cfi_rel_offset (x5, 56); \
+ stp x6, x7, [sp, #64]; \
+ cfi_rel_offset (x6, 64); \
+ cfi_rel_offset (x7, 72); \
+ mov x0, x30; \
bl mcount; \
- ldr x30, [sp], #16 ;
+ ldp x0, x1, [sp, #16]; \
+ cfi_restore (x0); \
+ cfi_restore (x1); \
+ ldp x2, x3, [sp, #32]; \
+ cfi_restore (x2); \
+ cfi_restore (x3); \
+ ldp x4, x5, [sp, #48]; \
+ cfi_restore (x4); \
+ cfi_restore (x5); \
+ ldp x6, x7, [sp, #64]; \
+ cfi_restore (x6); \
+ cfi_restore (x7); \
+ ldr x30, [sp], #80; \
+ cfi_adjust_cfa_offset (-80); \
+ cfi_restore (x30);
#else
# define CALL_MCOUNT /* Do nothing. */
#endif