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[PATCH][AArch64] Fix libc internal asm profiling code
- From: Szabolcs Nagy <szabolcs dot nagy at arm dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Cc: Marcus Shawcroft <Marcus dot Shawcroft at arm dot com>, <nd at arm dot com>
- Date: Fri, 15 Jan 2016 15:46:11 +0000
- Subject: [PATCH][AArch64] Fix libc internal asm profiling code
- Authentication-results: sourceware.org; auth=none
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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.
diff --git a/sysdeps/aarch64/Makefile b/sysdeps/aarch64/Makefile
index 0632355..562c137 100644
--- a/sysdeps/aarch64/Makefile
+++ b/sysdeps/aarch64/Makefile
@@ -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
diff --git a/sysdeps/aarch64/sysdep.h b/sysdeps/aarch64/sysdep.h
index af1af70..d1f8c22 100644
--- a/sysdeps/aarch64/sysdep.h
+++ b/sysdeps/aarch64/sysdep.h
@@ -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