diff options
| author | Wu Zhangjin <wuzhangjin@gmail.com> | 2010-05-14 19:08:29 +0800 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2010-07-05 17:17:28 +0100 |
| commit | 56b49cd35fd56e29adb8f97ba051a1670d24d133 (patch) | |
| tree | 4c7d6ef25e414141721c8cd31f9582513f0f15ef /arch | |
| parent | 042e571d224707b777d0995317c74812b960bfeb (diff) | |
MIPS: Tracing: Fix argument passing of the 32bit support with gcc 4.5
As documented in the GCC 4.5 docs [1] -mmcount-ra-address uses register
$12 to pass the stack offset of the return address to the _mcount function.
On 64-bit kernels $12 is t0 but in 32-bit kernels it is t4 so we need to
use $12 instead of t0 here to be correct for both kernel types.
[1] GCC documentation: MIPS Options
http://gcc.gnu.org/onlinedocs/gcc/MIPS-Options.html
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Cc: David Daney <david.s.daney@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/1227/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/kernel/mcount.S | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index 9a029d40f6c..6bfcb7a00ec 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -57,6 +57,12 @@ move ra, AT .endm +/* + * The -mmcount-ra-address option of gcc 4.5 uses register $12 to pass + * the location of the parent's return address. + */ +#define MCOUNT_RA_ADDRESS_REG $12 + #ifdef CONFIG_DYNAMIC_FTRACE NESTED(ftrace_caller, PT_SIZE, ra) @@ -70,7 +76,7 @@ _mcount: MCOUNT_SAVE_REGS #ifdef KBUILD_MCOUNT_RA_ADDRESS - PTR_S t0, PT_R12(sp) /* save location of parent's return address */ + PTR_S MCOUNT_RA_ADDRESS_REG, PT_R12(sp) #endif move a0, ra /* arg1: self return address */ @@ -142,9 +148,9 @@ NESTED(ftrace_graph_caller, PT_SIZE, ra) #ifdef CONFIG_DYNAMIC_FTRACE PTR_L a0, PT_R12(sp) #else - move a0, t0 + move a0, MCOUNT_RA_ADDRESS_REG #endif - bnez a0, 1f /* non-leaf func: stored in t0 */ + bnez a0, 1f /* non-leaf func: stored in MCOUNT_RA_ADDRESS_REG */ nop #endif PTR_LA a0, PT_R1(sp) /* leaf func: the location in current stack */ |