From: Corey Minyard <cminyard@xxxxxxxxxx> Dynamic function tracing was not working on MIPS. When doing dynamic tracing, the tracer attempts to match up the passed in address with the one the compiler creates in the mcount tables. The MIPS code was passing in the return address from the tracing function call, but the compiler tables were the address of the function call. So they wouldn't match. Just subtracting 8 from the return address will give the address of the function call. Easy enough. Signed-off-by: Corey Minyard <cminyard@xxxxxxxxxx> [david.daney@xxxxxxxxxx: Adjusted code comment and patch Subject.] Signed-off-by: David Daney <david.daney@xxxxxxxxxx> --- arch/mips/kernel/mcount.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index a03e93c..539b629 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -83,7 +83,7 @@ _mcount: PTR_S MCOUNT_RA_ADDRESS_REG, PT_R12(sp) #endif - move a0, ra /* arg1: self return address */ + PTR_SUBU a0, ra, 8 /* arg1: self address */ .globl ftrace_call ftrace_call: nop /* a placeholder for the call to a real tracing function */ -- 1.7.11.7
