diff options
| author | Matthias Schiffer <mschiffer@universe-factory.net> | 2018-03-24 17:57:49 +0100 |
|---|---|---|
| committer | Paul Burton <paul.burton@mips.com> | 2018-06-19 15:00:12 -0700 |
| commit | 6fb8656646f996d1eef42e6d56203c4915cb9e08 (patch) | |
| tree | 782be6f9af41e298651cbb679a5d83bfc2d5de4e /arch | |
| parent | 2a027b47dba6b77ab8c8e47b589ae9bbc5ac6175 (diff) | |
mips: ftrace: fix static function graph tracing
ftrace_graph_caller was never run after calling ftrace_trace_function,
breaking the function graph tracer. Fix this, bringing it in line with the
x86 implementation.
While we're at it, also streamline the control flow of _mcount a bit to
reduce the number of branches.
This issue was reported before:
https://www.linux-mips.org/archives/linux-mips/2014-11/msg00295.html
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Tested-by: Matt Redfearn <matt.redfearn@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/18929/
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: stable@vger.kernel.org # v3.17+
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/kernel/mcount.S | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index f2ee7e1e3342..cff52b283e03 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -119,10 +119,20 @@ NESTED(_mcount, PT_SIZE, ra) EXPORT_SYMBOL(_mcount) PTR_LA t1, ftrace_stub PTR_L t2, ftrace_trace_function /* Prepare t2 for (1) */ - bne t1, t2, static_trace + beq t1, t2, fgraph_trace nop + MCOUNT_SAVE_REGS + + move a0, ra /* arg1: self return address */ + jalr t2 /* (1) call *ftrace_trace_function */ + move a1, AT /* arg2: parent's return address */ + + MCOUNT_RESTORE_REGS + +fgraph_trace: #ifdef CONFIG_FUNCTION_GRAPH_TRACER + PTR_LA t1, ftrace_stub PTR_L t3, ftrace_graph_return bne t1, t3, ftrace_graph_caller nop @@ -131,24 +141,11 @@ EXPORT_SYMBOL(_mcount) bne t1, t3, ftrace_graph_caller nop #endif - b ftrace_stub -#ifdef CONFIG_32BIT - addiu sp, sp, 8 -#else - nop -#endif -static_trace: - MCOUNT_SAVE_REGS - - move a0, ra /* arg1: self return address */ - jalr t2 /* (1) call *ftrace_trace_function */ - move a1, AT /* arg2: parent's return address */ - - MCOUNT_RESTORE_REGS #ifdef CONFIG_32BIT addiu sp, sp, 8 #endif + .globl ftrace_stub ftrace_stub: RETURN_BACK |