From: Matthias Schiffer Date: Sat, 24 Mar 2018 16:57:49 +0000 (+0100) Subject: mips: ftrace: fix static function graph tracing X-Git-Tag: v3.18.114~33 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e7e6fc525e156fda0e20875f8a751e212aee7eb5;p=thirdparty%2Fkernel%2Fstable.git mips: ftrace: fix static function graph tracing commit 6fb8656646f996d1eef42e6d56203c4915cb9e08 upstream. 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 Tested-by: Matt Redfearn Patchwork: https://patchwork.linux-mips.org/patch/18929/ Signed-off-by: Paul Burton Cc: stable@vger.kernel.org # v3.17+ Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index 2f7c734771f4e..0df911e772ae0 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -116,10 +116,20 @@ ftrace_stub: NESTED(_mcount, PT_SIZE, ra) 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 @@ -128,24 +138,11 @@ NESTED(_mcount, PT_SIZE, ra) 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