From 8a574cfa2652545eb95595d38ac2a0bb501af0ae Mon Sep 17 00:00:00 2001 From: Markos Chandras Date: Tue, 16 Sep 2014 15:55:12 +0100 Subject: [PATCH] MIPS: mcount: Adjust stack pointer for static trace in MIPS32 Every mcount() call in the MIPS 32-bit kernel is done as follows: [...] move at, ra jal _mcount addiu sp, sp, -8 [...] but upon returning from the mcount() function, the stack pointer is not adjusted properly. This is explained in details in 58b69401c797 (MIPS: Function tracer: Fix broken function tracing). Commit ad8c396936e3 ("MIPS: Unbreak function tracer for 64-bit kernel.) fixed the stack manipulation for 64-bit but it didn't fix it completely for MIPS32. Signed-off-by: Markos Chandras Cc: Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7792/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/mcount.S | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index 5d25462de8a6..2f7c734771f4 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -129,7 +129,11 @@ NESTED(_mcount, PT_SIZE, ra) nop #endif b ftrace_stub +#ifdef CONFIG_32BIT + addiu sp, sp, 8 +#else nop +#endif static_trace: MCOUNT_SAVE_REGS @@ -139,6 +143,9 @@ static_trace: 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 @@ -183,6 +190,11 @@ NESTED(ftrace_graph_caller, PT_SIZE, ra) jal prepare_ftrace_return nop MCOUNT_RESTORE_REGS +#ifndef CONFIG_DYNAMIC_FTRACE +#ifdef CONFIG_32BIT + addiu sp, sp, 8 +#endif +#endif RETURN_BACK END(ftrace_graph_caller) -- 2.20.1