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authorMarkos Chandras <markos.chandras@imgtec.com>2014-09-16 15:55:12 +0100
committerRalf Baechle <ralf@linux-mips.org>2014-09-26 11:41:17 +0200
commit8a574cfa2652545eb95595d38ac2a0bb501af0ae (patch)
tree9c49a781cda974d511d4239e172cdb10692d5cee
parentc8c0da6bdf0f0d6f59fc23aab6ee373a131df82d (diff)
downloadlinux-8a574cfa2652545eb95595d38ac2a0bb501af0ae.tar.gz
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 <markos.chandras@imgtec.com> Cc: <stable@vger.kernel.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7792/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
-rw-r--r--arch/mips/kernel/mcount.S12
1 files changed, 12 insertions, 0 deletions
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)