@@ -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)
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. Cc: <> Signed-off-by: Markos Chandras <> --- Hopefully this is the final version ;) Changes since v3: - Rework v3 to unbreak dynamic tracing on MIPS32 Changes since v2: - Also fix the case where the function graph tracer is enabled Changes since v1: - Also fix the case where the tracer is actually enabled --- arch/mips/kernel/mcount.S | 12 ++++++++++++ 1 file changed, 12 insertions(+)