2022-02-16 06:49:13

by Christophe Leroy

Subject: [PATCH v1 1/4] powerpc/ftrace: Also save r1 in ftrace_caller()

Also save r1 in ftrace_caller()

r1 is needed during unwinding when the function_graph tracer
is active.

Reported-by: Naveen N. Rao <[email protected]>
Fixes: 830213786c49 ("powerpc/ftrace: directly call of function graph tracer by ftrace caller")
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/kernel/trace/ftrace_mprofile.S | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S
index 56da60e98327..8443902d5a05 100644
--- a/arch/powerpc/kernel/trace/ftrace_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S
@@ -173,6 +173,10 @@ _GLOBAL(ftrace_caller)
beq ftrace_no_trace
#endif

+ /* Save previous stack pointer (r1) */
+ addi r8, r1, SWITCH_FRAME_SIZE
+ PPC_STL r8, GPR1(r1)
+
/* Get the _mcount() call site out of LR */
mflr r7
PPC_STL r7, _NIP(r1)
--
2.34.1

2022-03-02 23:49:38

by Michael Ellerman

Subject: Re: [PATCH v1 1/4] powerpc/ftrace: Also save r1 in ftrace_caller()

On Tue, 15 Feb 2022 19:31:22 +0100, Christophe Leroy wrote:
> Also save r1 in ftrace_caller()
>
> r1 is needed during unwinding when the function_graph tracer
> is active.
>
>

Applied to powerpc/next.

[1/4] powerpc/ftrace: Also save r1 in ftrace_caller()
https://git.kernel.org/powerpc/c/34d8dac807f0ee3dc42ab45bdb284a3caf2b5ed1
[2/4] powerpc/ftrace: Add recursion protection in prepare_ftrace_return()
https://git.kernel.org/powerpc/c/df45a55788286c541449d82ee09fef3ac5ff77a1
[3/4] powerpc/ftrace: Have arch_ftrace_get_regs() return NULL unless FL_SAVE_REGS is set
https://git.kernel.org/powerpc/c/fc75f87337983229b7355d6b77f30fb6e7f359ee
[4/4] powerpc/ftrace: Style cleanup in ftrace_mprofile.S
https://git.kernel.org/powerpc/c/76b372814b088aeb76f0f753d968c8aa6d297f2a

cheers