Patch "powerpc/ftrace: Pass the correct stack pointer for DYNAMIC_FTRACE_WITH_REGS" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

powerpc/ftrace: Pass the correct stack pointer for DYNAMIC_FTRACE_WITH_REGS

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
powerpc-ftrace-pass-the-correct-stack-pointer-for-dynamic_ftrace_with_regs.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

rom a4979a7e71eb8da976cbe4a0a1fa50636e76b04f Mon Sep 17 00:00:00 2001
From: "Naveen N. Rao" <[email protected]>
Date: Thu, 1 Jun 2017 16:18:16 +0530
Subject: powerpc/ftrace: Pass the correct stack pointer for DYNAMIC_FTRACE_WITH_REGS

From: Naveen N. Rao <[email protected]>

commit a4979a7e71eb8da976cbe4a0a1fa50636e76b04f upstream.

For DYNAMIC_FTRACE_WITH_REGS, we should be passing-in the original set of registers in pt_regs, to capture the state _before_ ftrace_caller. However, we are instead passing the stack pointer *after* allocating a stack frame in ftrace_caller. Fix this by saving the proper value of r1 in pt_regs. Also, use SAVE_10GPRS() to simplify the code.

---
 arch/powerpc/kernel/entry_64.S |   20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

@@ -1235,10 +1235,14 @@ _GLOBAL(ftrace_caller)
 	stdu	r1,-SWITCH_FRAME_SIZE(r1)
 
 	/* Save all gprs to pt_regs */
-	SAVE_8GPRS(0,r1)
-	SAVE_8GPRS(8,r1)
-	SAVE_8GPRS(16,r1)
-	SAVE_8GPRS(24,r1)
+	SAVE_GPR(0, r1)
+	SAVE_10GPRS(2, r1)
+	SAVE_10GPRS(12, r1)
+	SAVE_10GPRS(22, r1)
+
+	/* Save previous stack pointer (r1) */
+	addi	r8, r1, SWITCH_FRAME_SIZE
+	std	r8, GPR1(r1)
 
 	/* Load special regs for save below */
 	mfmsr   r8

@@ -1292,10 +1296,10 @@ ftrace_call:
 #endif
 
 	/* Restore gprs */
-	REST_8GPRS(0,r1)
-	REST_8GPRS(8,r1)
-	REST_8GPRS(16,r1)
-	REST_8GPRS(24,r1)
+	REST_GPR(0,r1)
+	REST_10GPRS(2,r1)
+	REST_10GPRS(12,r1)
+	REST_10GPRS(22,r1)
 
 	/* Restore callee's TOC */
 	ld	r2, 24(r1)

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/powerpc-ftrace-pass-the-correct-stack-pointer-for-dynamic_ftrace_with_regs.patch