From: Guo Ren <guoren@linux.alibaba.com>
Date: Tue, 28 Jul 2020 16:25:23 +0000 (+0000)
Subject: csky: Fixup kprobes handler couldn't change pc
X-Git-Tag: v5.9-rc1~130^2~8
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a5447fb9b32eb33b2f0f09a63e4852b46af5b056;p=users%2Fhch%2Fmisc.git

csky: Fixup kprobes handler couldn't change pc

The "Changing Execution Path" section in the Documentation/kprobes.txt
said:

Since kprobes can probe into a running kernel code, it can change the
register set, including instruction pointer.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---

diff --git a/arch/csky/abiv2/mcount.S b/arch/csky/abiv2/mcount.S
index 911512bf480f..d745e10c10b0 100644
--- a/arch/csky/abiv2/mcount.S
+++ b/arch/csky/abiv2/mcount.S
@@ -55,7 +55,9 @@
 
 .macro mcount_exit_regs
 	RESTORE_REGS_FTRACE
-	ldw	t1, (sp, 0)
+	subi	sp, 152
+	ldw	t1, (sp, 4)
+	addi	sp, 152
 	ldw	r8, (sp, 4)
 	ldw	lr, (sp, 8)
 	addi	sp, 12