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authorSteven Rostedt <srostedt@redhat.com>2012-04-26 08:31:18 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2012-07-03 14:14:38 +1000
commitb6e3796834faefe4b6e9a2aedfe12665cd51fbc5 (patch)
treed330be3540cf441198f630c8fa0eda9899ddb8b5 /arch/powerpc/lib
parentee456bb346e75a9b6d941224b108250e6ee5f79f (diff)
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powerpc: Have patch_instruction detect faults
For ftrace to use the patch_instruction code, it needs to check for faults on write. Ftrace updates code all over the kernel, and we need to know if code is updated or not due to protections that are placed on some portions of the kernel. If ftrace does not detect a fault, it will error later on, and it will be much more difficult to find the problem. By changing patch_instruction() to detect faults, then ftrace will be able to make use of it too. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/lib')
-rw-r--r--arch/powerpc/lib/code-patching.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 7c975d43e3f3..dd223b3eb333 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -13,17 +13,23 @@
#include <linux/mm.h>
#include <asm/page.h>
#include <asm/code-patching.h>
+#include <asm/uaccess.h>
-void patch_instruction(unsigned int *addr, unsigned int instr)
+int patch_instruction(unsigned int *addr, unsigned int instr)
{
- *addr = instr;
+ int err;
+
+ err = __put_user(instr, addr);
+ if (err)
+ return err;
asm ("dcbst 0, %0; sync; icbi 0,%0; sync; isync" : : "r" (addr));
+ return 0;
}
-void patch_branch(unsigned int *addr, unsigned long target, int flags)
+int patch_branch(unsigned int *addr, unsigned long target, int flags)
{
- patch_instruction(addr, create_branch(addr, target, flags));
+ return patch_instruction(addr, create_branch(addr, target, flags));
}
unsigned int create_branch(const unsigned int *addr,
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