[PATCH v4 2/5] powerpc/code-patching: Add data patch alignment check

[Benjamin Gray]

The new data patching still needs to be aligned within a
cacheline too for the flushes to work correctly. To simplify
this requirement, we just say data patches must be aligned.

Detect when data patching is not aligned, returning an invalid
argument error.

Signed-off-by: Benjamin Gray <bg...@linux.ibm.com>

---

v3: * New in v3
---
 arch/powerpc/include/asm/code-patching.h | 6 ++++++
 arch/powerpc/lib/code-patching.c         | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/arch/powerpc/include/asm/code-patching.h 
b/arch/powerpc/include/asm/code-patching.h
index 21a36e2c4e26..e7f14720f630 100644
--- a/arch/powerpc/include/asm/code-patching.h
+++ b/arch/powerpc/include/asm/code-patching.h
@@ -95,11 +95,17 @@ int patch_ulong(void *addr, unsigned long val);
 
 static inline int patch_uint(void *addr, unsigned int val)
 {
+       if (!IS_ALIGNED((unsigned long)addr, sizeof(unsigned int)))
+               return -EINVAL;
+
        return patch_instruction(addr, ppc_inst(val));
 }
 
 static inline int patch_ulong(void *addr, unsigned long val)
 {
+       if (!IS_ALIGNED((unsigned long)addr, sizeof(unsigned long)))
+               return -EINVAL;
+
        return patch_instruction(addr, ppc_inst(val));
 }
 
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 18f762616db9..384b275d1bc5 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -386,12 +386,18 @@ NOKPROBE_SYMBOL(patch_instruction);
 
 int patch_uint(void *addr, unsigned int val)
 {
+       if (!IS_ALIGNED((unsigned long)addr, sizeof(unsigned int)))
+               return -EINVAL;
+
        return patch_mem(addr, val, false);
 }
 NOKPROBE_SYMBOL(patch_uint);
 
 int patch_ulong(void *addr, unsigned long val)
 {
+       if (!IS_ALIGNED((unsigned long)addr, sizeof(unsigned long)))
+               return -EINVAL;
+
        return patch_mem(addr, val, true);
 }
 NOKPROBE_SYMBOL(patch_ulong);
-- 
2.45.0