powerpc/code-patching: Add data patch alignment check

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 <bgray@linux.ibm.com>
Reviewed-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240515024445.236364-3-bgray@linux.ibm.com

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));
 }
 

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);