[PATCH v9 4/7] powerpc/code-patching: Verify instruction patch succeeded

[Benjamin Gray]

Verifies that if the instruction patching did not return an error then
the value stored at the given address to patch is now equal to the
instruction we patched it to.

Signed-off-by: Benjamin Gray <bgray at linux.ibm.com>
---
 arch/powerpc/lib/code-patching.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 3b3b09d5d2e1..b0a12b2d5a9b 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -192,6 +192,8 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr)
 	err = __do_patch_instruction(addr, instr);
 	local_irq_restore(flags);
 
+	WARN_ON(!err && !ppc_inst_equal(instr, ppc_inst_read(addr)));
+
 	return err;
 }
 #else /* !CONFIG_STRICT_KERNEL_RWX */
-- 
2.37.3