Commit be993e44 authored Feb 07, 2020 by Peter Zijlstra Committed by Ingo Molnar Feb 11, 2020

arm/ftrace: Fix BE text poking



The __patch_text() function already applies __opcode_to_mem_*(), so
when __opcode_to_mem_*() is not the identity (BE*), it is applied
twice, wrecking the instruction.

Fixes: 42e51f187f86 ("arm/ftrace: Use __patch_text()")
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Dmitry Osipenko <digetx@gmail.com>

parent 0a679e13

arch/arm/kernel/ftrace.c

+2 −5

Original line number	Diff line number	Diff line
		@@ -78,13 +78,10 @@ static int ftrace_modify_code(unsigned long pc, unsigned long old,
		{
		unsigned long replaced;

		if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
		if (IS_ENABLED(CONFIG_THUMB2_KERNEL))
		old = __opcode_to_mem_thumb32(old);
		new = __opcode_to_mem_thumb32(new);
		} else {
		else
		old = __opcode_to_mem_arm(old);
		new = __opcode_to_mem_arm(new);
		}

		if (validate) {
		if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE))

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