x86/alternative: Remove text_poke_loc::len (97e6c977) · Commits · 戴 / test

Per the BUG_ON(len != insn.length) in text_poke_loc_init(), tp->len must indeed be the same as text_opcode_size(tp->opcode). Use this to remove this field from the structure. Sadly, due to 8 byte alignment, this only increases the structure padding. Tested-by:

Alexei Starovoitov <ast@kernel.org> Tested-by:

Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:

Alexei Starovoitov <ast@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20191111132457.989922744@infradead.org Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/alternative.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -938,7 +938,6 @@ static void do_sync_core(void *info)

		struct text_poke_loc {
		void *addr;
		int len;
		s32 rel32;
		u8 opcode;
		const u8 text[POKE_MAX_OPCODE_SIZE];
		@@ -965,6 +964,7 @@ int notrace poke_int3_handler(struct pt_regs *regs)
		{
		struct text_poke_loc *tp;
		void *ip;
		int len;

		/*
		* Having observed our INT3 instruction, we now must observe
		@@ -1004,7 +1004,8 @@ int notrace poke_int3_handler(struct pt_regs *regs)
		return 0;
		}

		ip += tp->len;
		len = text_opcode_size(tp->opcode);
		ip += len;

		switch (tp->opcode) {
		case INT3_INSN_OPCODE:
		@@ -1085,10 +1086,12 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries
		* Second step: update all but the first byte of the patched range.
		*/
		for (do_sync = 0, i = 0; i < nr_entries; i++) {
		if (tp[i].len - sizeof(int3) > 0) {
		int len = text_opcode_size(tp[i].opcode);

		if (len - sizeof(int3) > 0) {
		text_poke((char *)tp[i].addr + sizeof(int3),
		(const char *)tp[i].text + sizeof(int3),
		tp[i].len - sizeof(int3));
		len - sizeof(int3));
		do_sync++;
		}
		}
		@@ -1141,7 +1144,6 @@ void text_poke_loc_init(struct text_poke_loc tp, void addr,
		BUG_ON(len != insn.length);

		tp->addr = addr;
		tp->len = len;
		tp->opcode = insn.opcode.bytes[0];

		switch (tp->opcode) {

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