Commit eaa24c91 authored Apr 11, 2025 by Ingo Molnar

x86/alternatives: Remove the 'addr == NULL means forced-flush' hack from...


x86/alternatives: Remove the 'addr == NULL means forced-flush' hack from smp_text_poke_batch_finish()/smp_text_poke_batch_flush()/text_poke_addr_ordered()

There's this weird hack used by smp_text_poke_batch_finish() to indicate
a 'forced flush':

	smp_text_poke_batch_flush(NULL);

Just open-code the vector-flush in a straightforward fashion:

	smp_text_poke_batch_process(tp_vec, tp_vec_nr);
	tp_vec_nr = 0;

And get rid of !addr hack from text_poke_addr_ordered().

Leave a WARN_ON_ONCE(), just in case some external code learned
to rely on this behavior.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250411054105.2341982-24-mingo@kernel.org

parent 2d0cf10a

arch/x86/kernel/alternative.c

+10 −8

Original line number	Diff line number	Diff line
		@@ -2845,12 +2845,11 @@ static bool text_poke_addr_ordered(void *addr)
		{
		struct smp_text_poke_loc *tp;

		WARN_ON_ONCE(!addr);

		if (!tp_vec_nr)
		return true;

		if (!addr) /* force */
		return false;

		/*
		* If the last current entry's address is higher than the
		* new entry's address we'd like to add, then ordering
		@@ -2864,6 +2863,14 @@ static bool text_poke_addr_ordered(void *addr)
		return true;
		}

		void smp_text_poke_batch_finish(void)
		{
		if (tp_vec_nr) {
		smp_text_poke_batch_process(tp_vec, tp_vec_nr);
		tp_vec_nr = 0;
		}
		}

		static void smp_text_poke_batch_flush(void *addr)
		{
		lockdep_assert_held(&text_mutex);
		@@ -2874,11 +2881,6 @@ static void smp_text_poke_batch_flush(void *addr)
		}
		}

		void smp_text_poke_batch_finish(void)
		{
		smp_text_poke_batch_flush(NULL);
		}

		void __ref smp_text_poke_batch_add(void addr, const void opcode, size_t len, const void *emulate)
		{
		struct smp_text_poke_loc *tp;