Commit 64478288 authored by Nikolay Borisov's avatar Nikolay Borisov Committed by Borislav Petkov (AMD)
Browse files

x86/mce/inject: Remove call to mce_notify_irq() 



The call to mce_notify_irq() has been there since the initial version of
the soft inject mce machinery, introduced in

  ea149b36 ("x86, mce: add basic error injection infrastructure").

At that time it was functional since injecting an MCE resulted in the
following call chain:

  raise_mce()
    ->machine_check_poll()
        ->mce_log() - sets notfiy_user_bit
  ->mce_notify_user() (current mce_notify_irq) consumed the bit and called the
  usermode helper.

However, with the introduction of

  011d8261 ("RAS: Add a Corrected Errors Collector")

the code got moved around and the usermode helper began to be called via the
early notifier mce_first_notifier() rendering the call in raise_local()
defunct as the mce_need_notify bit (ex notify_user) is only being set from the
early notifier.

Remove the noop call and make mce_notify_irq() static.

No functional changes.

Signed-off-by: default avatarNikolay Borisov <nik.borisov@suse.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250225143348.268469-1-nik.borisov@suse.com
parent d082ecbc

arch/x86/include/asm/mce.h

+0 −2
Original line number Diff line number Diff line
@@ -296,8 +296,6 @@ enum mcp_flags { 


void machine_check_poll(enum mcp_flags flags, mce_banks_t *b);



bool mce_notify_irq(void);



DECLARE_PER_CPU(struct mce, injectm);



/* Disable CMCI/polling for MCA bank claimed by firmware */

arch/x86/kernel/cpu/mce/core.c

+22 −22
Original line number Diff line number Diff line
@@ -584,6 +584,28 @@ bool mce_is_correctable(struct mce *m) 
}

EXPORT_SYMBOL_GPL(mce_is_correctable);



/*

 * Notify the user(s) about new machine check events.

 * Can be called from interrupt context, but not from machine check/NMI

 * context.

 */

static bool mce_notify_irq(void)

{

	/* Not more than two messages every minute */

	static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);



	if (test_and_clear_bit(0, &mce_need_notify)) {

		mce_work_trigger();



		if (__ratelimit(&ratelimit))

			pr_info(HW_ERR "Machine check events logged\n");



		return true;

	}



	return false;

}



static int mce_early_notifier(struct notifier_block *nb, unsigned long val,

			      void *data)

{
@@ -1773,28 +1795,6 @@ static void mce_timer_delete_all(void) 
		del_timer_sync(&per_cpu(mce_timer, cpu));

}



/*

 * Notify the user(s) about new machine check events.

 * Can be called from interrupt context, but not from machine check/NMI

 * context.

 */

bool mce_notify_irq(void)

{

	/* Not more than two messages every minute */

	static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);



	if (test_and_clear_bit(0, &mce_need_notify)) {

		mce_work_trigger();



		if (__ratelimit(&ratelimit))

			pr_info(HW_ERR "Machine check events logged\n");



		return true;

	}

	return false;

}

EXPORT_SYMBOL_GPL(mce_notify_irq);



static void __mcheck_cpu_mce_banks_init(void)

{

	struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array);

arch/x86/kernel/cpu/mce/inject.c

+0 −1
Original line number Diff line number Diff line
@@ -229,7 +229,6 @@ static int raise_local(void) 
	} else if (m->status) {

		pr_info("Starting machine check poll CPU %d\n", cpu);

		raise_poll(m);

		mce_notify_irq();

		pr_info("Machine check poll done on CPU %d\n", cpu);

	} else

		m->finished = 0;