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x86/smp: Split sending INIT IPI out into a helper function

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Putting CPUs into INIT is a safer place during kexec() to park CPUs.

Split the INIT assert/deassert sequence out so it can be reused.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20230615193330.551157083@linutronix.de
This commit is contained in:
Thomas Gleixner
2023-06-15 22:33:58 +02:00
parent d7893093a7
commit 6087dd5e86
1 changed files with 20 additions and 29 deletions
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49
arch/x86/kernel/smpboot.c
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@@ -853,47 +853,38 @@ wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip)
return (send_status | accept_status);
}
static int
wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
static void send_init_sequence(int phys_apicid)
{
unsigned long send_status = 0, accept_status = 0;
int maxlvt, num_starts, j;
int maxlvt = lapic_get_maxlvt();
maxlvt = lapic_get_maxlvt();
/*
* Be paranoid about clearing APIC errors.
*/
/* Be paranoid about clearing APIC errors. */
if (APIC_INTEGRATED(boot_cpu_apic_version)) {
if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
/* Due to the Pentium erratum 3AP. */
if (maxlvt > 3)
apic_write(APIC_ESR, 0);
apic_read(APIC_ESR);
}
pr_debug("Asserting INIT\n");
/*
* Turn INIT on target chip
*/
/*
* Send IPI
*/
apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT,
phys_apicid);
pr_debug("Waiting for send to finish...\n");
send_status = safe_apic_wait_icr_idle();
/* Assert INIT on the target CPU */
apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT, phys_apicid);
safe_apic_wait_icr_idle();
udelay(init_udelay);
pr_debug("Deasserting INIT\n");
/* Target chip */
/* Send IPI */
/* Deassert INIT on the target CPU */
apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
safe_apic_wait_icr_idle();
}
pr_debug("Waiting for send to finish...\n");
send_status = safe_apic_wait_icr_idle();
/*
* Wake up AP by INIT, INIT, STARTUP sequence.
*/
static int wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
{
unsigned long send_status = 0, accept_status = 0;
int num_starts, j, maxlvt = lapic_get_maxlvt();
send_init_sequence(phys_apicid);
mb();