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Message-ID: <20240325103911.2651793-15-kirill.shutemov@linux.intel.com>
Date: Mon, 25 Mar 2024 12:39:08 +0200
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
x86@...nel.org
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>,
Elena Reshetova <elena.reshetova@...el.com>,
Jun Nakajima <jun.nakajima@...el.com>,
Rick Edgecombe <rick.p.edgecombe@...el.com>,
Tom Lendacky <thomas.lendacky@....com>,
"Kalra, Ashish" <ashish.kalra@....com>,
Sean Christopherson <seanjc@...gle.com>,
"Huang, Kai" <kai.huang@...el.com>,
Baoquan He <bhe@...hat.com>,
kexec@...ts.infradead.org,
linux-coco@...ts.linux.dev,
linux-kernel@...r.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCHv9 14/17] x86/smp: Add smp_ops.stop_this_cpu() callback
If the helper is defined, it is called instead of halt() to stop the CPU
at the end of stop_this_cpu() and on crash CPU shutdown.
ACPI MADT will use it to hand over the CPU to BIOS in order to be able
to wake it up again after kexec.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Acked-by: Kai Huang <kai.huang@...el.com>
Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
---
arch/x86/include/asm/smp.h | 1 +
arch/x86/kernel/process.c | 7 +++++++
arch/x86/kernel/reboot.c | 6 ++++++
3 files changed, 14 insertions(+)
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index a35936b512fe..ca073f40698f 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -35,6 +35,7 @@ struct smp_ops {
int (*cpu_disable)(void);
void (*cpu_die)(unsigned int cpu);
void (*play_dead)(void);
+ void (*stop_this_cpu)(void);
void (*send_call_func_ipi)(const struct cpumask *mask);
void (*send_call_func_single_ipi)(int cpu);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index b8441147eb5e..f63f8fd00a91 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -835,6 +835,13 @@ void __noreturn stop_this_cpu(void *dummy)
*/
cpumask_clear_cpu(cpu, &cpus_stop_mask);
+#ifdef CONFIG_SMP
+ if (smp_ops.stop_this_cpu) {
+ smp_ops.stop_this_cpu();
+ unreachable();
+ }
+#endif
+
for (;;) {
/*
* Use native_halt() so that memory contents don't change
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 1ec478f40963..293ded05a4b0 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -880,6 +880,12 @@ static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
cpu_emergency_disable_virtualization();
atomic_dec(&waiting_for_crash_ipi);
+
+ if (smp_ops.stop_this_cpu) {
+ smp_ops.stop_this_cpu();
+ unreachable();
+ }
+
/* Assume hlt works */
halt();
for (;;)
--
2.43.0
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