AuxXxilium/linux_dsm_epyc7002
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Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse Source 
Pull x86 apic updates from Ingo Molnar:
 "The main changes in this cycle were:

   - introduce optimized single IPI sending methods on modern APICs
     (Linus Torvalds, Thomas Gleixner)

   - kexec/crash APIC handling fixes and enhancements (Hidehiro Kawai)

   - extend lapic vector saving/restoring to the CMCI (MCE) vector as
     well (Juergen Gross)

   - various fixes and enhancements (Jake Oshins, Len Brown)"

* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  x86/irq: Export functions to allow MSI domains in modules
  Documentation: Document kernel.panic_on_io_nmi sysctl
  x86/nmi: Save regs in crash dump on external NMI
  x86/apic: Introduce apic_extnmi command line parameter
  kexec: Fix race between panic() and crash_kexec()
  panic, x86: Allow CPUs to save registers even if looping in NMI context
  panic, x86: Fix re-entrance problem due to panic on NMI
  x86/apic: Fix the saving and restoring of lapic vectors during suspend/resume
  x86/smpboot: Re-enable init_udelay=0 by default on modern CPUs
  x86/smp: Remove single IPI wrapper
  x86/apic: Use default send single IPI wrapper
  x86/apic: Provide default send single IPI wrapper
  x86/apic: Implement single IPI for apic_noop
  x86/apic: Wire up single IPI for apic_numachip
  x86/apic: Wire up single IPI for x2apic_uv
  x86/apic: Implement single IPI for x2apic_phys
  x86/apic: Wire up single IPI for bigsmp_apic
  x86/apic: Remove pointless indirections from bigsmp_apic
  x86/apic: Wire up single IPI for apic_physflat
  x86/apic: Remove pointless indirections from apic_physflat
  ...
This commit is contained in:
Linus Torvalds 2016-01-11 15:37:06 -08:00
commit 4f19b8803b
26 changed files with 284 additions and 42 deletions
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9
Documentation/kernel-parameters.txt
View File

@ -472,6 +472,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Change the amount of debugging information output
when initialising the APIC and IO-APIC components.
apic_extnmi= [APIC,X86] External NMI delivery setting
Format: { bsp (default) | all | none }
bsp: External NMI is delivered only to CPU 0
all: External NMIs are broadcast to all CPUs as a
backup of CPU 0
none: External NMI is masked for all CPUs. This is
useful so that a dump capture kernel won't be
shot down by NMI
autoconf= [IPV6]
See Documentation/networking/ipv6.txt.

15
Documentation/sysctl/kernel.txt
View File

@ -551,6 +551,21 @@ the recommended setting is 60.
==============================================================
panic_on_io_nmi:
Controls the kernel's behavior when a CPU receives an NMI caused by
an IO error.
0: try to continue operation (default)
1: panic immediately. The IO error triggered an NMI. This indicates a
serious system condition which could result in IO data corruption.
Rather than continuing, panicking might be a better choice. Some
servers issue this sort of NMI when the dump button is pushed,
and you can use this option to take a crash dump.
==============================================================
panic_on_oops:
Controls the kernel's behaviour when an oops or BUG is encountered.

6
arch/x86/include/asm/apic.h
View File

@ -23,6 +23,11 @@
#define APIC_VERBOSE 1
#define APIC_DEBUG 2
/* Macros for apic_extnmi which controls external NMI masking */
#define APIC_EXTNMI_BSP 0 /* Default */
#define APIC_EXTNMI_ALL 1
#define APIC_EXTNMI_NONE 2
/*
* Define the default level of output to be very little
* This can be turned up by using apic=verbose for more
@ -303,6 +308,7 @@ struct apic {
unsigned int *apicid);
/* ipi */
void (*send_IPI)(int cpu, int vector);
void (*send_IPI_mask)(const struct cpumask *mask, int vector);
void (*send_IPI_mask_allbutself)(const struct cpumask *mask,
int vector);

2
arch/x86/include/asm/ipi.h
View File

@ -119,6 +119,8 @@ static inline void
native_apic_mem_write(APIC_ICR, cfg);
}
extern void default_send_IPI_single(int cpu, int vector);
extern void default_send_IPI_single_phys(int cpu, int vector);
extern void default_send_IPI_mask_sequence_phys(const struct cpumask *mask,
int vector);
extern void default_send_IPI_mask_allbutself_phys(const struct cpumask *mask,

6
arch/x86/include/asm/msi.h
View File

@ -1,7 +1,13 @@
#ifndef _ASM_X86_MSI_H
#define _ASM_X86_MSI_H
#include <asm/hw_irq.h>
#include <asm/irqdomain.h>
typedef struct irq_alloc_info msi_alloc_info_t;
int pci_msi_prepare(struct irq_domain *domain, struct device *dev, int nvec,
msi_alloc_info_t *arg);
void pci_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc);
#endif /* _ASM_X86_MSI_H */

1
arch/x86/include/asm/reboot.h
View File

@ -25,5 +25,6 @@ void __noreturn machine_real_restart(unsigned int type);
typedef void (*nmi_shootdown_cb)(int, struct pt_regs*);
void nmi_shootdown_cpus(nmi_shootdown_cb callback);
void run_crash_ipi_callback(struct pt_regs *regs);
#endif /* _ASM_X86_REBOOT_H */

45
arch/x86/kernel/apic/apic.c
View File

@ -81,6 +81,12 @@ physid_mask_t phys_cpu_present_map;
*/
static unsigned int disabled_cpu_apicid __read_mostly = BAD_APICID;
/*
* This variable controls which CPUs receive external NMIs. By default,
* external NMIs are delivered only to the BSP.
*/
static int apic_extnmi = APIC_EXTNMI_BSP;
/*
* Map cpu index to physical APIC ID
*/
@ -1161,6 +1167,8 @@ void __init init_bsp_APIC(void)
value = APIC_DM_NMI;
if (!lapic_is_integrated()) /* 82489DX */
value |= APIC_LVT_LEVEL_TRIGGER;
if (apic_extnmi == APIC_EXTNMI_NONE)
value |= APIC_LVT_MASKED;
apic_write(APIC_LVT1, value);
}
@ -1378,9 +1386,11 @@ void setup_local_APIC(void)
apic_write(APIC_LVT0, value);
/*
* only the BP should see the LINT1 NMI signal, obviously.
* Only the BSP sees the LINT1 NMI signal by default. This can be
* modified by apic_extnmi= boot option.
*/
if (!cpu)
if ((!cpu && apic_extnmi != APIC_EXTNMI_NONE) ||
apic_extnmi == APIC_EXTNMI_ALL)
value = APIC_DM_NMI;
else
value = APIC_DM_NMI | APIC_LVT_MASKED;
@ -2270,6 +2280,7 @@ static struct {
unsigned int apic_tmict;
unsigned int apic_tdcr;
unsigned int apic_thmr;
unsigned int apic_cmci;
} apic_pm_state;
static int lapic_suspend(void)
@ -2299,6 +2310,10 @@ static int lapic_suspend(void)
if (maxlvt >= 5)
apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
#endif
#ifdef CONFIG_X86_MCE_INTEL
if (maxlvt >= 6)
apic_pm_state.apic_cmci = apic_read(APIC_LVTCMCI);
#endif
local_irq_save(flags);
disable_local_APIC();
@ -2355,9 +2370,13 @@ static void lapic_resume(void)
apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
#if defined(CONFIG_X86_MCE_INTEL)
#ifdef CONFIG_X86_THERMAL_VECTOR
if (maxlvt >= 5)
apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr);
#endif
#ifdef CONFIG_X86_MCE_INTEL
if (maxlvt >= 6)
apic_write(APIC_LVTCMCI, apic_pm_state.apic_cmci);
#endif
if (maxlvt >= 4)
apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
@ -2548,3 +2567,23 @@ static int __init apic_set_disabled_cpu_apicid(char *arg)
return 0;
}
early_param("disable_cpu_apicid", apic_set_disabled_cpu_apicid);
static int __init apic_set_extnmi(char *arg)
{
if (!arg)
return -EINVAL;
if (!strncmp("all", arg, 3))
apic_extnmi = APIC_EXTNMI_ALL;
else if (!strncmp("none", arg, 4))
apic_extnmi = APIC_EXTNMI_NONE;
else if (!strncmp("bsp", arg, 3))
apic_extnmi = APIC_EXTNMI_BSP;
else {
pr_warn("Unknown external NMI delivery mode `%s' ignored\n", arg);
return -EINVAL;
}
return 0;
}
early_param("apic_extnmi", apic_set_extnmi);

19
arch/x86/kernel/apic/apic_flat_64.c
View File

@ -185,6 +185,7 @@ static struct apic apic_flat = {
.cpu_mask_to_apicid_and = flat_cpu_mask_to_apicid_and,
.send_IPI = default_send_IPI_single,
.send_IPI_mask = flat_send_IPI_mask,
.send_IPI_mask_allbutself = flat_send_IPI_mask_allbutself,
.send_IPI_allbutself = flat_send_IPI_allbutself,
@ -230,17 +231,6 @@ static int physflat_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
return 0;
}
static void physflat_send_IPI_mask(const struct cpumask *cpumask, int vector)
{
default_send_IPI_mask_sequence_phys(cpumask, vector);
}
static void physflat_send_IPI_mask_allbutself(const struct cpumask *cpumask,
int vector)
{
default_send_IPI_mask_allbutself_phys(cpumask, vector);
}
static void physflat_send_IPI_allbutself(int vector)
{
default_send_IPI_mask_allbutself_phys(cpu_online_mask, vector);
@ -248,7 +238,7 @@ static void physflat_send_IPI_allbutself(int vector)
static void physflat_send_IPI_all(int vector)
{
physflat_send_IPI_mask(cpu_online_mask, vector);
default_send_IPI_mask_sequence_phys(cpu_online_mask, vector);
}
static int physflat_probe(void)
@ -292,8 +282,9 @@ static struct apic apic_physflat = {
.cpu_mask_to_apicid_and = default_cpu_mask_to_apicid_and,
.send_IPI_mask = physflat_send_IPI_mask,
.send_IPI_mask_allbutself = physflat_send_IPI_mask_allbutself,
.send_IPI = default_send_IPI_single_phys,
.send_IPI_mask = default_send_IPI_mask_sequence_phys,
.send_IPI_mask_allbutself = default_send_IPI_mask_allbutself_phys,
.send_IPI_allbutself = physflat_send_IPI_allbutself,
.send_IPI_all = physflat_send_IPI_all,
.send_IPI_self = apic_send_IPI_self,

2
arch/x86/kernel/apic/apic_noop.c
View File

@ -30,6 +30,7 @@
#include <asm/e820.h>
static void noop_init_apic_ldr(void) { }
static void noop_send_IPI(int cpu, int vector) { }
static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
static void noop_send_IPI_allbutself(int vector) { }
@ -144,6 +145,7 @@ struct apic apic_noop = {
.cpu_mask_to_apicid_and = flat_cpu_mask_to_apicid_and,
.send_IPI = noop_send_IPI,
.send_IPI_mask = noop_send_IPI_mask,
.send_IPI_mask_allbutself = noop_send_IPI_mask_allbutself,
.send_IPI_allbutself = noop_send_IPI_allbutself,

2
arch/x86/kernel/apic/apic_numachip.c
View File

@ -273,6 +273,7 @@ static const struct apic apic_numachip1 __refconst = {
.cpu_mask_to_apicid_and = default_cpu_mask_to_apicid_and,
.send_IPI = numachip_send_IPI_one,
.send_IPI_mask = numachip_send_IPI_mask,
.send_IPI_mask_allbutself = numachip_send_IPI_mask_allbutself,
.send_IPI_allbutself = numachip_send_IPI_allbutself,
@ -324,6 +325,7 @@ static const struct apic apic_numachip2 __refconst = {
.cpu_mask_to_apicid_and = default_cpu_mask_to_apicid_and,
.send_IPI = numachip_send_IPI_one,
.send_IPI_mask = numachip_send_IPI_mask,
.send_IPI_mask_allbutself = numachip_send_IPI_mask_allbutself,
.send_IPI_allbutself = numachip_send_IPI_allbutself,

10
arch/x86/kernel/apic/bigsmp_32.c
View File

@ -96,11 +96,6 @@ static int bigsmp_phys_pkg_id(int cpuid_apic, int index_msb)
return cpuid_apic >> index_msb;
}
static inline void bigsmp_send_IPI_mask(const struct cpumask *mask, int vector)
{
default_send_IPI_mask_sequence_phys(mask, vector);
}
static void bigsmp_send_IPI_allbutself(int vector)
{
default_send_IPI_mask_allbutself_phys(cpu_online_mask, vector);
@ -108,7 +103,7 @@ static void bigsmp_send_IPI_allbutself(int vector)
static void bigsmp_send_IPI_all(int vector)
{
bigsmp_send_IPI_mask(cpu_online_mask, vector);
default_send_IPI_mask_sequence_phys(cpu_online_mask, vector);
}
static int dmi_bigsmp; /* can be set by dmi scanners */
@ -180,7 +175,8 @@ static struct apic apic_bigsmp = {
.cpu_mask_to_apicid_and = default_cpu_mask_to_apicid_and,
.send_IPI_mask = bigsmp_send_IPI_mask,
.send_IPI = default_send_IPI_single_phys,
.send_IPI_mask = default_send_IPI_mask_sequence_phys,
.send_IPI_mask_allbutself = NULL,
.send_IPI_allbutself = bigsmp_send_IPI_allbutself,
.send_IPI_all = bigsmp_send_IPI_all,

18
arch/x86/kernel/apic/ipi.c
View File

@ -18,6 +18,16 @@
#include <asm/proto.h>
#include <asm/ipi.h>
void default_send_IPI_single_phys(int cpu, int vector)
{
unsigned long flags;
local_irq_save(flags);
__default_send_IPI_dest_field(per_cpu(x86_cpu_to_apicid, cpu),
vector, APIC_DEST_PHYSICAL);
local_irq_restore(flags);
}
void default_send_IPI_mask_sequence_phys(const struct cpumask *mask, int vector)
{
unsigned long query_cpu;
@ -55,6 +65,14 @@ void default_send_IPI_mask_allbutself_phys(const struct cpumask *mask,
local_irq_restore(flags);
}
/*
* Helper function for APICs which insist on cpumasks
*/
void default_send_IPI_single(int cpu, int vector)
{
apic->send_IPI_mask(cpumask_of(cpu), vector);
}
#ifdef CONFIG_X86_32
void default_send_IPI_mask_sequence_logical(const struct cpumask *mask,

8
arch/x86/kernel/apic/msi.c
View File

@ -96,8 +96,8 @@ static irq_hw_number_t pci_msi_get_hwirq(struct msi_domain_info *info,
return arg->msi_hwirq;
}
static int pci_msi_prepare(struct irq_domain *domain, struct device *dev,
int nvec, msi_alloc_info_t *arg)
int pci_msi_prepare(struct irq_domain *domain, struct device *dev, int nvec,
msi_alloc_info_t *arg)
{
struct pci_dev *pdev = to_pci_dev(dev);
struct msi_desc *desc = first_pci_msi_entry(pdev);
@ -113,11 +113,13 @@ static int pci_msi_prepare(struct irq_domain *domain, struct device *dev,
return 0;
}
EXPORT_SYMBOL_GPL(pci_msi_prepare);
static void pci_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
void pci_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
{
arg->msi_hwirq = pci_msi_domain_calc_hwirq(arg->msi_dev, desc);
}
EXPORT_SYMBOL_GPL(pci_msi_set_desc);
static struct msi_domain_ops pci_msi_domain_ops = {
.get_hwirq = pci_msi_get_hwirq,

1
arch/x86/kernel/apic/probe_32.c
View File

@ -105,6 +105,7 @@ static struct apic apic_default = {
.cpu_mask_to_apicid_and = flat_cpu_mask_to_apicid_and,
.send_IPI = default_send_IPI_single,
.send_IPI_mask = default_send_IPI_mask_logical,
.send_IPI_mask_allbutself = default_send_IPI_mask_allbutself_logical,
.send_IPI_allbutself = default_send_IPI_allbutself,

2
arch/x86/kernel/apic/vector.c
View File

@ -29,6 +29,7 @@ struct apic_chip_data {
};
struct irq_domain *x86_vector_domain;
EXPORT_SYMBOL_GPL(x86_vector_domain);
static DEFINE_RAW_SPINLOCK(vector_lock);
static cpumask_var_t vector_cpumask;
static struct irq_chip lapic_controller;
@ -66,6 +67,7 @@ struct irq_cfg *irqd_cfg(struct irq_data *irq_data)
return data ? &data->cfg : NULL;
}
EXPORT_SYMBOL_GPL(irqd_cfg);
struct irq_cfg *irq_cfg(unsigned int irq)
{

9
arch/x86/kernel/apic/x2apic_cluster.c
View File

@ -23,6 +23,14 @@ static inline u32 x2apic_cluster(int cpu)
return per_cpu(x86_cpu_to_logical_apicid, cpu) >> 16;
}
static void x2apic_send_IPI(int cpu, int vector)
{
u32 dest = per_cpu(x86_cpu_to_logical_apicid, cpu);
x2apic_wrmsr_fence();
__x2apic_send_IPI_dest(dest, vector, APIC_DEST_LOGICAL);
}
static void
__x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
{
@ -266,6 +274,7 @@ static struct apic apic_x2apic_cluster = {
.cpu_mask_to_apicid_and = x2apic_cpu_mask_to_apicid_and,
.send_IPI = x2apic_send_IPI,
.send_IPI_mask = x2apic_send_IPI_mask,
.send_IPI_mask_allbutself = x2apic_send_IPI_mask_allbutself,
.send_IPI_allbutself = x2apic_send_IPI_allbutself,

9
arch/x86/kernel/apic/x2apic_phys.c
View File

@ -36,6 +36,14 @@ static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
return x2apic_enabled() && (x2apic_phys || x2apic_fadt_phys());
}
static void x2apic_send_IPI(int cpu, int vector)
{
u32 dest = per_cpu(x86_cpu_to_apicid, cpu);
x2apic_wrmsr_fence();
__x2apic_send_IPI_dest(dest, vector, APIC_DEST_PHYSICAL);
}
static void
__x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
{
@ -122,6 +130,7 @@ static struct apic apic_x2apic_phys = {
.cpu_mask_to_apicid_and = default_cpu_mask_to_apicid_and,
.send_IPI = x2apic_send_IPI,
.send_IPI_mask = x2apic_send_IPI_mask,
.send_IPI_mask_allbutself = x2apic_send_IPI_mask_allbutself,
.send_IPI_allbutself = x2apic_send_IPI_allbutself,

1
arch/x86/kernel/apic/x2apic_uv_x.c
View File

@ -406,6 +406,7 @@ static struct apic __refdata apic_x2apic_uv_x = {
.cpu_mask_to_apicid_and = uv_cpu_mask_to_apicid_and,
.send_IPI = uv_send_IPI_one,
.send_IPI_mask = uv_send_IPI_mask,
.send_IPI_mask_allbutself = uv_send_IPI_mask_allbutself,
.send_IPI_allbutself = uv_send_IPI_allbutself,

32
arch/x86/kernel/nmi.c
View File

@ -29,6 +29,7 @@
#include <asm/mach_traps.h>
#include <asm/nmi.h>
#include <asm/x86_init.h>
#include <asm/reboot.h>
#define CREATE_TRACE_POINTS
#include <trace/events/nmi.h>
@ -231,7 +232,7 @@ pci_serr_error(unsigned char reason, struct pt_regs *regs)
#endif
if (panic_on_unrecovered_nmi)
panic("NMI: Not continuing");
nmi_panic(regs, "NMI: Not continuing");
pr_emerg("Dazed and confused, but trying to continue\n");
@ -255,8 +256,16 @@ io_check_error(unsigned char reason, struct pt_regs *regs)
reason, smp_processor_id());
show_regs(regs);
if (panic_on_io_nmi)
panic("NMI IOCK error: Not continuing");
if (panic_on_io_nmi) {
nmi_panic(regs, "NMI IOCK error: Not continuing");
/*
* If we end up here, it means we have received an NMI while
* processing panic(). Simply return without delaying and
* re-enabling NMIs.
*/
return;
}
/* Re-enable the IOCK line, wait for a few seconds */
reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_IOCHK;
@ -297,7 +306,7 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
pr_emerg("Do you have a strange power saving mode enabled?\n");
if (unknown_nmi_panic || panic_on_unrecovered_nmi)
panic("NMI: Not continuing");
nmi_panic(regs, "NMI: Not continuing");
pr_emerg("Dazed and confused, but trying to continue\n");
}
@ -348,8 +357,19 @@ static void default_do_nmi(struct pt_regs *regs)
return;
}
/* Non-CPU-specific NMI: NMI sources can be processed on any CPU */
raw_spin_lock(&nmi_reason_lock);
/*
* Non-CPU-specific NMI: NMI sources can be processed on any CPU.
*
* Another CPU may be processing panic routines while holding
* nmi_reason_lock. Check if the CPU issued the IPI for crash dumping,
* and if so, call its callback directly. If there is no CPU preparing
* crash dump, we simply loop here.
*/
while (!raw_spin_trylock(&nmi_reason_lock)) {
run_crash_ipi_callback(regs);
cpu_relax();
}
reason = x86_platform.get_nmi_reason();
if (reason & NMI_REASON_MASK) {

30
arch/x86/kernel/reboot.c
View File

@ -718,6 +718,7 @@ static int crashing_cpu;
static nmi_shootdown_cb shootdown_callback;
static atomic_t waiting_for_crash_ipi;
static int crash_ipi_issued;
static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
{
@ -780,6 +781,9 @@ void nmi_shootdown_cpus(nmi_shootdown_cb callback)
smp_send_nmi_allbutself();
/* Kick CPUs looping in NMI context. */
WRITE_ONCE(crash_ipi_issued, 1);
msecs = 1000; /* Wait at most a second for the other cpus to stop */
while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
mdelay(1);
@ -788,9 +792,35 @@ void nmi_shootdown_cpus(nmi_shootdown_cb callback)
/* Leave the nmi callback set */
}
/*
* Check if the crash dumping IPI got issued and if so, call its callback
* directly. This function is used when we have already been in NMI handler.
* It doesn't return.
*/
void run_crash_ipi_callback(struct pt_regs *regs)
{
if (crash_ipi_issued)
crash_nmi_callback(0, regs);
}
/* Override the weak function in kernel/panic.c */
void nmi_panic_self_stop(struct pt_regs *regs)
{
while (1) {
/* If no CPU is preparing crash dump, we simply loop here. */
run_crash_ipi_callback(regs);
cpu_relax();
}
}
#else /* !CONFIG_SMP */
void nmi_shootdown_cpus(nmi_shootdown_cb callback)
{
/* No other CPUs to shoot down */
}
void run_crash_ipi_callback(struct pt_regs *regs)
{
}
#endif

4
arch/x86/kernel/smp.c
View File

@ -125,12 +125,12 @@ static void native_smp_send_reschedule(int cpu)
WARN_ON(1);
return;
}
apic->send_IPI_mask(cpumask_of(cpu), RESCHEDULE_VECTOR);
apic->send_IPI(cpu, RESCHEDULE_VECTOR);
}
void native_send_call_func_single_ipi(int cpu)
{
apic->send_IPI_mask(cpumask_of(cpu), CALL_FUNCTION_SINGLE_VECTOR);
apic->send_IPI(cpu, CALL_FUNCTION_SINGLE_VECTOR);
}
void native_send_call_func_ipi(const struct cpumask *mask)

28
include/linux/kernel.h
View File

@ -255,6 +255,7 @@ extern long (*panic_blink)(int state);
__printf(1, 2)
void panic(const char *fmt, ...)
__noreturn __cold;
void nmi_panic_self_stop(struct pt_regs *);
extern void oops_enter(void);
extern void oops_exit(void);
void print_oops_end_marker(void);
@ -445,6 +446,33 @@ extern int sysctl_panic_on_stackoverflow;
extern bool crash_kexec_post_notifiers;
/*
* panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
* holds a CPU number which is executing panic() currently. A value of
* PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
*/
extern atomic_t panic_cpu;
#define PANIC_CPU_INVALID -1
/*
* A variant of panic() called from NMI context. We return if we've already
* panicked on this CPU. If another CPU already panicked, loop in
* nmi_panic_self_stop() which can provide architecture dependent code such
* as saving register state for crash dump.
*/
#define nmi_panic(regs, fmt, ...) \
do { \
int old_cpu, cpu; \
\
cpu = raw_smp_processor_id(); \
old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); \
\
if (old_cpu == PANIC_CPU_INVALID) \
panic(fmt, ##__VA_ARGS__); \
else if (old_cpu != cpu) \
nmi_panic_self_stop(regs); \
} while (0)
/*
* Only to be used by arch init code. If the user over-wrote the default
* CONFIG_PANIC_TIMEOUT, honor it.

2
include/linux/kexec.h
View File

@ -237,6 +237,7 @@ extern int kexec_purgatory_get_set_symbol(struct kimage *image,
unsigned int size, bool get_value);
extern void *kexec_purgatory_get_symbol_addr(struct kimage *image,
const char *name);
extern void __crash_kexec(struct pt_regs *);
extern void crash_kexec(struct pt_regs *);
int kexec_should_crash(struct task_struct *);
void crash_save_cpu(struct pt_regs *regs, int cpu);
@ -332,6 +333,7 @@ int __weak arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
#else /* !CONFIG_KEXEC_CORE */
struct pt_regs;
struct task_struct;
static inline void __crash_kexec(struct pt_regs *regs) { }
static inline void crash_kexec(struct pt_regs *regs) { }
static inline int kexec_should_crash(struct task_struct *p) { return 0; }
#define kexec_in_progress false

30
kernel/kexec_core.c
View File

@ -853,7 +853,12 @@ struct kimage *kexec_image;
struct kimage *kexec_crash_image;
int kexec_load_disabled;
void crash_kexec(struct pt_regs *regs)
/*
* No panic_cpu check version of crash_kexec(). This function is called
* only when panic_cpu holds the current CPU number; this is the only CPU
* which processes crash_kexec routines.
*/
void __crash_kexec(struct pt_regs *regs)
{
/* Take the kexec_mutex here to prevent sys_kexec_load
* running on one cpu from replacing the crash kernel
@ -876,6 +881,29 @@ void crash_kexec(struct pt_regs *regs)
}
}
void crash_kexec(struct pt_regs *regs)
{
int old_cpu, this_cpu;
/*
* Only one CPU is allowed to execute the crash_kexec() code as with
* panic(). Otherwise parallel calls of panic() and crash_kexec()
* may stop each other. To exclude them, we use panic_cpu here too.
*/
this_cpu = raw_smp_processor_id();
old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
if (old_cpu == PANIC_CPU_INVALID) {
/* This is the 1st CPU which comes here, so go ahead. */
__crash_kexec(regs);
/*
* Reset panic_cpu to allow another panic()/crash_kexec()
* call.
*/
atomic_set(&panic_cpu, PANIC_CPU_INVALID);
}
}
size_t crash_get_memory_size(void)
{
size_t size = 0;

33
kernel/panic.c
View File

@ -61,6 +61,17 @@ void __weak panic_smp_self_stop(void)
cpu_relax();
}
/*
* Stop ourselves in NMI context if another CPU has already panicked. Arch code
* may override this to prepare for crash dumping, e.g. save regs info.
*/
void __weak nmi_panic_self_stop(struct pt_regs *regs)
{
panic_smp_self_stop();
}
atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
/**
* panic - halt the system
* @fmt: The text string to print
@ -71,17 +82,17 @@ void __weak panic_smp_self_stop(void)
*/
void panic(const char *fmt, ...)
{
static DEFINE_SPINLOCK(panic_lock);
static char buf[1024];
va_list args;
long i, i_next = 0;
int state = 0;
int old_cpu, this_cpu;
/*
* Disable local interrupts. This will prevent panic_smp_self_stop
* from deadlocking the first cpu that invokes the panic, since
* there is nothing to prevent an interrupt handler (that runs
* after the panic_lock is acquired) from invoking panic again.
* after setting panic_cpu) from invoking panic() again.
*/
local_irq_disable();
@ -94,8 +105,16 @@ void panic(const char *fmt, ...)
* multiple parallel invocations of panic, all other CPUs either
* stop themself or will wait until they are stopped by the 1st CPU
* with smp_send_stop().
*
* `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which
* comes here, so go ahead.
* `old_cpu == this_cpu' means we came from nmi_panic() which sets
* panic_cpu to this CPU. In this case, this is also the 1st CPU.
*/
if (!spin_trylock(&panic_lock))
this_cpu = raw_smp_processor_id();
old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
panic_smp_self_stop();
console_verbose();
@ -117,9 +136,11 @@ void panic(const char *fmt, ...)
* everything else.
* If we want to run this after calling panic_notifiers, pass
* the "crash_kexec_post_notifiers" option to the kernel.
*
* Bypass the panic_cpu check and call __crash_kexec directly.
*/
if (!crash_kexec_post_notifiers)
crash_kexec(NULL);
__crash_kexec(NULL);
/*
* Note smp_send_stop is the usual smp shutdown function, which
@ -142,9 +163,11 @@ void panic(const char *fmt, ...)
* panic_notifiers and dumping kmsg before kdump.
* Note: since some panic_notifiers can make crashed kernel
* more unstable, it can increase risks of the kdump failure too.
*
* Bypass the panic_cpu check and call __crash_kexec directly.
*/
if (crash_kexec_post_notifiers)
crash_kexec(NULL);
__crash_kexec(NULL);
bust_spinlocks(0);

2
kernel/watchdog.c
View File

@ -351,7 +351,7 @@ static void watchdog_overflow_callback(struct perf_event *event,
trigger_allbutself_cpu_backtrace();
if (hardlockup_panic)
panic("Hard LOCKUP");
nmi_panic(regs, "Hard LOCKUP");
__this_cpu_write(hard_watchdog_warn, true);
return;