* [PATCH V3 1/3] riscv: kexec: Disable all interrupts in kexec crash path
2022-08-19 2:54 [PATCH V3 0/3] riscv: kexec: Fixup crash_save percpu and machine_kexec_mask_interrupts guoren
@ 2022-08-19 2:54 ` guoren
2022-08-19 2:54 ` [PATCH V3 2/3] riscv: kexec: Fixup crash_smp_send_stop with percpu crash_save_cpu guoren
2022-08-19 2:54 ` [PATCH V3 3/3] arch: crash: Remove duplicate declaration in smp.h guoren
2 siblings, 0 replies; 5+ messages in thread
From: guoren @ 2022-08-19 2:54 UTC (permalink / raw)
To: xianting.tian, palmer, heiko, guoren, conor.dooley
Cc: linux-arch, linux-kernel, linux-riscv, liaochang1, mick, jszhang,
Guo Ren, Will Deacon, AKASHI Takahiro
From: Guo Ren <guoren@linux.alibaba.com>
If a crash happens on cpu3 and all interrupts are binding on cpu0, the
bad irq routing will cause a crash kernel which can't receive any irq.
Because crash kernel won't clean up all harts' PLIC enable bits in
enable registers. This patch is similar to 9141a003a491 ("ARM: 7316/1:
kexec: EOI active and mask all interrupts in kexec crash path") and
78fd584cdec0 ("arm64: kdump: implement machine_crash_shutdown()"), and
PowerPC also has the same mechanism.
Fixes: fba8a8674f68 ("RISC-V: Add kexec support")
Reviewed-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Nick Kossifidis <mick@ics.forth.gr>
---
arch/riscv/kernel/machine_kexec.c | 35 +++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c
index ee79e6839b86..db41c676e5a2 100644
--- a/arch/riscv/kernel/machine_kexec.c
+++ b/arch/riscv/kernel/machine_kexec.c
@@ -15,6 +15,8 @@
#include <linux/compiler.h> /* For unreachable() */
#include <linux/cpu.h> /* For cpu_down() */
#include <linux/reboot.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
/*
* kexec_image_info - Print received image details
@@ -154,6 +156,37 @@ void crash_smp_send_stop(void)
cpus_stopped = 1;
}
+static void machine_kexec_mask_interrupts(void)
+{
+ unsigned int i;
+ struct irq_desc *desc;
+
+ for_each_irq_desc(i, desc) {
+ struct irq_chip *chip;
+ int ret;
+
+ chip = irq_desc_get_chip(desc);
+ if (!chip)
+ continue;
+
+ /*
+ * First try to remove the active state. If this
+ * fails, try to EOI the interrupt.
+ */
+ ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
+
+ if (ret && irqd_irq_inprogress(&desc->irq_data) &&
+ chip->irq_eoi)
+ chip->irq_eoi(&desc->irq_data);
+
+ if (chip->irq_mask)
+ chip->irq_mask(&desc->irq_data);
+
+ if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
+ chip->irq_disable(&desc->irq_data);
+ }
+}
+
/*
* machine_crash_shutdown - Prepare to kexec after a kernel crash
*
@@ -169,6 +202,8 @@ machine_crash_shutdown(struct pt_regs *regs)
crash_smp_send_stop();
crash_save_cpu(regs, smp_processor_id());
+ machine_kexec_mask_interrupts();
+
pr_info("Starting crashdump kernel...\n");
}
--
2.36.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH V3 2/3] riscv: kexec: Fixup crash_smp_send_stop with percpu crash_save_cpu
2022-08-19 2:54 [PATCH V3 0/3] riscv: kexec: Fixup crash_save percpu and machine_kexec_mask_interrupts guoren
2022-08-19 2:54 ` [PATCH V3 1/3] riscv: kexec: Disable all interrupts in kexec crash path guoren
@ 2022-08-19 2:54 ` guoren
2022-08-19 2:54 ` [PATCH V3 3/3] arch: crash: Remove duplicate declaration in smp.h guoren
2 siblings, 0 replies; 5+ messages in thread
From: guoren @ 2022-08-19 2:54 UTC (permalink / raw)
To: xianting.tian, palmer, heiko, guoren, conor.dooley
Cc: linux-arch, linux-kernel, linux-riscv, liaochang1, mick, jszhang,
Guo Ren, AKASHI Takahiro
From: Guo Ren <guoren@linux.alibaba.com>
Current crash_smp_send_stop is the same as the generic one in
kernel/panic and misses crash_save_cpu in percpu. This patch is inspired
by 78fd584cdec0 ("arm64: kdump: implement machine_crash_shutdown()")
and adds the same mechanism for riscv.
Fixes: ad943893d5f1 ("RISC-V: Fixup schedule out issue in machine_crash_shutdown()")
Reviewed-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
arch/riscv/include/asm/smp.h | 3 ++
arch/riscv/kernel/machine_kexec.c | 21 ++------
arch/riscv/kernel/smp.c | 89 ++++++++++++++++++++++++++++++-
3 files changed, 95 insertions(+), 18 deletions(-)
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index d3443be7eedc..3831b638ecab 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -50,6 +50,9 @@ void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops);
/* Clear IPI for current CPU */
void riscv_clear_ipi(void);
+/* Check other CPUs stop or not */
+bool smp_crash_stop_failed(void);
+
/* Secondary hart entry */
asmlinkage void smp_callin(void);
diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c
index db41c676e5a2..2d139b724bc8 100644
--- a/arch/riscv/kernel/machine_kexec.c
+++ b/arch/riscv/kernel/machine_kexec.c
@@ -140,22 +140,6 @@ void machine_shutdown(void)
#endif
}
-/* Override the weak function in kernel/panic.c */
-void crash_smp_send_stop(void)
-{
- static int cpus_stopped;
-
- /*
- * This function can be called twice in panic path, but obviously
- * we execute this only once.
- */
- if (cpus_stopped)
- return;
-
- smp_send_stop();
- cpus_stopped = 1;
-}
-
static void machine_kexec_mask_interrupts(void)
{
unsigned int i;
@@ -230,6 +214,11 @@ machine_kexec(struct kimage *image)
void *control_code_buffer = page_address(image->control_code_page);
riscv_kexec_method kexec_method = NULL;
+#ifdef CONFIG_SMP
+ WARN(smp_crash_stop_failed(),
+ "Some CPUs may be stale, kdump will be unreliable.\n");
+#endif
+
if (image->type != KEXEC_TYPE_CRASH)
kexec_method = control_code_buffer;
else
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 760a64518c58..a75ad9c373cd 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -12,6 +12,7 @@
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/module.h>
+#include <linux/kexec.h>
#include <linux/profile.h>
#include <linux/smp.h>
#include <linux/sched.h>
@@ -27,6 +28,7 @@ enum ipi_message_type {
IPI_RESCHEDULE,
IPI_CALL_FUNC,
IPI_CPU_STOP,
+ IPI_CPU_CRASH_STOP,
IPI_IRQ_WORK,
IPI_TIMER,
IPI_MAX
@@ -71,6 +73,22 @@ static void ipi_stop(void)
wait_for_interrupt();
}
+#ifdef CONFIG_KEXEC_CORE
+static atomic_t waiting_for_crash_ipi = ATOMIC_INIT(0);
+
+static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
+{
+ crash_save_cpu(regs, cpu);
+
+ atomic_dec(&waiting_for_crash_ipi);
+
+ local_irq_disable();
+
+ while(1)
+ wait_for_interrupt();
+}
+#endif
+
static const struct riscv_ipi_ops *ipi_ops __ro_after_init;
void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops)
@@ -124,8 +142,9 @@ void arch_irq_work_raise(void)
void handle_IPI(struct pt_regs *regs)
{
- unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
- unsigned long *stats = ipi_data[smp_processor_id()].stats;
+ unsigned int cpu = smp_processor_id();
+ unsigned long *pending_ipis = &ipi_data[cpu].bits;
+ unsigned long *stats = ipi_data[cpu].stats;
riscv_clear_ipi();
@@ -154,6 +173,13 @@ void handle_IPI(struct pt_regs *regs)
ipi_stop();
}
+ if (ops & (1 << IPI_CPU_CRASH_STOP)) {
+#ifdef CONFIG_KEXEC_CORE
+ ipi_cpu_crash_stop(cpu, get_irq_regs());
+#endif
+ unreachable();
+ }
+
if (ops & (1 << IPI_IRQ_WORK)) {
stats[IPI_IRQ_WORK]++;
irq_work_run();
@@ -176,6 +202,7 @@ static const char * const ipi_names[] = {
[IPI_RESCHEDULE] = "Rescheduling interrupts",
[IPI_CALL_FUNC] = "Function call interrupts",
[IPI_CPU_STOP] = "CPU stop interrupts",
+ [IPI_CPU_CRASH_STOP] = "CPU stop (for crash dump) interrupts",
[IPI_IRQ_WORK] = "IRQ work interrupts",
[IPI_TIMER] = "Timer broadcast interrupts",
};
@@ -235,6 +262,64 @@ void smp_send_stop(void)
cpumask_pr_args(cpu_online_mask));
}
+#ifdef CONFIG_KEXEC_CORE
+/*
+ * The number of CPUs online, not counting this CPU (which may not be
+ * fully online and so not counted in num_online_cpus()).
+ */
+static inline unsigned int num_other_online_cpus(void)
+{
+ unsigned int this_cpu_online = cpu_online(smp_processor_id());
+
+ return num_online_cpus() - this_cpu_online;
+}
+
+void crash_smp_send_stop(void)
+{
+ static int cpus_stopped;
+ cpumask_t mask;
+ unsigned long timeout;
+
+ /*
+ * This function can be called twice in panic path, but obviously
+ * we execute this only once.
+ */
+ if (cpus_stopped)
+ return;
+
+ cpus_stopped = 1;
+
+ /*
+ * If this cpu is the only one alive at this point in time, online or
+ * not, there are no stop messages to be sent around, so just back out.
+ */
+ if (num_other_online_cpus() == 0)
+ return;
+
+ cpumask_copy(&mask, cpu_online_mask);
+ cpumask_clear_cpu(smp_processor_id(), &mask);
+
+ atomic_set(&waiting_for_crash_ipi, num_other_online_cpus());
+
+ pr_crit("SMP: stopping secondary CPUs\n");
+ send_ipi_mask(&mask, IPI_CPU_CRASH_STOP);
+
+ /* Wait up to one second for other CPUs to stop */
+ timeout = USEC_PER_SEC;
+ while ((atomic_read(&waiting_for_crash_ipi) > 0) && timeout--)
+ udelay(1);
+
+ if (atomic_read(&waiting_for_crash_ipi) > 0)
+ pr_warn("SMP: failed to stop secondary CPUs %*pbl\n",
+ cpumask_pr_args(&mask));
+}
+
+bool smp_crash_stop_failed(void)
+{
+ return (atomic_read(&waiting_for_crash_ipi) > 0);
+}
+#endif
+
void smp_send_reschedule(int cpu)
{
send_ipi_single(cpu, IPI_RESCHEDULE);
--
2.36.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH V3 3/3] arch: crash: Remove duplicate declaration in smp.h
2022-08-19 2:54 [PATCH V3 0/3] riscv: kexec: Fixup crash_save percpu and machine_kexec_mask_interrupts guoren
2022-08-19 2:54 ` [PATCH V3 1/3] riscv: kexec: Disable all interrupts in kexec crash path guoren
2022-08-19 2:54 ` [PATCH V3 2/3] riscv: kexec: Fixup crash_smp_send_stop with percpu crash_save_cpu guoren
@ 2022-08-19 2:54 ` guoren
2022-08-20 9:41 ` Catalin Marinas
2 siblings, 1 reply; 5+ messages in thread
From: guoren @ 2022-08-19 2:54 UTC (permalink / raw)
To: xianting.tian, palmer, heiko, guoren, conor.dooley
Cc: linux-arch, linux-kernel, linux-riscv, liaochang1, mick, jszhang,
Guo Ren, Arnd Bergmann, Will Deacon, Catalin Marinas, x86
From: Guo Ren <guoren@linux.alibaba.com>
Remove crash_smp_send_stop declarations in arm64, x86 asm/smp.h which
has been done in include/linux/smp.h.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: x86@kernel.org
---
arch/arm64/include/asm/smp.h | 1 -
arch/x86/include/asm/crash.h | 1 -
2 files changed, 2 deletions(-)
diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h
index fc55f5a57a06..a108ac93fd8f 100644
--- a/arch/arm64/include/asm/smp.h
+++ b/arch/arm64/include/asm/smp.h
@@ -141,7 +141,6 @@ static inline void cpu_panic_kernel(void)
*/
bool cpus_are_stuck_in_kernel(void);
-extern void crash_smp_send_stop(void);
extern bool smp_crash_stop_failed(void);
extern void panic_smp_self_stop(void);
diff --git a/arch/x86/include/asm/crash.h b/arch/x86/include/asm/crash.h
index 8b6bd63530dc..6a9be4907c82 100644
--- a/arch/x86/include/asm/crash.h
+++ b/arch/x86/include/asm/crash.h
@@ -7,6 +7,5 @@ struct kimage;
int crash_load_segments(struct kimage *image);
int crash_setup_memmap_entries(struct kimage *image,
struct boot_params *params);
-void crash_smp_send_stop(void);
#endif /* _ASM_X86_CRASH_H */
--
2.36.1
^ permalink raw reply related [flat|nested] 5+ messages in thread