From: marc.zyngier@arm•com (Marc Zyngier)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v12 12/16] arm64: kdump: implement machine_crash_shutdown()
Date: Fri, 27 Nov 2015 14:39:35 +0000 [thread overview]
Message-ID: <56586B27.9080508@arm.com> (raw)
In-Reply-To: <9ae67f7515c66bfd747486c8dc1c1772913a8d46.1448403503.git.geoff@infradead.org>
On 24/11/15 22:25, Geoff Levand wrote:
> From: AKASHI Takahiro <takahiro.akashi@linaro•org>
>
> kdump calls machine_crash_shutdown() to shut down non-boot cpus and
> save registers' status in per-cpu ELF notes before starting the crash
> dump kernel. See kernel_kexec().
>
> ipi_cpu_stop() is a bit modified and used to support this behavior.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro•org>
> ---
> arch/arm64/include/asm/kexec.h | 34 +++++++++++++++++++++++++++++++++-
> arch/arm64/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++--
> arch/arm64/kernel/smp.c | 16 ++++++++++++++--
> 3 files changed, 76 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index 46d63cd..555a955 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -30,6 +30,8 @@
>
> #if !defined(__ASSEMBLY__)
>
> +extern bool in_crash_kexec;
> +
> /**
> * crash_setup_regs() - save registers for the panic kernel
> *
> @@ -40,7 +42,37 @@
> static inline void crash_setup_regs(struct pt_regs *newregs,
> struct pt_regs *oldregs)
> {
> - /* Empty routine needed to avoid build errors. */
> + if (oldregs) {
> + memcpy(newregs, oldregs, sizeof(*newregs));
> + } else {
> + __asm__ __volatile__ (
> + "stp x0, x1, [%3, #16 * 0]\n"
> + "stp x2, x3, [%3, #16 * 1]\n"
> + "stp x4, x5, [%3, #16 * 2]\n"
> + "stp x6, x7, [%3, #16 * 3]\n"
> + "stp x8, x9, [%3, #16 * 4]\n"
> + "stp x10, x11, [%3, #16 * 5]\n"
> + "stp x12, x13, [%3, #16 * 6]\n"
> + "stp x14, x15, [%3, #16 * 7]\n"
> + "stp x16, x17, [%3, #16 * 8]\n"
> + "stp x18, x19, [%3, #16 * 9]\n"
> + "stp x20, x21, [%3, #16 * 10]\n"
> + "stp x22, x23, [%3, #16 * 11]\n"
> + "stp x24, x25, [%3, #16 * 12]\n"
> + "stp x26, x27, [%3, #16 * 13]\n"
> + "stp x28, x29, [%3, #16 * 14]\n"
> + "str x30, [%3, #16 * 15]\n"
> + "mov %0, sp\n"
> + "adr %1, 1f\n"
> + "mrs %2, spsr_el1\n"
> + "1:"
> + : "=r" (newregs->sp),
> + "=r" (newregs->pc),
> + "=r" (newregs->pstate)
> + : "r" (&newregs->regs)
> + : "memory"
> + );
I wonder how useful this thing is, given that it starts by corrupting
whatever register is holding newregs->regs. Maybe this is not supposed
to be accurate anyway...
> + }
> }
>
> #endif /* !defined(__ASSEMBLY__) */
> diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
> index da28a26..d2d7e90 100644
> --- a/arch/arm64/kernel/machine_kexec.c
> +++ b/arch/arm64/kernel/machine_kexec.c
> @@ -9,6 +9,7 @@
> * published by the Free Software Foundation.
> */
>
> +#include <linux/kernel.h>
> #include <linux/kexec.h>
> #include <linux/of_fdt.h>
> #include <linux/slab.h>
> @@ -23,6 +24,7 @@
> extern const unsigned char arm64_relocate_new_kernel[];
> extern const unsigned long arm64_relocate_new_kernel_size;
>
> +bool in_crash_kexec;
> static unsigned long kimage_start;
>
> /**
> @@ -203,13 +205,38 @@ void machine_kexec(struct kimage *kimage)
> */
>
> cpu_soft_restart(virt_to_phys(cpu_reset),
> - is_hyp_mode_available(),
> + in_crash_kexec ? 0 : is_hyp_mode_available(),
> reboot_code_buffer_phys, kimage->head, kimage_start);
>
> BUG(); /* Should never get here. */
> }
>
> +/**
> + * machine_crash_shutdown - shutdown non-boot cpus and save registers
> + */
> void machine_crash_shutdown(struct pt_regs *regs)
> {
> - /* Empty routine needed to avoid build errors. */
> + struct pt_regs dummy_regs;
> + int cpu;
> +
> + local_irq_disable();
> +
> + in_crash_kexec = true;
> +
> + /*
> + * clear and initialize the per-cpu info. This is necessary
> + * because, otherwise, slots for offline cpus would never be
> + * filled up. See smp_send_stop().
> + */
> + memset(&dummy_regs, 0, sizeof(dummy_regs));
> + for_each_possible_cpu(cpu)
> + crash_save_cpu(&dummy_regs, cpu);
> +
> + /* shutdown non-boot cpus */
> + smp_send_stop();
> +
> + /* for boot cpu */
> + crash_save_cpu(regs, smp_processor_id());
> +
> + pr_info("Starting crashdump kernel...\n");
> }
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index b1adc51..15aabef 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -37,6 +37,7 @@
> #include <linux/completion.h>
> #include <linux/of.h>
> #include <linux/irq_work.h>
> +#include <linux/kexec.h>
>
> #include <asm/alternative.h>
> #include <asm/atomic.h>
> @@ -54,6 +55,8 @@
> #include <asm/ptrace.h>
> #include <asm/virt.h>
>
> +#include "cpu-reset.h"
> +
> #define CREATE_TRACE_POINTS
> #include <trace/events/ipi.h>
>
> @@ -683,8 +686,12 @@ static DEFINE_RAW_SPINLOCK(stop_lock);
> /*
> * ipi_cpu_stop - handle IPI from smp_send_stop()
> */
> -static void ipi_cpu_stop(unsigned int cpu)
> +static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)
> {
> +#ifdef CONFIG_KEXEC
> + /* printing messages may slow down the shutdown. */
> + if (!in_crash_kexec)
> +#endif
> if (system_state == SYSTEM_BOOTING ||
> system_state == SYSTEM_RUNNING) {
> raw_spin_lock(&stop_lock);
Irrespective of how useful this change is, how about having a predicate
instead? Something like:
static inline bool is_in_crash_kexec(void)
{
#ifdef CONFIG_KEXEC
return in_crash_kexec;
#else
return false;
#endif
}
located in machine_kexec.c (making the in_crash_kernel static), and then
if (!is_in_crash_kexec() && (systen_state == ... || ...) {
It would certainly look better.
> @@ -697,6 +704,11 @@ static void ipi_cpu_stop(unsigned int cpu)
>
> local_irq_disable();
>
> +#ifdef CONFIG_KEXEC
> + if (in_crash_kexec)
> + crash_save_cpu(regs, cpu);
> +#endif /* CONFIG_KEXEC */
> +
Same here.
> while (1)
> cpu_relax();
> }
> @@ -727,7 +739,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
>
> case IPI_CPU_STOP:
> irq_enter();
> - ipi_cpu_stop(cpu);
> + ipi_cpu_stop(cpu, regs);
> irq_exit();
> break;
>
>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2015-11-27 14:39 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-24 22:25 [PATCH v12 00/16] arm64 kexec kernel patches v12 Geoff Levand
2015-11-24 22:25 ` [PATCH v12 04/16] arm64: kvm: allows kvm cpu hotplug Geoff Levand
2015-11-27 13:54 ` Marc Zyngier
2015-12-02 22:40 ` Ashwin Chaugule
2015-12-03 13:55 ` Ashwin Chaugule
2015-12-03 13:58 ` Marc Zyngier
2015-12-10 18:31 ` Geoff Levand
2015-12-11 16:31 ` Will Deacon
2015-12-15 8:48 ` AKASHI Takahiro
2015-12-10 18:44 ` Shi, Yang
2015-12-11 8:09 ` AKASHI Takahiro
2015-12-14 18:00 ` Shi, Yang
2015-12-11 8:06 ` AKASHI Takahiro
2015-12-11 13:00 ` Shanker Donthineni
2015-12-11 16:28 ` Marc Zyngier
2015-12-11 18:00 ` Shanker Donthineni
2015-12-11 18:11 ` Marc Zyngier
2015-12-11 19:11 ` Shanker Donthineni
2015-12-11 20:13 ` Ashwin Chaugule
2015-12-14 7:33 ` AKASHI Takahiro
2015-12-14 17:33 ` Marc Zyngier
2015-12-15 7:51 ` AKASHI Takahiro
2015-12-15 8:45 ` Marc Zyngier
2015-12-15 9:51 ` AKASHI Takahiro
2015-12-15 10:13 ` Marc Zyngier
2015-11-24 22:25 ` [PATCH v12 01/16] arm64: Fold proc-macros.S into assembler.h Geoff Levand
2015-11-24 22:25 ` [PATCH v12 02/16] arm64: Convert hcalls to use HVC immediate value Geoff Levand
2015-11-24 22:25 ` [PATCH v12 05/16] arm64: Add back cpu_reset routines Geoff Levand
2015-11-27 14:19 ` Marc Zyngier
2015-11-30 5:28 ` Pratyush Anand
2015-11-30 10:40 ` Marc Zyngier
2015-12-02 22:57 ` Geoff Levand
2015-12-03 9:32 ` Will Deacon
2015-12-10 0:49 ` Geoff Levand
2015-12-10 10:17 ` Will Deacon
2015-11-30 20:03 ` Geoff Levand
2015-12-01 9:38 ` Marc Zyngier
2015-11-24 22:25 ` [PATCH v12 06/16] Revert "arm64: mm: remove unused cpu_set_idmap_tcr_t0sz function" Geoff Levand
2015-11-24 22:25 ` [PATCH v12 03/16] arm64: Add new hcall HVC_CALL_FUNC Geoff Levand
2015-11-24 22:25 ` [PATCH v12 07/16] Revert "arm64: remove dead code" Geoff Levand
2015-11-24 22:25 ` [PATCH v12 10/16] arm64/kexec: Enable kexec in the arm64 defconfig Geoff Levand
2015-11-24 22:25 ` [PATCH v12 14/16] arm64: kdump: update a kernel doc Geoff Levand
2015-12-15 17:17 ` Will Deacon
2015-12-16 5:48 ` AKASHI Takahiro
2015-11-24 22:25 ` [PATCH v12 11/16] arm64: kdump: reserve memory for crash dump kernel Geoff Levand
2015-12-15 17:29 ` Will Deacon
2015-12-16 5:19 ` AKASHI Takahiro
2015-12-16 7:36 ` Pratyush Anand
2015-11-24 22:25 ` [PATCH v12 13/16] arm64: kdump: add kdump support Geoff Levand
2015-12-15 17:45 ` Will Deacon
2015-12-16 5:41 ` AKASHI Takahiro
2015-11-24 22:25 ` [PATCH v12 12/16] arm64: kdump: implement machine_crash_shutdown() Geoff Levand
2015-11-27 14:39 ` Marc Zyngier [this message]
2015-12-10 11:34 ` AKASHI Takahiro
2015-12-10 11:44 ` Marc Zyngier
2015-12-10 12:55 ` AKASHI Takahiro
2015-12-10 13:43 ` Marc Zyngier
2015-12-03 4:15 ` Pratyush Anand
2015-12-10 11:42 ` AKASHI Takahiro
2015-12-10 11:50 ` Pratyush Anand
2015-11-24 22:25 ` [PATCH v12 09/16] arm64/kexec: Add pr_devel output Geoff Levand
2015-12-15 17:15 ` Will Deacon
2015-12-16 0:45 ` Geoff Levand
2015-12-16 0:46 ` [PATCH v12.4] arm64/kexec: Add pr_debug output Geoff Levand
2015-11-24 22:25 ` [PATCH v12 16/16] arm64: kdump: relax BUG_ON() if more than one cpus are still active Geoff Levand
2015-12-15 17:05 ` Will Deacon
2015-12-16 5:51 ` AKASHI Takahiro
2015-11-24 22:25 ` [PATCH v12 15/16] arm64: kdump: enable kdump in the arm64 defconfig Geoff Levand
2015-11-24 22:25 ` [PATCH v12 08/16] arm64/kexec: Add core kexec support Geoff Levand
2015-11-27 13:13 ` Pratyush Anand
2015-11-30 18:51 ` Geoff Levand
2015-12-01 2:16 ` Pratyush Anand
2015-12-01 18:32 ` Azriel Samson
2015-12-02 22:49 ` Geoff Levand
2015-12-03 4:37 ` Azriel Samson
2015-12-03 19:56 ` Geoff Levand
2015-12-04 0:39 ` Azriel Samson
2015-12-04 3:54 ` Pratyush Anand
2015-12-07 18:47 ` Geoff Levand
2015-12-03 6:09 ` Pratyush Anand
2015-12-01 19:03 ` Mark Rutland
2015-12-02 21:08 ` Geoff Levand
2015-12-03 16:06 ` Mark Rutland
2015-12-15 18:29 ` Will Deacon
2015-12-16 0:14 ` Geoff Levand
2015-12-16 7:18 ` Pratyush Anand
2015-12-16 9:30 ` James Morse
2015-12-16 10:32 ` Pratyush Anand
2015-12-16 0:14 ` [PATCH v12.4] " Geoff Levand
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