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MIPS: kexec: Make a framework for both jumping and halting on nonboot CPUs

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The existing implementation lets machine_kexec() CPU jump to reboot code
buffer, whereas other CPUs to relocated_kexec_smp_wait. The natural way to
bring up an SMP new kernel would be to let CPU0 do it while others being
halted. For those failing to do so, fall back to the jumping method.

Signed-off-by: Dengcheng Zhu <dzhu@wavecomp.com>
[paul.burton@mips.com: Guard kexec_nonboot_cpu_jump with CONFIG_SMP]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20570/
Cc: pburton@wavecomp.com
Cc: ralf@linux-mips.org
Cc: linux-mips@linux-mips.org
Cc: rachel.mozes@intel.com
This commit is contained in:
Dengcheng Zhu 2018-09-11 14:49:21 -07:00 • committed by Paul Burton
parent dc57aaf95a
commit 62cac480f3
No known key found for this signature in database
GPG key ID: 3EA79FACB57500DD
8 changed files with 126 additions and 10 deletions
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90
arch/mips/kernel/machine_kexec.c
View file

@ -19,15 +19,19 @@ extern const size_t relocate_new_kernel_size;
extern unsigned long kexec_start_address;
extern unsigned long kexec_indirection_page;
int (*_machine_kexec_prepare)(struct kimage *) = NULL;
void (*_machine_kexec_shutdown)(void) = NULL;
void (*_machine_crash_shutdown)(struct pt_regs *regs) = NULL;
static unsigned long reboot_code_buffer;
#ifdef CONFIG_SMP
void (*relocated_kexec_smp_wait) (void *);
static void (*relocated_kexec_smp_wait)(void *);
atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0);
void (*_crash_smp_send_stop)(void) = NULL;
#endif
int (*_machine_kexec_prepare)(struct kimage *) = NULL;
void (*_machine_kexec_shutdown)(void) = NULL;
void (*_machine_crash_shutdown)(struct pt_regs *regs) = NULL;
static void kexec_image_info(const struct kimage *kimage)
{
unsigned long i;
@ -51,10 +55,16 @@ static void kexec_image_info(const struct kimage *kimage)
int
machine_kexec_prepare(struct kimage *kimage)
{
#ifdef CONFIG_SMP
if (!kexec_nonboot_cpu_func())
return -EINVAL;
#endif
kexec_image_info(kimage);
if (_machine_kexec_prepare)
return _machine_kexec_prepare(kimage);
return 0;
}
@ -63,11 +73,41 @@ machine_kexec_cleanup(struct kimage *kimage)
{
}
#ifdef CONFIG_SMP
static void kexec_shutdown_secondary(void *param)
{
int cpu = smp_processor_id();
if (!cpu_online(cpu))
return;
/* We won't be sent IPIs any more. */
set_cpu_online(cpu, false);
local_irq_disable();
while (!atomic_read(&kexec_ready_to_reboot))
cpu_relax();
kexec_reboot();
/* NOTREACHED */
}
#endif
void
machine_shutdown(void)
{
if (_machine_kexec_shutdown)
_machine_kexec_shutdown();
#ifdef CONFIG_SMP
smp_call_function(kexec_shutdown_secondary, NULL, 0);
while (num_online_cpus() > 1) {
cpu_relax();
mdelay(1);
}
#endif
}
void
@ -79,12 +119,47 @@ machine_crash_shutdown(struct pt_regs *regs)
default_machine_crash_shutdown(regs);
}
typedef void (*noretfun_t)(void) __noreturn;
#ifdef CONFIG_SMP
void kexec_nonboot_cpu_jump(void)
{
local_flush_icache_range((unsigned long)relocated_kexec_smp_wait,
reboot_code_buffer + relocate_new_kernel_size);
relocated_kexec_smp_wait(NULL);
}
#endif
void kexec_reboot(void)
{
void (*do_kexec)(void) __noreturn;
#ifdef CONFIG_SMP
if (smp_processor_id() > 0) {
/*
* Instead of cpu_relax() or wait, this is needed for kexec
* smp reboot. Kdump usually doesn't require an smp new
* kernel, but kexec may do.
*/
kexec_nonboot_cpu();
/* NOTREACHED */
}
#endif
/*
* Make sure we get correct instructions written by the
* machine_kexec() CPU.
*/
local_flush_icache_range(reboot_code_buffer,
reboot_code_buffer + relocate_new_kernel_size);
do_kexec = (void *)reboot_code_buffer;
do_kexec();
}
void
machine_kexec(struct kimage *image)
{
unsigned long reboot_code_buffer;
unsigned long entry;
unsigned long *ptr;
@ -128,6 +203,7 @@ machine_kexec(struct kimage *image)
printk("Will call new kernel at %08lx\n", image->start);
printk("Bye ...\n");
/* Make reboot code buffer available to the boot CPU. */
__flush_cache_all();
#ifdef CONFIG_SMP
/* All secondary cpus now may jump to kexec_wait cycle */
@ -136,5 +212,5 @@ machine_kexec(struct kimage *image)
smp_wmb();
atomic_set(&kexec_ready_to_reboot, 1);
#endif
((noretfun_t) reboot_code_buffer)();
kexec_reboot();
}