![Michael Neuling](/assets/img/avatar_default.png)
In kexec_prepare_cpus, the primary CPU IPIs the secondary CPUs to kexec_smp_down(). kexec_smp_down() calls kexec_smp_wait() which sets the hw_cpu_id() to -1. The primary does this while leaving IRQs on which means the primary can take a timer interrupt which can lead to the IPIing one of the secondary CPUs (say, for a scheduler re-balance) but since the secondary CPU now has a hw_cpu_id = -1, we IPI CPU -1... Kaboom! We are hitting this case regularly on POWER7 machines. There is also a second race, where the primary will tear down the MMU mappings before knowing the secondaries have entered real mode. Also, the secondaries are clearing out any pending IPIs before guaranteeing that no more will be received. This changes kexec_prepare_cpus() so that we turn off IRQs in the primary CPU much earlier. It adds a paca flag to say that the secondaries have entered the kexec_smp_down() IPI and turned off IRQs, rather than overloading hw_cpu_id with -1. This new paca flag is again used to in indicate when the secondaries has entered real mode. It also ensures that all CPUs have their IRQs off before we clear out any pending IPI requests (in kexec_cpu_down()) to ensure there are no trailing IPIs left unacknowledged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
107 lines
2.8 KiB
C
107 lines
2.8 KiB
C
#ifndef _ASM_POWERPC_KEXEC_H
|
|
#define _ASM_POWERPC_KEXEC_H
|
|
#ifdef __KERNEL__
|
|
|
|
/*
|
|
* Maximum page that is mapped directly into kernel memory.
|
|
* XXX: Since we copy virt we can use any page we allocate
|
|
*/
|
|
#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
|
|
|
|
/*
|
|
* Maximum address we can reach in physical address mode.
|
|
* XXX: I want to allow initrd in highmem. Otherwise set to rmo on LPAR.
|
|
*/
|
|
#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
|
|
|
|
/* Maximum address we can use for the control code buffer */
|
|
#ifdef __powerpc64__
|
|
#define KEXEC_CONTROL_MEMORY_LIMIT (-1UL)
|
|
#else
|
|
/* TASK_SIZE, probably left over from use_mm ?? */
|
|
#define KEXEC_CONTROL_MEMORY_LIMIT TASK_SIZE
|
|
#endif
|
|
|
|
#define KEXEC_CONTROL_PAGE_SIZE 4096
|
|
|
|
/* The native architecture */
|
|
#ifdef __powerpc64__
|
|
#define KEXEC_ARCH KEXEC_ARCH_PPC64
|
|
#else
|
|
#define KEXEC_ARCH KEXEC_ARCH_PPC
|
|
#endif
|
|
|
|
#define KEXEC_STATE_NONE 0
|
|
#define KEXEC_STATE_IRQS_OFF 1
|
|
#define KEXEC_STATE_REAL_MODE 2
|
|
|
|
#ifndef __ASSEMBLY__
|
|
#include <linux/cpumask.h>
|
|
#include <asm/reg.h>
|
|
|
|
typedef void (*crash_shutdown_t)(void);
|
|
|
|
#ifdef CONFIG_KEXEC
|
|
|
|
/*
|
|
* This function is responsible for capturing register states if coming
|
|
* via panic or invoking dump using sysrq-trigger.
|
|
*/
|
|
static inline void crash_setup_regs(struct pt_regs *newregs,
|
|
struct pt_regs *oldregs)
|
|
{
|
|
if (oldregs)
|
|
memcpy(newregs, oldregs, sizeof(*newregs));
|
|
else
|
|
ppc_save_regs(newregs);
|
|
}
|
|
|
|
extern void kexec_smp_wait(void); /* get and clear naca physid, wait for
|
|
master to copy new code to 0 */
|
|
extern int crashing_cpu;
|
|
extern void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *));
|
|
extern cpumask_t cpus_in_sr;
|
|
static inline int kexec_sr_activated(int cpu)
|
|
{
|
|
return cpu_isset(cpu,cpus_in_sr);
|
|
}
|
|
|
|
struct kimage;
|
|
struct pt_regs;
|
|
extern void default_machine_kexec(struct kimage *image);
|
|
extern int default_machine_kexec_prepare(struct kimage *image);
|
|
extern void default_machine_crash_shutdown(struct pt_regs *regs);
|
|
extern int crash_shutdown_register(crash_shutdown_t handler);
|
|
extern int crash_shutdown_unregister(crash_shutdown_t handler);
|
|
|
|
extern void machine_kexec_simple(struct kimage *image);
|
|
extern void crash_kexec_secondary(struct pt_regs *regs);
|
|
extern int overlaps_crashkernel(unsigned long start, unsigned long size);
|
|
extern void reserve_crashkernel(void);
|
|
|
|
#else /* !CONFIG_KEXEC */
|
|
static inline int kexec_sr_activated(int cpu) { return 0; }
|
|
static inline void crash_kexec_secondary(struct pt_regs *regs) { }
|
|
|
|
static inline int overlaps_crashkernel(unsigned long start, unsigned long size)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void reserve_crashkernel(void) { ; }
|
|
|
|
static inline int crash_shutdown_register(crash_shutdown_t handler)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline int crash_shutdown_unregister(crash_shutdown_t handler)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_KEXEC */
|
|
#endif /* ! __ASSEMBLY__ */
|
|
#endif /* __KERNEL__ */
|
|
#endif /* _ASM_POWERPC_KEXEC_H */
|