Piteball/android_kernel_google_msm
1
0
Fork 0
mirror of https://github.com/followmsi/android_kernel_google_msm.git synced 2024-11-06 23:17:41 +00:00
Code Issues Projects Releases Wiki Activity

powerpc: Remove broken and complicated kdump system reset code

Browse source 
We have a lot of complicated logic that handles possible recursion between
kdump and a system reset exception. We can solve this in a much simpler
way using the same setjmp/longjmp tricks xmon does.

As a first step, this patch removes the old system reset code.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Anton Blanchard 2011-11-30 00:23:10 +00:00 committed by Benjamin Herrenschmidt
parent 58154c8ce7
commit 9b00ac0697
3 changed files with 25 additions and 101 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
arch/powerpc/include/asm/kexec.h
View file

@ -73,11 +73,6 @@ 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 cpumask_test_cpu(cpu, &cpus_in_sr);
}
struct kimage;
struct pt_regs;
@ -94,7 +89,6 @@ extern void reserve_crashkernel(void);
extern void machine_kexec_mask_interrupts(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)

87
arch/powerpc/kernel/crash.c
View file

@ -47,7 +47,6 @@
/* This keeps a track of which one is crashing cpu. */
int crashing_cpu = -1;
static cpumask_t cpus_in_crash = CPU_MASK_NONE;
cpumask_t cpus_in_sr = CPU_MASK_NONE;
#define CRASH_HANDLER_MAX 3
/* NULL terminated list of shutdown handles */
@ -55,7 +54,6 @@ static crash_shutdown_t crash_shutdown_handles[CRASH_HANDLER_MAX+1];
static DEFINE_SPINLOCK(crash_handlers_lock);
#ifdef CONFIG_SMP
static atomic_t enter_on_soft_reset = ATOMIC_INIT(0);
void crash_ipi_callback(struct pt_regs *regs)
{
@ -69,24 +67,9 @@ void crash_ipi_callback(struct pt_regs *regs)
crash_save_cpu(regs, cpu);
cpumask_set_cpu(cpu, &cpus_in_crash);
/*
* Entered via soft-reset - could be the kdump
* process is invoked using soft-reset or user activated
* it if some CPU did not respond to an IPI.
* For soft-reset, the secondary CPU can enter this func
* twice. 1 - using IPI, and 2. soft-reset.
* Tell the kexec CPU that entered via soft-reset and ready
* to go down.
*/
if (cpumask_test_cpu(cpu, &cpus_in_sr)) {
cpumask_clear_cpu(cpu, &cpus_in_sr);
atomic_inc(&enter_on_soft_reset);
}
/*
* Starting the kdump boot.
* This barrier is needed to make sure that all CPUs are stopped.
* If not, soft-reset will be invoked to bring other CPUs.
*/
while (!cpumask_test_cpu(crashing_cpu, &cpus_in_crash))
cpu_relax();
@ -103,25 +86,14 @@ void crash_ipi_callback(struct pt_regs *regs)
/* NOTREACHED */
}
/*
* Wait until all CPUs are entered via soft-reset.
*/
static void crash_soft_reset_check(int cpu)
{
unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
cpumask_clear_cpu(cpu, &cpus_in_sr);
while (atomic_read(&enter_on_soft_reset) != ncpus)
cpu_relax();
}
static void crash_kexec_prepare_cpus(int cpu)
{
unsigned int msecs;
unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
printk(KERN_EMERG "Sending IPI to other CPUs\n");
crash_send_ipi(crash_ipi_callback);
smp_wmb();
@ -131,7 +103,6 @@ static void crash_kexec_prepare_cpus(int cpu)
* respond.
* Delay of at least 10 seconds.
*/
printk(KERN_EMERG "Sending IPI to other cpus...\n");
msecs = 10000;
while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
cpu_relax();
@ -140,69 +111,36 @@ static void crash_kexec_prepare_cpus(int cpu)
/* Would it be better to replace the trap vector here? */
/*
* FIXME: In case if we do not get all CPUs, one possibility: ask the
* user to do soft reset such that we get all.
* Soft-reset will be used until better mechanism is implemented.
*/
if (cpumask_weight(&cpus_in_crash) < ncpus) {
printk(KERN_EMERG "done waiting: %d cpu(s) not responding\n",
printk(KERN_EMERG "ERROR: %d CPU(s) not responding\n",
ncpus - cpumask_weight(&cpus_in_crash));
printk(KERN_EMERG "Activate soft-reset to stop other cpu(s)\n");
cpumask_clear(&cpus_in_sr);
atomic_set(&enter_on_soft_reset, 0);
while (cpumask_weight(&cpus_in_crash) < ncpus)
cpu_relax();
}
/*
* Make sure all CPUs are entered via soft-reset if the kdump is
* invoked using soft-reset.
*/
if (cpumask_test_cpu(cpu, &cpus_in_sr))
crash_soft_reset_check(cpu);
/* Leave the IPI callback set */
printk(KERN_EMERG "IPI complete\n");
}
/*
* This function will be called by secondary cpus or by kexec cpu
* if soft-reset is activated to stop some CPUs.
* This function will be called by secondary cpus.
*/
void crash_kexec_secondary(struct pt_regs *regs)
{
int cpu = smp_processor_id();
unsigned long flags;
int msecs = 5;
int msecs = 500;
local_irq_save(flags);
/* Wait 5ms if the kexec CPU is not entered yet. */
/* Wait 500ms for the primary crash CPU to signal its progress */
while (crashing_cpu < 0) {
if (--msecs < 0) {
/*
* Either kdump image is not loaded or
* kdump process is not started - Probably xmon
* exited using 'x'(exit and recover) or
* kexec_should_crash() failed for all running tasks.
*/
cpumask_clear_cpu(cpu, &cpus_in_sr);
/* No response, kdump image may not have been loaded */
local_irq_restore(flags);
return;
}
mdelay(1);
cpu_relax();
}
if (cpu == crashing_cpu) {
/*
* Panic CPU will enter this func only via soft-reset.
* Wait until all secondary CPUs entered and
* then start kexec boot.
*/
crash_soft_reset_check(cpu);
cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
if (ppc_md.kexec_cpu_down)
ppc_md.kexec_cpu_down(1, 0);
machine_kexec(kexec_crash_image);
/* NOTREACHED */
}
crash_ipi_callback(regs);
}
@ -225,7 +163,6 @@ static void crash_kexec_prepare_cpus(int cpu)
void crash_kexec_secondary(struct pt_regs *regs)
{
cpumask_clear(&cpus_in_sr);
}
#endif /* CONFIG_SMP */

33
arch/powerpc/kernel/traps.c
View file

@ -162,10 +162,20 @@ int die(const char *str, struct pt_regs *regs, long err)
printk("\n");
raw_spin_unlock_irqrestore(&die.lock, flags);
if (kexec_should_crash(current) ||
kexec_sr_activated(smp_processor_id()))
/*
* A system reset (0x100) is a request to dump, so we always send
* it through the crashdump code.
*/
if (kexec_should_crash(current) || (TRAP(regs) == 0x100)) {
crash_kexec(regs);
crash_kexec_secondary(regs);
/*
* We aren't the primary crash CPU. We need to send it
* to a holding pattern to avoid it ending up in the panic
* code.
*/
crash_kexec_secondary(regs);
}
/*
* While our oops output is serialised by a spinlock, output
@ -232,25 +242,8 @@ void system_reset_exception(struct pt_regs *regs)
return;
}
#ifdef CONFIG_KEXEC
cpumask_set_cpu(smp_processor_id(), &cpus_in_sr);
#endif
die("System Reset", regs, SIGABRT);
/*
* Some CPUs when released from the debugger will execute this path.
* These CPUs entered the debugger via a soft-reset. If the CPU was
* hung before entering the debugger it will return to the hung
* state when exiting this function. This causes a problem in
* kdump since the hung CPU(s) will not respond to the IPI sent
* from kdump. To prevent the problem we call crash_kexec_secondary()
* here. If a kdump had not been initiated or we exit the debugger
* with the "exit and recover" command (x) crash_kexec_secondary()
* will return after 5ms and the CPU returns to its previous state.
*/
crash_kexec_secondary(regs);
/* Must die if the interrupt is not recoverable */
if (!(regs->msr & MSR_RI))
panic("Unrecoverable System Reset");