On Wed, 2007-12-12 at 16:45 +1100, Michael Neuling wrote: > This adds hooks into the default_machine_crash_shutdown so drivers can > register a function to be run in the first kernel before we hand off > to the second kernel. This should only be used in exceptional > circumstances, like where the device can't be reset in the second > kernel alone (as is the case with eHEA). To emphasize this, the > number of handles allowed to be registered is currently #def to 1. > > This uses the setjmp/longjmp code to call out to the registered hooks, > so any bogus exceptions we encounter will hopefully be recoverable. > > I've tested with bogus data and instruction exceptions. > > Signed-off-by: Michael Neuling <[EMAIL PROTECTED]> > --- > > arch/powerpc/kernel/crash.c | 90 > +++++++++++++++++++++++++++++++++++++++++--- > include/asm-powerpc/kexec.h | 3 + > 2 files changed, 88 insertions(+), 5 deletions(-) > > Index: linux-2.6-ozlabs/arch/powerpc/kernel/crash.c > =================================================================== > --- linux-2.6-ozlabs.orig/arch/powerpc/kernel/crash.c > +++ linux-2.6-ozlabs/arch/powerpc/kernel/crash.c > @@ -32,6 +32,8 @@ > #include <asm/lmb.h> > #include <asm/firmware.h> > #include <asm/smp.h> > +#include <asm/system.h> > +#include <asm/setjmp.h> > > #ifdef DEBUG > #include <asm/udbg.h> > @@ -45,6 +47,11 @@ int crashing_cpu = -1; > static cpumask_t cpus_in_crash = CPU_MASK_NONE; > cpumask_t cpus_in_sr = CPU_MASK_NONE; > > +#define CRASH_SHUTDOWN_HANDLES_NUM 1
CRASH_HANDLER_MAX ?
> +/* NULL terminated list of shutdown handles */
> +static crash_shutdown_t crash_shutdown_handles[CRASH_SHUTDOWN_HANDLES_NUM+1];
> +static DEFINE_SPINLOCK(crash_handles_lock);
> +
> #ifdef CONFIG_SMP
> static atomic_t enter_on_soft_reset = ATOMIC_INIT(0);
>
> @@ -285,9 +292,69 @@ static inline void crash_kexec_stop_spus
> }
> #endif /* CONFIG_SPU_BASE */
>
> +/*
> + * Register a function to be called on shutdown. Only use this if you
> + * can't reset your device in the second kernel.
> + */
> +int crash_shutdown_register(crash_shutdown_t handler)
> +{
> + unsigned int i, rc;
> +
> + spin_lock(&crash_handles_lock);
> + for(i = 0 ; i <= CRASH_SHUTDOWN_HANDLES_NUM; i++) {
> + if (!crash_shutdown_handles[i]) {
> + /* Insert handle at end */
> + crash_shutdown_handles[i] = handler;
> + rc = 0;
> + break;
> + }
> + }
>
> + if (i == CRASH_SHUTDOWN_HANDLES_NUM){
> + printk(KERN_ERR "Crash shutdown handles full, "
> + "not registered.\n");
> + rc = 1;
> + }
> +
> + spin_unlock(&crash_handles_lock);
Perhaps?
> + return rc;
> +}
> +EXPORT_SYMBOL(crash_shutdown_register);
> +
> +int crash_shutdown_unregister(crash_shutdown_t handler)
> +{
> + unsigned int i;
> +
> + spin_lock(&crash_handles_lock);
> + for(i = 0 ; i <= CRASH_SHUTDOWN_HANDLES_NUM; i++)
> + if (crash_shutdown_handles[i] == handler)
> + break;
> +
> + if (i == CRASH_SHUTDOWN_HANDLES_NUM){
> + printk(KERN_ERR "Crash shutdown handle not found\n");
> + spin_unlock(&crash_handles_lock);
> + return 1;
> + }
> +
> + /* Shift handles down */
> + while(crash_shutdown_handles[i]) {
> + crash_shutdown_handles[i] = crash_shutdown_handles[i+1];
> + i++;
> + }
> + spin_unlock(&crash_handles_lock);
> + return 0;
> +}
> +EXPORT_SYMBOL(crash_shutdown_unregister);
> +
> +static long crash_shutdown_buf[SETJMP_BUF_LEN];
unsigned long?
> +
> +static int handle_fault(struct pt_regs *regs)
> +{
> + longjmp(crash_shutdown_buf, 1);
> + return 0;
> +}
> +
> void default_machine_crash_shutdown(struct pt_regs *regs)
> {
> - unsigned int irq;
> + unsigned int i;
>
> /*
> * This function is only called after the system
> @@ -301,14 +368,27 @@ void default_machine_crash_shutdown(stru
> */
> hard_irq_disable();
>
> - for_each_irq(irq) {
> - struct irq_desc *desc = irq_desc + irq;
> + for_each_irq(i) {
> + struct irq_desc *desc = irq_desc + i;
>
> if (desc->status & IRQ_INPROGRESS)
> - desc->chip->eoi(irq);
> + desc->chip->eoi(i);
>
> if (!(desc->status & IRQ_DISABLED))
> - desc->chip->disable(irq);
> + desc->chip->disable(i);
> + }
> +
> + /* Call registered shutdown routines */
> + __debugger_fault_handler = handle_fault;
> + i = 0;
> + while(crash_shutdown_handles[i]){
> + if (setjmp(crash_shutdown_buf) == 0) {
> + asm volatile("sync; isync");
> + crash_shutdown_handles[i]();
> + asm volatile("sync; isync");
> + __delay(200);
> + }
> + i++;
> }
You should probably reset __debugger_fault_handler, just to be safe.
cheers
--
Michael Ellerman
OzLabs, IBM Australia Development Lab
wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)
We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person
signature.asc
Description: This is a digitally signed message part
_______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
