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Blackfin: make EVT3->EVT5 lowering more robust wrt IPEND[4]

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We handle many exceptions at EVT5 (hardware error level) so that we can
catch exceptions in our exception handling code.  Today - if the global
interrupt enable bit (IPEND[4]) is set (interrupts disabled) our trap
handling code goes into a infinite loop, since we need interrupts to be
on to defer things to EVT5.

Normal kernel code should not trigger this for any reason as IPEND[4] gets
cleared early (when doing an interrupt context save) and the kernel stack
there should be sane (or something much worse is happening in the system).
But there have been a few times where this has happened, so this change
makes sure we dump a proper crash message even when things have gone south.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
This commit is contained in:
Robin Getz
2009-06-22 02:02:16 +00:00
committed by Mike Frysinger
parent d4b834c139
commit ae4f073c40
4 changed files with 66 additions and 41 deletions
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1
arch/blackfin/kernel/asm-offsets.c
View File

@ -145,6 +145,7 @@ int main(void)
DEFINE(PDA_EXBUF, offsetof(struct blackfin_pda, ex_buf));
DEFINE(PDA_EXIMASK, offsetof(struct blackfin_pda, ex_imask));
DEFINE(PDA_EXSTACK, offsetof(struct blackfin_pda, ex_stack));
DEFINE(PDA_EXIPEND, offsetof(struct blackfin_pda, ex_ipend));
#ifdef ANOMALY_05000261
DEFINE(PDA_LFRETX, offsetof(struct blackfin_pda, last_cplb_fault_retx));
#endif

19
arch/blackfin/kernel/traps.c
View File

@ -267,11 +267,6 @@ asmlinkage void trap_c(struct pt_regs *fp)
* double faults if the stack has become corrupt
*/
#ifndef CONFIG_KGDB
/* IPEND is skipped if KGDB isn't enabled (see entry code) */
fp->ipend = bfin_read_IPEND();
#endif
/* trap_c() will be called for exceptions. During exceptions
* processing, the pc value should be set with retx value.
* With this change we can cleanup some code in signal.c- TODO
@ -1116,10 +1111,16 @@ void show_regs(struct pt_regs *fp)
verbose_printk(KERN_NOTICE "%s", linux_banner);
verbose_printk(KERN_NOTICE "\nSEQUENCER STATUS:\t\t%s\n",
print_tainted());
verbose_printk(KERN_NOTICE " SEQSTAT: %08lx IPEND: %04lx SYSCFG: %04lx\n",
(long)fp->seqstat, fp->ipend, fp->syscfg);
verbose_printk(KERN_NOTICE "\nSEQUENCER STATUS:\t\t%s\n", print_tainted());
verbose_printk(KERN_NOTICE " SEQSTAT: %08lx IPEND: %04lx IMASK: %04lx SYSCFG: %04lx\n",
(long)fp->seqstat, fp->ipend, cpu_pda[smp_processor_id()].ex_imask, fp->syscfg);
if (fp->ipend & EVT_IRPTEN)
verbose_printk(KERN_NOTICE " Global Interrupts Disabled (IPEND[4])\n");
if (!(cpu_pda[smp_processor_id()].ex_imask & (EVT_IVG13 | EVT_IVG12 | EVT_IVG11 |
EVT_IVG10 | EVT_IVG9 | EVT_IVG8 | EVT_IVG7 | EVT_IVTMR)))
verbose_printk(KERN_NOTICE " Peripheral interrupts masked off\n");
if (!(cpu_pda[smp_processor_id()].ex_imask & (EVT_IVG15 | EVT_IVG14)))
verbose_printk(KERN_NOTICE " Kernel interrupts masked off\n");
if ((fp->seqstat & SEQSTAT_EXCAUSE) == VEC_HWERR) {
verbose_printk(KERN_NOTICE " HWERRCAUSE: 0x%lx\n",
(fp->seqstat & SEQSTAT_HWERRCAUSE) >> 14);