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linux/arch/blackfin/mach-common/interrupt.S
Robin Getz b9a3899d59 Blackfin: make deferred hardware errors more exact 
Hardware errors on the Blackfin architecture are queued by nature of the
hardware design.  Things that could generate a hardware level queue up at
the system interface and might not process until much later, at which
point the system would send a notification back to the core.

As such, it is possible for user space code to do something that would
trigger a hardware error, but have it delay long enough for the process
context to switch.  So when the hardware error does signal, we mistakenly
evaluate it as a different process or as kernel context and panic (erp!).
This makes it pretty difficult to find the offending context.  But wait,
there is good news somewhere.

By forcing a SSYNC in the interrupt entry, we force all pending queues at
the system level to be processed and all hardware errors to be signaled.
Then we check the current interrupt state to see if the hardware error is
now signaled.  If so, we re-queue the current interrupt and return thus
allowing the higher priority hardware error interrupt to process properly.
Since we haven't done any other context processing yet, the right context
will be selected and killed.  There is still the possibility that the
exact offending instruction will be unknown, but at least we'll have a
much better idea of where to look.

The downside of course is that this causes system-wide syncs at every
interrupt point which results in significant performance degradation.
Since this situation should not occur in any properly configured system
(as hardware errors are triggered by things like bad pointers), make it a
debug configuration option and disable it by default.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-06-12 06:11:44 -04:00

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/*
* File: arch/blackfin/mach-common/interrupt.S
* Based on:
* Author: D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>
* Kenneth Albanowski <kjahds@kjahds.com>
*
* Created: ?
* Description: Interrupt Entries
*
* Modified:
* Copyright 2004-2006 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <asm/blackfin.h>
#include <mach/irq.h>
#include <linux/linkage.h>
#include <asm/entry.h>
#include <asm/asm-offsets.h>
#include <asm/trace.h>
#include <asm/traps.h>
#include <asm/thread_info.h>
#include <asm/context.S>
.extern _ret_from_exception
#ifdef CONFIG_I_ENTRY_L1
.section .l1.text
#else
.text
#endif
.align 4 /* just in case */
/* Common interrupt entry code. First we do CLI, then push
* RETI, to keep interrupts disabled, but to allow this state to be changed
* by local_bh_enable.
* R0 contains the interrupt number, while R1 may contain the value of IPEND,
* or garbage if IPEND won't be needed by the ISR. */
__common_int_entry:
[--sp] = fp;
[--sp] = usp;
[--sp] = i0;
[--sp] = i1;
[--sp] = i2;
[--sp] = i3;
[--sp] = m0;
[--sp] = m1;
[--sp] = m2;
[--sp] = m3;
[--sp] = l0;
[--sp] = l1;
[--sp] = l2;
[--sp] = l3;
[--sp] = b0;
[--sp] = b1;
[--sp] = b2;
[--sp] = b3;
[--sp] = a0.x;
[--sp] = a0.w;
[--sp] = a1.x;
[--sp] = a1.w;
[--sp] = LC0;
[--sp] = LC1;
[--sp] = LT0;
[--sp] = LT1;
[--sp] = LB0;
[--sp] = LB1;
[--sp] = ASTAT;
[--sp] = r0; /* Skip reserved */
[--sp] = RETS;
r2 = RETI;
[--sp] = r2;
[--sp] = RETX;
[--sp] = RETN;
[--sp] = RETE;
[--sp] = SEQSTAT;
[--sp] = r1; /* IPEND - R1 may or may not be set up before jumping here. */
/* Switch to other method of keeping interrupts disabled. */
#ifdef CONFIG_DEBUG_HWERR
r1 = 0x3f;
sti r1;
#else
cli r1;
#endif
[--sp] = RETI; /* orig_pc */
/* Clear all L registers. */
r1 = 0 (x);
l0 = r1;
l1 = r1;
l2 = r1;
l3 = r1;
#ifdef CONFIG_FRAME_POINTER
fp = 0;
#endif
#if ANOMALY_05000283 || ANOMALY_05000315
cc = r7 == r7;
p5.h = HI(CHIPID);
p5.l = LO(CHIPID);
if cc jump 1f;
r7.l = W[p5];
1:
#endif
r1 = sp;
SP += -12;
#ifdef CONFIG_IPIPE
call ___ipipe_grab_irq
SP += 12;
cc = r0 == 0;
if cc jump .Lcommon_restore_context;
#else /* CONFIG_IPIPE */
call _do_irq;
SP += 12;
#endif /* CONFIG_IPIPE */
call _return_from_int;
.Lcommon_restore_context:
RESTORE_CONTEXT
rti;
/* interrupt routine for ivhw - 5 */
ENTRY(_evt_ivhw)
/* In case a single action kicks off multiple memory transactions, (like
* a cache line fetch, - this can cause multiple hardware errors, let's
* catch them all. First - make sure all the actions are complete, and
* the core sees the hardware errors.
*/
SSYNC;
SSYNC;
SAVE_ALL_SYS
#ifdef CONFIG_FRAME_POINTER
fp = 0;
#endif
#if ANOMALY_05000283 || ANOMALY_05000315
cc = r7 == r7;
p5.h = HI(CHIPID);
p5.l = LO(CHIPID);
if cc jump 1f;
r7.l = W[p5];
1:
#endif
/* Handle all stacked hardware errors
* To make sure we don't hang forever, only do it 10 times
*/
R0 = 0;
R2 = 10;
1:
P0.L = LO(ILAT);
P0.H = HI(ILAT);
R1 = [P0];
CC = BITTST(R1, EVT_IVHW_P);
IF ! CC JUMP 2f;
/* OK a hardware error is pending - clear it */
R1 = EVT_IVHW_P;
[P0] = R1;
R0 += 1;
CC = R1 == R2;
if CC JUMP 2f;
JUMP 1b;
2:
# We are going to dump something out, so make sure we print IPEND properly
p2.l = lo(IPEND);
p2.h = hi(IPEND);
r0 = [p2];
[sp + PT_IPEND] = r0;
/* set the EXCAUSE to HWERR for trap_c */
r0 = [sp + PT_SEQSTAT];
R1.L = LO(VEC_HWERR);
R1.H = HI(VEC_HWERR);
R0 = R0 | R1;
[sp + PT_SEQSTAT] = R0;
r0 = sp; /* stack frame pt_regs pointer argument ==> r0 */
SP += -12;
call _trap_c;
SP += 12;
#ifdef EBIU_ERRMST
/* make sure EBIU_ERRMST is clear */
p0.l = LO(EBIU_ERRMST);
p0.h = HI(EBIU_ERRMST);
r0.l = (CORE_ERROR | CORE_MERROR);
w[p0] = r0.l;
#endif
call _ret_from_exception;
.Lcommon_restore_all_sys:
RESTORE_ALL_SYS
rti;
ENDPROC(_evt_ivhw)
/* Interrupt routine for evt2 (NMI).
* We don't actually use this, so just return.
* For inner circle type details, please see:
* http://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:nmi
*/
ENTRY(_evt_nmi)
.weak _evt_nmi
rtn;
ENDPROC(_evt_nmi)
/* interrupt routine for core timer - 6 */
ENTRY(_evt_timer)
TIMER_INTERRUPT_ENTRY(EVT_IVTMR_P)
/* interrupt routine for evt7 - 7 */
ENTRY(_evt_evt7)
INTERRUPT_ENTRY(EVT_IVG7_P)
ENTRY(_evt_evt8)
INTERRUPT_ENTRY(EVT_IVG8_P)
ENTRY(_evt_evt9)
INTERRUPT_ENTRY(EVT_IVG9_P)
ENTRY(_evt_evt10)
INTERRUPT_ENTRY(EVT_IVG10_P)
ENTRY(_evt_evt11)
INTERRUPT_ENTRY(EVT_IVG11_P)
ENTRY(_evt_evt12)
INTERRUPT_ENTRY(EVT_IVG12_P)
ENTRY(_evt_evt13)
INTERRUPT_ENTRY(EVT_IVG13_P)
/* interrupt routine for system_call - 15 */
ENTRY(_evt_system_call)
SAVE_CONTEXT_SYSCALL
#ifdef CONFIG_FRAME_POINTER
fp = 0;
#endif
call _system_call;
jump .Lcommon_restore_context;
ENDPROC(_evt_system_call)
#ifdef CONFIG_IPIPE
ENTRY(___ipipe_call_irqtail)
p0 = r0;
r0.l = 1f;
r0.h = 1f;
reti = r0;
rti;
1:
[--sp] = rets;
[--sp] = ( r7:4, p5:3 );
sp += -12;
call (p0);
sp += 12;
( r7:4, p5:3 ) = [sp++];
rets = [sp++];
[--sp] = reti;
reti = [sp++]; /* IRQs are off. */
r0.h = 3f;
r0.l = 3f;
p0.l = lo(EVT14);
p0.h = hi(EVT14);
[p0] = r0;
csync;
r0 = 0x401f (z);
sti r0;
raise 14;
[--sp] = reti; /* IRQs on. */
2:
jump 2b; /* Likely paranoid. */
3:
sp += 4; /* Discard saved RETI */
r0.h = _evt14_softirq;
r0.l = _evt14_softirq;
p0.l = lo(EVT14);
p0.h = hi(EVT14);
[p0] = r0;
csync;
p0.l = _bfin_irq_flags;
p0.h = _bfin_irq_flags;
r0 = [p0];
sti r0;
rts;
ENDPROC(___ipipe_call_irqtail)
#endif /* CONFIG_IPIPE */
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