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linux/arch/blackfin/mach-common/interrupt.S
Philippe Gerum 9169b51f8c Blackfin/ipipe: fix deferred pipeline sync for the root stage 
This patch makes sure to sync the pipeline for the root stage only
from the outer interrupt level, when resuming kernel code after an
interrupt.

This fixes a bug causing EVT15 to be spuriously popped off upon nested
interrupts, which in turn would cause the preempted kernel code to
resume without supervisor privileges.

Signed-off-by: Philippe Gerum <rpm@xenomai.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:11 -04:00

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7.1 KiB
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/*
* Interrupt Entries
*
* Copyright 2005-2009 Analog Devices Inc.
* D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>
* Kenneth Albanowski <kjahds@kjahds.com>
*
* Licensed under the GPL-2 or later.
*/
#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
#ifdef CONFIG_TRACE_IRQFLAGS
[--sp] = r0;
sp += -12;
call _trace_hardirqs_off;
sp += 12;
r0 = [sp++];
#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
ANOMALY_283_315_WORKAROUND(p5, r7)
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 */
#ifdef CONFIG_PREEMPT
r7 = sp;
r4.l = lo(ALIGN_PAGE_MASK);
r4.h = hi(ALIGN_PAGE_MASK);
r7 = r7 & r4;
p5 = r7;
r7 = [p5 + TI_PREEMPT]; /* get preempt count */
r7 += 1; /* increment it */
[p5 + TI_PREEMPT] = r7;
#endif
pseudo_long_call _do_irq, p2;
#ifdef CONFIG_PREEMPT
r7 += -1;
[p5 + TI_PREEMPT] = r7; /* restore preempt count */
#endif
SP += 12;
#endif /* CONFIG_IPIPE */
pseudo_long_call _return_from_int, p2;
.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
ANOMALY_283_315_WORKAROUND(p5, r7)
/* 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;
pseudo_long_call _trap_c, p5;
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
pseudo_long_call _ret_from_exception, p2;
.Lcommon_restore_all_sys:
RESTORE_ALL_SYS
rti;
ENDPROC(_evt_ivhw)
/* Interrupt routine for evt2 (NMI).
* For inner circle type details, please see:
* http://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:nmi
*/
ENTRY(_evt_nmi)
#ifndef CONFIG_NMI_WATCHDOG
.weak _evt_nmi
#else
/* Not take account of CPLBs, this handler will not return */
SAVE_ALL_SYS
r0 = sp;
r1 = retn;
[sp + PT_PC] = r1;
trace_buffer_save(p4,r5);
ANOMALY_283_315_WORKAROUND(p4, r5)
SP += -12;
call _do_nmi;
SP += 12;
1:
jump 1b;
#endif
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
pseudo_long_call _system_call, p2;
jump .Lcommon_restore_context;
ENDPROC(_evt_system_call)
#ifdef CONFIG_IPIPE
/*
* __ipipe_call_irqtail: lowers the current priority level to EVT15
* before running a user-defined routine, then raises the priority
* level to EVT14 to prepare the caller for a normal interrupt
* return through RTI.
*
* We currently use this feature in two occasions:
*
* - before branching to __ipipe_irq_tail_hook as requested by a high
* priority domain after the pipeline delivered an interrupt,
* e.g. such as Xenomai, in order to start its rescheduling
* procedure, since we may not switch tasks when IRQ levels are
* nested on the Blackfin, so we have to fake an interrupt return
* so that we may reschedule immediately.
*
* - before branching to __ipipe_sync_root(), in order to play any interrupt
* pending for the root domain (i.e. the Linux kernel). This lowers
* the core priority level enough so that Linux IRQ handlers may
* never delay interrupts handled by high priority domains; we defer
* those handlers until this point instead. This is a substitute
* to using a threaded interrupt model for the Linux kernel.
*
* r0: address of user-defined routine
* context: caller must have preempted EVT15, hw interrupts must be off.
*/
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++];
#ifdef CONFIG_DEBUG_HWERR
/* enable irq14 & hwerr interrupt, until we transition to _evt_evt14 */
r0 = (EVT_IVG14 | EVT_IVHW | \
EVT_IRPTEN | EVT_EVX | EVT_NMI | EVT_RST | EVT_EMU);
#else
/* Only enable irq14 interrupt, until we transition to _evt_evt14 */
r0 = (EVT_IVG14 | \
EVT_IRPTEN | EVT_EVX | EVT_NMI | EVT_RST | EVT_EMU);
#endif
sti r0;
raise 14; /* Branches to _evt_evt14 */
2:
jump 2b; /* Likely paranoid. */
ENDPROC(___ipipe_call_irqtail)
#endif /* CONFIG_IPIPE */
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