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| author | Max Filippov <jcmvbkbc@gmail.com> | 2013-03-26 02:51:43 +0400 |
|---|---|---|
| committer | Chris Zankel <chris@zankel.net> | 2013-05-09 01:07:11 -0700 |
| commit | 895666a9920f19bc256340aaf58d01da6e677a16 (patch) | |
| tree | ff0b0fc50790d6ae5a37c5317e67523985f87bbd /arch/xtensa/kernel/entry.S | |
| parent | 8f371c7521545ee120364466514a4a2fc156c64f (diff) | |
| download | linux-895666a9920f19bc256340aaf58d01da6e677a16.tar.gz linux-895666a9920f19bc256340aaf58d01da6e677a16.tar.bz2 linux-895666a9920f19bc256340aaf58d01da6e677a16.zip | |
xtensa: disable IRQs while IRQ handler is running
IRQ handlers are expected to run with IRQs disabled.
See e.g. http://lwn.net/Articles/380931/ for a longer story.
This was overlooked in the commit
2d1c645 xtensa: dispatch medium-priority interrupts
Revert to old behavior and simplify interrupt entry and exit code.
Interrupt handler still honours IRQ priority.
do_notify_resume/schedule must be called with interrupts enabled, enable
interrupts if we return from user exception.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'arch/xtensa/kernel/entry.S')
| -rw-r--r-- | arch/xtensa/kernel/entry.S | 52 |
1 files changed, 11 insertions, 41 deletions
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index 3729b48d798d..5082507d5631 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -354,16 +354,16 @@ common_exception: * so we can allow exceptions and interrupts (*) again. * Set PS(EXCM = 0, UM = 0, RING = 0, OWB = 0, WOE = 1, INTLEVEL = X) * - * (*) We only allow interrupts of higher priority than current IRQ + * (*) We only allow interrupts if they were previously enabled and + * we're not handling an IRQ */ rsr a3, ps - addi a0, a0, -4 - movi a2, 1 + addi a0, a0, -EXCCAUSE_LEVEL1_INTERRUPT + movi a2, LOCKLEVEL extui a3, a3, PS_INTLEVEL_SHIFT, PS_INTLEVEL_WIDTH # a3 = PS.INTLEVEL - movnez a2, a3, a3 # a2 = 1: level-1, > 1: high priority - moveqz a3, a2, a0 # a3 = IRQ level iff interrupt + moveqz a3, a2, a0 # a3 = LOCKLEVEL iff interrupt movi a2, 1 << PS_WOE_BIT or a3, a3, a2 rsr a0, exccause @@ -444,6 +444,8 @@ common_exception_return: 1: l32i a3, a1, PT_PS _bbci.l a3, PS_UM_BIT, 4f + rsil a2, 0 + /* Specific to a user exception exit: * We need to check some flags for signal handling and rescheduling, * and have to restore WB and WS, extra states, and all registers @@ -684,51 +686,19 @@ common_exception_exit: l32i a0, a1, PT_DEPC l32i a3, a1, PT_AREG3 - _bltui a0, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f - - wsr a0, depc l32i a2, a1, PT_AREG2 - l32i a0, a1, PT_AREG0 - l32i a1, a1, PT_AREG1 - rfde + _bgeui a0, VALID_DOUBLE_EXCEPTION_ADDRESS, 1f -1: /* Restore a0...a3 and return */ - rsr a0, ps - extui a2, a0, PS_INTLEVEL_SHIFT, PS_INTLEVEL_WIDTH - movi a0, 2f - slli a2, a2, 4 - add a0, a2, a0 - l32i a2, a1, PT_AREG2 - jx a0 - - .macro irq_exit_level level - .align 16 - .if XCHAL_EXCM_LEVEL >= \level - l32i a0, a1, PT_PC - wsr a0, epc\level l32i a0, a1, PT_AREG0 l32i a1, a1, PT_AREG1 - rfi \level - .endif - .endm + rfe - .align 16 -2: +1: wsr a0, depc l32i a0, a1, PT_AREG0 l32i a1, a1, PT_AREG1 - rfe - - .align 16 - /* no rfi for level-1 irq, handled by rfe above*/ - nop - - irq_exit_level 2 - irq_exit_level 3 - irq_exit_level 4 - irq_exit_level 5 - irq_exit_level 6 + rfde ENDPROC(kernel_exception) |