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powerpc: Disable interrupts in 64-bit kernel FP and vector faults

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If we get a floating point, altivec or vsx unavaible interrupt in
kernel, we trigger a kernel error. There is no point preserving
the interrupt state, in fact, that can even make debugging harder
as the processor state might change (we may even preempt) between
taking the exception and landing in a debugger.

So just make those 3 disable interrupts unconditionally.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

v2: On BookE only disable when hitting the kernel unavailable
    path, otherwise it will fail to restore softe as
    fast_exception_return doesn't do it.
This commit is contained in:
Benjamin Herrenschmidt 2012-03-01 15:47:44 +11:00
parent a546498f3b
commit 9f2f79e3a3
3 changed files with 9 additions and 7 deletions
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7
arch/powerpc/kernel/exceptions-64e.S
View file

@ -354,9 +354,9 @@ interrupt_end_book3e:
/* we can probably do a shorter exception entry for that one... */
EXCEPTION_COMMON(0x800, PACA_EXGEN, INTS_KEEP)
bne 1f /* if from user, just load it up */
INTS_DISABLE_ALL
bl .save_nvgprs
addi r3,r1,STACK_FRAME_OVERHEAD
INTS_RESTORE_HARD
bl .kernel_fp_unavailable_exception
BUG_OPCODE
1: ld r12,_MSR(r1)
@ -391,10 +391,9 @@ interrupt_end_book3e:
/* Auxiliary Processor Unavailable Interrupt */
START_EXCEPTION(ap_unavailable);
NORMAL_EXCEPTION_PROLOG(0xf20, PROLOG_ADDITION_NONE)
EXCEPTION_COMMON(0xf20, PACA_EXGEN, INTS_KEEP)
addi r3,r1,STACK_FRAME_OVERHEAD
EXCEPTION_COMMON(0xf20, PACA_EXGEN, INTS_DISABLE_ALL)
bl .save_nvgprs
INTS_RESTORE_HARD
addi r3,r1,STACK_FRAME_OVERHEAD
bl .unknown_exception
b .ret_from_except

6
arch/powerpc/kernel/exceptions-64s.S
View file

@ -762,8 +762,8 @@ fp_unavailable_common:
EXCEPTION_PROLOG_COMMON(0x800, PACA_EXGEN)
bne 1f /* if from user, just load it up */
bl .save_nvgprs
DISABLE_INTS
addi r3,r1,STACK_FRAME_OVERHEAD
ENABLE_INTS
bl .kernel_fp_unavailable_exception
BUG_OPCODE
1: bl .load_up_fpu
@ -782,8 +782,8 @@ BEGIN_FTR_SECTION
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
bl .save_nvgprs
DISABLE_INTS
addi r3,r1,STACK_FRAME_OVERHEAD
ENABLE_INTS
bl .altivec_unavailable_exception
b .ret_from_except
@ -798,8 +798,8 @@ BEGIN_FTR_SECTION
END_FTR_SECTION_IFSET(CPU_FTR_VSX)
#endif
bl .save_nvgprs
DISABLE_INTS
addi r3,r1,STACK_FRAME_OVERHEAD
ENABLE_INTS
bl .vsx_unavailable_exception
b .ret_from_except

3
arch/powerpc/kernel/traps.c
View file

@ -247,6 +247,9 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
addr, regs->nip, regs->link, code);
}
if (!arch_irq_disabled_regs(regs))
local_irq_enable();
memset(&info, 0, sizeof(info));
info.si_signo = signr;
info.si_code = code;