We were using CR0.EQ after EXCEPTION_COMMON, hoping it still
contained whether we came from userspace or kernel space.
However, under some circumstances, EXCEPTION_COMMON will
call C code and clobber non-volatile registers, so we really
need to re-load the previous MSR from the stackframe and
re-test.
While there, invert the condition to make the fast path more
obvious and remove the BUG_OPCODE which was a debugging
leftover and call .ret_from_except as we should.
Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
---
arch/powerpc/kernel/exceptions-64e.S | 13 +++++++------
1 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/kernel/exceptions-64e.S
b/arch/powerpc/kernel/exceptions-64e.S
index 3de9993..c4c3466 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -353,15 +353,16 @@ interrupt_end_book3e:
NORMAL_EXCEPTION_PROLOG(0x800, PROLOG_ADDITION_NONE)
/* 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
+ ld r12,_MSR(r1)
+ andi. r0,r12,MSR_PR;
+ beq- 1f
+ bl .load_up_fpu
+ b fast_exception_return
+1: INTS_DISABLE_ALL
bl .save_nvgprs
addi r3,r1,STACK_FRAME_OVERHEAD
bl .kernel_fp_unavailable_exception
- BUG_OPCODE
-1: ld r12,_MSR(r1)
- bl .load_up_fpu
- b fast_exception_return
+ b .ret_from_except
/* Decrementer Interrupt */
MASKABLE_EXCEPTION(0x900, decrementer, .timer_interrupt, ACK_DEC)
--
1.7.9
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