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Commit 9424fabf authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

powerpc: Fix 64-bit BookE FP unavailable exceptions 



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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 990118c8

arch/powerpc/kernel/exceptions-64e.S

+7 −6
Original line number Diff line number Diff line
@@ -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)