From: Benjamin Herrenschmidt Date: Sun, 4 Mar 2012 23:55:04 +0000 (+1100) Subject: powerpc: Fix 64-bit BookE FP unavailable exceptions X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=9424fabf8617c15e18a5ffd29bc3bcfa36620473;p=openwrt%2Fstaging%2Fblogic.git 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: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S index 3de9993c5c65..c4c34665c221 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)