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authorKim Phillips <kim.phillips@freescale.com>2006-12-08 02:43:30 -0600
committerKumar Gala <galak@kernel.crashing.org>2006-12-08 02:43:30 -0600
commitaa42c69c67f82e88f0726258efe7306708e1cf14 (patch)
treed5305de3285d504e1bd1e955155e5e06b5b9ef76 /arch/powerpc/kernel/head_32.S
parentc99767974ebd2a719d849fdeaaa1674456f5283f (diff)
[POWERPC] Add support for FP emulation for the e300c2 core
The e300c2 has no FPU. Its MSR[FP] is grounded to zero. If an attempt is made to execute a floating point instruction (including floating-point load, store, or move instructions), the e300c2 takes a floating-point unavailable interrupt. This patch adds support for FP emulation on the e300c2 by declaring a new CPU_FTR_FP_TAKES_FPUNAVAIL, where FP unavail interrupts are intercepted and redirected to the ProgramCheck exception path for correct emulation handling. (If we run out of CPU_FTR bits we could look to reclaim this bit by adding support to test the cpu_user_features for PPC_FEATURE_HAS_FPU instead) It adds a nop to the exception path for 32-bit processors with a FPU. Signed-off-by: Kim Phillips <kim.phillips@freescale.com> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/head_32.S')
-rw-r--r--arch/powerpc/kernel/head_32.S7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index d88e182e40b3..9417cf5b4b7e 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -437,6 +437,13 @@ Alignment:
/* Floating-point unavailable */
. = 0x800
FPUnavailable:
+BEGIN_FTR_SECTION
+/*
+ * Certain Freescale cores don't have a FPU and treat fp instructions
+ * as a FP Unavailable exception. Redirect to illegal/emulation handling.
+ */
+ b ProgramCheck
+END_FTR_SECTION_IFSET(CPU_FTR_FPU_UNAVAILABLE)
EXCEPTION_PROLOG
bne load_up_fpu /* if from user, just load it up */
addi r3,r1,STACK_FRAME_OVERHEAD