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| author | Kim Phillips <kim.phillips@freescale.com> | 2006-12-08 11:43:30 +0300 |
|---|---|---|
| committer | Kumar Gala <galak@kernel.crashing.org> | 2006-12-08 11:43:30 +0300 |
| commit | aa42c69c67f82e88f0726258efe7306708e1cf14 (patch) | |
| tree | d5305de3285d504e1bd1e955155e5e06b5b9ef76 /arch/powerpc/kernel/head_32.S | |
| parent | c99767974ebd2a719d849fdeaaa1674456f5283f (diff) | |
| download | linux-aa42c69c67f82e88f0726258efe7306708e1cf14.tar.xz | |
[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.S | 7 |
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 |