[POWERPC] Add support for FP emulation for the e300c2 core

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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>

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This commit is contained in:

Kim Phillips 2006-12-08 02:43:30 -06:00 • committed by Kumar Gala

parent c99767974e

commit aa42c69c67

5 changed files with 19 additions and 4 deletions

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2

arch/powerpc/Kconfig

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2

arch/powerpc/kernel/cputable.c

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7

arch/powerpc/kernel/head_32.S

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arch/powerpc/kernel/traps.c

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include/asm-powerpc/cputable.h

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