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[ARM] 4581/1: Fix the conditional execution of the NWFPE instructions

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Starting with ARMv7-A, conditional execution of undefined instructions
can trigger an exception even if the condition check fails. This patch
modifies the NWFPE support to check the condition before emulating the
instruction.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Catalin Marinas 2007-09-25 15:21:00 +01:00 committed by Russell King
parent ec6b148226
commit c1f438f5ee
1 changed files with 14 additions and 11 deletions
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25
arch/arm/nwfpe/entry.S
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@ -70,13 +70,24 @@ floating point instructions. GCC attempts to group floating point
instructions to allow the emulator to spread the cost of the trap over
several floating point instructions. */
#include <asm/asm-offsets.h>
.globl nwfpe_enter
nwfpe_enter:
mov r4, lr @ save the failure-return addresses
mov sl, sp @ we access the registers via 'sl'
ldr r5, [sp, #60] @ get contents of PC;
ldr r5, [sp, #S_PC] @ get contents of PC;
mov r6, r0 @ save the opcode
emulate:
ldr r1, [sp, #S_PSR] @ fetch the PSR
bl checkCondition @ check the condition
cmp r0, #0 @ r0 = 0 ==> condition failed
@ if condition code failed to match, next insn
beq next @ get the next instruction;
mov r0, r6 @ prepare for EmulateAll()
bl EmulateAll @ emulate the instruction
cmp r0, #0 @ was emulation successful
moveq pc, r4 @ no, return failure
@ -91,18 +102,10 @@ next:
teqne r2, #0x0E000000
movne pc, r9 @ return ok if not a fp insn
str r5, [sp, #60] @ update PC copy in regs
str r5, [sp, #S_PC] @ update PC copy in regs
mov r0, r6 @ save a copy
ldr r1, [sp, #64] @ fetch the condition codes
bl checkCondition @ check the condition
cmp r0, #0 @ r0 = 0 ==> condition failed
@ if condition code failed to match, next insn
beq next @ get the next instruction;
mov r0, r6 @ prepare for EmulateAll()
b emulate @ if r0 != 0, goto EmulateAll
b emulate @ check condition and emulate
@ We need to be prepared for the instructions at .Lx1 and .Lx2
@ to fault. Emit the appropriate exception gunk to fix things up.