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Subject[PATCH] powerpc/8xx: drop unused self-modifying code alternative to FixupDAR.
Date
The code which fixups the DAR on TLB errors for dbcX instructions
has a self-modifying code alternative that has never been used.

Drop it.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/kernel/head_8xx.S | 24 ------------------------
1 file changed, 24 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index b8ca5b43e587..19f583e18402 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -575,8 +575,6 @@ InstructionBreakpoint:
* by decoding the registers used by the dcbx instruction and adding them.
* DAR is set to the calculated address.
*/
- /* define if you don't want to use self modifying code */
-#define NO_SELF_MODIFYING_CODE
FixupDAR:/* Entry point for dcbx workaround. */
mtspr SPRN_M_TW, r10
/* fetch instruction from memory. */
@@ -640,27 +638,6 @@ FixupDAR:/* Entry point for dcbx workaround. */
rlwinm r10, r10,0,7,5 /* Clear store bit for buggy dcbst insn */
mtspr SPRN_DSISR, r10
142: /* continue, it was a dcbx, dcbi instruction. */
-#ifndef NO_SELF_MODIFYING_CODE
- andis. r10,r11,0x1f /* test if reg RA is r0 */
- li r10,modified_instr@l
- dcbtst r0,r10 /* touch for store */
- rlwinm r11,r11,0,0,20 /* Zero lower 10 bits */
- oris r11,r11,640 /* Transform instr. to a "add r10,RA,RB" */
- ori r11,r11,532
- stw r11,0(r10) /* store add/and instruction */
- dcbf 0,r10 /* flush new instr. to memory. */
- icbi 0,r10 /* invalidate instr. cache line */
- mfspr r11, SPRN_SPRG_SCRATCH1 /* restore r11 */
- mfspr r10, SPRN_SPRG_SCRATCH0 /* restore r10 */
- isync /* Wait until new instr is loaded from memory */
-modified_instr:
- .space 4 /* this is where the add instr. is stored */
- bne+ 143f
- subf r10,r0,r10 /* r10=r10-r0, only if reg RA is r0 */
-143: mtdar r10 /* store faulting EA in DAR */
- mfspr r10,SPRN_M_TW
- b DARFixed /* Go back to normal TLB handling */
-#else
mfctr r10
mtdar r10 /* save ctr reg in DAR */
rlwinm r10, r11, 24, 24, 28 /* offset into jump table for reg RB */
@@ -724,7 +701,6 @@ modified_instr:
add r10, r10, r11 /* add it */
mfctr r11 /* restore r11 */
b 151b
-#endif

/*
* This is where the main kernel code starts.
--
2.13.3
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