This is an assembler version to fixup DAR not being set
by dcbX, icbi instructions. There are two versions, one
uses selfmodifing code, the other uses a
jump table but is much bigger(default).
---
arch/powerpc/kernel/head_8xx.S | 146 +++++++++++++++++++++++++++++++++++++++-
1 files changed, 145 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 093176c..9839e79 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -494,7 +494,8 @@ DataTLBError:
mfspr r10, SPRN_DAR
cmpwi cr0, r10, 0x00f0
- beq- 2f /* must be a buggy dcbX, icbi insn. */
+ beq- FixDAR /* must be a buggy dcbX, icbi insn. */
+DARFix: /* Return from dcbx instruction bug workaround, r10 holds value
of DAR */
mfspr r11, SPRN_DSISR
andis. r11, r11, 0x4800 /* !translation or protection */
@@ -604,6 +605,149 @@ DataTLBError:
. = 0x2000
+/* This is the procedure to calculate the data EA for buggy dcbx,dcbi
instructions
+ * by decoding the registers used by the dcbx instruction and adding them.
+ * DAR is set to the calculated address and r10 also holds the EA on exit.
+ */
+#define NO_SELF_MODIFYING_CODE /* define if you don't want to use self
modifying code */
+ nop /* A few nops to make the modified_instr: space below cache
line aligned */
+ nop
+139: /* fetch instruction from userspace memory */
+ DO_8xx_CPU6(0x3780, r3)
+ mtspr SPRN_MD_EPN, r10
+ mfspr r11, SPRN_M_TWB /* Get level 1 table entry address */
+ lwz r11, 0(r11) /* Get the level 1 entry */
+ tophys (r11, r11)
+ DO_8xx_CPU6(0x3b80, r3)
+ mtspr SPRN_MD_TWC, r11 /* Load pte table base address */
+ mfspr r11, SPRN_MD_TWC /* ....and get the pte address */
+ lwz r11, 0(r11) /* Get the pte */
+ /* concat physical page address(r11) and page offset(r10) */
+ rlwimi r11, r10, 0, 20, 31
+ b 140f
+FixDAR: /* Entry point for dcbx workaround. */
+ /* fetch instruction from memory. */
+ mfspr r10, SPRN_SRR0
+ andis. r11, r10, 0x8000
+ tophys (r11, r10)
+ beq- 139b /* Branch if user space address */
+140: lwz r11,0(r11)
+#ifdef CONFIG_8xx_CPU6
+ lwz r3, 8(r0) /* restore r3 from memory */
+#endif
+#ifndef NO_SELF_MODIFYING_CODE
+ andis. r10,r11,0x1f /* test if reg RA is r0 */
+ li r10,modified_in...@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 */
+ lwz r11, 4(r0) /* restore r11 from memory */
+ mfspr r10, SPRN_M_TW /* restore r10 from M_TW */
+ isync /* Wait until new instr is loaded from memory */
+modified_instr:
+ .space 4 /* this is where the add/and 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 */
+ b DARFix /* 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 */
+ addi r10, r10, 1...@l /* add start of table */
+ mtctr r10 /* load ctr with jump address */
+ xor r10, r10, r10 /* sum starts at zero */
+ bctr /* jump into table */
+150:
+ add r10, r10, r0
+ b 151f
+ add r10, r10, r1
+ b 151f
+ add r10, r10, r2
+ b 151f
+ add r10, r10, r3
+ b 151f
+ add r10, r10, r4
+ b 151f
+ add r10, r10, r5
+ b 151f
+ add r10, r10, r6
+ b 151f
+ add r10, r10, r7
+ b 151f
+ add r10, r10, r8
+ b 151f
+ add r10, r10, r9
+ b 151f
+ add r10, r10, r10
+ b 151f
+ add r10, r10, r11
+ b 151f
+ add r10, r10, r12
+ b 151f
+ add r10, r10, r13
+ b 151f
+ add r10, r10, r14
+ b 151f
+ add r10, r10, r15
+ b 151f
+ add r10, r10, r16
+ b 151f
+ add r10, r10, r17
+ b 151f
+ add r10, r10, r18
+ b 151f
+ add r10, r10, r19
+ b 151f
+ mtctr r11 /* r10 needs special handling */
+ b 154f
+ mtctr r11 /* r11 needs special handling */
+ b 153f
+ add r10, r10, r22
+ b 151f
+ add r10, r10, r23
+ b 151f
+ add r10, r10, r24
+ b 151f
+ add r10, r10, r25
+ b 151f
+ add r10, r10, r25
+ b 151f
+ add r10, r10, r27
+ b 151f
+ add r10, r10, r28
+ b 151f
+ add r10, r10, r29
+ b 151f
+ add r10, r10, r30
+ b 151f
+ add r10, r10, r31
+151:
+ rlwinm. r11,r11,19,24,28 /* offset into jump table for reg RA */
+ beq 152f /* if reg RA is zero, don't add it */
+ addi r11, r11, 1...@l /* add start of table */
+ mtctr r11 /* load ctr with jump address */
+ rlwinm r11,r11,0,16,10 /* make sure we don't execute this more
than once */
+ bctr /* jump into table */
+152:
+ mfdar r11
+ mtctr r11 /* restore ctr reg from DAR */
+ mtdar r10 /* save fault EA to DAR */
+ b DARFix /* Go back to normal TLB handling */
+
+ /* special handling for r10,r11 since these are modified already */
+153: lwz r11, 4(r0) /* load r11 from memory */
+ b 155f
+154: mfspr r11, SPRN_M_TW /* load r10 from M_TW */
+155: add r10, r10, r11 /* add it */
+ mfctr r11 /* restore r11 */
+ b 151b
+#endif
+
.globl giveup_fpu
giveup_fpu:
blr
--
1.6.4.4
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