dcbst should not set the store bit(bit 6, DSISR) when
trapping into a DTLB Error. Clear this bit while doing
the dcbX missing DAR workaround.
---
arch/powerpc/kernel/head_8xx.S | 34 +++++++++++++++++++++++++++++++---
1 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 9839e79..027856e 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -496,10 +496,14 @@ DataTLBError:
cmpwi cr0, r10, 0x00f0
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 */
- bne 2f /* branch if either is set */
+ /* As the DAR fixup may clear store we may have all 3 states zero.
+ * Make sure only 0x0200(store) falls down into DIRTY handling
+ */
+ andis. r11, r11, 0x4a00 /* !translation, protection or store */
+ srwi r11, r11, 16
+ cmpwi cr0, r11, 0x0200 /* just store ? */
+ bne 2f
/* Only Change bit left now, do it here as it is faster
* than trapping to the C fault handler.
*/
@@ -632,6 +636,30 @@ FixDAR: /* Entry point for dcbx workaround. */
tophys (r11, r10)
beq- 139b /* Branch if user space address */
140: lwz r11,0(r11)
+/* Check if it really is a dcbx instruction. */
+/* dcbt and dcbtst does not generate DTLB Misses/Errors,
+ * no need to include them here */
+ srwi r10, r11, 26 /* check if major OP code is 31 */
+ cmpwi cr0, r10, 31
+ bne- 141f
+ rlwinm r10, r11, 0, 21, 30
+ cmpwi cr0, r10, 2028 /* Is dcbz? */
+ beq+ 142f
+ cmpwi cr0, r10, 940 /* Is dcbi? */
+ beq+ 142f
+ cmpwi cr0, r10, 108 /* Is dcbst? */
+ beq+ 144f /* Fix up store bit! */
+ cmpwi cr0, r10, 172 /* Is dcbf? */
+ beq+ 142f
+ cmpwi cr0, r10, 1964 /* Is icbi? */
+ beq+ 142f
+141: mfspr r10, SPRN_DAR /* r10 must hold DAR at exit */
+ b DARfix /* Nope, go back to normal TLB processing */
+
+144: mfspr r10, SPRN_DSISR
+ 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. */
#ifdef CONFIG_8xx_CPU6
lwz r3, 8(r0) /* restore r3 from memory */
#endif
--
1.6.4.4
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