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powerpc/8xx: Tag DAR with 0x00f0 to catch buggy instructions.

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dcbz, dcbf, dcbi, dcbst and icbi do not set DAR when they
cause a DTLB Error. Dectect this by tagging DAR with 0x00f0
at every exception exit that modifies DAR.
Test for DAR=0x00f0 in DataTLBError and bail
to handle_page_fault().

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Joakim Tjernlund 2009-11-20 00:21:04 +00:00 committed by Benjamin Herrenschmidt
parent fe11dc3f96
commit 60e071fee9
1 changed files with 14 additions and 1 deletions
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15
arch/powerpc/kernel/head_8xx.S
View file

@ -206,6 +206,8 @@ MachineCheck:
EXCEPTION_PROLOG
mfspr r4,SPRN_DAR
stw r4,_DAR(r11)
li r5,0x00f0
mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */
mfspr r5,SPRN_DSISR
stw r5,_DSISR(r11)
addi r3,r1,STACK_FRAME_OVERHEAD
@ -222,6 +224,8 @@ DataAccess:
stw r10,_DSISR(r11)
mr r5,r10
mfspr r4,SPRN_DAR
li r10,0x00f0
mtspr SPRN_DAR,r10 /* Tag DAR, to be used in DTLB Error */
EXC_XFER_EE_LITE(0x300, handle_page_fault)
/* Instruction access exception.
@ -244,6 +248,8 @@ Alignment:
EXCEPTION_PROLOG
mfspr r4,SPRN_DAR
stw r4,_DAR(r11)
li r5,0x00f0
mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */
mfspr r5,SPRN_DSISR
stw r5,_DSISR(r11)
addi r3,r1,STACK_FRAME_OVERHEAD
@ -445,6 +451,7 @@ DataStoreTLBMiss:
* of the MMU.
*/
2: li r11, 0x00f0
mtspr SPRN_DAR,r11 /* Tag DAR */
rlwimi r10, r11, 0, 24, 28 /* Set 24-27, clear 28 */
DO_8xx_CPU6(0x3d80, r3)
mtspr SPRN_MD_RPN, r10 /* Update TLB entry */
@ -485,6 +492,10 @@ DataTLBError:
stw r10, 0(r0)
stw r11, 4(r0)
mfspr r10, SPRN_DAR
cmpwi cr0, r10, 0x00f0
beq- 2f /* must be a buggy dcbX, icbi insn. */
mfspr r11, SPRN_DSISR
andis. r11, r11, 0x4800 /* !translation or protection */
bne 2f /* branch if either is set */
@ -508,7 +519,8 @@ DataTLBError:
* are initialized in mapin_ram(). This will avoid the problem,
* assuming we only use the dcbi instruction on kernel addresses.
*/
mfspr r10, SPRN_DAR
/* DAR is in r10 already */
rlwinm r11, r10, 0, 0, 19
ori r11, r11, MD_EVALID
mfspr r10, SPRN_M_CASID
@ -550,6 +562,7 @@ DataTLBError:
* of the MMU.
*/
li r11, 0x00f0
mtspr SPRN_DAR,r11 /* Tag DAR */
rlwimi r10, r11, 0, 24, 28 /* Set 24-27, clear 28 */
DO_8xx_CPU6(0x3d80, r3)
mtspr SPRN_MD_RPN, r10 /* Update TLB entry */