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authorJoakim Tjernlund <joakim.tjernlund@transmode.se>2009-11-20 00:21:10 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-12-09 17:10:37 +1100
commit2321f33790a6c5b80322d907a92d5739e7521a13 (patch)
tree1cb6c6a3aba5862ca7877aac6bca054377c305ec /arch/powerpc/kernel/head_8xx.S
parent15d914d72a3f4f1531c41c084cb556be22aa1d2e (diff)
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powerpc/8xx: Remove DIRTY pte handling in DTLB Error.
There is no need to do set the DIRTY bit directly in DTLB Error. Trap to do_page_fault() and let the generic MM code do the work. Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/head_8xx.S')
-rw-r--r--arch/powerpc/kernel/head_8xx.S96
1 files changed, 0 insertions, 96 deletions
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index c4ae85b8f8c0..f2de8e8a825c 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -500,102 +500,6 @@ DataTLBError:
cmpwi cr0, r10, 0x00f0
beq- FixupDAR /* must be a buggy dcbX, icbi insn. */
DARFixed:/* Return from dcbx instruction bug workaround, r10 holds value of DAR */
- mfspr r11, SPRN_DSISR
- /* 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.
- */
-
- /* The EA of a data TLB miss is automatically stored in the MD_EPN
- * register. The EA of a data TLB error is automatically stored in
- * the DAR, but not the MD_EPN register. We must copy the 20 most
- * significant bits of the EA from the DAR to MD_EPN before we
- * start walking the page tables. We also need to copy the CASID
- * value from the M_CASID register.
- * Addendum: The EA of a data TLB error is _supposed_ to be stored
- * in DAR, but it seems that this doesn't happen in some cases, such
- * as when the error is due to a dcbi instruction to a page with a
- * TLB that doesn't have the changed bit set. In such cases, there
- * does not appear to be any way to recover the EA of the error
- * since it is neither in DAR nor MD_EPN. As a workaround, the
- * _PAGE_HWWRITE bit is set for all kernel data pages when the PTEs
- * are initialized in mapin_ram(). This will avoid the problem,
- * assuming we only use the dcbi instruction on kernel addresses.
- */
-
- /* DAR is in r10 already */
- rlwinm r11, r10, 0, 0, 19
- ori r11, r11, MD_EVALID
- mfspr r10, SPRN_M_CASID
- rlwimi r11, r10, 0, 28, 31
- DO_8xx_CPU6(0x3780, r3)
- mtspr SPRN_MD_EPN, r11
-
- mfspr r10, SPRN_M_TWB /* Get level 1 table entry address */
-
- /* If we are faulting a kernel address, we have to use the
- * kernel page tables.
- */
- andi. r11, r10, 0x0800
- beq 3f
- lis r11, swapper_pg_dir@h
- ori r11, r11, swapper_pg_dir@l
- rlwimi r10, r11, 0, 2, 19
-3:
- lwz r11, 0(r10) /* Get the level 1 entry */
- rlwinm. r10, r11,0,0,19 /* Extract page descriptor page address */
- beq 2f /* If zero, bail */
-
- /* We have a pte table, so fetch the pte from the table.
- */
- ori r11, r11, 1 /* Set valid bit in physical L2 page */
- DO_8xx_CPU6(0x3b80, r3)
- mtspr SPRN_MD_TWC, r11 /* Load pte table base address */
- mfspr r10, SPRN_MD_TWC /* ....and get the pte address */
- lwz r10, 0(r10) /* Get the pte */
- /* Insert the Guarded flag into the TWC from the Linux PTE.
- * It is bit 27 of both the Linux PTE and the TWC
- */
- rlwimi r11, r10, 0, 27, 27
- /* Insert the WriteThru flag into the TWC from the Linux PTE.
- * It is bit 25 in the Linux PTE and bit 30 in the TWC
- */
- rlwimi r11, r10, 32-5, 30, 30
- DO_8xx_CPU6(0x3b80, r3)
- mtspr SPRN_MD_TWC, r11
- mfspr r11, SPRN_MD_TWC /* get the pte address again */
-
- ori r10, r10, _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_HWWRITE
- stw r10, 0(r11) /* and update pte in table */
- xori r10, r10, _PAGE_RW /* RW bit is inverted */
-
- /* The Linux PTE won't go exactly into the MMU TLB.
- * Software indicator bits 22 and 28 must be clear.
- * Software indicator bits 24, 25, 26, and 27 must be
- * set. All other Linux PTE bits control the behavior
- * 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 */
-
- mfspr r10, SPRN_M_TW /* Restore registers */
- lwz r11, 0(r0)
- mtcr r11
- lwz r11, 4(r0)
-#ifdef CONFIG_8xx_CPU6
- lwz r3, 8(r0)
-#endif
- rfi
-2:
mfspr r10, SPRN_M_TW /* Restore registers */
lwz r11, 0(r0)
mtcr r11