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>

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index c4ae85b8f8c035f8eab576e4f93fcdc467df7fa5..f2de8e8a825c3241121e7c78f4035b79578c86cb 100644 (file)
--- 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