powerpc/8xx: Handle PAGE_USER via APG bits

Use of APG for handling PAGE_USER.

All pages PP exec bits are set to either 000 or 011, which means
respectively RW for Supervisor and no access for User, or RO for
Supervisor and no access for user.

Then we use the APG to say whether accesses are according to
Page rules or "all Supervisor" rules (Access to all)

Therefore, we define 2 APG groups corresponding to _PAGE_USER.
Mx_AP are initialised as follows:
GP0 => No user => 01 (all accesses performed according
				to page definition)
GP1 => User => 00 (all accesses performed as supervisor
                                according to page definition)

This removes the special 8xx handling in pte_update()

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>

1 files changed, 12 insertions, 9 deletions

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index c640bbb042b5..c79184d86f58 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -351,12 +351,15 @@ InstructionTLBMiss:
         rlwimi  r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
         lwz     r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11)        /* Get the level 1 entry */
 
-        /* Load the MI_TWC with the attributes for this "segment." */
-        MTSPR_CPU6(SPRN_MI_TWC, r11, r3)        /* Set segment attributes */
-        rlwinm  r11, r11,0,0,19 /* Extract page descriptor page address */
         /* Extract level 2 index */
         rlwinm  r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
-        lwzx    r10, r10, r11   /* Get the pte */
+        rlwimi  r10, r11, 0, 0, 32 - PAGE_SHIFT - 1     /* Add level 2 base */
+        lwz     r10, 0(r10)     /* Get the pte */
+
+        /* Insert the APG into the TWC from the Linux PTE. */
+        rlwimi  r11, r10, 0, 26, 26
+        /* Load the MI_TWC with the attributes for this "segment." */
+        MTSPR_CPU6(SPRN_MI_TWC, r11, r3)        /* Set segment attributes */
 
 #ifdef CONFIG_SWAP
         rlwinm  r11, r10, 32-5, _PAGE_PRESENT
@@ -365,12 +368,12 @@ InstructionTLBMiss:
 #endif
         li      r11, RPN_PATTERN
         /* The Linux PTE won't go exactly into the MMU TLB.
-         * Software indicator bits 21 and 28 must be clear.
+         * Software indicator bits 20-23 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.
          */
-        rlwimi  r10, r11, 0, 0x07f8     /* Set 24-27, clear 21-23,28 */
+        rlwimi  r10, r11, 0, 0x0ff8     /* Set 24-27, clear 20-23,28 */
         MTSPR_CPU6(SPRN_MI_RPN, r10, r3)        /* Update TLB entry */
 
         /* Restore registers */
@@ -411,13 +414,13 @@ DataStoreTLBMiss:
         rlwimi  r10, r11, 0, 0, 32 - PAGE_SHIFT - 1     /* Add level 2 base */
         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 (at least
+        /* Insert the Guarded flag and APG into the TWC from the Linux PTE.
+         * It is bit 26-27 of both the Linux PTE and the TWC (at least
          * I got that right :-).  It will be better when we can put
          * this into the Linux pgd/pmd and load it in the operation
          * above.
          */
-        rlwimi  r11, r10, 0, 27, 27
+        rlwimi  r11, r10, 0, 26, 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
          */