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Subject[PATCH v2 07/14] powerpc/8xx: set GUARDED attribute in the PMD directly
Date
On the 8xx, the GUARDED attribute of the pages is managed in the
L1 entry, therefore to avoid having to copy it into L1 entry
at each TLB miss, we set it in the PMD.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/include/asm/nohash/32/pte-8xx.h | 3 ++-
arch/powerpc/kernel/head_8xx.S | 18 +++++++-----------
arch/powerpc/platforms/Kconfig.cputype | 1 +
3 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
index f04cb46ae8a1..a9a2919251e0 100644
--- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
@@ -47,10 +47,11 @@
#define _PAGE_RO 0x0600 /* Supervisor RO, User no access */

#define _PMD_PRESENT 0x0001
-#define _PMD_BAD 0x0fd0
+#define _PMD_BAD 0x0fc0
#define _PMD_PAGE_MASK 0x000c
#define _PMD_PAGE_8M 0x000c
#define _PMD_PAGE_512K 0x0004
+#define _PMD_GUARDED 0x0010
#define _PMD_USER 0x0020 /* APG 1 */

/* Until my rework is finished, 8xx still needs atomic PTE updates */
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index c3b831bb8bad..85b017c67e11 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -345,6 +345,10 @@ _ENTRY(ITLBMiss_cmp)
rlwinm r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
#ifdef CONFIG_HUGETLB_PAGE
mtcr r11
+#endif
+ /* Load the MI_TWC with the attributes for this "segment." */
+ mtspr SPRN_MI_TWC, r11 /* Set segment attributes */
+#ifdef CONFIG_HUGETLB_PAGE
bt- 28, 10f /* bit 28 = Large page (8M) */
bt- 29, 20f /* bit 29 = Large page (8M or 512k) */
#endif
@@ -354,8 +358,6 @@ _ENTRY(ITLBMiss_cmp)
#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE)
mtcr r12
#endif
- /* Load the MI_TWC with the attributes for this "segment." */
- mtspr SPRN_MI_TWC, r11 /* Set segment attributes */

#ifdef CONFIG_SWAP
rlwinm r11, r10, 32-5, _PAGE_PRESENT
@@ -457,6 +459,9 @@ _ENTRY(DTLBMiss_jmp)
rlwinm r10, r10, 32 - (PAGE_SHIFT - 2), 32 - PAGE_SHIFT, 29
#ifdef CONFIG_HUGETLB_PAGE
mtcr r11
+#endif
+ mtspr SPRN_MD_TWC, r11
+#ifdef CONFIG_HUGETLB_PAGE
bt- 28, 10f /* bit 28 = Large page (8M) */
bt- 29, 20f /* bit 29 = Large page (8M or 512k) */
#endif
@@ -465,15 +470,6 @@ _ENTRY(DTLBMiss_jmp)
4:
mtcr r12

- /* 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
- * 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, _PAGE_GUARDED
- mtspr SPRN_MD_TWC, r11
-
/* Both _PAGE_ACCESSED and _PAGE_PRESENT has to be set.
* We also need to know if the insn is a load/store, so:
* Clear _PAGE_PRESENT and load that which will
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index ba6b4c86b637..8606fa253089 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -34,6 +34,7 @@ config PPC_8xx
bool "Freescale 8xx"
select FSL_SOC
select SYS_SUPPORTS_HUGETLBFS
+ select PPC_GUARDED_PAGE_IN_PMD

config 40x
bool "AMCC 40x"
--
2.13.3
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