[RFC PATCH 1/2] arm: mm: Switch back to L_PTE_WRITE
Steve Capper
steve.capper at linaro.org
Fri Feb 14 11:55:12 EST 2014
For LPAE, we have the following means for encoding writable or dirty
ptes:
L_PTE_DIRTY L_PTE_RDONLY
!pte_dirty && !pte_write 0 1
!pte_dirty && pte_write 0 1
pte_dirty && !pte_write 1 1
pte_dirty && pte_write 1 0
So we can't distinguish between writable clean ptes and read only
ptes. This can cause problems with ptes being incorrectly flagged as
read only when they are writable but not dirty.
This patch re-introduces the L_PTE_WRITE bit for both short descriptors
and long descriptors, by reverting:
36bb94b ARM: pgtable: provide RDONLY page table bit rather than WRITE bit
For short descriptors the L_PTE_RDONLY bit is renamed to L_PTE_WRITE
and the pertinent logic changed. For long descriptors, L_PTE_WRITE is
implemented as a new software bit and L_PTE_RDONLY is renamed to
PTE_RDONLY to highlight the fact that it is a hardware bit.
Signed-off-by: Steve Capper <steve.capper at linaro.org>
---
arch/arm/include/asm/pgtable-2level.h | 2 +-
arch/arm/include/asm/pgtable-3level.h | 4 ++--
arch/arm/include/asm/pgtable.h | 36 +++++++++++++++++------------------
arch/arm/mm/dump.c | 8 ++++----
arch/arm/mm/mmu.c | 25 ++++++++++++------------
arch/arm/mm/proc-macros.S | 16 ++++++++--------
arch/arm/mm/proc-v7-2level.S | 6 +++---
arch/arm/mm/proc-v7-3level.S | 6 ++++--
arch/arm/mm/proc-xscale.S | 4 ++--
9 files changed, 55 insertions(+), 52 deletions(-)
diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h
index dfff709..ca43b84 100644
--- a/arch/arm/include/asm/pgtable-2level.h
+++ b/arch/arm/include/asm/pgtable-2level.h
@@ -120,7 +120,7 @@
#define L_PTE_YOUNG (_AT(pteval_t, 1) << 1)
#define L_PTE_FILE (_AT(pteval_t, 1) << 2) /* only when !PRESENT */
#define L_PTE_DIRTY (_AT(pteval_t, 1) << 6)
-#define L_PTE_RDONLY (_AT(pteval_t, 1) << 7)
+#define L_PTE_WRITE (_AT(pteval_t, 1) << 7)
#define L_PTE_USER (_AT(pteval_t, 1) << 8)
#define L_PTE_XN (_AT(pteval_t, 1) << 9)
#define L_PTE_SHARED (_AT(pteval_t, 1) << 10) /* shared(v6), coherent(xsc3) */
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 03243f7..8a392ef 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -79,12 +79,12 @@
#define L_PTE_PRESENT (_AT(pteval_t, 3) << 0) /* Present */
#define L_PTE_FILE (_AT(pteval_t, 1) << 2) /* only when !PRESENT */
#define L_PTE_USER (_AT(pteval_t, 1) << 6) /* AP[1] */
-#define L_PTE_RDONLY (_AT(pteval_t, 1) << 7) /* AP[2] */
+#define PTE_RDONLY (_AT(pteval_t, 1) << 7) /* AP[2] */
#define L_PTE_SHARED (_AT(pteval_t, 3) << 8) /* SH[1:0], inner shareable */
#define L_PTE_YOUNG (_AT(pteval_t, 1) << 10) /* AF */
#define L_PTE_XN (_AT(pteval_t, 1) << 54) /* XN */
#define L_PTE_DIRTY (_AT(pteval_t, 1) << 55) /* unused */
-#define L_PTE_SPECIAL (_AT(pteval_t, 1) << 56) /* unused */
+#define L_PTE_WRITE (_AT(pteval_t, 1) << 56)
#define L_PTE_NONE (_AT(pteval_t, 1) << 57) /* PROT_NONE */
#define PMD_SECT_VALID (_AT(pmdval_t, 1) << 0)
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 7d59b52..7a17611 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -88,13 +88,13 @@ extern pgprot_t pgprot_s2_device;
#define _MOD_PROT(p, b) __pgprot(pgprot_val(p) | (b))
-#define PAGE_NONE _MOD_PROT(pgprot_user, L_PTE_XN | L_PTE_RDONLY | L_PTE_NONE)
-#define PAGE_SHARED _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_XN)
-#define PAGE_SHARED_EXEC _MOD_PROT(pgprot_user, L_PTE_USER)
-#define PAGE_COPY _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
-#define PAGE_COPY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY)
-#define PAGE_READONLY _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
-#define PAGE_READONLY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY)
+#define PAGE_NONE _MOD_PROT(pgprot_user, L_PTE_XN | L_PTE_NONE)
+#define PAGE_SHARED _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_WRITE | L_PTE_XN)
+#define PAGE_SHARED_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_WRITE)
+#define PAGE_COPY _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_XN)
+#define PAGE_COPY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER)
+#define PAGE_READONLY _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_XN)
+#define PAGE_READONLY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER)
#define PAGE_KERNEL _MOD_PROT(pgprot_kernel, L_PTE_XN)
#define PAGE_KERNEL_EXEC pgprot_kernel
#define PAGE_HYP _MOD_PROT(pgprot_kernel, L_PTE_HYP)
@@ -102,13 +102,13 @@ extern pgprot_t pgprot_s2_device;
#define PAGE_S2 _MOD_PROT(pgprot_s2, L_PTE_S2_RDONLY)
#define PAGE_S2_DEVICE _MOD_PROT(pgprot_s2_device, L_PTE_S2_RDWR)
-#define __PAGE_NONE __pgprot(_L_PTE_DEFAULT | L_PTE_RDONLY | L_PTE_XN | L_PTE_NONE)
-#define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_XN)
-#define __PAGE_SHARED_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER)
-#define __PAGE_COPY __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
-#define __PAGE_COPY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY)
-#define __PAGE_READONLY __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY | L_PTE_XN)
-#define __PAGE_READONLY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_RDONLY)
+#define __PAGE_NONE __pgprot(_L_PTE_DEFAULT | L_PTE_XN | L_PTE_NONE)
+#define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_WRITE | L_PTE_XN)
+#define __PAGE_SHARED_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_WRITE)
+#define __PAGE_COPY __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_XN)
+#define __PAGE_COPY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER)
+#define __PAGE_READONLY __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_XN)
+#define __PAGE_READONLY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER)
#define __pgprot_modify(prot,mask,bits) \
__pgprot((pgprot_val(prot) & ~(mask)) | (bits))
@@ -216,7 +216,7 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd)
#define pte_none(pte) (!pte_val(pte))
#define pte_present(pte) (pte_val(pte) & L_PTE_PRESENT)
-#define pte_write(pte) (!(pte_val(pte) & L_PTE_RDONLY))
+#define pte_write(pte) (pte_val(pte) & L_PTE_WRITE)
#define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY)
#define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG)
#define pte_exec(pte) (!(pte_val(pte) & L_PTE_XN))
@@ -248,8 +248,8 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
#define PTE_BIT_FUNC(fn,op) \
static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
-PTE_BIT_FUNC(wrprotect, |= L_PTE_RDONLY);
-PTE_BIT_FUNC(mkwrite, &= ~L_PTE_RDONLY);
+PTE_BIT_FUNC(wrprotect, &= ~L_PTE_WRITE);
+PTE_BIT_FUNC(mkwrite, |= L_PTE_WRITE);
PTE_BIT_FUNC(mkclean, &= ~L_PTE_DIRTY);
PTE_BIT_FUNC(mkdirty, |= L_PTE_DIRTY);
PTE_BIT_FUNC(mkold, &= ~L_PTE_YOUNG);
@@ -261,7 +261,7 @@ static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
- const pteval_t mask = L_PTE_XN | L_PTE_RDONLY | L_PTE_USER |
+ const pteval_t mask = L_PTE_XN | L_PTE_WRITE | L_PTE_USER |
L_PTE_NONE | L_PTE_VALID;
pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
return pte;
diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
index 2b3a564..715ca93 100644
--- a/arch/arm/mm/dump.c
+++ b/arch/arm/mm/dump.c
@@ -58,10 +58,10 @@ static const struct prot_bits pte_bits[] = {
.set = "USR",
.clear = " ",
}, {
- .mask = L_PTE_RDONLY,
- .val = L_PTE_RDONLY,
- .set = "ro",
- .clear = "RW",
+ .mask = L_PTE_WRITE,
+ .val = L_PTE_WRITE,
+ .set = "RW",
+ .clear = "ro",
}, {
.mask = L_PTE_XN,
.val = L_PTE_XN,
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4f08c13..38f40df 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -231,7 +231,7 @@ __setup("noalign", noalign_setup);
#endif /* ifdef CONFIG_CPU_CP15 / else */
-#define PROT_PTE_DEVICE L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_XN
+#define PROT_PTE_DEVICE L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_WRITE|L_PTE_XN
#define PROT_SECT_DEVICE PMD_TYPE_SECT|PMD_SECT_AP_WRITE
static struct mem_type mem_types[] = {
@@ -277,26 +277,26 @@ static struct mem_type mem_types[] = {
},
#endif
[MT_LOW_VECTORS] = {
- .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
- L_PTE_RDONLY,
+ .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
.prot_l1 = PMD_TYPE_TABLE,
.domain = DOMAIN_USER,
},
[MT_HIGH_VECTORS] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
- L_PTE_USER | L_PTE_RDONLY,
+ L_PTE_USER,
.prot_l1 = PMD_TYPE_TABLE,
.domain = DOMAIN_USER,
},
[MT_MEMORY_RWX] = {
- .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
+ .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
+ L_PTE_WRITE,
.prot_l1 = PMD_TYPE_TABLE,
.prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
.domain = DOMAIN_KERNEL,
},
[MT_MEMORY_RW] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
- L_PTE_XN,
+ L_PTE_WRITE | L_PTE_XN,
.prot_l1 = PMD_TYPE_TABLE,
.prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
.domain = DOMAIN_KERNEL,
@@ -307,26 +307,27 @@ static struct mem_type mem_types[] = {
},
[MT_MEMORY_RWX_NONCACHED] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
- L_PTE_MT_BUFFERABLE,
+ L_PTE_WRITE | L_PTE_MT_BUFFERABLE,
.prot_l1 = PMD_TYPE_TABLE,
.prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
.domain = DOMAIN_KERNEL,
},
[MT_MEMORY_RW_DTCM] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
- L_PTE_XN,
+ L_PTE_WRITE | L_PTE_XN,
.prot_l1 = PMD_TYPE_TABLE,
.prot_sect = PMD_TYPE_SECT | PMD_SECT_XN,
.domain = DOMAIN_KERNEL,
},
[MT_MEMORY_RWX_ITCM] = {
- .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
+ .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
+ L_PTE_WRITE,
.prot_l1 = PMD_TYPE_TABLE,
.domain = DOMAIN_KERNEL,
},
[MT_MEMORY_RW_SO] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
- L_PTE_MT_UNCACHED | L_PTE_XN,
+ L_PTE_MT_UNCACHED | L_PTE_WRITE | L_PTE_XN,
.prot_l1 = PMD_TYPE_TABLE,
.prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_S |
PMD_SECT_UNCACHED | PMD_SECT_XN,
@@ -334,7 +335,7 @@ static struct mem_type mem_types[] = {
},
[MT_MEMORY_DMA_READY] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
- L_PTE_XN,
+ L_PTE_WRITE | L_PTE_XN,
.prot_l1 = PMD_TYPE_TABLE,
.domain = DOMAIN_KERNEL,
},
@@ -588,7 +589,7 @@ static void __init build_mem_type_table(void)
pgprot_user = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | user_pgprot);
pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG |
- L_PTE_DIRTY | kern_pgprot);
+ L_PTE_DIRTY | L_PTE_WRITE | kern_pgprot);
pgprot_s2 = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | s2_pgprot);
pgprot_s2_device = __pgprot(s2_device_pgprot);
pgprot_hyp_device = __pgprot(hyp_device_pgprot);
diff --git a/arch/arm/mm/proc-macros.S b/arch/arm/mm/proc-macros.S
index e3c48a3..c62fd89 100644
--- a/arch/arm/mm/proc-macros.S
+++ b/arch/arm/mm/proc-macros.S
@@ -97,7 +97,7 @@
#error PTE shared bit mismatch
#endif
#if !defined (CONFIG_ARM_LPAE) && \
- (L_PTE_XN+L_PTE_USER+L_PTE_RDONLY+L_PTE_DIRTY+L_PTE_YOUNG+\
+ (L_PTE_XN+L_PTE_USER+L_PTE_WRITE+L_PTE_DIRTY+L_PTE_YOUNG+\
L_PTE_FILE+L_PTE_PRESENT) > L_PTE_SHARED
#error Invalid Linux PTE bit settings
#endif
@@ -152,9 +152,9 @@
and r2, r1, #L_PTE_MT_MASK
ldr r2, [ip, r2]
- eor r1, r1, #L_PTE_DIRTY
- tst r1, #L_PTE_DIRTY|L_PTE_RDONLY
- orrne r3, r3, #PTE_EXT_APX
+ tst r1, #L_PTE_WRITE
+ tstne r1, #L_PTE_DIRTY
+ orreq r3, r3, #PTE_EXT_APX
tst r1, #L_PTE_USER
orrne r3, r3, #PTE_EXT_AP1
@@ -199,7 +199,7 @@
.macro armv3_set_pte_ext wc_disable=1
str r1, [r0], #2048 @ linux version
- eor r3, r1, #L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY
+ eor r3, r1, #L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_WRITE | L_PTE_DIRTY
bic r2, r1, #PTE_SMALL_AP_MASK @ keep C, B bits
bic r2, r2, #PTE_TYPE_MASK
@@ -208,7 +208,7 @@
tst r3, #L_PTE_USER @ user?
orrne r2, r2, #PTE_SMALL_AP_URO_SRW
- tst r3, #L_PTE_RDONLY | L_PTE_DIRTY @ write and dirty?
+ tst r3, #L_PTE_WRITE | L_PTE_DIRTY @ write and dirty?
orreq r2, r2, #PTE_SMALL_AP_UNO_SRW
tst r3, #L_PTE_PRESENT | L_PTE_YOUNG @ present and young?
@@ -242,7 +242,7 @@
.macro xscale_set_pte_ext_prologue
str r1, [r0] @ linux version
- eor r3, r1, #L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY
+ eor r3, r1, #L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_WRITE | L_PTE_DIRTY
bic r2, r1, #PTE_SMALL_AP_MASK @ keep C, B bits
orr r2, r2, #PTE_TYPE_EXT @ extended page
@@ -250,7 +250,7 @@
tst r3, #L_PTE_USER @ user?
orrne r2, r2, #PTE_EXT_AP_URO_SRW @ yes -> user r/o, system r/w
- tst r3, #L_PTE_RDONLY | L_PTE_DIRTY @ write and dirty?
+ tst r3, #L_PTE_WRITE | L_PTE_DIRTY @ write and dirty?
orreq r2, r2, #PTE_EXT_AP_UNO_SRW @ yes -> user n/a, system r/w
@ combined with user -> user r/w
.endm
diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S
index bdd3be4..297fccf 100644
--- a/arch/arm/mm/proc-v7-2level.S
+++ b/arch/arm/mm/proc-v7-2level.S
@@ -84,9 +84,9 @@ ENTRY(cpu_v7_set_pte_ext)
tst r1, #1 << 4
orrne r3, r3, #PTE_EXT_TEX(1)
- eor r1, r1, #L_PTE_DIRTY
- tst r1, #L_PTE_RDONLY | L_PTE_DIRTY
- orrne r3, r3, #PTE_EXT_APX
+ tst r1, #L_PTE_WRITE
+ tstne r1, #L_PTE_DIRTY
+ orreq r3, r3, #PTE_EXT_APX
tst r1, #L_PTE_USER
orrne r3, r3, #PTE_EXT_AP1
diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S
index 01a719e..7793b2e 100644
--- a/arch/arm/mm/proc-v7-3level.S
+++ b/arch/arm/mm/proc-v7-3level.S
@@ -78,8 +78,10 @@ ENTRY(cpu_v7_set_pte_ext)
tst r3, #1 << (57 - 32) @ L_PTE_NONE
bicne r2, #L_PTE_VALID
bne 1f
- tst r3, #1 << (55 - 32) @ L_PTE_DIRTY
- orreq r2, #L_PTE_RDONLY
+ bic r2, #PTE_RDONLY
+ tst r3, #1 << (56 - 32) @ L_PTE_WRITE
+ tstne r3, #1 << (55 - 32) @ L_PTE_DIRTY
+ orreq r2, #PTE_RDONLY
1: strd r2, r3, [r0]
ALT_SMP(W(nop))
ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte
diff --git a/arch/arm/mm/proc-xscale.S b/arch/arm/mm/proc-xscale.S
index d19b1cf..d5b23e8 100644
--- a/arch/arm/mm/proc-xscale.S
+++ b/arch/arm/mm/proc-xscale.S
@@ -510,8 +510,8 @@ ENTRY(cpu_xscale_set_pte_ext)
@
@ Erratum 40: must set memory to write-through for user read-only pages
@
- and ip, r1, #(L_PTE_MT_MASK | L_PTE_USER | L_PTE_RDONLY) & ~(4 << 2)
- teq ip, #L_PTE_MT_WRITEBACK | L_PTE_USER | L_PTE_RDONLY
+ and ip, r1, #(L_PTE_MT_MASK | L_PTE_USER | L_PTE_WRITE) & ~(4 << 2)
+ teq ip, #L_PTE_MT_WRITEBACK | L_PTE_USER
moveq r1, #L_PTE_MT_WRITETHROUGH
and r1, r1, #L_PTE_MT_MASK
--
1.8.1.4
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