* [RFC PATCH 0/2] ARM: Switch back to L_PTE_WRITE
@ 2014-02-14 16:55 Steve Capper
2014-02-14 16:55 ` [RFC PATCH 1/2] arm: mm: " Steve Capper
2014-02-14 16:55 ` [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() Steve Capper
0 siblings, 2 replies; 11+ messages in thread
From: Steve Capper @ 2014-02-14 16:55 UTC (permalink / raw)
To: linux-arm-kernel
Hello,
This RFC switches both the short and long descriptors back to using
L_PTE_WRITE to represent a writable pte, rather than !L_PTE_RDONLY.
This allows us, for long descriptors, to distinguish between writable
clean ptes and read only ptes; fixing a few problems with huge pages,
and possibly other areas of code.
(For short descriptors the distinction was possible already due to the
separate Linux/hardware ptes).
I originally attempted to leave the short descriptor code alone and
only modify the long descriptors to use L_PTE_WRITE. This turned out
to be both overly complicated and confusing. So, I have instead
reverted:
36bb94b ARM: pgtable: provide RDONLY page table bit rather than WRITE bit
And introduced a separate L_PTE_WRITE software bit for long descriptors.
This series has been tested on an Arndale board running 3.14-rc2, and
both short and long descriptors. The libhugetlbfs tests have passed for
LPAE. I am currently running a barrage of ltp tests for both short and
long descriptors.
Whilst testing this patch with libhugetlbfs, I came across a horrible
bug in the handling of huge_pte_write(). For LPAE, both L_PTE_DIRTY and
L_PTE_WRITE are in the upper 32 bits of the ptes. The huge_pte_write()
function downcasts the result of pte_write() to 32-bits, meaning that
huge_pte_write() always returned false! I've noticed this downcasting
to 32-bits taking place in the following functions:
o gather_stats
o huge_pte_dirty
o huge_pte_write
o make_migration_entry
(under arm64, the downcasting doesn't take place on the huge_pte_
functions as they use long, but the others use int....)
To fix this issue, I have added a double logical invert to pte_write()
and pte_dirty() when LPAE is enabled (in the second patch in this
series). This fixes the problem, but it's leaving me feeling rather
filthy. Any suggestions on a cleaner way around this would be very
welcome.
Cheers,
--
Steve
Steve Capper (2):
arm: mm: Switch back to L_PTE_WRITE
arm: mm: Double logical invert for LPAE pte_write(), pte_dirty()
arch/arm/include/asm/pgtable-2level.h | 4 +++-
arch/arm/include/asm/pgtable-3level.h | 18 ++++++++++++++++--
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, 70 insertions(+), 53 deletions(-)
--
1.8.1.4
^ permalink raw reply [flat|nested] 11+ messages in thread* [RFC PATCH 1/2] arm: mm: Switch back to L_PTE_WRITE 2014-02-14 16:55 [RFC PATCH 0/2] ARM: Switch back to L_PTE_WRITE Steve Capper @ 2014-02-14 16:55 ` Steve Capper 2014-02-20 17:22 ` Will Deacon 2014-02-14 16:55 ` [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() Steve Capper 1 sibling, 1 reply; 11+ messages in thread From: Steve Capper @ 2014-02-14 16:55 UTC (permalink / raw) To: linux-arm-kernel 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@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 ^ permalink raw reply related [flat|nested] 11+ messages in thread
* [RFC PATCH 1/2] arm: mm: Switch back to L_PTE_WRITE 2014-02-14 16:55 ` [RFC PATCH 1/2] arm: mm: " Steve Capper @ 2014-02-20 17:22 ` Will Deacon 2014-02-21 8:37 ` Steve Capper 0 siblings, 1 reply; 11+ messages in thread From: Will Deacon @ 2014-02-20 17:22 UTC (permalink / raw) To: linux-arm-kernel Hi Steve, On Fri, Feb 14, 2014 at 04:55:12PM +0000, Steve Capper wrote: > 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. This would be a lot easier to review if it was a true revert, but I guess that doesn't apply cleanly to mainline? > Signed-off-by: Steve Capper <steve.capper@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] */ Why? I think we're just using L_ for consistency here, rather than to distinguish between h/w and Linux bits (e.g. L_PTE_XN). > #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) Why have you killed L_PTE_SPECIAL? We could actually use that for LPAE... > #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/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 Hehe, I have a patch pending in this macro which is sitting in -next. Take a look at b6ccb9803e90 ("ARM: 7954/1: mm: remove remaining domain support from ARMv6"), since this will probably conflict in horrible ways. > 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 Why do you need this bic? Will ^ permalink raw reply [flat|nested] 11+ messages in thread
* [RFC PATCH 1/2] arm: mm: Switch back to L_PTE_WRITE 2014-02-20 17:22 ` Will Deacon @ 2014-02-21 8:37 ` Steve Capper 2014-02-24 11:03 ` Will Deacon 0 siblings, 1 reply; 11+ messages in thread From: Steve Capper @ 2014-02-21 8:37 UTC (permalink / raw) To: linux-arm-kernel On Thu, Feb 20, 2014 at 05:22:22PM +0000, Will Deacon wrote: > Hi Steve, Hey Will, > > On Fri, Feb 14, 2014 at 04:55:12PM +0000, Steve Capper wrote: > > 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. > > This would be a lot easier to review if it was a true revert, but I guess > that doesn't apply cleanly to mainline? Unfortunately not, we've had the split to 2/3-level pagetables since then. Also there are minor alterations to the kernel pte dumping code. > > > Signed-off-by: Steve Capper <steve.capper@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] */ > > Why? I think we're just using L_ for consistency here, rather than to > distinguish between h/w and Linux bits (e.g. L_PTE_XN). The name was changed to break anything that used L_PTE_RDONLY, i.e. in case another patch slipped through and started behaving strangely. I will change this to something like L_PTE_HW_RDONLY. > > > #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) > > Why have you killed L_PTE_SPECIAL? We could actually use that for LPAE... > I was trying to be efficient, as it was unused. On the subject of future use of L_PTE_SPECIAL... It was pointed out to me that my fast_gup series had a bug in that it didn't check for special ptes (and it really should). So I would like to introduce L_PTE_SPECIAL usage in another patch ;-). > > #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/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 > > Hehe, I have a patch pending in this macro which is sitting in -next. Take a > look at b6ccb9803e90 ("ARM: 7954/1: mm: remove remaining domain support > from ARMv6"), since this will probably conflict in horrible ways. Eeeep, okay. I'll rebase this series to follow that patch. (Yes some careful changes to logic will be needed :-) ). > > > 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 > > Why do you need this bic? I want to clear the read only bit if the pte is writable and dirty. Cheers, -- Steve ^ permalink raw reply [flat|nested] 11+ messages in thread
* [RFC PATCH 1/2] arm: mm: Switch back to L_PTE_WRITE 2014-02-21 8:37 ` Steve Capper @ 2014-02-24 11:03 ` Will Deacon 0 siblings, 0 replies; 11+ messages in thread From: Will Deacon @ 2014-02-24 11:03 UTC (permalink / raw) To: linux-arm-kernel On Fri, Feb 21, 2014 at 08:37:16AM +0000, Steve Capper wrote: > On Thu, Feb 20, 2014 at 05:22:22PM +0000, Will Deacon wrote: > > On Fri, Feb 14, 2014 at 04:55:12PM +0000, Steve Capper wrote: > > > 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. > > > > This would be a lot easier to review if it was a true revert, but I guess > > that doesn't apply cleanly to mainline? > > Unfortunately not, we've had the split to 2/3-level pagetables since then. > Also there are minor alterations to the kernel pte dumping code. Yeah, I guess as much. Oh well. > > > 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] */ > > > > Why? I think we're just using L_ for consistency here, rather than to > > distinguish between h/w and Linux bits (e.g. L_PTE_XN). > > The name was changed to break anything that used L_PTE_RDONLY, i.e. in > case another patch slipped through and started behaving strangely. > I will change this to something like L_PTE_HW_RDONLY. I'd personally just stick with L_PTE_RDONLY and have a quick grep around after the merge window which includes this patch, to see if any new users have turned up. > > > > > #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) > > > > Why have you killed L_PTE_SPECIAL? We could actually use that for LPAE... > > > > I was trying to be efficient, as it was unused. > > On the subject of future use of L_PTE_SPECIAL... It was pointed out to > me that my fast_gup series had a bug in that it didn't check for special > ptes (and it really should). So I would like to introduce L_PTE_SPECIAL > usage in another patch ;-). Leaving the flag intact should be fine, since the pte_mkspecial pte_special macros don't use it yet iirc (although we *do* have them on arch/arm64, so you should check your GUP code there :). > > > 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 > > > > Why do you need this bic? > > I want to clear the read only bit if the pte is writable and dirty. Ah yes, because that's no longer done by pte_mkwrite. Will ^ permalink raw reply [flat|nested] 11+ messages in thread
* [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() 2014-02-14 16:55 [RFC PATCH 0/2] ARM: Switch back to L_PTE_WRITE Steve Capper 2014-02-14 16:55 ` [RFC PATCH 1/2] arm: mm: " Steve Capper @ 2014-02-14 16:55 ` Steve Capper 2014-02-20 17:26 ` Will Deacon 2014-02-21 11:28 ` Russell King - ARM Linux 1 sibling, 2 replies; 11+ messages in thread From: Steve Capper @ 2014-02-14 16:55 UTC (permalink / raw) To: linux-arm-kernel On LPAE, L_PTE_WRITE and L_PTE_DIRTY are in the upper 32-bits. Unfortunately, results from pte_write() and pte_dirty() are downcast to 32-bits by core code: o gather_stats o huge_pte_dirty o huge_pte_write o make_migration_entry This patch adds a double logical invert to pte_write() and pte_dirty() for LPAE to ensure that the lower 32-bits are set if true. Signed-off-by: Steve Capper <steve.capper@linaro.org> --- arch/arm/include/asm/pgtable-2level.h | 2 ++ arch/arm/include/asm/pgtable-3level.h | 14 ++++++++++++++ arch/arm/include/asm/pgtable.h | 2 -- 3 files changed, 16 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h index ca43b84..7e8ebe7 100644 --- a/arch/arm/include/asm/pgtable-2level.h +++ b/arch/arm/include/asm/pgtable-2level.h @@ -162,6 +162,8 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr) #define pmd_large(pmd) (pmd_val(pmd) & 2) #define pmd_bad(pmd) (pmd_val(pmd) & 2) +#define pte_write(pte) (pte_val(pte) & L_PTE_WRITE) +#define pte_dirty(pte) (pte_val(pte) & L_PTE_DIRTY) #define copy_pmd(pmdpd,pmdps) \ do { \ diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h index 8a392ef..62efcc5 100644 --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -135,6 +135,20 @@ #ifndef __ASSEMBLY__ +/* + * On LPAE, L_PTE_WRITE and L_PTE_DIRTY are in the upper 32-bits. + * Unfortunately, results from pte_write() and pte_dirty() are downcast + * to 32-bits by core code: + * o gather_stats + * o huge_pte_dirty + * o huge_pte_write + * o make_migration_entry + * + * Double logical invert to make sure lower 32-bits are set if true. + */ +#define pte_write(pte) (!!(pte_val(pte) & L_PTE_WRITE)) +#define pte_dirty(pte) (!!(pte_val(pte) & L_PTE_DIRTY)) + #define pud_none(pud) (!pud_val(pud)) #define pud_bad(pud) (!(pud_val(pud) & 2)) #define pud_present(pud) (pud_val(pud)) diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index 7a17611..e94a616 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -216,8 +216,6 @@ 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_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)) #define pte_special(pte) (0) -- 1.8.1.4 ^ permalink raw reply related [flat|nested] 11+ messages in thread
* [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() 2014-02-14 16:55 ` [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() Steve Capper @ 2014-02-20 17:26 ` Will Deacon 2014-02-21 8:39 ` Steve Capper 2014-02-21 11:20 ` Catalin Marinas 2014-02-21 11:28 ` Russell King - ARM Linux 1 sibling, 2 replies; 11+ messages in thread From: Will Deacon @ 2014-02-20 17:26 UTC (permalink / raw) To: linux-arm-kernel On Fri, Feb 14, 2014 at 04:55:13PM +0000, Steve Capper wrote: > On LPAE, L_PTE_WRITE and L_PTE_DIRTY are in the upper 32-bits. > Unfortunately, results from pte_write() and pte_dirty() are downcast > to 32-bits by core code: > o gather_stats > o huge_pte_dirty > o huge_pte_write > o make_migration_entry > > This patch adds a double logical invert to pte_write() and pte_dirty() > for LPAE to ensure that the lower 32-bits are set if true. Yikes, this sounds like something we should put in -stable, no? If so, better make it patch 1 of this series. Reviewed-by: Will Deacon <will.deacon@arm.com> Will ^ permalink raw reply [flat|nested] 11+ messages in thread
* [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() 2014-02-20 17:26 ` Will Deacon @ 2014-02-21 8:39 ` Steve Capper 2014-02-21 11:20 ` Catalin Marinas 1 sibling, 0 replies; 11+ messages in thread From: Steve Capper @ 2014-02-21 8:39 UTC (permalink / raw) To: linux-arm-kernel On Thu, Feb 20, 2014 at 05:26:51PM +0000, Will Deacon wrote: > On Fri, Feb 14, 2014 at 04:55:13PM +0000, Steve Capper wrote: > > On LPAE, L_PTE_WRITE and L_PTE_DIRTY are in the upper 32-bits. > > Unfortunately, results from pte_write() and pte_dirty() are downcast > > to 32-bits by core code: > > o gather_stats > > o huge_pte_dirty > > o huge_pte_write > > o make_migration_entry > > > > This patch adds a double logical invert to pte_write() and pte_dirty() > > for LPAE to ensure that the lower 32-bits are set if true. > > Yikes, this sounds like something we should put in -stable, no? If so, > better make it patch 1 of this series. Yeah, it makes sense to have this as the first patch. It probably should go through stable, I will mark the next version of this patch for stable. > > Reviewed-by: Will Deacon <will.deacon@arm.com> Thanks Will. Cheers, -- Steve ^ permalink raw reply [flat|nested] 11+ messages in thread
* [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() 2014-02-20 17:26 ` Will Deacon 2014-02-21 8:39 ` Steve Capper @ 2014-02-21 11:20 ` Catalin Marinas 1 sibling, 0 replies; 11+ messages in thread From: Catalin Marinas @ 2014-02-21 11:20 UTC (permalink / raw) To: linux-arm-kernel On Thu, Feb 20, 2014 at 05:26:51PM +0000, Will Deacon wrote: > On Fri, Feb 14, 2014 at 04:55:13PM +0000, Steve Capper wrote: > > On LPAE, L_PTE_WRITE and L_PTE_DIRTY are in the upper 32-bits. > > Unfortunately, results from pte_write() and pte_dirty() are downcast > > to 32-bits by core code: > > o gather_stats > > o huge_pte_dirty > > o huge_pte_write > > o make_migration_entry > > > > This patch adds a double logical invert to pte_write() and pte_dirty() > > for LPAE to ensure that the lower 32-bits are set if true. > > Yikes, this sounds like something we should put in -stable, no? If so, > better make it patch 1 of this series. That's a bug on arm64 as well since functions like gather_stats() take an int as argument. However, my preference is for a static inline function instead of "!!" on arm64. Steve, would you send a patch for arm64? If not, I can do it (with your reported-by). Thanks. -- Catalin ^ permalink raw reply [flat|nested] 11+ messages in thread
* [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() 2014-02-14 16:55 ` [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() Steve Capper 2014-02-20 17:26 ` Will Deacon @ 2014-02-21 11:28 ` Russell King - ARM Linux 2014-02-21 11:51 ` Steve Capper 1 sibling, 1 reply; 11+ messages in thread From: Russell King - ARM Linux @ 2014-02-21 11:28 UTC (permalink / raw) To: linux-arm-kernel On Fri, Feb 14, 2014 at 04:55:13PM +0000, Steve Capper wrote: > On LPAE, L_PTE_WRITE and L_PTE_DIRTY are in the upper 32-bits. > Unfortunately, results from pte_write() and pte_dirty() are downcast > to 32-bits by core code: > o gather_stats > o huge_pte_dirty > o huge_pte_write > o make_migration_entry > > This patch adds a double logical invert to pte_write() and pte_dirty() > for LPAE to ensure that the lower 32-bits are set if true. We should ensure all those functions return something which is compatible with "int" correctly. It didn't matter for non-LPAE as the PTEs fit in 32-bit, but with LPAE, that really needs fixing independently of your other patch. -- FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad. Estimate before purchase was "up to 13.2Mbit". ^ permalink raw reply [flat|nested] 11+ messages in thread
* [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() 2014-02-21 11:28 ` Russell King - ARM Linux @ 2014-02-21 11:51 ` Steve Capper 0 siblings, 0 replies; 11+ messages in thread From: Steve Capper @ 2014-02-21 11:51 UTC (permalink / raw) To: linux-arm-kernel On Fri, Feb 21, 2014 at 11:28:12AM +0000, Russell King - ARM Linux wrote: > On Fri, Feb 14, 2014 at 04:55:13PM +0000, Steve Capper wrote: > > On LPAE, L_PTE_WRITE and L_PTE_DIRTY are in the upper 32-bits. > > Unfortunately, results from pte_write() and pte_dirty() are downcast > > to 32-bits by core code: > > o gather_stats > > o huge_pte_dirty > > o huge_pte_write > > o make_migration_entry > > > > This patch adds a double logical invert to pte_write() and pte_dirty() > > for LPAE to ensure that the lower 32-bits are set if true. > > We should ensure all those functions return something which is compatible > with "int" correctly. It didn't matter for non-LPAE as the PTEs fit in > 32-bit, but with LPAE, that really needs fixing independently of your > other patch. Agreed, I'm getting that written/tested now for arm and arm64. Cheers, -- Steve > > -- > FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation > in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad. > Estimate before purchase was "up to 13.2Mbit". ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2014-02-24 11:03 UTC | newest] Thread overview: 11+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-02-14 16:55 [RFC PATCH 0/2] ARM: Switch back to L_PTE_WRITE Steve Capper 2014-02-14 16:55 ` [RFC PATCH 1/2] arm: mm: " Steve Capper 2014-02-20 17:22 ` Will Deacon 2014-02-21 8:37 ` Steve Capper 2014-02-24 11:03 ` Will Deacon 2014-02-14 16:55 ` [RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty() Steve Capper 2014-02-20 17:26 ` Will Deacon 2014-02-21 8:39 ` Steve Capper 2014-02-21 11:20 ` Catalin Marinas 2014-02-21 11:28 ` Russell King - ARM Linux 2014-02-21 11:51 ` Steve Capper
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