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ARM: pgtable: invert L_PTE_EXEC to L_PTE_XN
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The hardware page tables use an XN bit 'execute never'.  Historically,
we've had a Linux 'execute allow' bit, in the positive sense.  Get rid
of this artifact as future hardware will continue to have the XN sense.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Russell King committed Dec 22, 2010
1 parent e926f44 commit 9522d7e
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Showing 4 changed files with 34 additions and 35 deletions.
44 changes: 22 additions & 22 deletions arch/arm/include/asm/pgtable.h
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Original file line number Diff line number Diff line change
Expand Up @@ -171,7 +171,7 @@ extern void __pgd_error(const char *file, int line, pgd_t);
#define L_PTE_DIRTY (_AT(pteval_t, 1) << 6)
#define L_PTE_WRITE (_AT(pteval_t, 1) << 7)
#define L_PTE_USER (_AT(pteval_t, 1) << 8)
#define L_PTE_EXEC (_AT(pteval_t, 1) << 9)
#define L_PTE_XN (_AT(pteval_t, 1) << 9)
#define L_PTE_SHARED (_AT(pteval_t, 1) << 10) /* shared(v6), coherent(xsc3) */

/*
Expand Down Expand Up @@ -205,23 +205,23 @@ extern pgprot_t pgprot_kernel;

#define _MOD_PROT(p, b) __pgprot(pgprot_val(p) | (b))

#define PAGE_NONE pgprot_user
#define PAGE_SHARED _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_WRITE)
#define PAGE_SHARED_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_WRITE | L_PTE_EXEC)
#define PAGE_COPY _MOD_PROT(pgprot_user, L_PTE_USER)
#define PAGE_COPY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_EXEC)
#define PAGE_READONLY _MOD_PROT(pgprot_user, L_PTE_USER)
#define PAGE_READONLY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_EXEC)
#define PAGE_KERNEL pgprot_kernel
#define PAGE_KERNEL_EXEC _MOD_PROT(pgprot_kernel, L_PTE_EXEC)

#define __PAGE_NONE __pgprot(_L_PTE_DEFAULT)
#define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_WRITE)
#define __PAGE_SHARED_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_WRITE | L_PTE_EXEC)
#define __PAGE_COPY __pgprot(_L_PTE_DEFAULT | L_PTE_USER)
#define __PAGE_COPY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_EXEC)
#define __PAGE_READONLY __pgprot(_L_PTE_DEFAULT | L_PTE_USER)
#define __PAGE_READONLY_EXEC __pgprot(_L_PTE_DEFAULT | L_PTE_USER | L_PTE_EXEC)
#define PAGE_NONE _MOD_PROT(pgprot_user, L_PTE_XN)
#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_NONE __pgprot(_L_PTE_DEFAULT | L_PTE_XN)
#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))
Expand All @@ -234,14 +234,14 @@ extern pgprot_t pgprot_kernel;

#ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE
#define pgprot_dmacoherent(prot) \
__pgprot_modify(prot, L_PTE_MT_MASK|L_PTE_EXEC, L_PTE_MT_BUFFERABLE)
__pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_BUFFERABLE | L_PTE_XN)
#define __HAVE_PHYS_MEM_ACCESS_PROT
struct file;
extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
unsigned long size, pgprot_t vma_prot);
#else
#define pgprot_dmacoherent(prot) \
__pgprot_modify(prot, L_PTE_MT_MASK|L_PTE_EXEC, L_PTE_MT_UNCACHED)
__pgprot_modify(prot, L_PTE_MT_MASK, L_PTE_MT_UNCACHED | L_PTE_XN)
#endif

#endif /* __ASSEMBLY__ */
Expand Down Expand Up @@ -383,7 +383,7 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
#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_EXEC)
#define pte_exec(pte) (!(pte_val(pte) & L_PTE_XN))
#define pte_special(pte) (0)

#define pte_present_user(pte) \
Expand All @@ -404,7 +404,7 @@ 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_EXEC | L_PTE_WRITE | L_PTE_USER;
const pteval_t mask = L_PTE_XN | L_PTE_WRITE | L_PTE_USER;
pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
return pte;
}
Expand Down
15 changes: 7 additions & 8 deletions arch/arm/mm/mmu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -190,7 +190,7 @@ void adjust_cr(unsigned long mask, unsigned long set)
}
#endif

#define PROT_PTE_DEVICE L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_WRITE
#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[] = {
Expand Down Expand Up @@ -234,20 +234,19 @@ static struct mem_type mem_types[] = {
.domain = DOMAIN_KERNEL,
},
[MT_LOW_VECTORS] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
L_PTE_EXEC,
.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_EXEC,
L_PTE_USER,
.prot_l1 = PMD_TYPE_TABLE,
.domain = DOMAIN_USER,
},
[MT_MEMORY] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
L_PTE_WRITE | L_PTE_EXEC,
L_PTE_WRITE,
.prot_l1 = PMD_TYPE_TABLE,
.prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
.domain = DOMAIN_KERNEL,
Expand All @@ -258,21 +257,21 @@ static struct mem_type mem_types[] = {
},
[MT_MEMORY_NONCACHED] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
L_PTE_WRITE | L_PTE_EXEC | 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_DTCM] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
L_PTE_WRITE,
L_PTE_WRITE | L_PTE_XN,
.prot_l1 = PMD_TYPE_TABLE,
.prot_sect = PMD_TYPE_SECT | PMD_SECT_XN,
.domain = DOMAIN_KERNEL,
},
[MT_MEMORY_ITCM] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
L_PTE_WRITE | L_PTE_EXEC,
L_PTE_WRITE,
.prot_l1 = PMD_TYPE_TABLE,
.domain = DOMAIN_KERNEL,
},
Expand Down
6 changes: 3 additions & 3 deletions arch/arm/mm/proc-macros.S
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Original file line number Diff line number Diff line change
Expand Up @@ -81,7 +81,7 @@
#if L_PTE_SHARED != PTE_EXT_SHARED
#error PTE shared bit mismatch
#endif
#if (L_PTE_EXEC+L_PTE_USER+L_PTE_WRITE+L_PTE_DIRTY+L_PTE_YOUNG+\
#if (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
Expand Down Expand Up @@ -141,8 +141,8 @@
tstne r3, #PTE_EXT_APX
bicne r3, r3, #PTE_EXT_APX | PTE_EXT_AP0

tst r1, #L_PTE_EXEC
orreq r3, r3, #PTE_EXT_XN
tst r1, #L_PTE_XN
orrne r3, r3, #PTE_EXT_XN

orr r3, r3, r2

Expand Down
4 changes: 2 additions & 2 deletions arch/arm/mm/proc-v7.S
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Original file line number Diff line number Diff line change
Expand Up @@ -149,8 +149,8 @@ ENTRY(cpu_v7_set_pte_ext)
tstne r3, #PTE_EXT_APX
bicne r3, r3, #PTE_EXT_APX | PTE_EXT_AP0

tst r1, #L_PTE_EXEC
orreq r3, r3, #PTE_EXT_XN
tst r1, #L_PTE_XN
orrne r3, r3, #PTE_EXT_XN

tst r1, #L_PTE_YOUNG
tstne r1, #L_PTE_PRESENT
Expand Down

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