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ARM: domains: keep vectors in separate domain 

Keep the machine vectors in its own domain to avoid software based
user access control from making the vector code inaccessible, and
thereby deadlocking the machine.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2015-08-21 09:38:31 +01:00
parent 3c2aed5b28
commit a02d8dfd54
4 changed files with 16 additions and 3 deletions
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4
arch/arm/include/asm/domain.h
View File

@ -43,6 +43,7 @@
#define DOMAIN_USER 1
#define DOMAIN_IO 0
#endif
#define DOMAIN_VECTORS 3
/*
* Domain types
@ -62,7 +63,8 @@
(domain_val(DOMAIN_USER, DOMAIN_CLIENT) | \
domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \
domain_val(DOMAIN_TABLE, DOMAIN_MANAGER) | \
domain_val(DOMAIN_IO, DOMAIN_CLIENT))
domain_val(DOMAIN_IO, DOMAIN_CLIENT) | \
domain_val(DOMAIN_VECTORS, DOMAIN_CLIENT))
#ifndef __ASSEMBLY__

1
arch/arm/include/asm/pgtable-2level-hwdef.h
View File

@ -23,6 +23,7 @@
#define PMD_PXNTABLE (_AT(pmdval_t, 1) << 2) /* v7 */
#define PMD_BIT4 (_AT(pmdval_t, 1) << 4)
#define PMD_DOMAIN(x) (_AT(pmdval_t, (x)) << 5)
#define PMD_DOMAIN_MASK PMD_DOMAIN(0x0f)
#define PMD_PROTECTION (_AT(pmdval_t, 1) << 9) /* v5 */
/*
* - section

4
arch/arm/mm/mmu.c
View File

@ -291,13 +291,13 @@ static struct mem_type mem_types[] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
L_PTE_RDONLY,
.prot_l1 = PMD_TYPE_TABLE,
.domain = DOMAIN_USER,
.domain = DOMAIN_VECTORS,
},
[MT_HIGH_VECTORS] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
L_PTE_USER | L_PTE_RDONLY,
.prot_l1 = PMD_TYPE_TABLE,
.domain = DOMAIN_USER,
.domain = DOMAIN_VECTORS,
},
[MT_MEMORY_RWX] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,

10
arch/arm/mm/pgd.c
View File

@ -84,6 +84,16 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
if (!new_pte)
goto no_pte;
#ifndef CONFIG_ARM_LPAE
/*
* Modify the PTE pointer to have the correct domain. This
* needs to be the vectors domain to avoid the low vectors
* being unmapped.
*/
pmd_val(*new_pmd) &= ~PMD_DOMAIN_MASK;
pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS);
#endif
init_pud = pud_offset(init_pgd, 0);
init_pmd = pmd_offset(init_pud, 0);
init_pte = pte_offset_map(init_pmd, 0);