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>

diff --git a/arch/arm/include/asm/domain.h b/arch/arm/include/asm/domain.h
index 08b601e..396a12e 100644 (file)
--- a/arch/arm/include/asm/domain.h
+++ b/arch/arm/include/asm/domain.h
@@ -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__
 

diff --git a/arch/arm/include/asm/pgtable-2level-hwdef.h b/arch/arm/include/asm/pgtable-2level-hwdef.h
index 5e68278..d0131ee 100644 (file)
--- a/arch/arm/include/asm/pgtable-2level-hwdef.h
+++ b/arch/arm/include/asm/pgtable-2level-hwdef.h
@@ -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

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 6ca7d9a..a016de2 100644 (file)
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -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,

diff --git a/arch/arm/mm/pgd.c b/arch/arm/mm/pgd.c
index a3681f1..e683db1 100644 (file)
--- a/arch/arm/mm/pgd.c
+++ b/arch/arm/mm/pgd.c
@@ -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);