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 08b601e69ddce08c44e5ea08e030c211a21f0c1b..396a12e486fe98baa6620137ae802bbd42b672c4 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 5e68278e953e2513f904cc253d200705c999a673..d0131ee6f6af920d5c3bc6479c2e515e1d706539 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 6ca7d9aa896f4e14804e1096407b16e9b1020456..a016de2480349f15a2ad7036961992b5478f50ba 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 a3681f11dd9f12ceb8260df36e09a11ec0c22066..e683db1b90a3f805d1de8f92a9c0ebe544960368 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);