From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Fri, 21 Aug 2015 08:38:31 +0000 (+0100)
Subject: ARM: domains: keep vectors in separate domain
X-Git-Tag: v4.3-rc1~88^2~1^5~6
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a02d8dfd54cdf3b1b0464ccc2c1c4afe2c003a35;p=users%2Fjedix%2Flinux-maple.git

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 08b601e69ddce..396a12e486fe9 100644
--- 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 5e68278e953e2..d0131ee6f6af9 100644
--- 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 6ca7d9aa896f4..a016de2480349 100644
--- 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 a3681f11dd9f1..e683db1b90a3f 100644
--- 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);