From 4d9c5b89cf3605bbc39c6e274351ff25f0d83e6a Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Sun, 2 Feb 2014 22:21:31 +0100 Subject: ARM: 7950/1: mm: Fix stage-2 device memory attributes The stage-2 memory attributes are distinct from the Hyp memory attributes and the Stage-1 memory attributes. We were using the stage-1 memory attributes for stage-2 mappings causing device mappings to be mapped as normal memory. Add the S2 equivalent defines for memory attributes and fix the comments explaining the defines while at it. Add a prot_pte_s2 field to the mem_type struct and fill out the field for device mappings accordingly. Cc: [3.9+] Acked-by: Marc Zyngier Acked-by: Catalin Marinas Signed-off-by: Christoffer Dall Signed-off-by: Russell King --- arch/arm/mm/mmu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'arch/arm/mm/mmu.c') diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 4f08c133cc25..a623cb3ad012 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -232,12 +232,16 @@ __setup("noalign", noalign_setup); #endif /* ifdef CONFIG_CPU_CP15 / else */ #define PROT_PTE_DEVICE L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_XN +#define PROT_PTE_S2_DEVICE PROT_PTE_DEVICE #define PROT_SECT_DEVICE PMD_TYPE_SECT|PMD_SECT_AP_WRITE static struct mem_type mem_types[] = { [MT_DEVICE] = { /* Strongly ordered / ARMv6 shared device */ .prot_pte = PROT_PTE_DEVICE | L_PTE_MT_DEV_SHARED | L_PTE_SHARED, + .prot_pte_s2 = s2_policy(PROT_PTE_S2_DEVICE) | + s2_policy(L_PTE_S2_MT_DEV_SHARED) | + L_PTE_SHARED, .prot_l1 = PMD_TYPE_TABLE, .prot_sect = PROT_SECT_DEVICE | PMD_SECT_S, .domain = DOMAIN_IO, @@ -508,7 +512,8 @@ static void __init build_mem_type_table(void) cp = &cache_policies[cachepolicy]; vecs_pgprot = kern_pgprot = user_pgprot = cp->pte; s2_pgprot = cp->pte_s2; - hyp_device_pgprot = s2_device_pgprot = mem_types[MT_DEVICE].prot_pte; + hyp_device_pgprot = mem_types[MT_DEVICE].prot_pte; + s2_device_pgprot = mem_types[MT_DEVICE].prot_pte_s2; /* * ARMv6 and above have extended page tables. -- cgit From b6ccb9803e90c16b212cf4ed62913a7591e79a39 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 7 Feb 2014 19:12:27 +0100 Subject: ARM: 7954/1: mm: remove remaining domain support from ARMv6 CPU_32v6 currently selects CPU_USE_DOMAINS if CPU_V6 and MMU. This is because ARM 1136 r0pX CPUs lack the v6k extensions, and therefore do not have hardware thread registers. The lack of these registers requires the kernel to update the vectors page at each context switch in order to write a new TLS pointer. This write must be done via the userspace mapping, since aliasing caches can lead to expensive flushing when using kmap. Finally, this requires the vectors page to be mapped r/w for kernel and r/o for user, which has implications for things like put_user which must trigger CoW appropriately when targetting user pages. The upshot of all this is that a v6/v7 kernel makes use of domains to segregate kernel and user memory accesses. This has the nasty side-effect of making device mappings executable, which has been observed to cause subtle bugs on recent cores (e.g. Cortex-A15 performing a speculative instruction fetch from the GIC and acking an interrupt in the process). This patch solves this problem by removing the remaining domain support from ARMv6. A new memory type is added specifically for the vectors page which allows that page (and only that page) to be mapped as user r/o, kernel r/w. All other user r/o pages are mapped also as kernel r/o. Patch co-developed with Russell King. Cc: Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/mm/mmu.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/arm/mm/mmu.c') diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 4f08c133cc25..6ec07a84f759 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -510,6 +510,16 @@ static void __init build_mem_type_table(void) s2_pgprot = cp->pte_s2; hyp_device_pgprot = s2_device_pgprot = mem_types[MT_DEVICE].prot_pte; + /* + * We don't use domains on ARMv6 (since this causes problems with + * v6/v7 kernels), so we must use a separate memory type for user + * r/o, kernel r/w to map the vectors page. + */ +#ifndef CONFIG_ARM_LPAE + if (cpu_arch == CPU_ARCH_ARMv6) + vecs_pgprot |= L_PTE_MT_VECTORS; +#endif + /* * ARMv6 and above have extended page tables. */ -- cgit