arm64: kpti: Make use of nG dependent on arm64_kernel_unmapped_at_el0()

BugLink: http://bugs.launchpad.net/bugs/1751064
Commit 41acec624087 upstream.

To allow systems which do not require kpti to continue running with
global kernel mappings (which appears to be a requirement for Cavium
ThunderX due to a CPU erratum), make the use of nG in the kernel page
tables dependent on arm64_kernel_unmapped_at_el0(), which is resolved
at runtime.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
index 77a27af013710de1d4bed56655ee587c5e6ef349..7803343e5881fbd7b2f635b25082d3e91d2583f8 100644 (file)
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -78,16 +78,8 @@
 /*
  * Initial memory map attributes.
  */
-#define _SWAPPER_PTE_FLAGS     (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
-#define _SWAPPER_PMD_FLAGS     (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
-
-#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-#define SWAPPER_PTE_FLAGS      (_SWAPPER_PTE_FLAGS | PTE_NG)
-#define SWAPPER_PMD_FLAGS      (_SWAPPER_PMD_FLAGS | PMD_SECT_NG)
-#else
-#define SWAPPER_PTE_FLAGS      _SWAPPER_PTE_FLAGS
-#define SWAPPER_PMD_FLAGS      _SWAPPER_PMD_FLAGS
-#endif
+#define SWAPPER_PTE_FLAGS      (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
+#define SWAPPER_PMD_FLAGS      (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
 
 #if ARM64_SWAPPER_USES_SECTION_MAPS
 #define SWAPPER_MM_MMUFLAGS    (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)

diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 22a926825e3fb87f19a3b4d0015b29db0e8a9ab1..2db84df5eb422497d32f039bf5fa17d6c444a775 100644 (file)
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -37,13 +37,11 @@
 #define _PROT_DEFAULT          (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
 #define _PROT_SECT_DEFAULT     (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
 
-#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-#define PROT_DEFAULT           (_PROT_DEFAULT | PTE_NG)
-#define PROT_SECT_DEFAULT      (_PROT_SECT_DEFAULT | PMD_SECT_NG)
-#else
-#define PROT_DEFAULT           _PROT_DEFAULT
-#define PROT_SECT_DEFAULT      _PROT_SECT_DEFAULT
-#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
+#define PTE_MAYBE_NG           (arm64_kernel_unmapped_at_el0() ? PTE_NG : 0)
+#define PMD_MAYBE_NG           (arm64_kernel_unmapped_at_el0() ? PMD_SECT_NG : 0)
+
+#define PROT_DEFAULT           (_PROT_DEFAULT | PTE_MAYBE_NG)
+#define PROT_SECT_DEFAULT      (_PROT_SECT_DEFAULT | PMD_MAYBE_NG)
 
 #define PROT_DEVICE_nGnRnE     (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_ATTRINDX(MT_DEVICE_nGnRnE))
 #define PROT_DEVICE_nGnRE      (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_ATTRINDX(MT_DEVICE_nGnRE))
@@ -55,22 +53,22 @@
 #define PROT_SECT_NORMAL       (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
 #define PROT_SECT_NORMAL_EXEC  (PROT_SECT_DEFAULT | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
 
-#define _PAGE_DEFAULT          (PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
-#define _HYP_PAGE_DEFAULT      (_PAGE_DEFAULT & ~PTE_NG)
+#define _PAGE_DEFAULT          (_PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
+#define _HYP_PAGE_DEFAULT      _PAGE_DEFAULT
 
-#define PAGE_KERNEL            __pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE)
-#define PAGE_KERNEL_RO         __pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_RDONLY)
-#define PAGE_KERNEL_ROX                __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_RDONLY)
-#define PAGE_KERNEL_EXEC       __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE)
-#define PAGE_KERNEL_EXEC_CONT  __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_CONT)
+#define PAGE_KERNEL            __pgprot(PROT_NORMAL)
+#define PAGE_KERNEL_RO         __pgprot((PROT_NORMAL & ~PTE_WRITE) | PTE_RDONLY)
+#define PAGE_KERNEL_ROX                __pgprot((PROT_NORMAL & ~(PTE_WRITE | PTE_PXN)) | PTE_RDONLY)
+#define PAGE_KERNEL_EXEC       __pgprot(PROT_NORMAL & ~PTE_PXN)
+#define PAGE_KERNEL_EXEC_CONT  __pgprot((PROT_NORMAL & ~PTE_PXN) | PTE_CONT)
 
 #define PAGE_HYP               __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_HYP_XN)
 #define PAGE_HYP_EXEC          __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY)
 #define PAGE_HYP_RO            __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY | PTE_HYP_XN)
 #define PAGE_HYP_DEVICE                __pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
 
-#define PAGE_S2                        __pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
-#define PAGE_S2_DEVICE         __pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_UXN)
+#define PAGE_S2                        __pgprot(_PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
+#define PAGE_S2_DEVICE         __pgprot(_PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_UXN)
 
 #define PAGE_NONE              __pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
 #define PAGE_SHARED            __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)