summaryrefslogtreecommitdiff
path: root/arch/x86/boot
diff options
context:
space:
mode:
authorArvind Sankar <nivedita@alum.mit.edu>2020-10-10 22:11:10 +0300
committerBorislav Petkov <bp@suse.de>2020-10-19 13:47:21 +0300
commite5ceb9a02402b984feecb95a82239be151c9f4e2 (patch)
treec0ea17ca8e1d466a48abb1c37f4c67a3bf3fc7da /arch/x86/boot
parentda9803dfd3955bd2f9909d55e23f188ad76dbe58 (diff)
downloadlinux-e5ceb9a02402b984feecb95a82239be151c9f4e2.tar.xz
x86/boot/64: Initialize 5-level paging variables earlier
Commit ca0e22d4f011 ("x86/boot/compressed/64: Always switch to own page table") started using a new set of pagetables even without KASLR. After that commit, initialize_identity_maps() is called before the 5-level paging variables are setup in choose_random_location(), which will not work if 5-level paging is actually enabled. Fix this by moving the initialization of __pgtable_l5_enabled, pgdir_shift and ptrs_per_p4d into cleanup_trampoline(), which is called immediately after the finalization of whether the kernel is executing with 4- or 5-level paging. This will be earlier than anything that might require those variables, and keeps the 4- vs 5-level paging code all in one place. Fixes: ca0e22d4f011 ("x86/boot/compressed/64: Always switch to own page table") Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Joerg Roedel <jroedel@suse.de> Tested-by: Joerg Roedel <jroedel@suse.de> Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Link: https://lkml.kernel.org/r/20201010191110.4060905-1-nivedita@alum.mit.edu
Diffstat (limited to 'arch/x86/boot')
-rw-r--r--arch/x86/boot/compressed/ident_map_64.c6
-rw-r--r--arch/x86/boot/compressed/kaslr.c8
-rw-r--r--arch/x86/boot/compressed/pgtable_64.c16
3 files changed, 16 insertions, 14 deletions
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index 063a60edcf99..c6f7aef7e85a 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -33,12 +33,6 @@
#define __PAGE_OFFSET __PAGE_OFFSET_BASE
#include "../../mm/ident_map.c"
-#ifdef CONFIG_X86_5LEVEL
-unsigned int __pgtable_l5_enabled;
-unsigned int pgdir_shift = 39;
-unsigned int ptrs_per_p4d = 1;
-#endif
-
/* Used by PAGE_KERN* macros: */
pteval_t __default_kernel_pte_mask __read_mostly = ~0;
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index b59547ce5b19..b92fffbe761f 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -840,14 +840,6 @@ void choose_random_location(unsigned long input,
return;
}
-#ifdef CONFIG_X86_5LEVEL
- if (__read_cr4() & X86_CR4_LA57) {
- __pgtable_l5_enabled = 1;
- pgdir_shift = 48;
- ptrs_per_p4d = 512;
- }
-#endif
-
boot_params->hdr.loadflags |= KASLR_FLAG;
if (IS_ENABLED(CONFIG_X86_32))
diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c
index 7d0394f4ebf9..5def1674d6f1 100644
--- a/arch/x86/boot/compressed/pgtable_64.c
+++ b/arch/x86/boot/compressed/pgtable_64.c
@@ -8,6 +8,13 @@
#define BIOS_START_MIN 0x20000U /* 128K, less than this is insane */
#define BIOS_START_MAX 0x9f000U /* 640K, absolute maximum */
+#ifdef CONFIG_X86_5LEVEL
+/* __pgtable_l5_enabled needs to be in .data to avoid being cleared along with .bss */
+unsigned int __section(.data) __pgtable_l5_enabled;
+unsigned int __section(.data) pgdir_shift = 39;
+unsigned int __section(.data) ptrs_per_p4d = 1;
+#endif
+
struct paging_config {
unsigned long trampoline_start;
unsigned long l5_required;
@@ -198,4 +205,13 @@ void cleanup_trampoline(void *pgtable)
/* Restore trampoline memory */
memcpy(trampoline_32bit, trampoline_save, TRAMPOLINE_32BIT_SIZE);
+
+ /* Initialize variables for 5-level paging */
+#ifdef CONFIG_X86_5LEVEL
+ if (__read_cr4() & X86_CR4_LA57) {
+ __pgtable_l5_enabled = 1;
+ pgdir_shift = 48;
+ ptrs_per_p4d = 512;
+ }
+#endif
}