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| author | William Grant <william.grant@canonical.com> | 2018-01-30 12:22:55 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-01-30 15:30:35 +0100 |
| commit | 55f49fcb879fbeebf2a8c1ac7c9e6d90df55f798 (patch) | |
| tree | 809736850942a87b269772a1bb1a51b14dc13f60 | |
| parent | objtool: Warn on stripped section symbol (diff) | |
| download | linux-55f49fcb879fbeebf2a8c1ac7c9e6d90df55f798.tar.xz linux-55f49fcb879fbeebf2a8c1ac7c9e6d90df55f798.zip | |
x86/mm: Fix overlap of i386 CPU_ENTRY_AREA with FIX_BTMAP
Since commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the
fixmap"), i386's CPU_ENTRY_AREA has been mapped to the memory area just
below FIXADDR_START. But already immediately before FIXADDR_START is the
FIX_BTMAP area, which means that early_ioremap can collide with the entry
area.
It's especially bad on PAE where FIX_BTMAP_BEGIN gets aligned to exactly
match CPU_ENTRY_AREA_BASE, so the first early_ioremap slot clobbers the
IDT and causes interrupts during early boot to reset the system.
The overlap wasn't a problem before the CPU entry area was introduced,
as the fixmap has classically been preceded by the pkmap or vmalloc
areas, neither of which is used until early_ioremap is out of the
picture.
Relocate CPU_ENTRY_AREA to below FIX_BTMAP, not just below the permanent
fixmap area.
Fixes: commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the fixmap")
Signed-off-by: William Grant <william.grant@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/7041d181-a019-e8b9-4e4e-48215f841e2c@canonical.com
| -rw-r--r-- | arch/x86/include/asm/fixmap.h | 6 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable_32_types.h | 5 |
2 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index 64c4a30e0d39..e203169931c7 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -137,8 +137,10 @@ enum fixed_addresses { extern void reserve_top_address(unsigned long reserve); -#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT) -#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) +#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT) +#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) +#define FIXADDR_TOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) +#define FIXADDR_TOT_START (FIXADDR_TOP - FIXADDR_TOT_SIZE) extern int fixmaps_set; diff --git a/arch/x86/include/asm/pgtable_32_types.h b/arch/x86/include/asm/pgtable_32_types.h index ce245b0cdfca..0777e18a1d23 100644 --- a/arch/x86/include/asm/pgtable_32_types.h +++ b/arch/x86/include/asm/pgtable_32_types.h @@ -44,8 +44,9 @@ extern bool __vmalloc_start_set; /* set once high_memory is set */ */ #define CPU_ENTRY_AREA_PAGES (NR_CPUS * 40) -#define CPU_ENTRY_AREA_BASE \ - ((FIXADDR_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) & PMD_MASK) +#define CPU_ENTRY_AREA_BASE \ + ((FIXADDR_TOT_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) \ + & PMD_MASK) #define PKMAP_BASE \ ((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK) |