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| author | Steve Capper <steve.capper@arm.com> | 2019-08-07 18:55:14 +0300 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2019-08-09 13:16:51 +0300 |
| commit | 14c127c957c1c6070647c171e72f06e0db275ebf (patch) | |
| tree | 6f5e57a4dd8c8cbe895b01513c2bd6a1cb3ddcff /arch/arm64/mm/dump.c | |
| parent | 9cb1c5ddd2c432834dd4f40c0170d6b639e8e5c3 (diff) | |
| download | linux-14c127c957c1c6070647c171e72f06e0db275ebf.tar.xz | |
arm64: mm: Flip kernel VA space
In order to allow for a KASAN shadow that changes size at boot time, one
must fix the KASAN_SHADOW_END for both 48 & 52-bit VAs and "grow" the
start address. Also, it is highly desirable to maintain the same
function addresses in the kernel .text between VA sizes. Both of these
requirements necessitate us to flip the kernel address space halves s.t.
the direct linear map occupies the lower addresses.
This patch puts the direct linear map in the lower addresses of the
kernel VA range and everything else in the higher ranges.
We need to adjust:
*) KASAN shadow region placement logic,
*) KASAN_SHADOW_OFFSET computation logic,
*) virt_to_phys, phys_to_virt checks,
*) page table dumper.
These are all small changes, that need to take place atomically, so they
are bundled into this commit.
As part of the re-arrangement, a guard region of 2MB (to preserve
alignment for fixed map) is added after the vmemmap. Otherwise the
vmemmap could intersect with IS_ERR pointers.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/mm/dump.c')
| -rw-r--r-- | arch/arm64/mm/dump.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c index 82b3a7fdb4a6..beec87488e97 100644 --- a/arch/arm64/mm/dump.c +++ b/arch/arm64/mm/dump.c @@ -26,6 +26,8 @@ #include <asm/ptdump.h> static const struct addr_marker address_markers[] = { + { PAGE_OFFSET, "Linear Mapping start" }, + { VA_START, "Linear Mapping end" }, #ifdef CONFIG_KASAN { KASAN_SHADOW_START, "Kasan shadow start" }, { KASAN_SHADOW_END, "Kasan shadow end" }, @@ -42,7 +44,6 @@ static const struct addr_marker address_markers[] = { { VMEMMAP_START, "vmemmap start" }, { VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" }, #endif - { PAGE_OFFSET, "Linear mapping" }, { -1, NULL }, }; @@ -376,7 +377,7 @@ static void ptdump_initialize(void) static struct ptdump_info kernel_ptdump_info = { .mm = &init_mm, .markers = address_markers, - .base_addr = VA_START, + .base_addr = PAGE_OFFSET, }; void ptdump_check_wx(void) |