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| author |  Ard Biesheuvel <ardb@kernel.org>
| 2022-06-24 17:06:42 +0200 |
|---|---|---|
| committer |  Will Deacon <will@kernel.org>
| 2022-06-24 17:18:10 +0100 |
| commit | c3cee924bd855184d15bc4aa6088dcf8e2c1394c (patch) | |
| tree | afe531afe391eadbcdf03355a5c2e5b97df39a64 /arch/arm64/include/asm/kernel-pgtable.h | |
| parent | arm64: head: add helper function to remap regions in early page tables (diff) | |
| download | linux-c3cee924bd855184d15bc4aa6088dcf8e2c1394c.tar.gz linux-c3cee924bd855184d15bc4aa6088dcf8e2c1394c.tar.bz2 linux-c3cee924bd855184d15bc4aa6088dcf8e2c1394c.zip | |
arm64: head: cover entire kernel image in initial ID map
As a first step towards avoiding the need to create, tear down and
recreate the kernel virtual mapping with MMU and caches disabled, start
by expanding the ID map so it covers the page tables as well as all
executable code. This will allow us to populate the page tables with the
MMU and caches on, and call KASLR init code before setting up the
virtual mapping.
Since this ID map is only needed at boot, create it as a temporary set
of page tables, and populate the permanent ID map after enabling the MMU
and caches. While at it, switch to read-only attributes for the where
possible, as writable permissions are only needed for the initial kernel
page tables. Note that on 4k granule configurations, the permanent ID
map will now be reduced to a single page rather than a 2M block mapping.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220624150651.1358849-13-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/include/asm/kernel-pgtable.h')
| -rw-r--r-- | arch/arm64/include/asm/kernel-pgtable.h | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h index 96dc0f7da258..5395e5a04f35 100644 --- a/arch/arm64/include/asm/kernel-pgtable.h +++ b/arch/arm64/include/asm/kernel-pgtable.h @@ -35,10 +35,8 @@ */ #if ARM64_KERNEL_USES_PMD_MAPS #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1) -#define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT) - 1) #else #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS) -#define IDMAP_PGTABLE_LEVELS (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT)) #endif @@ -87,7 +85,13 @@ + EARLY_PUDS((vstart), (vend)) /* each PUD needs a next level page table */ \ + EARLY_PMDS((vstart), (vend))) /* each PMD needs a next level page table */ #define INIT_DIR_SIZE (PAGE_SIZE * EARLY_PAGES(KIMAGE_VADDR, _end)) -#define IDMAP_DIR_SIZE (IDMAP_PGTABLE_LEVELS * PAGE_SIZE) + +/* the initial ID map may need two extra pages if it needs to be extended */ +#if VA_BITS < 48 +#define INIT_IDMAP_DIR_SIZE (INIT_DIR_SIZE + (2 * PAGE_SIZE)) +#else +#define INIT_IDMAP_DIR_SIZE INIT_DIR_SIZE +#endif /* Initial memory map size */ #if ARM64_KERNEL_USES_PMD_MAPS @@ -107,9 +111,11 @@ #define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S) #if ARM64_KERNEL_USES_PMD_MAPS -#define SWAPPER_MM_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS) +#define SWAPPER_RW_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS) +#define SWAPPER_RX_MMUFLAGS (SWAPPER_RW_MMUFLAGS | PMD_SECT_RDONLY) #else -#define SWAPPER_MM_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS) +#define SWAPPER_RW_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS) +#define SWAPPER_RX_MMUFLAGS (SWAPPER_RW_MMUFLAGS | PTE_RDONLY) #endif /* |