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| author | Ard Biesheuvel <ardb@kernel.org> | 2020-10-08 17:35:59 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-10-15 12:14:57 +0200 |
| commit | 7bc1a0f9e1765830e945669c99c59c35cf9bca82 (patch) | |
| tree | d52db7b64e7bd9cb4e0c4e3dd592f54cb2f7c43e /arch/arm64/include/asm | |
| parent | arm64: reject prctl(PR_PAC_RESET_KEYS) on compat tasks (diff) | |
| download | linux-7bc1a0f9e1765830e945669c99c59c35cf9bca82.tar.xz linux-7bc1a0f9e1765830e945669c99c59c35cf9bca82.zip | |
arm64: mm: use single quantity to represent the PA to VA translation
On arm64, the global variable memstart_addr represents the physical
address of PAGE_OFFSET, and so physical to virtual translations or
vice versa used to come down to simple additions or subtractions
involving the values of PAGE_OFFSET and memstart_addr.
When support for 52-bit virtual addressing was introduced, we had to
deal with PAGE_OFFSET potentially being outside of the region that
can be covered by the virtual range (as the 52-bit VA capable build
needs to be able to run on systems that are only 48-bit VA capable),
and for this reason, another translation was introduced, and recorded
in the global variable physvirt_offset.
However, if we go back to the original definition of memstart_addr,
i.e., the physical address of PAGE_OFFSET, it turns out that there is
no need for two separate translations: instead, we can simply subtract
the size of the unaddressable VA space from memstart_addr to make the
available physical memory appear in the 48-bit addressable VA region.
This simplifies things, but also fixes a bug on KASLR builds, which
may update memstart_addr later on in arm64_memblock_init(), but fails
to update vmemmap and physvirt_offset accordingly.
Fixes: 5383cc6efed1 ("arm64: mm: Introduce vabits_actual")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Link: https://lore.kernel.org/r/20201008153602.9467-2-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/include/asm')
| -rw-r--r-- | arch/arm64/include/asm/memory.h | 5 | ||||
| -rw-r--r-- | arch/arm64/include/asm/pgtable.h | 4 |
2 files changed, 4 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 43640d797455..cd61239bae8c 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -169,7 +169,6 @@ extern u64 vabits_actual; #define PAGE_END (_PAGE_END(vabits_actual)) -extern s64 physvirt_offset; extern s64 memstart_addr; /* PHYS_OFFSET - the physical address of the start of memory. */ #define PHYS_OFFSET ({ VM_BUG_ON(memstart_addr & 1); memstart_addr; }) @@ -245,7 +244,7 @@ static inline const void *__tag_set(const void *addr, u8 tag) */ #define __is_lm_address(addr) (!(((u64)addr) & BIT(vabits_actual - 1))) -#define __lm_to_phys(addr) (((addr) + physvirt_offset)) +#define __lm_to_phys(addr) (((addr) & ~PAGE_OFFSET) + PHYS_OFFSET) #define __kimg_to_phys(addr) ((addr) - kimage_voffset) #define __virt_to_phys_nodebug(x) ({ \ @@ -263,7 +262,7 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x); #define __phys_addr_symbol(x) __pa_symbol_nodebug(x) #endif /* CONFIG_DEBUG_VIRTUAL */ -#define __phys_to_virt(x) ((unsigned long)((x) - physvirt_offset)) +#define __phys_to_virt(x) ((unsigned long)((x) - PHYS_OFFSET) | PAGE_OFFSET) #define __phys_to_kimg(x) ((unsigned long)((x) + kimage_voffset)) /* diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index a11bf52e0c38..4ff12a7adcfd 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -24,6 +24,8 @@ #define VMALLOC_START (MODULES_END) #define VMALLOC_END (- PUD_SIZE - VMEMMAP_SIZE - SZ_64K) +#define vmemmap ((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT)) + #define FIRST_USER_ADDRESS 0UL #ifndef __ASSEMBLY__ @@ -34,8 +36,6 @@ #include <linux/mm_types.h> #include <linux/sched.h> -extern struct page *vmemmap; - #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE |