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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2016-02-26 19:57:14 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2016-02-29 21:31:03 +0300 |
| commit | 020d044f66874eba058ce8264fc550f3eca67879 (patch) | |
| tree | 77456326c82899b4ef57593788b0bebf02f00ed0 | |
| parent | a6e1f7273b709328ed19e1b8ca5ae61dc1d9b4c0 (diff) | |
| download | linux-020d044f66874eba058ce8264fc550f3eca67879.tar.xz | |
arm64: mm: treat memstart_addr as a signed quantity
Commit c031a4213c11 ("arm64: kaslr: randomize the linear region")
implements randomization of the linear region, by subtracting a random
multiple of PUD_SIZE from memstart_addr. This causes the virtual mapping
of system RAM to move upwards in the linear region, and at the same time
causes memstart_addr to assume a value which may be negative if the offset
of system RAM in the physical space is smaller than its offset relative to
PAGE_OFFSET in the virtual space.
Since memstart_addr is effectively an offset now, redefine its type as s64
so that expressions involving shifting or division preserve its sign.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/memory.h | 2 | ||||
| -rw-r--r-- | arch/arm64/mm/init.c | 4 |
2 files changed, 3 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 5f8667a99e41..12f8a00fb3f1 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -135,7 +135,7 @@ #include <linux/bitops.h> #include <linux/mmdebug.h> -extern phys_addr_t memstart_addr; +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; }) diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 3b897b9f8807..22c6758b01aa 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -54,7 +54,7 @@ * executes, which assigns it its actual value. So use a default value * that cannot be mistaken for a real physical address. */ -phys_addr_t memstart_addr __read_mostly = ~0ULL; +s64 memstart_addr __read_mostly = -1; phys_addr_t arm64_dma_phys_limit __read_mostly; #ifdef CONFIG_BLK_DEV_INITRD @@ -181,7 +181,7 @@ void __init arm64_memblock_init(void) * linear mapping. Take care not to clip the kernel which may be * high in memory. */ - memblock_remove(max(memstart_addr + linear_region_size, __pa(_end)), + memblock_remove(max_t(u64, memstart_addr + linear_region_size, __pa(_end)), ULLONG_MAX); if (memblock_end_of_DRAM() > linear_region_size) memblock_remove(0, memblock_end_of_DRAM() - linear_region_size); |