diff options
author | Nicolas Pitre <nicolas.pitre@linaro.org> | 2016-07-28 20:38:07 +0200 |
---|---|---|
committer | Russell King <rmk+kernel@armlinux.org.uk> | 2016-08-09 23:57:40 +0200 |
commit | b9a019899f61acca18df5fb5e38a8fcdfea86fcd (patch) | |
tree | b82cffdfbc870cf30555cfe57459559d62a60eee /arch/arm/mm/mmu.c | |
parent | Linux 4.8-rc1 (diff) | |
download | linux-b9a019899f61acca18df5fb5e38a8fcdfea86fcd.tar.xz linux-b9a019899f61acca18df5fb5e38a8fcdfea86fcd.zip |
ARM: 8590/1: sanity_check_meminfo(): avoid overflow on vmalloc_limit
To limit the amount of mapped low memory, we determine a physical address
boundary based on the start of the vmalloc area using __pa().
Strictly speaking, the vmalloc area location is arbitrary and does not
necessarily corresponds to a valid physical address. For example, if
PAGE_OFFSET = 0x80000000
PHYS_OFFSET = 0x90000000
vmalloc_min = 0xf0000000
then __pa(vmalloc_min) overflows and returns a wrapped 0 when phys_addr_t
is a 32-bit type. Then the code that follows determines that the entire
physical memory is above that boundary and no low memory gets mapped at
all:
|[...]
|Machine model: Freescale i.MX51 NA04 Board
|Ignoring RAM at 0x90000000-0xb0000000 (!CONFIG_HIGHMEM)
|Consider using a HIGHMEM enabled kernel.
To avoid this problem let's make vmalloc_limit a 64-bit value all the
time and determine that boundary explicitly without using __pa().
Reported-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm/mmu.c')
-rw-r--r-- | arch/arm/mm/mmu.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 62f4d01941f7..12774c8e770c 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -1155,10 +1155,19 @@ void __init sanity_check_meminfo(void) { phys_addr_t memblock_limit = 0; int highmem = 0; - phys_addr_t vmalloc_limit = __pa(vmalloc_min - 1) + 1; + u64 vmalloc_limit; struct memblock_region *reg; bool should_use_highmem = false; + /* + * Let's use our own (unoptimized) equivalent of __pa() that is + * not affected by wrap-arounds when sizeof(phys_addr_t) == 4. + * The result is used as the upper bound on physical memory address + * and may itself be outside the valid range for which phys_addr_t + * and therefore __pa() is defined. + */ + vmalloc_limit = (u64)(uintptr_t)vmalloc_min - PAGE_OFFSET + PHYS_OFFSET; + for_each_memblock(memory, reg) { phys_addr_t block_start = reg->base; phys_addr_t block_end = reg->base + reg->size; @@ -1183,10 +1192,11 @@ void __init sanity_check_meminfo(void) if (reg->size > size_limit) { phys_addr_t overlap_size = reg->size - size_limit; - pr_notice("Truncating RAM at %pa-%pa to -%pa", - &block_start, &block_end, &vmalloc_limit); - memblock_remove(vmalloc_limit, overlap_size); + pr_notice("Truncating RAM at %pa-%pa", + &block_start, &block_end); block_end = vmalloc_limit; + pr_cont(" to -%pa", &block_end); + memblock_remove(vmalloc_limit, overlap_size); should_use_highmem = true; } } |