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SubjectRe: [PATCH] of: Use proper types for checking memory overflow
On Mon, 7 Jul 2014, Laura Abbott wrote:

> Commit a67a6ed15513541579d38bcbd127e7be170710e5
> (of: Check for phys_addr_t overflows in early_init_dt_add_memory_arch)
> corrected early_init_dt_add_memory_arch to account for overflows
> but did so in an unclean way using ULONG_MAX. There is no
> guarantee that sizeof(unsigned long) == sizeof(phys_addr_t).
> Check against phys_addr_t instead.
>
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

Acked-by: Nicolas Pitre <nico@linaro.org>

> ---
> drivers/of/fdt.c | 22 +++++++++++-----------
> 1 file changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index b777d8f..b88a68e 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -875,24 +875,24 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
> }
>
> #ifdef CONFIG_HAVE_MEMBLOCK
> +#define MAX_PHYS_ADDR ((phys_addr_t)~0)
> +
> void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
> {
> const u64 phys_offset = __pa(PAGE_OFFSET);
> base &= PAGE_MASK;
> size &= PAGE_MASK;
>
> - if (sizeof(phys_addr_t) < sizeof(u64)) {
> - if (base > ULONG_MAX) {
> - pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
> - base, base + size);
> - return;
> - }
> + if (base > MAX_PHYS_ADDR) {
> + pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
> + base, base + size);
> + return;
> + }
>
> - if (base + size > ULONG_MAX) {
> - pr_warning("Ignoring memory range 0x%lx - 0x%llx\n",
> - ULONG_MAX, base + size);
> - size = ULONG_MAX - base;
> - }
> + if (base + size > MAX_PHYS_ADDR) {
> + pr_warning("Ignoring memory range 0x%lx - 0x%llx\n",
> + ULONG_MAX, base + size);
> + size = MAX_PHYS_ADDR - base;
> }
>
> if (base + size < phys_offset) {
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation
>
>


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