On Fri, 10 Aug 2012, Cyril Chemparathy wrote:
> This patch modifies the highmem sanity checking code to use physical addresses
> instead. This change eliminates the wrap-around problems associated with the
> original virtual address based checks, and this simplifies the code a bit.
>
> The one constraint imposed here is that low physical memory must be mapped in
> a monotonically increasing fashion if there are multiple banks of memory,
> i.e., x < y must => pa(x) < pa(y).
>
> Signed-off-by: Cyril Chemparathy <cy...@ti.com>
> Signed-off-by: Vitaly Andrianov <vita...@ti.com>
Acked-by: Nicolas Pitre <n...@linaro.org>
> ---
> arch/arm/mm/mmu.c | 22 ++++++++++------------
> 1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index 53eeeb8..f764c03 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -895,6 +895,7 @@ phys_addr_t arm_lowmem_limit __initdata = 0;
> void __init sanity_check_meminfo(void)
> {
> int i, j, highmem = 0;
> + phys_addr_t vmalloc_limit = __pa(vmalloc_min - 1) + 1;
>
> for (i = 0, j = 0; i < meminfo.nr_banks; i++) {
> struct membank *bank = &meminfo.bank[j];
> @@ -904,8 +905,7 @@ void __init sanity_check_meminfo(void)
> highmem = 1;
>
> #ifdef CONFIG_HIGHMEM
> - if (__va(bank->start) >= vmalloc_min ||
> - __va(bank->start) < (void *)PAGE_OFFSET)
> + if (bank->start >= vmalloc_limit)
> highmem = 1;
>
> bank->highmem = highmem;
> @@ -914,8 +914,8 @@ void __init sanity_check_meminfo(void)
> * Split those memory banks which are partially overlapping
> * the vmalloc area greatly simplifying things later.
> */
> - if (!highmem && __va(bank->start) < vmalloc_min &&
> - bank->size > vmalloc_min - __va(bank->start)) {
> + if (!highmem && bank->start < vmalloc_limit &&
> + bank->size > vmalloc_limit - bank->start) {
> if (meminfo.nr_banks >= NR_BANKS) {
> printk(KERN_CRIT "NR_BANKS too low, "
> "ignoring high memory\n");
> @@ -924,12 +924,12 @@ void __init sanity_check_meminfo(void)
> (meminfo.nr_banks - i) * sizeof(*bank));
> meminfo.nr_banks++;
> i++;
> - bank[1].size -= vmalloc_min - __va(bank->start);
> - bank[1].start = __pa(vmalloc_min - 1) + 1;
> + bank[1].size -= vmalloc_limit - bank->start;
> + bank[1].start = vmalloc_limit;
> bank[1].highmem = highmem = 1;
> j++;
> }
> - bank->size = vmalloc_min - __va(bank->start);
> + bank->size = vmalloc_limit - bank->start;
> }
> #else
> bank->highmem = highmem;
> @@ -949,8 +949,7 @@ void __init sanity_check_meminfo(void)
> * Check whether this memory bank would entirely overlap
> * the vmalloc area.
> */
> - if (__va(bank->start) >= vmalloc_min ||
> - __va(bank->start) < (void *)PAGE_OFFSET) {
> + if (bank->start >= vmalloc_limit) {
> printk(KERN_NOTICE "Ignoring RAM at %.8llx-%.8llx "
> "(vmalloc region overlap).\n",
> (unsigned long long)bank->start,
> @@ -962,9 +961,8 @@ void __init sanity_check_meminfo(void)
> * Check whether this memory bank would partially overlap
> * the vmalloc area.
> */
> - if (__va(bank->start + bank->size) > vmalloc_min ||
> - __va(bank->start + bank->size) < __va(bank->start)) {
> - unsigned long newsize = vmalloc_min - __va(bank->start);
> + if (bank->start + bank->size > vmalloc_limit)
> + unsigned long newsize = vmalloc_limit - bank->start;
> printk(KERN_NOTICE "Truncating RAM at %.8llx-%.8llx "
> "to -%.8llx (vmalloc region overlap).\n",
> (unsigned long long)bank->start,
> --
> 1.7.9.5
>
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