diff options
| -rw-r--r-- | arch/x86/mm/pat.c | 56 |
1 files changed, 36 insertions, 20 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index f6ff57b7efa..bea6e573e02 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -158,31 +158,47 @@ static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type) return req_type; } +struct pagerange_state { + unsigned long cur_pfn; + int ram; + int not_ram; +}; + +static int +pagerange_is_ram_callback(unsigned long initial_pfn, unsigned long total_nr_pages, void *arg) +{ + struct pagerange_state *state = arg; + + state->not_ram |= initial_pfn > state->cur_pfn; + state->ram |= total_nr_pages > 0; + state->cur_pfn = initial_pfn + total_nr_pages; + + return state->ram && state->not_ram; +} + static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end) { - int ram_page = 0, not_rampage = 0; - unsigned long page_nr; + int ret = 0; + unsigned long start_pfn = start >> PAGE_SHIFT; + unsigned long end_pfn = (end + PAGE_SIZE - 1) >> PAGE_SHIFT; + struct pagerange_state state = {start_pfn, 0, 0}; - for (page_nr = (start >> PAGE_SHIFT); page_nr < (end >> PAGE_SHIFT); - ++page_nr) { - /* - * For legacy reasons, physical address range in the legacy ISA - * region is tracked as non-RAM. This will allow users of - * /dev/mem to map portions of legacy ISA region, even when - * some of those portions are listed(or not even listed) with - * different e820 types(RAM/reserved/..) - */ - if (page_nr >= (ISA_END_ADDRESS >> PAGE_SHIFT) && - page_is_ram(page_nr)) - ram_page = 1; - else - not_rampage = 1; - - if (ram_page == not_rampage) - return -1; + /* + * For legacy reasons, physical address range in the legacy ISA + * region is tracked as non-RAM. This will allow users of + * /dev/mem to map portions of legacy ISA region, even when + * some of those portions are listed(or not even listed) with + * different e820 types(RAM/reserved/..) + */ + if (start_pfn < ISA_END_ADDRESS >> PAGE_SHIFT) + start_pfn = ISA_END_ADDRESS >> PAGE_SHIFT; + + if (start_pfn < end_pfn) { + ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, + &state, pagerange_is_ram_callback); } - return ram_page; + return (ret > 0) ? -1 : (state.ram ? 1 : 0); } /* |