aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/mm/pat.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/mm/pat.c')
-rw-r--r--arch/x86/mm/pat.c56
1 files changed, 36 insertions, 20 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index f6ff57b7efa5..bea6e573e02b 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);
}
/*