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yaml
---
r: 309573
b: refs/heads/master
c: fa83523
h: refs/heads/master
i:
  309571: 9fa2543
v: v3
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John Dykstra authored and Ingo Molnar committed May 30, 2012
1 parent 02c877c commit e0392b2
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Showing 2 changed files with 37 additions and 21 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 1b38a3a10f2ad96a3c0130f63b7f3610bab7090d
refs/heads/master: fa83523f45fbb403eba4ebc5704bf98aa4da0163
56 changes: 36 additions & 20 deletions trunk/arch/x86/mm/pat.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);
}

/*
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