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x86, pat: fix warn_on_once() while mapping 0-1MB range with /dev/mem

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Jeff Mahoney reported:

> With Suse's hwinfo tool, on -tip:
> WARNING: at arch/x86/mm/pat.c:637 reserve_pfn_range+0x5b/0x26d()

reserve_pfn_range() is not tracking the memory range below 1MB
as non-RAM and as such is inconsistent with similar checks in
reserve_memtype() and free_memtype()

Rename the pagerange_is_ram() to pat_pagerange_is_ram() and add the
"track legacy 1MB region as non RAM" condition.

And also, fix reserve_pfn_range() to return -EINVAL, when the pfn
range is RAM. This is to be consistent with this API design.

Reported-and-tested-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Suresh Siddha 2009-02-11 11:20:23 -08:00 committed by Ingo Molnar
parent 4f06b0436b
commit be03d9e802
3 changed files with 45 additions and 58 deletions
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1
arch/x86/include/asm/page.h
View File

@ -57,7 +57,6 @@ typedef struct { pgdval_t pgd; } pgd_t;
typedef struct { pgprotval_t pgprot; } pgprot_t;
extern int page_is_ram(unsigned long pagenr);
extern int pagerange_is_ram(unsigned long start, unsigned long end);
extern int devmem_is_allowed(unsigned long pagenr);
extern void map_devmem(unsigned long pfn, unsigned long size,
pgprot_t vma_prot);

19
arch/x86/mm/ioremap.c
View File

@ -134,25 +134,6 @@ int page_is_ram(unsigned long pagenr)
return 0;
}
int pagerange_is_ram(unsigned long start, unsigned long end)
{
int ram_page = 0, not_rampage = 0;
unsigned long page_nr;
for (page_nr = (start >> PAGE_SHIFT); page_nr < (end >> PAGE_SHIFT);
++page_nr) {
if (page_is_ram(page_nr))
ram_page = 1;
else
not_rampage = 1;
if (ram_page == not_rampage)
return -1;
}
return ram_page;
}
/*
* Fix up the linear direct mapping of the kernel to avoid cache attribute
* conflicts.

83
arch/x86/mm/pat.c
View File

@ -211,6 +211,33 @@ chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type)
static struct memtype *cached_entry;
static u64 cached_start;
static int pat_pagerange_is_ram(unsigned long start, unsigned long end)
{
int ram_page = 0, not_rampage = 0;
unsigned long page_nr;
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;
}
return ram_page;
}
/*
* For RAM pages, mark the pages as non WB memory type using
* PageNonWB (PG_arch_1). We allow only one set_memory_uc() or
@ -336,20 +363,12 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
if (new_type)
*new_type = actual_type;
/*
* For legacy reasons, some parts of the physical address range in the
* legacy 1MB region is treated as non-RAM (even when listed as RAM in
* the e820 tables). So we will track the memory attributes of this
* legacy 1MB region using the linear memtype_list always.
*/
if (end >= ISA_END_ADDRESS) {
is_range_ram = pagerange_is_ram(start, end);
if (is_range_ram == 1)
return reserve_ram_pages_type(start, end, req_type,
new_type);
else if (is_range_ram < 0)
return -EINVAL;
}
is_range_ram = pat_pagerange_is_ram(start, end);
if (is_range_ram == 1)
return reserve_ram_pages_type(start, end, req_type,
new_type);
else if (is_range_ram < 0)
return -EINVAL;
new = kmalloc(sizeof(struct memtype), GFP_KERNEL);
if (!new)
@ -446,19 +465,11 @@ int free_memtype(u64 start, u64 end)
if (is_ISA_range(start, end - 1))
return 0;
/*
* For legacy reasons, some parts of the physical address range in the
* legacy 1MB region is treated as non-RAM (even when listed as RAM in
* the e820 tables). So we will track the memory attributes of this
* legacy 1MB region using the linear memtype_list always.
*/
if (end >= ISA_END_ADDRESS) {
is_range_ram = pagerange_is_ram(start, end);
if (is_range_ram == 1)
return free_ram_pages_type(start, end);
else if (is_range_ram < 0)
return -EINVAL;
}
is_range_ram = pat_pagerange_is_ram(start, end);
if (is_range_ram == 1)
return free_ram_pages_type(start, end);
else if (is_range_ram < 0)
return -EINVAL;
spin_lock(&memtype_lock);
list_for_each_entry(entry, &memtype_list, nd) {
@ -626,17 +637,13 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
unsigned long flags;
unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
is_ram = pagerange_is_ram(paddr, paddr + size);
is_ram = pat_pagerange_is_ram(paddr, paddr + size);
if (is_ram != 0) {
/*
* For mapping RAM pages, drivers need to call
* set_memory_[uc|wc|wb] directly, for reserve and free, before
* setting up the PTE.
*/
WARN_ON_ONCE(1);
return 0;
}
/*
* reserve_pfn_range() doesn't support RAM pages.
*/
if (is_ram != 0)
return -EINVAL;
ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
if (ret)
@ -693,7 +700,7 @@ static void free_pfn_range(u64 paddr, unsigned long size)
{
int is_ram;
is_ram = pagerange_is_ram(paddr, paddr + size);
is_ram = pat_pagerange_is_ram(paddr, paddr + size);
if (is_ram == 0)
free_memtype(paddr, paddr + size);
}