Commit be03d9e8 authored by Suresh Siddha's avatar Suresh Siddha Committed by Ingo Molnar

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

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: default avatarJeff Mahoney <jeffm@suse.com>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 4f06b043
...@@ -57,7 +57,6 @@ typedef struct { pgdval_t pgd; } pgd_t; ...@@ -57,7 +57,6 @@ typedef struct { pgdval_t pgd; } pgd_t;
typedef struct { pgprotval_t pgprot; } pgprot_t; typedef struct { pgprotval_t pgprot; } pgprot_t;
extern int page_is_ram(unsigned long pagenr); 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 int devmem_is_allowed(unsigned long pagenr);
extern void map_devmem(unsigned long pfn, unsigned long size, extern void map_devmem(unsigned long pfn, unsigned long size,
pgprot_t vma_prot); pgprot_t vma_prot);
......
...@@ -134,25 +134,6 @@ int page_is_ram(unsigned long pagenr) ...@@ -134,25 +134,6 @@ int page_is_ram(unsigned long pagenr)
return 0; 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 * Fix up the linear direct mapping of the kernel to avoid cache attribute
* conflicts. * conflicts.
......
...@@ -211,6 +211,33 @@ chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type) ...@@ -211,6 +211,33 @@ chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type)
static struct memtype *cached_entry; static struct memtype *cached_entry;
static u64 cached_start; 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 * For RAM pages, mark the pages as non WB memory type using
* PageNonWB (PG_arch_1). We allow only one set_memory_uc() or * 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, ...@@ -336,20 +363,12 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
if (new_type) if (new_type)
*new_type = actual_type; *new_type = actual_type;
/* is_range_ram = pat_pagerange_is_ram(start, end);
* 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) if (is_range_ram == 1)
return reserve_ram_pages_type(start, end, req_type, return reserve_ram_pages_type(start, end, req_type,
new_type); new_type);
else if (is_range_ram < 0) else if (is_range_ram < 0)
return -EINVAL; return -EINVAL;
}
new = kmalloc(sizeof(struct memtype), GFP_KERNEL); new = kmalloc(sizeof(struct memtype), GFP_KERNEL);
if (!new) if (!new)
...@@ -446,19 +465,11 @@ int free_memtype(u64 start, u64 end) ...@@ -446,19 +465,11 @@ int free_memtype(u64 start, u64 end)
if (is_ISA_range(start, end - 1)) if (is_ISA_range(start, end - 1))
return 0; return 0;
/* is_range_ram = pat_pagerange_is_ram(start, end);
* 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) if (is_range_ram == 1)
return free_ram_pages_type(start, end); return free_ram_pages_type(start, end);
else if (is_range_ram < 0) else if (is_range_ram < 0)
return -EINVAL; return -EINVAL;
}
spin_lock(&memtype_lock); spin_lock(&memtype_lock);
list_for_each_entry(entry, &memtype_list, nd) { 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, ...@@ -626,17 +637,13 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
unsigned long flags; unsigned long flags;
unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK); 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 * reserve_pfn_range() doesn't support RAM pages.
* set_memory_[uc|wc|wb] directly, for reserve and free, before
* setting up the PTE.
*/ */
WARN_ON_ONCE(1); if (is_ram != 0)
return 0; return -EINVAL;
}
ret = reserve_memtype(paddr, paddr + size, want_flags, &flags); ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
if (ret) if (ret)
...@@ -693,7 +700,7 @@ static void free_pfn_range(u64 paddr, unsigned long size) ...@@ -693,7 +700,7 @@ static void free_pfn_range(u64 paddr, unsigned long size)
{ {
int is_ram; int is_ram;
is_ram = pagerange_is_ram(paddr, paddr + size); is_ram = pat_pagerange_is_ram(paddr, paddr + size);
if (is_ram == 0) if (is_ram == 0)
free_memtype(paddr, paddr + size); free_memtype(paddr, paddr + size);
} }
......
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