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Commit 70f15287 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Ingo Molnar
Browse files

x86/mm: Fix regression with huge pages on PAE 



Recent PAT patchset has caused issue on 32-bit PAE machines:

  page:eea45000 count:0 mapcount:-128 mapping:  (null) index:0x0 flags: 0x40000000()
  page dumped because: VM_BUG_ON_PAGE(page_mapcount(page) < 0)
  ------------[ cut here ]------------
  kernel BUG at /home/build/linux-boris/mm/huge_memory.c:1485!
  invalid opcode: 0000 [#1] SMP
  [...]
  Call Trace:
   unmap_single_vma
   ? __wake_up
   unmap_vmas
   unmap_region
   do_munmap
   vm_munmap
   SyS_munmap
   do_fast_syscall_32
   ? __do_page_fault
   sysenter_past_esp
  Code: ...
  EIP: [<c11bde80>] zap_huge_pmd+0x240/0x260 SS:ESP 0068:f6459d98

The problem is in pmd_pfn_mask() and pmd_flags_mask(). These
helpers use PMD_PAGE_MASK to calculate resulting mask.
PMD_PAGE_MASK is 'unsigned long', not 'unsigned long long' as
phys_addr_t is on 32-bit PAE (ARCH_PHYS_ADDR_T_64BIT). As a
result, the upper bits of resulting mask get truncated.

pud_pfn_mask() and pud_flags_mask() aren't problematic since we
don't have PUD page table level on 32-bit systems, but it's
reasonable to keep them consistent with PMD counterpart.

Introduce PHYSICAL_PMD_PAGE_MASK and PHYSICAL_PUD_PAGE_MASK in
addition to existing PHYSICAL_PAGE_MASK and reworks helpers to
use them.

Reported-and-Tested-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
[ Fix -Woverflow warnings from the realmode code. ]
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarToshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jürgen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: elliott@hpe.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Fixes: f70abb0f ("x86/asm: Fix pud/pmd interfaces to handle large PAT bit")
Link: http://lkml.kernel.org/r/1448878233-11390-2-git-send-email-bp@alien8.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>

Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 656279a1

arch/x86/boot/boot.h

+0 −1
Original line number Diff line number Diff line
@@ -23,7 +23,6 @@ 
#include <stdarg.h>

#include <linux/types.h>

#include <linux/edd.h>

#include <asm/boot.h>

#include <asm/setup.h>

#include "bitops.h"

#include "ctype.h"

arch/x86/boot/video-mode.c

+2 −0
Original line number Diff line number Diff line
@@ -19,6 +19,8 @@ 
#include "video.h"

#include "vesa.h"



#include <uapi/asm/boot.h>



/*

 * Common variables

 */

arch/x86/boot/video.c

+2 −0
Original line number Diff line number Diff line
@@ -13,6 +13,8 @@ 
 * Select video mode

 */



#include <uapi/asm/boot.h>



#include "boot.h"

#include "video.h"

#include "vesa.h"

arch/x86/include/asm/page_types.h

+9 −7
Original line number Diff line number Diff line
@@ -9,19 +9,21 @@ 
#define PAGE_SIZE	(_AC(1,UL) << PAGE_SHIFT)

#define PAGE_MASK	(~(PAGE_SIZE-1))



#define PMD_PAGE_SIZE		(_AC(1, UL) << PMD_SHIFT)

#define PMD_PAGE_MASK		(~(PMD_PAGE_SIZE-1))



#define PUD_PAGE_SIZE		(_AC(1, UL) << PUD_SHIFT)

#define PUD_PAGE_MASK		(~(PUD_PAGE_SIZE-1))



#define __PHYSICAL_MASK		((phys_addr_t)((1ULL << __PHYSICAL_MASK_SHIFT) - 1))

#define __VIRTUAL_MASK		((1UL << __VIRTUAL_MASK_SHIFT) - 1)



/* Cast PAGE_MASK to a signed type so that it is sign-extended if

/* Cast *PAGE_MASK to a signed type so that it is sign-extended if

   virtual addresses are 32-bits but physical addresses are larger

   (ie, 32-bit PAE). */

#define PHYSICAL_PAGE_MASK	(((signed long)PAGE_MASK) & __PHYSICAL_MASK)



#define PMD_PAGE_SIZE		(_AC(1, UL) << PMD_SHIFT)

#define PMD_PAGE_MASK		(~(PMD_PAGE_SIZE-1))



#define PUD_PAGE_SIZE		(_AC(1, UL) << PUD_SHIFT)

#define PUD_PAGE_MASK		(~(PUD_PAGE_SIZE-1))

#define PHYSICAL_PMD_PAGE_MASK	(((signed long)PMD_PAGE_MASK) & __PHYSICAL_MASK)

#define PHYSICAL_PUD_PAGE_MASK	(((signed long)PUD_PAGE_MASK) & __PHYSICAL_MASK)



#define HPAGE_SHIFT		PMD_SHIFT

#define HPAGE_SIZE		(_AC(1,UL) << HPAGE_SHIFT)

arch/x86/include/asm/pgtable_types.h

+4 −10
Original line number Diff line number Diff line
@@ -279,17 +279,14 @@ static inline pmdval_t native_pmd_val(pmd_t pmd) 
static inline pudval_t pud_pfn_mask(pud_t pud)

{

	if (native_pud_val(pud) & _PAGE_PSE)

		return PUD_PAGE_MASK & PHYSICAL_PAGE_MASK;

		return PHYSICAL_PUD_PAGE_MASK;

	else

		return PTE_PFN_MASK;

}



static inline pudval_t pud_flags_mask(pud_t pud)

{

	if (native_pud_val(pud) & _PAGE_PSE)

		return ~(PUD_PAGE_MASK & (pudval_t)PHYSICAL_PAGE_MASK);

	else

		return ~PTE_PFN_MASK;

	return ~pud_pfn_mask(pud);

}



static inline pudval_t pud_flags(pud_t pud)
@@ -300,17 +297,14 @@ static inline pudval_t pud_flags(pud_t pud) 
static inline pmdval_t pmd_pfn_mask(pmd_t pmd)

{

	if (native_pmd_val(pmd) & _PAGE_PSE)

		return PMD_PAGE_MASK & PHYSICAL_PAGE_MASK;

		return PHYSICAL_PMD_PAGE_MASK;

	else

		return PTE_PFN_MASK;

}



static inline pmdval_t pmd_flags_mask(pmd_t pmd)

{

	if (native_pmd_val(pmd) & _PAGE_PSE)

		return ~(PMD_PAGE_MASK & (pmdval_t)PHYSICAL_PAGE_MASK);

	else

		return ~PTE_PFN_MASK;

	return ~pmd_pfn_mask(pmd);

}



static inline pmdval_t pmd_flags(pmd_t pmd)