| From f15b9000eb1d09bbaa4b0a6b2089d7e1f64e84b3 Mon Sep 17 00:00:00 2001 |
| From: Richard Weinberger <richard@nod.at> |
| Date: Sat, 14 Apr 2012 17:29:30 +0200 |
| Subject: um: Implement a custom pte_same() function |
| |
| From: Richard Weinberger <richard@nod.at> |
| |
| commit f15b9000eb1d09bbaa4b0a6b2089d7e1f64e84b3 upstream. |
| |
| UML uses the _PAGE_NEWPAGE flag to mark pages which are not jet |
| installed on the host side using mmap(). |
| pte_same() has to ignore this flag, otherwise unuse_pte_range() |
| is unable to unuse the page because two identical |
| page tables entries with different _PAGE_NEWPAGE flags would not |
| match and swapoff() would never return. |
| |
| Analyzed-by: Hugh Dickins <hughd@google.com> |
| Signed-off-by: Richard Weinberger <richard@nod.at> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/um/include/asm/pgtable.h | 6 ++++++ |
| 1 file changed, 6 insertions(+) |
| |
| --- a/arch/um/include/asm/pgtable.h |
| +++ b/arch/um/include/asm/pgtable.h |
| @@ -271,6 +271,12 @@ static inline void set_pte(pte_t *pteptr |
| } |
| #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval) |
| |
| +#define __HAVE_ARCH_PTE_SAME |
| +static inline int pte_same(pte_t pte_a, pte_t pte_b) |
| +{ |
| + return !((pte_val(pte_a) ^ pte_val(pte_b)) & ~_PAGE_NEWPAGE); |
| +} |
| + |
| /* |
| * Conversion functions: convert a page and protection to a page entry, |
| * and a page entry and page directory to the page they refer to. |
