diff options
| -rw-r--r-- | arch/sparc/include/asm/pgtable_64.h | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h index fd9d9bac7cfa..5a9e96be1665 100644 --- a/arch/sparc/include/asm/pgtable_64.h +++ b/arch/sparc/include/asm/pgtable_64.h @@ -231,6 +231,36 @@ extern unsigned long _PAGE_ALL_SZ_BITS; extern struct page *mem_map_zero; #define ZERO_PAGE(vaddr) (mem_map_zero) +/* This macro must be updated when the size of struct page grows above 80 + * or reduces below 64. + * The idea that compiler optimizes out switch() statement, and only + * leaves clrx instructions + */ +#define mm_zero_struct_page(pp) do { \ + unsigned long *_pp = (void *)(pp); \ + \ + /* Check that struct page is either 64, 72, or 80 bytes */ \ + BUILD_BUG_ON(sizeof(struct page) & 7); \ + BUILD_BUG_ON(sizeof(struct page) < 64); \ + BUILD_BUG_ON(sizeof(struct page) > 80); \ + \ + switch (sizeof(struct page)) { \ + case 80: \ + _pp[9] = 0; /* fallthrough */ \ + case 72: \ + _pp[8] = 0; /* fallthrough */ \ + default: \ + _pp[7] = 0; \ + _pp[6] = 0; \ + _pp[5] = 0; \ + _pp[4] = 0; \ + _pp[3] = 0; \ + _pp[2] = 0; \ + _pp[1] = 0; \ + _pp[0] = 0; \ + } \ +} while (0) + /* PFNs are real physical page numbers. However, mem_map only begins to record * per-page information starting at pfn_base. This is to handle systems where * the first physical page in the machine is at some huge physical address, |