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authorJeff Dike <jdike@addtoit.com>2007-05-06 14:51:45 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-07 12:13:04 -0700
commit64f60841c096594b8073e408cd9b40d7d08dcfdd (patch)
tree3ad05b0b5f83d174eb2a7efdfd95d09f171aa51d /arch/um/kernel/skas
parent8603ec81487a5fefbc29611ff0d635b33b6da990 (diff)
uml: speed page fault path
Give the page fault code a specialized path. There is only one page to look at, so there's no point in going into the general page table walking code. There's only going to be one host operation, so there are no opportunities for merging. So, we go straight to the pte we want, figure out what needs doing, and do it. While I was in here, I fixed the wart where the address passed to unmap was a void *, but an unsigned long to map and protect. This gives me just under 10% on a kernel build. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um/kernel/skas')
-rw-r--r--arch/um/kernel/skas/tlb.c66
1 files changed, 64 insertions, 2 deletions
diff --git a/arch/um/kernel/skas/tlb.c b/arch/um/kernel/skas/tlb.c
index 304a5b0695a..c43901aa936 100644
--- a/arch/um/kernel/skas/tlb.c
+++ b/arch/um/kernel/skas/tlb.c
@@ -32,8 +32,7 @@ static int do_ops(union mm_context *mmu, struct host_vm_op *ops, int last,
op->u.mmap.offset, finished, flush);
break;
case MUNMAP:
- ret = unmap(&mmu->skas.id,
- (void *) op->u.munmap.addr,
+ ret = unmap(&mmu->skas.id, op->u.munmap.addr,
op->u.munmap.len, finished, flush);
break;
case MPROTECT:
@@ -94,3 +93,66 @@ void force_flush_all_skas(void)
unsigned long end = proc_mm ? task_size : CONFIG_STUB_START;
fix_range(current->mm, 0, end, 1);
}
+
+void flush_tlb_page_skas(struct vm_area_struct *vma, unsigned long address)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ struct mm_struct *mm = vma->vm_mm;
+ void *flush = NULL;
+ int r, w, x, err = 0;
+ struct mm_id *mm_id;
+
+ pgd = pgd_offset(vma->vm_mm, address);
+ if(!pgd_present(*pgd))
+ goto kill;
+
+ pud = pud_offset(pgd, address);
+ if(!pud_present(*pud))
+ goto kill;
+
+ pmd = pmd_offset(pud, address);
+ if(!pmd_present(*pmd))
+ goto kill;
+
+ pte = pte_offset_kernel(pmd, address);
+
+ r = pte_read(*pte);
+ w = pte_write(*pte);
+ x = pte_exec(*pte);
+ if (!pte_young(*pte)) {
+ r = 0;
+ w = 0;
+ } else if (!pte_dirty(*pte)) {
+ w = 0;
+ }
+
+ mm_id = &mm->context.skas.id;
+ if(pte_newpage(*pte)){
+ if(pte_present(*pte)){
+ unsigned long long offset;
+ int fd;
+
+ fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
+ err = map(mm_id, address, PAGE_SIZE, r, w, x, fd,
+ offset, 1, &flush);
+ }
+ else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
+ }
+ else if(pte_newprot(*pte))
+ err = protect(mm_id, address, PAGE_SIZE, r, w, x, 1, &flush);
+
+ if(err)
+ goto kill;
+
+ *pte = pte_mkuptodate(*pte);
+
+ return;
+
+kill:
+ printk("Failed to flush page for address 0x%lx\n", address);
+ force_sig(SIGKILL, current);
+}
+