[PATCH] powerpc vDSO: use install_special_mapping
This patch uses install_special_mapping for the powerpc vDSO setup,
consolidating duplicated code.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index ae0ede1..50149ec 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -49,9 +49,13 @@
/* Max supported size for symbol names */
#define MAX_SYMNAME 64
+#define VDSO32_MAXPAGES (((0x3000 + PAGE_MASK) >> PAGE_SHIFT) + 2)
+#define VDSO64_MAXPAGES (((0x3000 + PAGE_MASK) >> PAGE_SHIFT) + 2)
+
extern char vdso32_start, vdso32_end;
static void *vdso32_kbase = &vdso32_start;
unsigned int vdso32_pages;
+static struct page *vdso32_pagelist[VDSO32_MAXPAGES];
unsigned long vdso32_sigtramp;
unsigned long vdso32_rt_sigtramp;
@@ -59,6 +63,7 @@
extern char vdso64_start, vdso64_end;
static void *vdso64_kbase = &vdso64_start;
unsigned int vdso64_pages;
+static struct page *vdso64_pagelist[VDSO64_MAXPAGES];
unsigned long vdso64_rt_sigtramp;
#endif /* CONFIG_PPC64 */
@@ -165,55 +170,6 @@
#endif /* DEBUG */
/*
- * Keep a dummy vma_close for now, it will prevent VMA merging.
- */
-static void vdso_vma_close(struct vm_area_struct * vma)
-{
-}
-
-/*
- * Our nopage() function, maps in the actual vDSO kernel pages, they will
- * be mapped read-only by do_no_page(), and eventually COW'ed, either
- * right away for an initial write access, or by do_wp_page().
- */
-static struct page * vdso_vma_nopage(struct vm_area_struct * vma,
- unsigned long address, int *type)
-{
- unsigned long offset = address - vma->vm_start;
- struct page *pg;
-#ifdef CONFIG_PPC64
- void *vbase = (vma->vm_mm->task_size > TASK_SIZE_USER32) ?
- vdso64_kbase : vdso32_kbase;
-#else
- void *vbase = vdso32_kbase;
-#endif
-
- DBG("vdso_vma_nopage(current: %s, address: %016lx, off: %lx)\n",
- current->comm, address, offset);
-
- if (address < vma->vm_start || address > vma->vm_end)
- return NOPAGE_SIGBUS;
-
- /*
- * Last page is systemcfg.
- */
- if ((vma->vm_end - address) <= PAGE_SIZE)
- pg = virt_to_page(vdso_data);
- else
- pg = virt_to_page(vbase + offset);
-
- get_page(pg);
- DBG(" ->page count: %d\n", page_count(pg));
-
- return pg;
-}
-
-static struct vm_operations_struct vdso_vmops = {
- .close = vdso_vma_close,
- .nopage = vdso_vma_nopage,
-};
-
-/*
* This is called from binfmt_elf, we create the special vma for the
* vDSO and insert it into the mm struct tree
*/
@@ -221,20 +177,23 @@
int executable_stack)
{
struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma;
+ struct page **vdso_pagelist;
unsigned long vdso_pages;
unsigned long vdso_base;
int rc;
#ifdef CONFIG_PPC64
if (test_thread_flag(TIF_32BIT)) {
+ vdso_pagelist = vdso32_pagelist;
vdso_pages = vdso32_pages;
vdso_base = VDSO32_MBASE;
} else {
+ vdso_pagelist = vdso64_pagelist;
vdso_pages = vdso64_pages;
vdso_base = VDSO64_MBASE;
}
#else
+ vdso_pagelist = vdso32_pagelist;
vdso_pages = vdso32_pages;
vdso_base = VDSO32_MBASE;
#endif
@@ -262,17 +221,6 @@
goto fail_mmapsem;
}
-
- /* Allocate a VMA structure and fill it up */
- vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
- if (vma == NULL) {
- rc = -ENOMEM;
- goto fail_mmapsem;
- }
- vma->vm_mm = mm;
- vma->vm_start = vdso_base;
- vma->vm_end = vma->vm_start + (vdso_pages << PAGE_SHIFT);
-
/*
* our vma flags don't have VM_WRITE so by default, the process isn't
* allowed to write those pages.
@@ -282,32 +230,26 @@
* and your nice userland gettimeofday will be totally dead.
* It's fine to use that for setting breakpoints in the vDSO code
* pages though
- */
- vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC;
- /*
+ *
* Make sure the vDSO gets into every core dump.
* Dumping its contents makes post-mortem fully interpretable later
* without matching up the same kernel and hardware config to see
* what PC values meant.
*/
- vma->vm_flags |= VM_ALWAYSDUMP;
- vma->vm_flags |= mm->def_flags;
- vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
- vma->vm_ops = &vdso_vmops;
-
- /* Insert new VMA */
- rc = insert_vm_struct(mm, vma);
+ rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
+ VM_READ|VM_EXEC|
+ VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
+ VM_ALWAYSDUMP,
+ vdso_pagelist);
if (rc)
- goto fail_vma;
+ goto fail_mmapsem;
- /* Put vDSO base into mm struct and account for memory usage */
+ /* Put vDSO base into mm struct */
current->mm->context.vdso_base = vdso_base;
- mm->total_vm += (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+
up_write(&mm->mmap_sem);
return 0;
- fail_vma:
- kmem_cache_free(vm_area_cachep, vma);
fail_mmapsem:
up_write(&mm->mmap_sem);
return rc;
@@ -778,18 +720,26 @@
}
/* Make sure pages are in the correct state */
+ BUG_ON(vdso32_pages + 2 > VDSO32_MAXPAGES);
for (i = 0; i < vdso32_pages; i++) {
struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
ClearPageReserved(pg);
get_page(pg);
-
+ vdso32_pagelist[i] = pg;
}
+ vdso32_pagelist[i++] = virt_to_page(vdso_data);
+ vdso32_pagelist[i] = NULL;
+
#ifdef CONFIG_PPC64
+ BUG_ON(vdso64_pages + 2 > VDSO64_MAXPAGES);
for (i = 0; i < vdso64_pages; i++) {
struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
ClearPageReserved(pg);
get_page(pg);
+ vdso64_pagelist[i] = pg;
}
+ vdso64_pagelist[i++] = virt_to_page(vdso_data);
+ vdso64_pagelist[i] = NULL;
#endif /* CONFIG_PPC64 */
get_page(virt_to_page(vdso_data));
