Re: [PATCH 1/11] Fix CONFIG_COMPAT_VDSO

Paul Mundt
2007-01-24T10:27:00Z

On Wed, Jan 17, 2007 at 01:03:34AM -0800, Roland McGrath wrote:
> > i think your patches #1...#7 are must-haves for v2.6.20, while #8-#11
> > could be delayed to v2.6.21?
>
> Indeed 1-7 are fixes while 8-11 are only cleanups not changing behavior.
>
Here's an update for the SH bits when the 8-11 parts are ready..

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
index deb4694..7b0f66f 100644
--- a/arch/sh/kernel/vsyscall/vsyscall.c
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -37,11 +37,12 @@ __setup("vdso=", vdso_setup);
* of the ELF DSO images included therein.
*/
extern const char vsyscall_trapa_start, vsyscall_trapa_end;
-static void *syscall_page;
+static struct page *syscall_pages[1];

int __init vsyscall_init(void)
{
- syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
+ void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
+ syscall_pages[0] = virt_to_page(syscall_page);

/*
* XXX: Map this page to a fixmap entry if we get around
@@ -55,37 +56,10 @@ int __init vsyscall_init(void)
return 0;
}

-static struct page *syscall_vma_nopage(struct vm_area_struct *vma,
- unsigned long address, int *type)
-{
- unsigned long offset = address - vma->vm_start;
- struct page *page;
-
- if (address < vma->vm_start || address > vma->vm_end)
- return NOPAGE_SIGBUS;
-
- page = virt_to_page(syscall_page + offset);
-
- get_page(page);
-
- return page;
-}
-
-/* Prevent VMA merging */
-static void syscall_vma_close(struct vm_area_struct *vma)
-{
-}
-
-static struct vm_operations_struct syscall_vm_ops = {
- .nopage = syscall_vma_nopage,
- .close = syscall_vma_close,
-};
-
/* Setup a VMA at program startup for the vsyscall page */
int arch_setup_additional_pages(struct linux_binprm *bprm,
int executable_stack)
{
- struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr;
int ret;
@@ -97,30 +71,16 @@ int arch_setup_additional_pages(struct l
goto up_fail;
}

- vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
- if (!vma) {
- ret = -ENOMEM;
+ ret = install_special_mapping(mm, addr, PAGE_SIZE,
+ VM_READ | VM_EXEC |
+ VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC |
+ VM_ALWAYSDUMP,
+ syscall_pages);
+ if (unlikely(ret))
goto up_fail;
- }
-
- vma->vm_start = addr;
- vma->vm_end = addr + PAGE_SIZE;
- /* MAYWRITE to allow gdb to COW and set breakpoints */
- vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
- vma->vm_flags |= mm->def_flags;
- vma->vm_page_prot = protection_map[vma->vm_flags & 7];
- vma->vm_ops = &syscall_vm_ops;
- vma->vm_mm = mm;
-
- ret = insert_vm_struct(mm, vma);
- if (unlikely(ret)) {
- kmem_cache_free(vm_area_cachep, vma);
- goto up_fail;
- }

current->mm->context.vdso = (void *)addr;

- mm->total_vm++;
up_fail:
up_write(&mm->mmap_sem);
return ret;