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Subject[PATCHv5 2/6] x86/vdso: replace calculate_addr in map_vdso() with addr
Date
That will allow to specify address where to map vDSO blob.
For the randomized vDSO mappings introduce map_vdso_randomized()
which will simplify calls to map_vdso.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mm@kvack.org
Cc: x86@kernel.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/entry/vdso/vma.c | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 3bab6ba3ffc5..5bcb25a9e573 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -176,11 +176,16 @@ static int vvar_fault(const struct vm_special_mapping *sm,
return VM_FAULT_SIGBUS;
}

-static int map_vdso(const struct vdso_image *image, bool calculate_addr)
+/*
+ * Add vdso and vvar mappings to current process.
+ * @image - blob to map
+ * @addr - request a specific address (zero to map at free addr)
+ */
+static int map_vdso(const struct vdso_image *image, unsigned long addr)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
- unsigned long addr, text_start;
+ unsigned long text_start;
int ret = 0;

static const struct vm_special_mapping vdso_mapping = {
@@ -193,13 +198,6 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
.fault = vvar_fault,
};

- if (calculate_addr) {
- addr = vdso_addr(current->mm->start_stack,
- image->size - image->sym_vvar_start);
- } else {
- addr = 0;
- }
-
if (down_write_killable(&mm->mmap_sem))
return -EINTR;

@@ -251,13 +249,20 @@ up_fail:
return ret;
}

+static int map_vdso_randomized(const struct vdso_image *image)
+{
+ unsigned long addr = vdso_addr(current->mm->start_stack,
+ image->size - image->sym_vvar_start);
+ return map_vdso(image, addr);
+}
+
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
static int load_vdso32(void)
{
if (vdso32_enabled != 1) /* Other values all mean "disabled" */
return 0;

- return map_vdso(&vdso_image_32, false);
+ return map_vdso(&vdso_image_32, 0);
}
#endif

@@ -267,7 +272,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
if (!vdso64_enabled)
return 0;

- return map_vdso(&vdso_image_64, true);
+ return map_vdso_randomized(&vdso_image_64);
}

#ifdef CONFIG_COMPAT
@@ -278,8 +283,7 @@ int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
if (test_thread_flag(TIF_X32)) {
if (!vdso64_enabled)
return 0;
-
- return map_vdso(&vdso_image_x32, true);
+ return map_vdso_randomized(&vdso_image_x32);
}
#endif
#ifdef CONFIG_IA32_EMULATION
--
2.9.0
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