[Devel] [PATCH RHEL7 COMMIT] x86/vdso: Add 64-bit vdso map API
Konstantin Khorenko
khorenko at virtuozzo.com
Wed Jul 12 12:36:19 MSK 2017
The commit is pushed to "branch-rh7-3.10.0-514.26.1.vz7.33.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.26.1.vz7.33.4
------>
commit ffe65f6a6e199387f353a2cd643de9fb16a791d9
Author: Dmitry Safonov <dsafonov at virtuozzo.com>
Date: Wed Jul 12 13:36:19 2017 +0400
x86/vdso: Add 64-bit vdso map API
Mainstream already has arch_prctl(MAP_VDSO_64), but this was
ommited for simplicity and we only have arch_prctl(MAP_VDSO_32).
This was not a problem as previously we needed MAP_VDSO_32 only
for ia32 applications C/R.
But as we've made vdso pages to be per-UTS-ns, pages differ between
host and uts-ns. As CRIU restore starts from init-ns, vdso that's
being preserved into restored application belongs to host and
thou has host's ve_time_spec.
Using this API we can map vdso in restored CT and it'll belong
to uts-ns of CT.
https://jira.sw.ru/browse/PSBM-67017
Cc: Andrey Ryabinin <aryabinin at virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov at virtuozzo.com>
---
arch/x86/include/asm/elf.h | 6 +++++-
arch/x86/kernel/process_64.c | 14 ++++++-------
arch/x86/vdso/vdso32-setup.c | 12 +----------
arch/x86/vdso/vma.c | 48 ++++++++++++++++++++++++++++++++++++--------
4 files changed, 53 insertions(+), 27 deletions(-)
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 8b0f639..920690b 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -353,7 +353,11 @@ extern int syscall32_setup_pages(struct linux_binprm *, int exstack);
#define compat_arch_setup_additional_pages syscall32_setup_pages
#ifdef CONFIG_X86_64
-extern int do_map_compat_vdso(unsigned long addr);
+extern bool vdso_or_vvar_present(struct mm_struct *mm);
+extern int do_map_vdso_64(unsigned long addr);
+# ifdef CONFIG_COMPAT
+extern int do_map_vdso_32(unsigned long addr);
+# endif
#endif
extern unsigned long arch_randomize_brk(struct mm_struct *mm);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index d2e444c..252f9f0 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -580,16 +580,16 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
}
#ifdef CONFIG_CHECKPOINT_RESTORE
+# ifdef CONFIG_COMPAT
case ARCH_MAP_VDSO_32:
- return do_map_compat_vdso(addr);
+ return do_map_vdso_32(addr);
+# endif
- /*
- * x32 and 64 vDSO remap API is omitted for simplicity.
- * We do need 32-bit vDSO blob mapping for compatible
- * applications Restore, but not x32/64 (at least, for now).
- */
- case ARCH_MAP_VDSO_X32:
case ARCH_MAP_VDSO_64:
+ return do_map_vdso_64(addr);
+
+ /* x32 vDSO remap API is omitted for simplicity. */
+ case ARCH_MAP_VDSO_X32:
#endif
default:
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index 81a16c8..30b9995 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -512,17 +512,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
#ifdef CONFIG_X86_64
-static bool vdso_or_vvar_present(struct mm_struct *mm)
-{
- struct vm_area_struct *vma;
-
- for (vma = mm->mmap; vma; vma = vma->vm_next)
- if (vma_is_vdso_or_vvar(vma, mm))
- return true;
- return false;
-}
-
-int do_map_compat_vdso(unsigned long req_addr)
+int do_map_vdso_32(unsigned long req_addr)
{
struct mm_struct *mm = current->mm;
unsigned long vdso_addr;
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index ad0e0ac..accca8e 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -171,28 +171,52 @@ static unsigned long vdso_addr(unsigned long start, unsigned len)
return addr;
}
+bool vdso_or_vvar_present(struct mm_struct *mm)
+{
+ struct vm_area_struct *vma;
+
+ for (vma = mm->mmap; vma; vma = vma->vm_next)
+ if (vma_is_vdso_or_vvar(vma, mm))
+ return true;
+ return false;
+}
+
/* Setup a VMA at program startup for the vsyscall page.
Not called for compat tasks */
static int setup_additional_pages(struct linux_binprm *bprm,
int uses_interp,
struct page **pages,
- unsigned size)
+ unsigned size,
+ unsigned long req_addr)
{
struct mm_struct *mm = current->mm;
- unsigned long addr;
+ unsigned long addr = req_addr;
int ret;
if (!vdso_enabled)
return 0;
down_write(&mm->mmap_sem);
- addr = vdso_addr(mm->start_stack, size);
+
+ if (vdso_or_vvar_present(mm)) {
+ ret = -EEXIST;
+ goto up_fail;
+ }
+
+ if (!req_addr)
+ addr = vdso_addr(mm->start_stack, size);
+
addr = get_unmapped_area(NULL, addr, size, 0, 0);
if (IS_ERR_VALUE(addr)) {
ret = addr;
goto up_fail;
}
+ if (req_addr && req_addr != addr) {
+ ret = -EFAULT;
+ goto up_fail;
+ }
+
current->mm->context.vdso = (void *)addr;
ret = install_special_mapping(mm, addr, size,
@@ -211,7 +235,8 @@ static int setup_additional_pages(struct linux_binprm *bprm,
static DEFINE_MUTEX(vdso_mutex);
-static int uts_arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+static int uts_arch_setup_additional_pages(struct linux_binprm *bprm,
+ int uses_interp, unsigned long addr)
{
struct uts_namespace *uts_ns = current->nsproxy->uts_ns;
struct ve_struct *ve = get_exec_env();
@@ -303,9 +328,11 @@ static int uts_arch_setup_additional_pages(struct linux_binprm *bprm, int uses_i
LINUX_VERSION_CODE, new_version, ve->veid);
map_uts:
- return setup_additional_pages(bprm, uses_interp, uts_ns->vdso.pages, uts_ns->vdso.size);
+ return setup_additional_pages(bprm, uses_interp, uts_ns->vdso.pages,
+ uts_ns->vdso.size, addr);
map_init_uts:
- return setup_additional_pages(bprm, uses_interp, init_uts_ns.vdso.pages, init_uts_ns.vdso.size);
+ return setup_additional_pages(bprm, uses_interp, init_uts_ns.vdso.pages,
+ init_uts_ns.vdso.size, addr);
out_unlock:
mutex_unlock(&vdso_mutex);
return -ENOMEM;
@@ -313,14 +340,19 @@ static int uts_arch_setup_additional_pages(struct linux_binprm *bprm, int uses_i
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
- return uts_arch_setup_additional_pages(bprm, uses_interp);
+ return uts_arch_setup_additional_pages(bprm, uses_interp, 0);
+}
+
+int do_map_vdso_64(unsigned long req_addr)
+{
+ return uts_arch_setup_additional_pages(0, 0, req_addr);
}
#ifdef CONFIG_X86_X32_ABI
int x32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
return setup_additional_pages(bprm, uses_interp, vdsox32_pages,
- vdsox32_size);
+ vdsox32_size, 0);
}
#endif
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