[PATCH 5.13 254/266] s390/vdso: always enable vdso

Greg Kroah-Hartman
2021-07-15T19:49:38Z

From: Sven Schnelle <svens@linux.ibm.com>

commit d57778feb9878aa6b79c615fd029c2112d40a747 upstream.

With the upcoming move of the svc sigreturn instruction from
the signal frame to vdso we need to have vdso always enabled.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/s390/include/asm/elf.h | 11 ++++-------
arch/s390/kernel/vdso.c | 21 ++++-----------------
2 files changed, 8 insertions(+), 24 deletions(-)

--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -146,8 +146,6 @@ typedef s390_compat_regs compat_elf_greg

#include <asm/vdso.h>

-extern unsigned int vdso_enabled;
-
/*
* This is used to ensure we don't load something for the wrong architecture.
*/
@@ -268,11 +266,10 @@ do { \
#define STACK_RND_MASK MMAP_RND_MASK

/* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
-#define ARCH_DLINFO \
-do { \
- if (vdso_enabled) \
- NEW_AUX_ENT(AT_SYSINFO_EHDR, \
- (unsigned long)current->mm->context.vdso_base); \
+#define ARCH_DLINFO \
+do { \
+ NEW_AUX_ENT(AT_SYSINFO_EHDR, \
+ (unsigned long)current->mm->context.vdso_base); \
} while (0)

struct linux_binprm;
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -37,18 +37,6 @@ enum vvar_pages {
VVAR_NR_PAGES,
};

-unsigned int __read_mostly vdso_enabled = 1;
-
-static int __init vdso_setup(char *str)
-{
- bool enabled;
-
- if (!kstrtobool(str, &enabled))
- vdso_enabled = enabled;
- return 1;
-}
-__setup("vdso=", vdso_setup);
-
#ifdef CONFIG_TIME_NS
struct vdso_data *arch_get_vdso_data(void *vvar_page)
{
@@ -176,7 +164,7 @@ int arch_setup_additional_pages(struct l
int rc;

BUILD_BUG_ON(VVAR_NR_PAGES != __VVAR_PAGES);
- if (!vdso_enabled || is_compat_task())
+ if (is_compat_task())
return 0;
if (mmap_write_lock_killable(mm))
return -EINTR;
@@ -218,10 +206,9 @@ static int __init vdso_init(void)

vdso_pages = (vdso64_end - vdso64_start) >> PAGE_SHIFT;
pages = kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL);
- if (!pages) {
- vdso_enabled = 0;
- return -ENOMEM;
- }
+ if (!pages)
+ panic("failed to allocate VDSO pages");
+
for (i = 0; i < vdso_pages; i++)
pages[i] = virt_to_page(vdso64_start + i * PAGE_SIZE);
pages[vdso_pages] = NULL;