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Subject[PATCH 2/5] y2038: futex: Add support for __kernel_timespec
Date
This prepares sys_futex for y2038 safe calling: the native
syscall is changed to receive a __kernel_timespec argument, which
will be switched to 64-bit time_t in the future. All the internal
time handling gets changed to timespec64, and the compat_sys_futex
entry point is moved under the CONFIG_COMPAT_32BIT_TIME check
to provide compatibility for existing 32-bit architectures.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
include/linux/syscalls.h | 2 +-
kernel/futex.c | 22 ++++++++++++----------
2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index a27cf407de92..247ad9eca955 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -553,7 +553,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags);

/* kernel/futex.c */
asmlinkage long sys_futex(u32 __user *uaddr, int op, u32 val,
- struct timespec __user *utime, u32 __user *uaddr2,
+ struct __kernel_timespec __user *utime, u32 __user *uaddr2,
u32 val3);
asmlinkage long sys_get_robust_list(int pid,
struct robust_list_head __user * __user *head_ptr,
diff --git a/kernel/futex.c b/kernel/futex.c
index 5cc7c3b098e9..b305beaab739 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -3558,10 +3558,10 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,


SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
- struct timespec __user *, utime, u32 __user *, uaddr2,
+ struct __kernel_timespec __user *, utime, u32 __user *, uaddr2,
u32, val3)
{
- struct timespec ts;
+ struct timespec64 ts;
ktime_t t, *tp = NULL;
u32 val2 = 0;
int cmd = op & FUTEX_CMD_MASK;
@@ -3571,12 +3571,12 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
cmd == FUTEX_WAIT_REQUEUE_PI)) {
if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG))))
return -EFAULT;
- if (copy_from_user(&ts, utime, sizeof(ts)) != 0)
+ if (get_timespec64(&ts, utime))
return -EFAULT;
- if (!timespec_valid(&ts))
+ if (!timespec64_valid(&ts))
return -EINVAL;

- t = timespec_to_ktime(ts);
+ t = timespec64_to_ktime(ts);
if (cmd == FUTEX_WAIT)
t = ktime_add_safe(ktime_get(), t);
tp = &t;
@@ -3747,12 +3747,14 @@ COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,

return ret;
}
+#endif /* CONFIG_COMPAT */

+#ifdef CONFIG_COMPAT_32BIT_TIME
COMPAT_SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
struct old_timespec32 __user *, utime, u32 __user *, uaddr2,
u32, val3)
{
- struct timespec ts;
+ struct timespec64 ts;
ktime_t t, *tp = NULL;
int val2 = 0;
int cmd = op & FUTEX_CMD_MASK;
@@ -3760,12 +3762,12 @@ COMPAT_SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI ||
cmd == FUTEX_WAIT_BITSET ||
cmd == FUTEX_WAIT_REQUEUE_PI)) {
- if (compat_get_timespec(&ts, utime))
+ if (get_old_timespec32(&ts, utime))
return -EFAULT;
- if (!timespec_valid(&ts))
+ if (!timespec64_valid(&ts))
return -EINVAL;

- t = timespec_to_ktime(ts);
+ t = timespec64_to_ktime(ts);
if (cmd == FUTEX_WAIT)
t = ktime_add_safe(ktime_get(), t);
tp = &t;
@@ -3776,7 +3778,7 @@ COMPAT_SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,

return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
}
-#endif /* CONFIG_COMPAT */
+#endif /* CONFIG_COMPAT_32BIT_TIME */

static void __init futex_detect_cmpxchg(void)
{
--
2.18.0
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