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Subject[patch 6/6] lightweight robust futexes: x86_64

x86_64: add the futex_atomic_cmpxchg_inuser() assembly implementation, and
wire up the new syscalls.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Acked-by: Ulrich Drepper <drepper@redhat.com>

----

arch/x86_64/ia32/ia32entry.S | 2 ++
include/asm-x86_64/futex.h | 20 +++++++++++++++++++-
include/asm-x86_64/unistd.h | 6 +++++-
3 files changed, 26 insertions(+), 2 deletions(-)

Index: linux-robust-list.q/arch/x86_64/ia32/ia32entry.S
===================================================================
--- linux-robust-list.q.orig/arch/x86_64/ia32/ia32entry.S
+++ linux-robust-list.q/arch/x86_64/ia32/ia32entry.S
@@ -688,6 +688,8 @@ ia32_sys_call_table:
.quad sys_ni_syscall /* pselect6 for now */
.quad sys_ni_syscall /* ppoll for now */
.quad sys_unshare /* 310 */
+ .quad compat_sys_set_robust_list
+ .quad compat_sys_get_robust_list
ia32_syscall_end:
.rept IA32_NR_syscalls-(ia32_syscall_end-ia32_sys_call_table)/8
.quad ni_syscall
Index: linux-robust-list.q/include/asm-x86_64/futex.h
===================================================================
--- linux-robust-list.q.orig/include/asm-x86_64/futex.h
+++ linux-robust-list.q/include/asm-x86_64/futex.h
@@ -97,7 +97,25 @@ futex_atomic_op_inuser (int encoded_op,
static inline int
futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval)
{
- return -ENOSYS;
+ __asm__ __volatile__(
+ "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n"
+
+ "2: .section .fixup, \"ax\" \n"
+ "3: mov %2, %0 \n"
+ " jmp 2b \n"
+ " .previous \n"
+
+ " .section __ex_table, \"a\" \n"
+ " .align 8 \n"
+ " .quad 1b,3b \n"
+ " .previous \n"
+
+ : "=a" (oldval), "=m" (*uaddr)
+ : "i" (-EFAULT), "r" (newval), "0" (oldval)
+ : "memory"
+ );
+
+ return oldval;
}

#endif
Index: linux-robust-list.q/include/asm-x86_64/unistd.h
===================================================================
--- linux-robust-list.q.orig/include/asm-x86_64/unistd.h
+++ linux-robust-list.q/include/asm-x86_64/unistd.h
@@ -605,8 +605,12 @@ __SYSCALL(__NR_pselect6, sys_ni_syscall)
__SYSCALL(__NR_ppoll, sys_ni_syscall) /* for now */
#define __NR_unshare 272
__SYSCALL(__NR_unshare, sys_unshare)
+#define __NR_set_robust_list 273
+__SYSCALL(__NR_set_robust_list, sys_set_robust_list)
+#define __NR_get_robust_list 274
+__SYSCALL(__NR_get_robust_list, sys_get_robust_list)

-#define __NR_syscall_max __NR_unshare
+#define __NR_syscall_max __NR_get_robust_list

#ifndef __NO_STUBS

-
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