[PATCH] 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> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S index 7549a43..35b2fac 100644 --- a/arch/x86_64/ia32/ia32entry.S +++ b/arch/x86_64/ia32/ia32entry.S
@@ -688,6 +688,8 @@ .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
diff --git a/include/asm-x86_64/futex.h b/include/asm-x86_64/futex.h index 4f4cb34..7d9eb1a 100644 --- a/include/asm-x86_64/futex.h +++ b/include/asm-x86_64/futex.h
@@ -97,7 +97,28 @@ static inline int futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval) { - return -ENOSYS; + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) + return -EFAULT; + + __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
diff --git a/include/asm-x86_64/unistd.h b/include/asm-x86_64/unistd.h index da0341c..fcc5163 100644 --- a/include/asm-x86_64/unistd.h +++ b/include/asm-x86_64/unistd.h
@@ -605,8 +605,12 @@ __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