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SubjectRe: [PATCH] futex: cmpxchg_futex_value_locked API change
On Wed, 9 Mar 2011, Michel Lespinasse wrote:

> On Tue, Mar 08, 2011 at 09:17:11PM +0100, Thomas Gleixner wrote:
> > On Sun, 6 Mar 2011, Michel Lespinasse wrote:
> > > The cmpxchg_futex_value_locked API was funny in that it returned either
> > > the original, user-exposed futex value OR an error code such as -EFAULT.
> > > This was confusing at best, and could be a source of livelocks in places
> > > that retry the cmpxchg_futex_value_locked after trying to fix the issue
> > > by running fault_in_user_writeable().
> > >
> > > This change makes the cmpxchg_futex_value_locked API more similar to the
> > > get_futex_value_locked one, returning an error code and updating the
> > > original value through a reference argument.
> >
> > Ack.
> >
> > > static inline int
> > > -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> > > +futex_atomic_cmpxchg_inatomic(int *uval, int __user *uaddr,
> > > + int oldval, int newval)
> >
> > Can we please change the arguments to u32 while at it? The futex core
> > code uses u32 all over the place so those inlines should do the same.
>
> All right. Attaching updated version of the diff. I also fixed the s390
> issue reported by Martin Schwidefsky.
>
> What's the proper path to check this in, could you send it towards
> the -next tree so it gets more testing ?

I'll pick it up and wait what explodes :)

Thanks,

tglx

> --------------------------------------8<-------------------------------
>
> The cmpxchg_futex_value_locked API was funny in that it returned either
> the original, user-exposed futex value OR an error code such as -EFAULT.
> This was confusing at best, and could be a source of livelocks in places
> that retry the cmpxchg_futex_value_locked after trying to fix the issue
> by running fault_in_user_writeable().
>
> This change makes the cmpxchg_futex_value_locked API more similar to the
> get_futex_value_locked one, returning an error code and updating the
> original value through a reference argument.
>
> Additionally, the futex pointer types have been changed to u32 * in both
> futex_atomic_cmpxchg_inatomic and futex_atomic_op_inuser internal APIs
> as suggested by Thomas Gleixner.
>
> Signed-off-by: Michel Lespinasse <walken@google.com>
> Acked-by: Chris Metcalf <cmetcalf@tilera.com> (for tile)
> Acked-by: Tony Luck <tony.luck@intel.com> (for ia64)
> Acked-by: Thomas Gleixner <tglx@linutronix.de>
> Tested-by: Michal Simek <monstr@monstr.eu> (for microblaze)
>
> ---
> arch/alpha/include/asm/futex.h | 29 ++++++++++++----------
> arch/arm/include/asm/futex.h | 30 ++++++++++++----------
> arch/frv/include/asm/futex.h | 5 ++-
> arch/frv/kernel/futex.c | 14 +++++-----
> arch/ia64/include/asm/futex.h | 15 +++++++----
> arch/microblaze/include/asm/futex.h | 31 +++++++++++++----------
> arch/mips/include/asm/futex.h | 39 ++++++++++++++++-------------
> arch/parisc/include/asm/futex.h | 24 +++++++++---------
> arch/powerpc/include/asm/futex.h | 27 +++++++++++---------
> arch/s390/include/asm/futex.h | 12 ++++----
> arch/s390/include/asm/uaccess.h | 4 +-
> arch/s390/lib/uaccess.h | 8 +++---
> arch/s390/lib/uaccess_pt.c | 17 +++++++-----
> arch/s390/lib/uaccess_std.c | 8 ++++--
> arch/sh/include/asm/futex-irq.h | 24 +++++++++---------
> arch/sh/include/asm/futex.h | 11 ++++----
> arch/sparc/include/asm/futex_64.h | 20 +++++++++------
> arch/tile/include/asm/futex.h | 27 ++++++++++----------
> arch/x86/include/asm/futex.h | 22 +++++++++-------
> include/asm-generic/futex.h | 7 +++--
> kernel/futex.c | 46 ++++++++++++----------------------
> 21 files changed, 219 insertions(+), 201 deletions(-)
>
> diff --git a/arch/alpha/include/asm/futex.h b/arch/alpha/include/asm/futex.h
> index 945de22..e8a761a 100644
> --- a/arch/alpha/include/asm/futex.h
> +++ b/arch/alpha/include/asm/futex.h
> @@ -29,7 +29,7 @@
> : "r" (uaddr), "r"(oparg) \
> : "memory")
>
> -static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> +static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -39,7 +39,7 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -81,21 +81,23 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> }
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> - int prev, cmp;
> + int ret = 0, cmp;
> + u32 prev;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> __asm__ __volatile__ (
> __ASM_SMP_MB
> - "1: ldl_l %0,0(%2)\n"
> - " cmpeq %0,%3,%1\n"
> - " beq %1,3f\n"
> - " mov %4,%1\n"
> - "2: stl_c %1,0(%2)\n"
> - " beq %1,4f\n"
> + "1: ldl_l %1,0(%3)\n"
> + " cmpeq %1,%4,%2\n"
> + " beq %2,3f\n"
> + " mov %5,%2\n"
> + "2: stl_c %2,0(%3)\n"
> + " beq %2,4f\n"
> "3: .subsection 2\n"
> "4: br 1b\n"
> " .previous\n"
> @@ -105,11 +107,12 @@ futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> " .long 2b-.\n"
> " lda $31,3b-2b(%0)\n"
> " .previous\n"
> - : "=&r"(prev), "=&r"(cmp)
> + : "+r"(ret), "=&r"(prev), "=&r"(cmp)
> : "r"(uaddr), "r"((long)oldval), "r"(newval)
> : "memory");
>
> - return prev;
> + *uval = prev;
> + return ret;
> }
>
> #endif /* __KERNEL__ */
> diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h
> index b33fe70..0e29d8e 100644
> --- a/arch/arm/include/asm/futex.h
> +++ b/arch/arm/include/asm/futex.h
> @@ -35,7 +35,7 @@
> : "cc", "memory")
>
> static inline int
> -futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> +futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -46,7 +46,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable(); /* implies preempt_disable() */
> @@ -88,36 +88,38 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> }
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> - int val;
> + int ret = 0;
> + u32 val;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> - pagefault_disable(); /* implies preempt_disable() */
> + /* Note that preemption is disabled by futex_atomic_cmpxchg_inatomic
> + * call sites. */
>
> __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
> - "1: " T(ldr) " %0, [%3]\n"
> - " teq %0, %1\n"
> + "1: " T(ldr) " %1, [%4]\n"
> + " teq %1, %2\n"
> " it eq @ explicit IT needed for the 2b label\n"
> - "2: " T(streq) " %2, [%3]\n"
> + "2: " T(streq) " %3, [%4]\n"
> "3:\n"
> " .pushsection __ex_table,\"a\"\n"
> " .align 3\n"
> " .long 1b, 4f, 2b, 4f\n"
> " .popsection\n"
> " .pushsection .fixup,\"ax\"\n"
> - "4: mov %0, %4\n"
> + "4: mov %0, %5\n"
> " b 3b\n"
> " .popsection"
> - : "=&r" (val)
> + : "+r" (ret), "=&r" (val)
> : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)
> : "cc", "memory");
>
> - pagefault_enable(); /* subsumes preempt_enable() */
> -
> - return val;
> + *uval = val;
> + return ret;
> }
>
> #endif /* !SMP */
> diff --git a/arch/frv/include/asm/futex.h b/arch/frv/include/asm/futex.h
> index 08b3d1d..4bea27f 100644
> --- a/arch/frv/include/asm/futex.h
> +++ b/arch/frv/include/asm/futex.h
> @@ -7,10 +7,11 @@
> #include <asm/errno.h>
> #include <asm/uaccess.h>
>
> -extern int futex_atomic_op_inuser(int encoded_op, int __user *uaddr);
> +extern int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr);
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> return -ENOSYS;
> }
> diff --git a/arch/frv/kernel/futex.c b/arch/frv/kernel/futex.c
> index 14f64b0..d155ca9 100644
> --- a/arch/frv/kernel/futex.c
> +++ b/arch/frv/kernel/futex.c
> @@ -18,7 +18,7 @@
> * the various futex operations; MMU fault checking is ignored under no-MMU
> * conditions
> */
> -static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr, int *_oldval)
> +static inline int atomic_futex_op_xchg_set(int oparg, u32 __user *uaddr, int *_oldval)
> {
> int oldval, ret;
>
> @@ -50,7 +50,7 @@ static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr, int *_o
> return ret;
> }
>
> -static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr, int *_oldval)
> +static inline int atomic_futex_op_xchg_add(int oparg, u32 __user *uaddr, int *_oldval)
> {
> int oldval, ret;
>
> @@ -83,7 +83,7 @@ static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr, int *_o
> return ret;
> }
>
> -static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr, int *_oldval)
> +static inline int atomic_futex_op_xchg_or(int oparg, u32 __user *uaddr, int *_oldval)
> {
> int oldval, ret;
>
> @@ -116,7 +116,7 @@ static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr, int *_ol
> return ret;
> }
>
> -static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr, int *_oldval)
> +static inline int atomic_futex_op_xchg_and(int oparg, u32 __user *uaddr, int *_oldval)
> {
> int oldval, ret;
>
> @@ -149,7 +149,7 @@ static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr, int *_o
> return ret;
> }
>
> -static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr, int *_oldval)
> +static inline int atomic_futex_op_xchg_xor(int oparg, u32 __user *uaddr, int *_oldval)
> {
> int oldval, ret;
>
> @@ -186,7 +186,7 @@ static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr, int *_o
> /*
> * do the futex operations
> */
> -int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> +int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -197,7 +197,7 @@ int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> diff --git a/arch/ia64/include/asm/futex.h b/arch/ia64/include/asm/futex.h
> index c7f0f06..8428525 100644
> --- a/arch/ia64/include/asm/futex.h
> +++ b/arch/ia64/include/asm/futex.h
> @@ -46,7 +46,7 @@ do { \
> } while (0)
>
> static inline int
> -futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> +futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -56,7 +56,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
> + if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -100,23 +100,26 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> }
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> {
> - register unsigned long r8 __asm ("r8");
> + register unsigned long r8 __asm ("r8") = 0;
> + unsigned long prev;
> __asm__ __volatile__(
> " mf;; \n"
> " mov ar.ccv=%3;; \n"
> "[1:] cmpxchg4.acq %0=[%1],%2,ar.ccv \n"
> " .xdata4 \"__ex_table\", 1b-., 2f-. \n"
> "[2:]"
> - : "=r" (r8)
> + : "=r" (prev)
> : "r" (uaddr), "r" (newval),
> "rO" ((long) (unsigned) oldval)
> : "memory");
> + *uval = prev;
> return r8;
> }
> }
> diff --git a/arch/microblaze/include/asm/futex.h b/arch/microblaze/include/asm/futex.h
> index ad3fd61..b0526d2 100644
> --- a/arch/microblaze/include/asm/futex.h
> +++ b/arch/microblaze/include/asm/futex.h
> @@ -29,7 +29,7 @@
> })
>
> static inline int
> -futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> +futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -39,7 +39,7 @@ futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -94,31 +94,34 @@ futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> }
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> - int prev, cmp;
> + int ret = 0, cmp;
> + u32 prev;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> - __asm__ __volatile__ ("1: lwx %0, %2, r0; \
> - cmp %1, %0, %3; \
> - beqi %1, 3f; \
> - 2: swx %4, %2, r0; \
> - addic %1, r0, 0; \
> - bnei %1, 1b; \
> + __asm__ __volatile__ ("1: lwx %1, %3, r0; \
> + cmp %2, %1, %4; \
> + beqi %2, 3f; \
> + 2: swx %5, %3, r0; \
> + addic %2, r0, 0; \
> + bnei %2, 1b; \
> 3: \
> .section .fixup,\"ax\"; \
> 4: brid 3b; \
> - addik %0, r0, %5; \
> + addik %0, r0, %6; \
> .previous; \
> .section __ex_table,\"a\"; \
> .word 1b,4b,2b,4b; \
> .previous;" \
> - : "=&r" (prev), "=&r"(cmp) \
> + : "+r" (ret), "=&r" (prev), "=&r"(cmp) \
> : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT));
>
> - return prev;
> + *uval = prev;
> + return ret;
> }
>
> #endif /* __KERNEL__ */
> diff --git a/arch/mips/include/asm/futex.h b/arch/mips/include/asm/futex.h
> index b9cce90..6ebf173 100644
> --- a/arch/mips/include/asm/futex.h
> +++ b/arch/mips/include/asm/futex.h
> @@ -75,7 +75,7 @@
> }
>
> static inline int
> -futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> +futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -85,7 +85,7 @@ futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
> + if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -132,11 +132,13 @@ futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> }
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> - int retval;
> + int ret = 0;
> + u32 val;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> if (cpu_has_llsc && R10000_LLSC_WAR) {
> @@ -145,25 +147,25 @@ futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> " .set push \n"
> " .set noat \n"
> " .set mips3 \n"
> - "1: ll %0, %2 \n"
> - " bne %0, %z3, 3f \n"
> + "1: ll %1, %3 \n"
> + " bne %1, %z4, 3f \n"
> " .set mips0 \n"
> - " move $1, %z4 \n"
> + " move $1, %z5 \n"
> " .set mips3 \n"
> - "2: sc $1, %1 \n"
> + "2: sc $1, %2 \n"
> " beqzl $1, 1b \n"
> __WEAK_LLSC_MB
> "3: \n"
> " .set pop \n"
> " .section .fixup,\"ax\" \n"
> - "4: li %0, %5 \n"
> + "4: li %0, %6 \n"
> " j 3b \n"
> " .previous \n"
> " .section __ex_table,\"a\" \n"
> " "__UA_ADDR "\t1b, 4b \n"
> " "__UA_ADDR "\t2b, 4b \n"
> " .previous \n"
> - : "=&r" (retval), "=R" (*uaddr)
> + : "+r" (ret), "=&r" (val), "=R" (*uaddr)
> : "R" (*uaddr), "Jr" (oldval), "Jr" (newval), "i" (-EFAULT)
> : "memory");
> } else if (cpu_has_llsc) {
> @@ -172,31 +174,32 @@ futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> " .set push \n"
> " .set noat \n"
> " .set mips3 \n"
> - "1: ll %0, %2 \n"
> - " bne %0, %z3, 3f \n"
> + "1: ll %1, %3 \n"
> + " bne %1, %z4, 3f \n"
> " .set mips0 \n"
> - " move $1, %z4 \n"
> + " move $1, %z5 \n"
> " .set mips3 \n"
> - "2: sc $1, %1 \n"
> + "2: sc $1, %2 \n"
> " beqz $1, 1b \n"
> __WEAK_LLSC_MB
> "3: \n"
> " .set pop \n"
> " .section .fixup,\"ax\" \n"
> - "4: li %0, %5 \n"
> + "4: li %0, %6 \n"
> " j 3b \n"
> " .previous \n"
> " .section __ex_table,\"a\" \n"
> " "__UA_ADDR "\t1b, 4b \n"
> " "__UA_ADDR "\t2b, 4b \n"
> " .previous \n"
> - : "=&r" (retval), "=R" (*uaddr)
> + : "+r" (ret), "=&r" (val), "=R" (*uaddr)
> : "R" (*uaddr), "Jr" (oldval), "Jr" (newval), "i" (-EFAULT)
> : "memory");
> } else
> return -ENOSYS;
>
> - return retval;
> + *uval = val;
> + return ret;
> }
>
> #endif
> diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h
> index 0c705c3..67a33cc 100644
> --- a/arch/parisc/include/asm/futex.h
> +++ b/arch/parisc/include/asm/futex.h
> @@ -8,7 +8,7 @@
> #include <asm/errno.h>
>
> static inline int
> -futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> +futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -18,7 +18,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
> + if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -51,10 +51,10 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
>
> /* Non-atomic version */
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> - int err = 0;
> - int uval;
> + u32 val;
>
> /* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
> * our gateway page, and causes no end of trouble...
> @@ -62,15 +62,15 @@ futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> if (segment_eq(KERNEL_DS, get_fs()) && !uaddr)
> return -EFAULT;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> - err = get_user(uval, uaddr);
> - if (err) return -EFAULT;
> - if (uval == oldval)
> - err = put_user(newval, uaddr);
> - if (err) return -EFAULT;
> - return uval;
> + if (get_user(val, uaddr))
> + return -EFAULT;
> + if (val == oldval && put_user(newval, uaddr))
> + return -EFAULT;
> + *uval = val;
> + return 0;
> }
>
> #endif /*__KERNEL__*/
> diff --git a/arch/powerpc/include/asm/futex.h b/arch/powerpc/include/asm/futex.h
> index 7c589ef..c94e4a3 100644
> --- a/arch/powerpc/include/asm/futex.h
> +++ b/arch/powerpc/include/asm/futex.h
> @@ -30,7 +30,7 @@
> : "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
> : "cr0", "memory")
>
> -static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> +static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -40,7 +40,7 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
> + if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -82,35 +82,38 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> }
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> - int prev;
> + int ret = 0;
> + u32 prev;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> __asm__ __volatile__ (
> PPC_RELEASE_BARRIER
> -"1: lwarx %0,0,%2 # futex_atomic_cmpxchg_inatomic\n\
> - cmpw 0,%0,%3\n\
> +"1: lwarx %1,0,%3 # futex_atomic_cmpxchg_inatomic\n\
> + cmpw 0,%1,%4\n\
> bne- 3f\n"
> - PPC405_ERR77(0,%2)
> -"2: stwcx. %4,0,%2\n\
> + PPC405_ERR77(0,%3)
> +"2: stwcx. %5,0,%3\n\
> bne- 1b\n"
> PPC_ACQUIRE_BARRIER
> "3: .section .fixup,\"ax\"\n\
> -4: li %0,%5\n\
> +4: li %0,%6\n\
> b 3b\n\
> .previous\n\
> .section __ex_table,\"a\"\n\
> .align 3\n\
> " PPC_LONG "1b,4b,2b,4b\n\
> .previous" \
> - : "=&r" (prev), "+m" (*uaddr)
> + : "+r" (ret), "=&r" (prev), "+m" (*uaddr)
> : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
> : "cc", "memory");
>
> - return prev;
> + *uval = prev;
> + return ret;
> }
>
> #endif /* __KERNEL__ */
> diff --git a/arch/s390/include/asm/futex.h b/arch/s390/include/asm/futex.h
> index 5c5d02d..81cf36b 100644
> --- a/arch/s390/include/asm/futex.h
> +++ b/arch/s390/include/asm/futex.h
> @@ -7,7 +7,7 @@
> #include <linux/uaccess.h>
> #include <asm/errno.h>
>
> -static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> +static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -18,7 +18,7 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
> + if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -39,13 +39,13 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> return ret;
> }
>
> -static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr,
> - int oldval, int newval)
> +static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> - if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
> + if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> - return uaccess.futex_atomic_cmpxchg(uaddr, oldval, newval);
> + return uaccess.futex_atomic_cmpxchg(uval, uaddr, oldval, newval);
> }
>
> #endif /* __KERNEL__ */
> diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
> index d6b1ed0..2d9ea11f 100644
> --- a/arch/s390/include/asm/uaccess.h
> +++ b/arch/s390/include/asm/uaccess.h
> @@ -83,8 +83,8 @@ struct uaccess_ops {
> size_t (*clear_user)(size_t, void __user *);
> size_t (*strnlen_user)(size_t, const char __user *);
> size_t (*strncpy_from_user)(size_t, const char __user *, char *);
> - int (*futex_atomic_op)(int op, int __user *, int oparg, int *old);
> - int (*futex_atomic_cmpxchg)(int __user *, int old, int new);
> + int (*futex_atomic_op)(int op, u32 __user *, int oparg, int *old);
> + int (*futex_atomic_cmpxchg)(u32 *, u32 __user *, u32 old, u32 new);
> };
>
> extern struct uaccess_ops uaccess;
> diff --git a/arch/s390/lib/uaccess.h b/arch/s390/lib/uaccess.h
> index 126011d..1d2536c 100644
> --- a/arch/s390/lib/uaccess.h
> +++ b/arch/s390/lib/uaccess.h
> @@ -12,12 +12,12 @@ extern size_t copy_from_user_std(size_t, const void __user *, void *);
> extern size_t copy_to_user_std(size_t, void __user *, const void *);
> extern size_t strnlen_user_std(size_t, const char __user *);
> extern size_t strncpy_from_user_std(size_t, const char __user *, char *);
> -extern int futex_atomic_cmpxchg_std(int __user *, int, int);
> -extern int futex_atomic_op_std(int, int __user *, int, int *);
> +extern int futex_atomic_cmpxchg_std(u32 *, u32 __user *, u32, u32);
> +extern int futex_atomic_op_std(int, u32 __user *, int, int *);
>
> extern size_t copy_from_user_pt(size_t, const void __user *, void *);
> extern size_t copy_to_user_pt(size_t, void __user *, const void *);
> -extern int futex_atomic_op_pt(int, int __user *, int, int *);
> -extern int futex_atomic_cmpxchg_pt(int __user *, int, int);
> +extern int futex_atomic_op_pt(int, u32 __user *, int, int *);
> +extern int futex_atomic_cmpxchg_pt(u32 *, u32 __user *, u32, u32);
>
> #endif /* __ARCH_S390_LIB_UACCESS_H */
> diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
> index 404f2de..afc716a 100644
> --- a/arch/s390/lib/uaccess_pt.c
> +++ b/arch/s390/lib/uaccess_pt.c
> @@ -302,7 +302,7 @@ fault:
> : "0" (-EFAULT), "d" (oparg), "a" (uaddr), \
> "m" (*uaddr) : "cc" );
>
> -static int __futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
> +static int __futex_atomic_op_pt(int op, u32 __user *uaddr, int oparg, int *old)
> {
> int oldval = 0, newval, ret;
>
> @@ -335,7 +335,7 @@ static int __futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
> return ret;
> }
>
> -int futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
> +int futex_atomic_op_pt(int op, u32 __user *uaddr, int oparg, int *old)
> {
> int ret;
>
> @@ -354,26 +354,29 @@ int futex_atomic_op_pt(int op, int __user *uaddr, int oparg, int *old)
> return ret;
> }
>
> -static int __futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval)
> +static int __futex_atomic_cmpxchg_pt(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> int ret;
>
> asm volatile("0: cs %1,%4,0(%5)\n"
> - "1: lr %0,%1\n"
> + "1: la %0,0\n"
> "2:\n"
> EX_TABLE(0b,2b) EX_TABLE(1b,2b)
> : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
> : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
> : "cc", "memory" );
> + *uval = oldval;
> return ret;
> }
>
> -int futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval)
> +int futex_atomic_cmpxchg_pt(int *uval, int __user *uaddr,
> + int oldval, int newval)
> {
> int ret;
>
> if (segment_eq(get_fs(), KERNEL_DS))
> - return __futex_atomic_cmpxchg_pt(uaddr, oldval, newval);
> + return __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
> spin_lock(&current->mm->page_table_lock);
> uaddr = (int __user *) __dat_user_addr((unsigned long) uaddr);
> if (!uaddr) {
> @@ -382,7 +385,7 @@ int futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval)
> }
> get_page(virt_to_page(uaddr));
> spin_unlock(&current->mm->page_table_lock);
> - ret = __futex_atomic_cmpxchg_pt(uaddr, oldval, newval);
> + ret = __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
> put_page(virt_to_page(uaddr));
> return ret;
> }
> diff --git a/arch/s390/lib/uaccess_std.c b/arch/s390/lib/uaccess_std.c
> index a6c4f7e..bb1a7ee 100644
> --- a/arch/s390/lib/uaccess_std.c
> +++ b/arch/s390/lib/uaccess_std.c
> @@ -255,7 +255,7 @@ size_t strncpy_from_user_std(size_t size, const char __user *src, char *dst)
> : "0" (-EFAULT), "d" (oparg), "a" (uaddr), \
> "m" (*uaddr) : "cc");
>
> -int futex_atomic_op_std(int op, int __user *uaddr, int oparg, int *old)
> +int futex_atomic_op_std(int op, u32 __user *uaddr, int oparg, int *old)
> {
> int oldval = 0, newval, ret;
>
> @@ -287,19 +287,21 @@ int futex_atomic_op_std(int op, int __user *uaddr, int oparg, int *old)
> return ret;
> }
>
> -int futex_atomic_cmpxchg_std(int __user *uaddr, int oldval, int newval)
> +int futex_atomic_cmpxchg_std(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> int ret;
>
> asm volatile(
> " sacf 256\n"
> "0: cs %1,%4,0(%5)\n"
> - "1: lr %0,%1\n"
> + "1: la %0,0\n"
> "2: sacf 0\n"
> EX_TABLE(0b,2b) EX_TABLE(1b,2b)
> : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
> : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
> : "cc", "memory" );
> + *uval = oldval;
> return ret;
> }
>
> diff --git a/arch/sh/include/asm/futex-irq.h b/arch/sh/include/asm/futex-irq.h
> index a9f16a7..6cb9f19 100644
> --- a/arch/sh/include/asm/futex-irq.h
> +++ b/arch/sh/include/asm/futex-irq.h
> @@ -3,7 +3,7 @@
>
> #include <asm/system.h>
>
> -static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr,
> +static inline int atomic_futex_op_xchg_set(int oparg, u32 __user *uaddr,
> int *oldval)
> {
> unsigned long flags;
> @@ -20,7 +20,7 @@ static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr,
> return ret;
> }
>
> -static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr,
> +static inline int atomic_futex_op_xchg_add(int oparg, u32 __user *uaddr,
> int *oldval)
> {
> unsigned long flags;
> @@ -37,7 +37,7 @@ static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr,
> return ret;
> }
>
> -static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr,
> +static inline int atomic_futex_op_xchg_or(int oparg, u32 __user *uaddr,
> int *oldval)
> {
> unsigned long flags;
> @@ -54,7 +54,7 @@ static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr,
> return ret;
> }
>
> -static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr,
> +static inline int atomic_futex_op_xchg_and(int oparg, u32 __user *uaddr,
> int *oldval)
> {
> unsigned long flags;
> @@ -71,7 +71,7 @@ static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr,
> return ret;
> }
>
> -static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr,
> +static inline int atomic_futex_op_xchg_xor(int oparg, u32 __user *uaddr,
> int *oldval)
> {
> unsigned long flags;
> @@ -88,11 +88,13 @@ static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr,
> return ret;
> }
>
> -static inline int atomic_futex_op_cmpxchg_inatomic(int __user *uaddr,
> - int oldval, int newval)
> +static inline int atomic_futex_op_cmpxchg_inatomic(u32 *uval,
> + u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> unsigned long flags;
> - int ret, prev = 0;
> + int ret;
> + u32 prev = 0;
>
> local_irq_save(flags);
>
> @@ -102,10 +104,8 @@ static inline int atomic_futex_op_cmpxchg_inatomic(int __user *uaddr,
>
> local_irq_restore(flags);
>
> - if (ret)
> - return ret;
> -
> - return prev;
> + *uval = prev;
> + return ret;
> }
>
> #endif /* __ASM_SH_FUTEX_IRQ_H */
> diff --git a/arch/sh/include/asm/futex.h b/arch/sh/include/asm/futex.h
> index 68256ec..7be39a6 100644
> --- a/arch/sh/include/asm/futex.h
> +++ b/arch/sh/include/asm/futex.h
> @@ -10,7 +10,7 @@
> /* XXX: UP variants, fix for SH-4A and SMP.. */
> #include <asm/futex-irq.h>
>
> -static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> +static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -21,7 +21,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -65,12 +65,13 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> }
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> - return atomic_futex_op_cmpxchg_inatomic(uaddr, oldval, newval);
> + return atomic_futex_op_cmpxchg_inatomic(uval, uaddr, oldval, newval);
> }
>
> #endif /* __KERNEL__ */
> diff --git a/arch/sparc/include/asm/futex_64.h b/arch/sparc/include/asm/futex_64.h
> index 47f9583..444e7be 100644
> --- a/arch/sparc/include/asm/futex_64.h
> +++ b/arch/sparc/include/asm/futex_64.h
> @@ -30,7 +30,7 @@
> : "r" (uaddr), "r" (oparg), "i" (-EFAULT) \
> : "memory")
>
> -static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> +static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -38,7 +38,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> int cmparg = (encoded_op << 20) >> 20;
> int oldval = 0, ret, tem;
>
> - if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(int))))
> + if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))))
> return -EFAULT;
> if (unlikely((((unsigned long) uaddr) & 0x3UL)))
> return -EINVAL;
> @@ -85,26 +85,30 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> }
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> + int ret = 0;
> +
> __asm__ __volatile__(
> - "\n1: casa [%3] %%asi, %2, %0\n"
> + "\n1: casa [%4] %%asi, %3, %1\n"
> "2:\n"
> " .section .fixup,#alloc,#execinstr\n"
> " .align 4\n"
> "3: sethi %%hi(2b), %0\n"
> " jmpl %0 + %%lo(2b), %%g0\n"
> - " mov %4, %0\n"
> + " mov %5, %0\n"
> " .previous\n"
> " .section __ex_table,\"a\"\n"
> " .align 4\n"
> " .word 1b, 3b\n"
> " .previous\n"
> - : "=r" (newval)
> - : "0" (newval), "r" (oldval), "r" (uaddr), "i" (-EFAULT)
> + : "+r" (ret), "=r" (newval)
> + : "1" (newval), "r" (oldval), "r" (uaddr), "i" (-EFAULT)
> : "memory");
>
> - return newval;
> + *uval = newval;
> + return ret;
> }
>
> #endif /* !(_SPARC64_FUTEX_H) */
> diff --git a/arch/tile/include/asm/futex.h b/arch/tile/include/asm/futex.h
> index fe0d10d..d03ec12 100644
> --- a/arch/tile/include/asm/futex.h
> +++ b/arch/tile/include/asm/futex.h
> @@ -29,16 +29,16 @@
> #include <linux/uaccess.h>
> #include <linux/errno.h>
>
> -extern struct __get_user futex_set(int __user *v, int i);
> -extern struct __get_user futex_add(int __user *v, int n);
> -extern struct __get_user futex_or(int __user *v, int n);
> -extern struct __get_user futex_andn(int __user *v, int n);
> -extern struct __get_user futex_cmpxchg(int __user *v, int o, int n);
> +extern struct __get_user futex_set(u32 __user *v, int i);
> +extern struct __get_user futex_add(u32 __user *v, int n);
> +extern struct __get_user futex_or(u32 __user *v, int n);
> +extern struct __get_user futex_andn(u32 __user *v, int n);
> +extern struct __get_user futex_cmpxchg(u32 __user *v, int o, int n);
>
> #ifndef __tilegx__
> -extern struct __get_user futex_xor(int __user *v, int n);
> +extern struct __get_user futex_xor(u32 __user *v, int n);
> #else
> -static inline struct __get_user futex_xor(int __user *uaddr, int n)
> +static inline struct __get_user futex_xor(u32 __user *uaddr, int n)
> {
> struct __get_user asm_ret = __get_user_4(uaddr);
> if (!asm_ret.err) {
> @@ -53,7 +53,7 @@ static inline struct __get_user futex_xor(int __user *uaddr, int n)
> }
> #endif
>
> -static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> +static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -65,7 +65,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -119,16 +119,17 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> return ret;
> }
>
> -static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval,
> - int newval)
> +static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> struct __get_user asm_ret;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> asm_ret = futex_cmpxchg(uaddr, oldval, newval);
> - return asm_ret.err ? asm_ret.err : asm_ret.val;
> + *uval = asm_ret.val;
> + return asm_ret.err;
> }
>
> #ifndef __tilegx__
> diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h
> index 1f11ce4..d09bb03 100644
> --- a/arch/x86/include/asm/futex.h
> +++ b/arch/x86/include/asm/futex.h
> @@ -37,7 +37,7 @@
> "+m" (*uaddr), "=&r" (tem) \
> : "r" (oparg), "i" (-EFAULT), "1" (0))
>
> -static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> +static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -48,7 +48,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_BSWAP)
> @@ -109,9 +109,10 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> return ret;
> }
>
> -static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval,
> - int newval)
> +static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> + int ret = 0;
>
> #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_BSWAP)
> /* Real i386 machines have no cmpxchg instruction */
> @@ -119,21 +120,22 @@ static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval,
> return -ENOSYS;
> #endif
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> - asm volatile("1:\t" LOCK_PREFIX "cmpxchgl %3, %1\n"
> + asm volatile("1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"
> "2:\t.section .fixup, \"ax\"\n"
> - "3:\tmov %2, %0\n"
> + "3:\tmov %3, %0\n"
> "\tjmp 2b\n"
> "\t.previous\n"
> _ASM_EXTABLE(1b, 3b)
> - : "=a" (oldval), "+m" (*uaddr)
> - : "i" (-EFAULT), "r" (newval), "0" (oldval)
> + : "+r" (ret), "=a" (oldval), "+m" (*uaddr)
> + : "i" (-EFAULT), "r" (newval), "1" (oldval)
> : "memory"
> );
>
> - return oldval;
> + *uval = oldval;
> + return ret;
> }
>
> #endif
> diff --git a/include/asm-generic/futex.h b/include/asm-generic/futex.h
> index 3c2344f..01f227e 100644
> --- a/include/asm-generic/futex.h
> +++ b/include/asm-generic/futex.h
> @@ -6,7 +6,7 @@
> #include <asm/errno.h>
>
> static inline int
> -futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> +futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -16,7 +16,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
> + if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();
> @@ -48,7 +48,8 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
> }
>
> static inline int
> -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
> +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
> + u32 oldval, u32 newval)
> {
> return -ENOSYS;
> }
> diff --git a/kernel/futex.c b/kernel/futex.c
> index 3184d3b..53b783f 100644
> --- a/kernel/futex.c
> +++ b/kernel/futex.c
> @@ -381,15 +381,16 @@ static struct futex_q *futex_top_waiter(struct futex_hash_bucket *hb,
> return NULL;
> }
>
> -static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval)
> +static int cmpxchg_futex_value_locked(u32 *curval, u32 __user *uaddr,
> + u32 uval, u32 newval)
> {
> - u32 curval;
> + int ret;
>
> pagefault_disable();
> - curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
> + ret = futex_atomic_cmpxchg_inatomic(curval, uaddr, uval, newval);
> pagefault_enable();
>
> - return curval;
> + return ret;
> }
>
> static int get_futex_value_locked(u32 *dest, u32 __user *from)
> @@ -688,9 +689,7 @@ retry:
> if (set_waiters)
> newval |= FUTEX_WAITERS;
>
> - curval = cmpxchg_futex_value_locked(uaddr, 0, newval);
> -
> - if (unlikely(curval == -EFAULT))
> + if (unlikely(cmpxchg_futex_value_locked(&curval, uaddr, 0, newval)))
> return -EFAULT;
>
> /*
> @@ -728,9 +727,7 @@ retry:
> lock_taken = 1;
> }
>
> - curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
> -
> - if (unlikely(curval == -EFAULT))
> + if (unlikely(cmpxchg_futex_value_locked(&curval, uaddr, uval, newval)))
> return -EFAULT;
> if (unlikely(curval != uval))
> goto retry;
> @@ -843,9 +840,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this)
>
> newval = FUTEX_WAITERS | task_pid_vnr(new_owner);
>
> - curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
> -
> - if (curval == -EFAULT)
> + if (cmpxchg_futex_value_locked(&curval, uaddr, uval, newval))
> ret = -EFAULT;
> else if (curval != uval)
> ret = -EINVAL;
> @@ -880,10 +875,8 @@ static int unlock_futex_pi(u32 __user *uaddr, u32 uval)
> * There is no waiter, so we unlock the futex. The owner died
> * bit has not to be preserved here. We are the owner:
> */
> - oldval = cmpxchg_futex_value_locked(uaddr, uval, 0);
> -
> - if (oldval == -EFAULT)
> - return oldval;
> + if (cmpxchg_futex_value_locked(&oldval, uaddr, uval, 0))
> + return -EFAULT;
> if (oldval != uval)
> return -EAGAIN;
>
> @@ -1578,9 +1571,7 @@ retry:
> while (1) {
> newval = (uval & FUTEX_OWNER_DIED) | newtid;
>
> - curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
> -
> - if (curval == -EFAULT)
> + if (cmpxchg_futex_value_locked(&curval, uaddr, uval, newval))
> goto handle_fault;
> if (curval == uval)
> break;
> @@ -2073,11 +2064,9 @@ retry:
> * again. If it succeeds then we can return without waking
> * anyone else up:
> */
> - if (!(uval & FUTEX_OWNER_DIED))
> - uval = cmpxchg_futex_value_locked(uaddr, task_pid_vnr(current), 0);
> -
> -
> - if (unlikely(uval == -EFAULT))
> + if (!(uval & FUTEX_OWNER_DIED) &&
> + unlikely(cmpxchg_futex_value_locked(&uval, uaddr,
> + task_pid_vnr(current), 0)))
> goto pi_faulted;
> /*
> * Rare case: we managed to release the lock atomically,
> @@ -2464,9 +2453,7 @@ retry:
> * userspace.
> */
> mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
> - nval = futex_atomic_cmpxchg_inatomic(uaddr, uval, mval);
> -
> - if (nval == -EFAULT)
> + if (futex_atomic_cmpxchg_inatomic(&nval, uaddr, uval, mval))
> return -1;
>
> if (nval != uval)
> @@ -2679,8 +2666,7 @@ static int __init futex_init(void)
> * implementation, the non-functional ones will return
> * -ENOSYS.
> */
> - curval = cmpxchg_futex_value_locked(NULL, 0, 0);
> - if (curval == -EFAULT)
> + if (cmpxchg_futex_value_locked(&curval, NULL, 0, 0) == -EFAULT)
> futex_cmpxchg_enabled = 1;
>
> for (i = 0; i < ARRAY_SIZE(futex_queues); i++) {
>
>
> --
> Michel "Walken" Lespinasse
> A program is never fully debugged until the last user dies.
>


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  Last update: 2011-03-09 16:09    [from the cache]
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