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futex: Sanitize cmpxchg_futex_value_locked API 

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.
    
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>  [tile]
Acked-by: Tony Luck <tony.luck@intel.com>  [ia64]
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michal Simek <monstr@monstr.eu>  [microblaze]
Acked-by: David Howells <dhowells@redhat.com> [frv]
Cc: Darren Hart <darren@dvhart.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110311024851.GC26122@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
hifive-unleashed-5.1
Michel Lespinasse 2011-03-10 18:48:51 -08:00 committed by Thomas Gleixner
parent 522d7decc0
commit 37a9d912b2
20 changed files with 144 additions and 132 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
arch/alpha/include/asm/futex.h
View File

@ -81,21 +81,22 @@ 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(int *uval, int __user *uaddr,
int oldval, int newval)
{
int prev, cmp;
int ret = 0, prev, cmp;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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 +106,12 @@ 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__ */

18
arch/arm/include/asm/futex.h
View File

@ -88,9 +88,10 @@ 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(int *uval, int __user *uaddr,
int oldval, int newval)
{
int val;
int ret = 0, val;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
@ -99,24 +100,25 @@ futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
* 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");
return val;
*uval = val;
return ret;
}
#endif /* !SMP */

3
arch/frv/include/asm/futex.h
View File

@ -10,7 +10,8 @@
extern 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(int *uval, int __user *uaddr,
int oldval, int newval)
{
return -ENOSYS;
}

9
arch/ia64/include/asm/futex.h
View File

@ -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(int *uval, int __user *uaddr,
int oldval, int newval)
{
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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;
}
}

24
arch/microblaze/include/asm/futex.h
View File

@ -94,31 +94,33 @@ 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(int *uval, int __user *uaddr,
int oldval, int newval)
{
int prev, cmp;
int ret = 0, prev, cmp;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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__ */

32
arch/mips/include/asm/futex.h
View File

@ -132,9 +132,10 @@ 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(int *uval, int __user *uaddr,
int oldval, int newval)
{
int retval;
int ret = 0, val;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
@ -145,25 +146,25 @@ 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 +173,32 @@ 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

18
arch/parisc/include/asm/futex.h
View File

@ -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(int *uval, int __user *uaddr,
int oldval, int newval)
{
int err = 0;
int uval;
int val;
/* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
* our gateway page, and causes no end of trouble...
@ -65,12 +65,12 @@ futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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__*/

20
arch/powerpc/include/asm/futex.h
View File

@ -82,35 +82,37 @@ 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(int *uval, int __user *uaddr,
int oldval, int newval)
{
int prev;
int ret = 0, prev;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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__ */

4
arch/s390/include/asm/futex.h
View File

@ -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,
static inline int futex_atomic_cmpxchg_inatomic(int *uval, int __user *uaddr,
int oldval, int newval)
{
if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
return uaccess.futex_atomic_cmpxchg(uaddr, oldval, newval);
return uaccess.futex_atomic_cmpxchg(uval, uaddr, oldval, newval);
}
#endif /* __KERNEL__ */

2
arch/s390/include/asm/uaccess.h
View File

@ -84,7 +84,7 @@ struct uaccess_ops {
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_cmpxchg)(int *, int __user *, int old, int new);
};
extern struct uaccess_ops uaccess;

4
arch/s390/lib/uaccess.h
View File

@ -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_cmpxchg_std(int *, int __user *, int, int);
extern int futex_atomic_op_std(int, int __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_cmpxchg_pt(int *, int __user *, int, int);
#endif /* __ARCH_S390_LIB_UACCESS_H */

13
arch/s390/lib/uaccess_pt.c
View File

@ -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(int *uval, int __user *uaddr,
int oldval, int 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;
}

6
arch/s390/lib/uaccess_std.c
View File

@ -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(int *uval, int __user *uaddr,
int oldval, int 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;
}

9
arch/sh/include/asm/futex-irq.h
View File

@ -88,7 +88,8 @@ 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,
static inline int atomic_futex_op_cmpxchg_inatomic(int *uval,
int __user *uaddr,
int oldval, int newval)
{
unsigned long flags;
@ -102,10 +103,8 @@ 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 */

5
arch/sh/include/asm/futex.h
View File

@ -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(int *uval, int __user *uaddr,
int oldval, int newval)
{
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
return atomic_futex_op_cmpxchg_inatomic(uaddr, oldval, newval);
return atomic_futex_op_cmpxchg_inatomic(uval, uaddr, oldval, newval);
}
#endif /* __KERNEL__ */

16
arch/sparc/include/asm/futex_64.h
View File

@ -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(int *uval, int __user *uaddr,
int oldval, int 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) */

7
arch/tile/include/asm/futex.h
View File

@ -119,8 +119,8 @@ 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(int *uval, int __user *uaddr,
int oldval, int newval)
{
struct __get_user asm_ret;
@ -128,7 +128,8 @@ static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval,
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__

16
arch/x86/include/asm/futex.h
View File

@ -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(int *uval, int __user *uaddr,
int oldval, int newval)
{
int ret = 0;
#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_BSWAP)
/* Real i386 machines have no cmpxchg instruction */
@ -122,18 +123,19 @@ static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval,
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
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

3
include/asm-generic/futex.h
View File

@ -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(int *uval, int __user *uaddr,
int oldval, int newval)
{
return -ENOSYS;
}

45
kernel/futex.c
View File

@ -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 +2064,8 @@ 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, vpid, 0);
if (unlikely(uval == -EFAULT))
if (!(uval & FUTEX_OWNER_DIED) &&
cmpxchg_futex_value_locked(&uval, uaddr, vpid, 0))
goto pi_faulted;
/*
* Rare case: we managed to release the lock atomically,
@ -2464,9 +2452,7 @@ 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 +2665,7 @@ 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++) {