diff options
Diffstat (limited to 'arch/arm/include/asm/futex.h')
| -rw-r--r-- | arch/arm/include/asm/futex.h | 81 |
1 files changed, 46 insertions, 35 deletions
diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h index e42cf597f6e6..a9151884bc85 100644 --- a/arch/arm/include/asm/futex.h +++ b/arch/arm/include/asm/futex.h @@ -1,13 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_ARM_FUTEX_H #define _ASM_ARM_FUTEX_H #ifdef __KERNEL__ -#if defined(CONFIG_CPU_USE_DOMAINS) && defined(CONFIG_SMP) -/* ARM doesn't provide unprivileged exclusive memory accessors */ -#include <asm-generic/futex.h> -#else - #include <linux/futex.h> #include <linux/uaccess.h> #include <asm/errno.h> @@ -18,7 +14,7 @@ " .align 3\n" \ " .long 1b, 4f, 2b, 4f\n" \ " .popsection\n" \ - " .pushsection .fixup,\"ax\"\n" \ + " .pushsection .text.fixup,\"ax\"\n" \ " .align 2\n" \ "4: mov %0, " err_reg "\n" \ " b 3b\n" \ @@ -27,7 +23,11 @@ #ifdef CONFIG_SMP #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ +({ \ + unsigned int __ua_flags; \ smp_mb(); \ + prefetchw(uaddr); \ + __ua_flags = uaccess_save_and_enable(); \ __asm__ __volatile__( \ "1: ldrex %1, [%3]\n" \ " " insn "\n" \ @@ -38,19 +38,25 @@ __futex_atomic_ex_table("%5") \ : "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \ : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ - : "cc", "memory") + : "cc", "memory"); \ + uaccess_restore(__ua_flags); \ +}) static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) { + unsigned int __ua_flags; int ret; u32 val; - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + if (!access_ok(uaddr, sizeof(u32))) return -EFAULT; smp_mb(); + /* Prefetching cannot fault */ + prefetchw(uaddr); + __ua_flags = uaccess_save_and_enable(); __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" "1: ldrex %1, [%4]\n" " teq %1, %2\n" @@ -63,6 +69,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, : "=&r" (ret), "=&r" (val) : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) : "cc", "memory"); + uaccess_restore(__ua_flags); smp_mb(); *uval = val; @@ -75,6 +82,8 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, #include <asm/domain.h> #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ +({ \ + unsigned int __ua_flags = uaccess_save_and_enable(); \ __asm__ __volatile__( \ "1: " TUSER(ldr) " %1, [%3]\n" \ " " insn "\n" \ @@ -83,50 +92,54 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, __futex_atomic_ex_table("%5") \ : "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \ : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ - : "cc", "memory") + : "cc", "memory"); \ + uaccess_restore(__ua_flags); \ +}) static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) { + unsigned int __ua_flags; int ret = 0; u32 val; - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + if (!access_ok(uaddr, sizeof(u32))) return -EFAULT; + preempt_disable(); + __ua_flags = uaccess_save_and_enable(); __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" + " .syntax unified\n" "1: " TUSER(ldr) " %1, [%4]\n" " teq %1, %2\n" " it eq @ explicit IT needed for the 2b label\n" - "2: " TUSER(streq) " %3, [%4]\n" + "2: " TUSERCOND(str, eq) " %3, [%4]\n" __futex_atomic_ex_table("%5") : "+r" (ret), "=&r" (val) : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) : "cc", "memory"); + uaccess_restore(__ua_flags); *uval = val; + preempt_enable(); + return ret; } #endif /* !SMP */ static inline int -futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) +arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr) { - int op = (encoded_op >> 28) & 7; - int cmp = (encoded_op >> 24) & 15; - int oparg = (encoded_op << 8) >> 20; - int cmparg = (encoded_op << 20) >> 20; int oldval = 0, ret, tmp; - if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) - oparg = 1 << oparg; - - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + if (!access_ok(uaddr, sizeof(u32))) return -EFAULT; - pagefault_disable(); /* implies preempt_disable() */ +#ifndef CONFIG_SMP + preempt_disable(); +#endif switch (op) { case FUTEX_OP_SET: @@ -148,22 +161,20 @@ futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) ret = -ENOSYS; } - pagefault_enable(); /* subsumes preempt_enable() */ - - if (!ret) { - switch (cmp) { - case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; - case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; - case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; - case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; - case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; - case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; - default: ret = -ENOSYS; - } - } +#ifndef CONFIG_SMP + preempt_enable(); +#endif + + /* + * Store unconditionally. If ret != 0 the extra store is the least + * of the worries but GCC cannot figure out that __futex_atomic_op() + * is either setting ret to -EFAULT or storing the old value in + * oldval which results in a uninitialized warning at the call site. + */ + *oval = oldval; + return ret; } -#endif /* !(CPU_USE_DOMAINS && SMP) */ #endif /* __KERNEL__ */ #endif /* _ASM_ARM_FUTEX_H */ |