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author | Baruch Siach <baruch@tkos.co.il> | 2013-11-18 06:46:43 +0200 |
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committer | Chris Zankel <chris@zankel.net> | 2014-01-14 10:19:51 -0800 |
commit | 220c062688c31bbf992921fca172ddd1e609f8f6 (patch) | |
tree | 1dcc29d05ab14df393f414b20bc9f29b28a1e137 /arch/xtensa | |
parent | a6e16b9aaf0df4b1de8853cad97f387ade9fa8f5 (diff) | |
download | op-kernel-dev-220c062688c31bbf992921fca172ddd1e609f8f6.zip op-kernel-dev-220c062688c31bbf992921fca172ddd1e609f8f6.tar.gz |
xtensa: implement robust futex atomic uaccess ops
This enables the set_robust_list(2) system call.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'arch/xtensa')
-rw-r--r-- | arch/xtensa/include/asm/Kbuild | 1 | ||||
-rw-r--r-- | arch/xtensa/include/asm/futex.h | 147 |
2 files changed, 147 insertions, 1 deletions
diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild index 228d6ae..5851db2 100644 --- a/arch/xtensa/include/asm/Kbuild +++ b/arch/xtensa/include/asm/Kbuild @@ -8,7 +8,6 @@ generic-y += emergency-restart.h generic-y += errno.h generic-y += exec.h generic-y += fcntl.h -generic-y += futex.h generic-y += hardirq.h generic-y += ioctl.h generic-y += irq_regs.h diff --git a/arch/xtensa/include/asm/futex.h b/arch/xtensa/include/asm/futex.h new file mode 100644 index 0000000..b39531b --- /dev/null +++ b/arch/xtensa/include/asm/futex.h @@ -0,0 +1,147 @@ +/* + * Atomic futex routines + * + * Based on the PowerPC implementataion + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Copyright (C) 2013 TangoTec Ltd. + * + * Baruch Siach <baruch@tkos.co.il> + */ + +#ifndef _ASM_XTENSA_FUTEX_H +#define _ASM_XTENSA_FUTEX_H + +#ifdef __KERNEL__ + +#include <linux/futex.h> +#include <linux/uaccess.h> +#include <linux/errno.h> + +#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ + __asm__ __volatile( \ + "1: l32i %0, %2, 0\n" \ + insn "\n" \ + " wsr %0, scompare1\n" \ + "2: s32c1i %1, %2, 0\n" \ + " bne %1, %0, 1b\n" \ + " movi %1, 0\n" \ + "3:\n" \ + " .section .fixup,\"ax\"\n" \ + " .align 4\n" \ + "4: .long 3b\n" \ + "5: l32r %0, 4b\n" \ + " movi %1, %3\n" \ + " jx %0\n" \ + " .previous\n" \ + " .section __ex_table,\"a\"\n" \ + " .long 1b,5b,2b,5b\n" \ + " .previous\n" \ + : "=&r" (oldval), "=&r" (ret) \ + : "r" (uaddr), "I" (-EFAULT), "r" (oparg) \ + : "memory") + +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; + int oparg = (encoded_op << 8) >> 20; + int cmparg = (encoded_op << 20) >> 20; + int oldval = 0, ret; + if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) + oparg = 1 << oparg; + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + return -EFAULT; + +#if !XCHAL_HAVE_S32C1I + return -ENOSYS; +#endif + + pagefault_disable(); + + switch (op) { + case FUTEX_OP_SET: + __futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg); + break; + case FUTEX_OP_ADD: + __futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr, + oparg); + break; + case FUTEX_OP_OR: + __futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr, + oparg); + break; + case FUTEX_OP_ANDN: + __futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr, + ~oparg); + break; + case FUTEX_OP_XOR: + __futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr, + oparg); + break; + default: + ret = -ENOSYS; + } + + pagefault_enable(); + + if (ret) + return ret; + + switch (cmp) { + case FUTEX_OP_CMP_EQ: return (oldval == cmparg); + case FUTEX_OP_CMP_NE: return (oldval != cmparg); + case FUTEX_OP_CMP_LT: return (oldval < cmparg); + case FUTEX_OP_CMP_GE: return (oldval >= cmparg); + case FUTEX_OP_CMP_LE: return (oldval <= cmparg); + case FUTEX_OP_CMP_GT: return (oldval > cmparg); + } + + return -ENOSYS; +} + +static inline int +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, + u32 oldval, u32 newval) +{ + int ret = 0; + u32 prev; + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + return -EFAULT; + +#if !XCHAL_HAVE_S32C1I + return -ENOSYS; +#endif + + __asm__ __volatile__ ( + " # futex_atomic_cmpxchg_inatomic\n" + "1: l32i %1, %3, 0\n" + " mov %0, %5\n" + " wsr %1, scompare1\n" + "2: s32c1i %0, %3, 0\n" + "3:\n" + " .section .fixup,\"ax\"\n" + " .align 4\n" + "4: .long 3b\n" + "5: l32r %1, 4b\n" + " movi %0, %6\n" + " jx %1\n" + " .previous\n" + " .section __ex_table,\"a\"\n" + " .long 1b,5b,2b,5b\n" + " .previous\n" + : "+r" (ret), "=&r" (prev), "+m" (*uaddr) + : "r" (uaddr), "r" (oldval), "r" (newval), "I" (-EFAULT) + : "memory"); + + *uval = prev; + return ret; +} + +#endif /* __KERNEL__ */ +#endif /* _ASM_XTENSA_FUTEX_H */ |