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sh: add working futex atomic ops on userspace addresses for smp
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The version of futex.h in asm-generic should really be adapted to do
the same thing so that this hideous code does not have to be
duplicated per-arch.

Signed-off-by: Rich Felker <dalias@libc.org>
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Rich Felker committed Aug 5, 2016
1 parent 2b47d54 commit 00b73d8
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Showing 4 changed files with 134 additions and 124 deletions.
34 changes: 34 additions & 0 deletions arch/sh/include/asm/futex-cas.h
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@@ -0,0 +1,34 @@
#ifndef __ASM_SH_FUTEX_CAS_H
#define __ASM_SH_FUTEX_CAS_H

static inline int atomic_futex_op_cmpxchg_inatomic(u32 *uval,
u32 __user *uaddr,
u32 oldval, u32 newval)
{
int err = 0;
__asm__ __volatile__(
"1:\n\t"
"cas.l %2, %1, @r0\n"
"2:\n\t"
#ifdef CONFIG_MMU
".section .fixup,\"ax\"\n"
"3:\n\t"
"mov.l 4f, %0\n\t"
"jmp @%0\n\t"
" mov %3, %0\n\t"
".balign 4\n"
"4: .long 2b\n\t"
".previous\n"
".section __ex_table,\"a\"\n\t"
".long 1b, 3b\n\t"
".previous"
#endif
:"+r" (err), "+r" (newval)
:"r" (oldval), "i" (-EFAULT), "z" (uaddr)
:"t", "memory");
if (err) return err;
*uval = newval;
return 0;
}

#endif /* __ASM_SH_FUTEX_CAS_H */
86 changes: 0 additions & 86 deletions arch/sh/include/asm/futex-irq.h
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Original file line number Diff line number Diff line change
@@ -1,92 +1,6 @@
#ifndef __ASM_SH_FUTEX_IRQ_H
#define __ASM_SH_FUTEX_IRQ_H


static inline int atomic_futex_op_xchg_set(int oparg, u32 __user *uaddr,
int *oldval)
{
unsigned long flags;
int ret;

local_irq_save(flags);

ret = get_user(*oldval, uaddr);
if (!ret)
ret = put_user(oparg, uaddr);

local_irq_restore(flags);

return ret;
}

static inline int atomic_futex_op_xchg_add(int oparg, u32 __user *uaddr,
int *oldval)
{
unsigned long flags;
int ret;

local_irq_save(flags);

ret = get_user(*oldval, uaddr);
if (!ret)
ret = put_user(*oldval + oparg, uaddr);

local_irq_restore(flags);

return ret;
}

static inline int atomic_futex_op_xchg_or(int oparg, u32 __user *uaddr,
int *oldval)
{
unsigned long flags;
int ret;

local_irq_save(flags);

ret = get_user(*oldval, uaddr);
if (!ret)
ret = put_user(*oldval | oparg, uaddr);

local_irq_restore(flags);

return ret;
}

static inline int atomic_futex_op_xchg_and(int oparg, u32 __user *uaddr,
int *oldval)
{
unsigned long flags;
int ret;

local_irq_save(flags);

ret = get_user(*oldval, uaddr);
if (!ret)
ret = put_user(*oldval & oparg, uaddr);

local_irq_restore(flags);

return ret;
}

static inline int atomic_futex_op_xchg_xor(int oparg, u32 __user *uaddr,
int *oldval)
{
unsigned long flags;
int ret;

local_irq_save(flags);

ret = get_user(*oldval, uaddr);
if (!ret)
ret = put_user(*oldval ^ oparg, uaddr);

local_irq_restore(flags);

return ret;
}

static inline int atomic_futex_op_cmpxchg_inatomic(u32 *uval,
u32 __user *uaddr,
u32 oldval, u32 newval)
Expand Down
41 changes: 41 additions & 0 deletions arch/sh/include/asm/futex-llsc.h
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@@ -0,0 +1,41 @@
#ifndef __ASM_SH_FUTEX_LLSC_H
#define __ASM_SH_FUTEX_LLSC_H

static inline int atomic_futex_op_cmpxchg_inatomic(u32 *uval,
u32 __user *uaddr,
u32 oldval, u32 newval)
{
int err = 0;
__asm__ __volatile__(
"synco\n"
"1:\n\t"
"movli.l @%2, r0\n\t"
"mov r0, %1\n\t"
"cmp/eq %1, %4\n\t"
"bf 2f\n\t"
"mov %5, r0\n\t"
"movco.l r0, @%2\n\t"
"bf 1b\n"
"2:\n\t"
"synco\n\t"
#ifdef CONFIG_MMU
".section .fixup,\"ax\"\n"
"3:\n\t"
"mov.l 4f, %0\n\t"
"jmp @%0\n\t"
" mov %3, %0\n\t"
".balign 4\n"
"4: .long 2b\n\t"
".previous\n"
".section __ex_table,\"a\"\n\t"
".long 1b, 3b\n\t"
".previous"
#endif
:"+r" (err), "=&r" (*uval)
:"r" (uaddr), "i" (-EFAULT), "r" (oldval), "r" (newval)
:"t", "memory", "r0");
if (err) return err;
return 0;
}

#endif /* __ASM_SH_FUTEX_LLSC_H */
97 changes: 59 additions & 38 deletions arch/sh/include/asm/futex.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,16 +7,34 @@
#include <linux/uaccess.h>
#include <asm/errno.h>

/* XXX: UP variants, fix for SH-4A and SMP.. */
#if !defined(CONFIG_SMP)
#include <asm/futex-irq.h>
#elif defined(CONFIG_CPU_J2)
#include <asm/futex-cas.h>
#elif defined(CONFIG_CPU_SH4A)
#include <asm/futex-llsc.h>
#else
#error SMP not supported on this configuration.
#endif

static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;

return atomic_futex_op_cmpxchg_inatomic(uval, uaddr, oldval, newval);
}

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;
u32 oparg = (encoded_op << 8) >> 20;
u32 cmparg = (encoded_op << 20) >> 20;
u32 oldval, newval, prev;
int ret;

if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
oparg = 1 << oparg;
Expand All @@ -26,53 +44,56 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)

pagefault_disable();

switch (op) {
case FUTEX_OP_SET:
ret = atomic_futex_op_xchg_set(oparg, uaddr, &oldval);
break;
case FUTEX_OP_ADD:
ret = atomic_futex_op_xchg_add(oparg, uaddr, &oldval);
break;
case FUTEX_OP_OR:
ret = atomic_futex_op_xchg_or(oparg, uaddr, &oldval);
break;
case FUTEX_OP_ANDN:
ret = atomic_futex_op_xchg_and(~oparg, uaddr, &oldval);
break;
case FUTEX_OP_XOR:
ret = atomic_futex_op_xchg_xor(oparg, uaddr, &oldval);
break;
default:
ret = -ENOSYS;
break;
}
do {
if (op == FUTEX_OP_SET)
ret = oldval = 0;
else
ret = get_user(oldval, uaddr);

if (ret) break;

switch (op) {
case FUTEX_OP_SET:
newval = oparg;
break;
case FUTEX_OP_ADD:
newval = oldval + oparg;
break;
case FUTEX_OP_OR:
newval = oldval | oparg;
break;
case FUTEX_OP_ANDN:
newval = oldval & ~oparg;
break;
case FUTEX_OP_XOR:
newval = oldval ^ oparg;
break;
default:
ret = -ENOSYS;
break;
}

if (ret) break;

ret = futex_atomic_cmpxchg_inatomic(&prev, uaddr, oldval, newval);
} while (!ret && prev != oldval);

pagefault_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;
case FUTEX_OP_CMP_LT: ret = ((int)oldval < (int)cmparg); break;
case FUTEX_OP_CMP_GE: ret = ((int)oldval >= (int)cmparg); break;
case FUTEX_OP_CMP_LE: ret = ((int)oldval <= (int)cmparg); break;
case FUTEX_OP_CMP_GT: ret = ((int)oldval > (int)cmparg); break;
default: ret = -ENOSYS;
}
}

return ret;
}

static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;

return atomic_futex_op_cmpxchg_inatomic(uval, uaddr, oldval, newval);
}

#endif /* __KERNEL__ */
#endif /* __ASM_SH_FUTEX_H */

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