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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
x86/futex: Convert to scoped user access
Replace the open coded implementation with the scoped user access
guards
No functional change intended.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://patch.msgid.link/20251027083745.799714344@linutronix.de
authored by
Thomas Gleixner
and committed by
Ingo Molnar
e02718c9
e4e28fd6
+33
-42
+33
-42
arch/x86/include/asm/futex.h
+33
-42
arch/x86/include/asm/futex.h
···
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} while(0)
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static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
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u32 __user *uaddr)
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u32 __user *uaddr)
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{
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if (can_do_masked_user_access())
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uaddr = masked_user_access_begin(uaddr);
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else if (!user_access_begin(uaddr, sizeof(u32)))
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return -EFAULT;
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-
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switch (op) {
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case FUTEX_OP_SET:
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unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault);
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break;
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case FUTEX_OP_ADD:
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unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval,
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uaddr, oparg, Efault);
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break;
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case FUTEX_OP_OR:
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unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault);
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break;
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case FUTEX_OP_ANDN:
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unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault);
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break;
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case FUTEX_OP_XOR:
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unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault);
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break;
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default:
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user_access_end();
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return -ENOSYS;
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scoped_user_rw_access(uaddr, Efault) {
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switch (op) {
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case FUTEX_OP_SET:
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unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault);
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break;
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case FUTEX_OP_ADD:
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unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval, uaddr, oparg, Efault);
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break;
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case FUTEX_OP_OR:
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unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault);
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break;
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case FUTEX_OP_ANDN:
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unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault);
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break;
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case FUTEX_OP_XOR:
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unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault);
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break;
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default:
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return -ENOSYS;
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}
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}
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user_access_end();
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return 0;
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Efault:
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user_access_end();
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return -EFAULT;
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}
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···
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{
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int ret = 0;
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if (can_do_masked_user_access())
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uaddr = masked_user_access_begin(uaddr);
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else if (!user_access_begin(uaddr, sizeof(u32)))
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return -EFAULT;
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asm volatile("\n"
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"1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"
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"2:\n"
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_ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0) \
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: "+r" (ret), "=a" (oldval), "+m" (*uaddr)
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: "r" (newval), "1" (oldval)
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: "memory"
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);
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user_access_end();
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*uval = oldval;
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scoped_user_rw_access(uaddr, Efault) {
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asm_inline volatile("\n"
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"1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"
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"2:\n"
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_ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0)
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: "+r" (ret), "=a" (oldval), "+m" (*uaddr)
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: "r" (newval), "1" (oldval)
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: "memory");
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*uval = oldval;
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}
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return ret;
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Efault:
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return -EFAULT;
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}
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#endif