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Fix __kuser_cmpxchg inline asm #218

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Merged
merged 1 commit into from
Dec 20, 2017
Merged

Fix __kuser_cmpxchg inline asm #218

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19 changes: 4 additions & 15 deletions src/arm_linux.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,23 +4,12 @@ use core::mem;
// Kernel-provided user-mode helper functions:
// https://www.kernel.org/doc/Documentation/arm/kernel_user_helpers.txt
unsafe fn __kuser_cmpxchg(oldval: u32, newval: u32, ptr: *mut u32) -> bool {
let out: u32;
// FIXME: we can't use BLX on ARMv4
asm!("blx ${0}"
: "={r0}" (out)
: "r" (0xffff0fc0u32)
"{r0}" (oldval),
"{r1}" (newval),
"{r2}" (ptr)
: "r3", "r12", "lr", "cc", "memory");
out == 0
let f: extern "C" fn (u32, u32, *mut u32) -> u32 = mem::transmute(0xffff0fc0u32);
f(oldval, newval, ptr) == 0
}
unsafe fn __kuser_memory_barrier() {
// FIXME: we can't use BLX on ARMv4
asm!("blx ${0}"
:
: "r" (0xffff0fa0u32)
: "lr", "memory");
let f: extern "C" fn () = mem::transmute(0xffff0fa0u32);
f();
}

// Word-align a pointer
Expand Down