sh: add working futex atomic ops on userspace addresses for smp

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>

1 files changed, 41 insertions, 0 deletions

diff --git a/arch/sh/include/asm/futex-llsc.h b/arch/sh/include/asm/futex-llsc.h
new file mode 100644
index 000000000000..23591703bec0
--- /dev/null
+++ b/arch/sh/include/asm/futex-llsc.h
@@ -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 */