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-rw-r--r--arch/unicore32/lib/clear_user.S57
1 files changed, 57 insertions, 0 deletions
diff --git a/arch/unicore32/lib/clear_user.S b/arch/unicore32/lib/clear_user.S
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+++ b/arch/unicore32/lib/clear_user.S
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+/*
+ * linux/arch/unicore32/lib/clear_user.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * 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.
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+ .text
+
+/* Prototype: int __clear_user(void *addr, size_t sz)
+ * Purpose : clear some user memory
+ * Params : addr - user memory address to clear
+ * : sz - number of bytes to clear
+ * Returns : number of bytes NOT cleared
+ */
+WEAK(__clear_user)
+ stm.w (lr), [sp-]
+ stm.w (r1), [sp-]
+ mov r2, #0
+ csub.a r1, #4
+ bsl 2f
+ and.a ip, r0, #3
+ beq 1f
+ csub.a ip, #2
+ strusr r2, r0, 1
+ strusr r2, r0, 1, el
+ strusr r2, r0, 1, sl
+ rsub ip, ip, #4
+ sub r1, r1, ip @ 7 6 5 4 3 2 1
+1: sub.a r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
+ strusr r2, r0, 4, ns, rept=2
+ bns 1b
+ add.a r1, r1, #4 @ 3 2 1 0 -1 -2 -3
+ strusr r2, r0, 4, ns
+2: cand.a r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
+ strusr r2, r0, 1, ne, rept=2
+ cand.a r1, #1 @ x1 x0 x1 x0 x1 x0 x1
+ beq 3f
+USER( stb.u r2, [r0])
+3: mov r0, #0
+ ldm.w (r1), [sp]+
+ ldm.w (pc), [sp]+
+ENDPROC(__clear_user)
+
+ .pushsection .fixup,"ax"
+ .align 0
+9001: ldm.w (r0), [sp]+
+ ldm.w (pc), [sp]+
+ .popsection
+