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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/x86/include/asm/div64.h
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/x86/include/asm/div64.h')
-rw-r--r--kernel/arch/x86/include/asm/div64.h66
1 files changed, 66 insertions, 0 deletions
diff --git a/kernel/arch/x86/include/asm/div64.h b/kernel/arch/x86/include/asm/div64.h
new file mode 100644
index 000000000..ced283ac7
--- /dev/null
+++ b/kernel/arch/x86/include/asm/div64.h
@@ -0,0 +1,66 @@
+#ifndef _ASM_X86_DIV64_H
+#define _ASM_X86_DIV64_H
+
+#ifdef CONFIG_X86_32
+
+#include <linux/types.h>
+#include <linux/log2.h>
+
+/*
+ * do_div() is NOT a C function. It wants to return
+ * two values (the quotient and the remainder), but
+ * since that doesn't work very well in C, what it
+ * does is:
+ *
+ * - modifies the 64-bit dividend _in_place_
+ * - returns the 32-bit remainder
+ *
+ * This ends up being the most efficient "calling
+ * convention" on x86.
+ */
+#define do_div(n, base) \
+({ \
+ unsigned long __upper, __low, __high, __mod, __base; \
+ __base = (base); \
+ if (__builtin_constant_p(__base) && is_power_of_2(__base)) { \
+ __mod = n & (__base - 1); \
+ n >>= ilog2(__base); \
+ } else { \
+ asm("" : "=a" (__low), "=d" (__high) : "A" (n));\
+ __upper = __high; \
+ if (__high) { \
+ __upper = __high % (__base); \
+ __high = __high / (__base); \
+ } \
+ asm("divl %2" : "=a" (__low), "=d" (__mod) \
+ : "rm" (__base), "0" (__low), "1" (__upper)); \
+ asm("" : "=A" (n) : "a" (__low), "d" (__high)); \
+ } \
+ __mod; \
+})
+
+static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
+{
+ union {
+ u64 v64;
+ u32 v32[2];
+ } d = { dividend };
+ u32 upper;
+
+ upper = d.v32[1];
+ d.v32[1] = 0;
+ if (upper >= divisor) {
+ d.v32[1] = upper / divisor;
+ upper %= divisor;
+ }
+ asm ("divl %2" : "=a" (d.v32[0]), "=d" (*remainder) :
+ "rm" (divisor), "0" (d.v32[0]), "1" (upper));
+ return d.v64;
+}
+#define div_u64_rem div_u64_rem
+
+#else
+# include <asm-generic/div64.h>
+#endif /* CONFIG_X86_32 */
+
+#endif /* _ASM_X86_DIV64_H */