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Subject[PATCH 4/5] __div64_32(): make it overridable at compile time
Date
Some architectures may want to override the default implementation
at compile time to do things inline. For example, ARM uses a
non-standard calling convention for better efficiency in this case.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
---
include/asm-generic/div64.h | 2 ++
lib/div64.c | 6 ++++--
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h
index 34722c5a80..6daad94055 100644
--- a/include/asm-generic/div64.h
+++ b/include/asm-generic/div64.h
@@ -204,7 +204,9 @@ static inline uint64_t __arch_xprod_64(const uint64_t m, uint64_t n, bool bias)
}
#endif

+#ifndef __div64_32
extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
+#endif

/* The unnecessary pointer compare is there
* to check for type safety (n must be 64bit)
diff --git a/lib/div64.c b/lib/div64.c
index 19ea7ed4b9..69df4f6d52 100644
--- a/lib/div64.c
+++ b/lib/div64.c
@@ -13,7 +13,8 @@
*
* Code generated for this function might be very inefficient
* for some CPUs. __div64_32() can be overridden by linking arch-specific
- * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S.
+ * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S
+ * or by defining a preprocessor macro in arch/include/asm/div64.h.
*/

#include <linux/export.h>
@@ -23,6 +24,7 @@
/* Not needed on 64bit architectures */
#if BITS_PER_LONG == 32

+#ifndef __div64_32
uint32_t __attribute__((weak)) __div64_32(uint64_t *n, uint32_t base)
{
uint64_t rem = *n;
@@ -55,8 +57,8 @@ uint32_t __attribute__((weak)) __div64_32(uint64_t *n, uint32_t base)
*n = res;
return rem;
}
-
EXPORT_SYMBOL(__div64_32);
+#endif

#ifndef div_s64_rem
s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
--
2.4.3


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