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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 1/2] make fls() and ffs() consistent across architectures
Their parameter types differed between ARM and x86.
Along with generalizing the functions this fixes
- x86's non-long functions having long parameter types
- ARM's ffs() using a long intermediate variable
- generic_fls64() being broken when the upper half of the input is
non-zero
- common (and in one case also ARM) code using fls() when flsl() was
meant
Also drop ARM's constant_fls() in favor of the identical generic_fls().
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
--- unstable.orig/xen/common/page_alloc.c 2014-11-07 17:16:38.000000000
+0100
+++ unstable/xen/common/page_alloc.c 2015-01-21 08:53:14.000000000 +0100
@@ -278,7 +278,7 @@ unsigned long __init alloc_boot_pages(
#define bits_to_zone(b) (((b) < (PAGE_SHIFT + 1)) ? 1 : ((b) - PAGE_SHIFT))
#define page_to_zone(pg) (is_xen_heap_page(pg) ? MEMZONE_XEN : \
- (fls(page_to_mfn(pg)) ? : 1))
+ (flsl(page_to_mfn(pg)) ? : 1))
typedef struct page_list_head heap_by_zone_and_order_t[NR_ZONES][MAX_ORDER+1];
static heap_by_zone_and_order_t *_heap[MAX_NUMNODES];
@@ -1259,7 +1259,7 @@ void __init end_boot_allocator(void)
{
#ifdef CONFIG_X86
dma_bitsize = min_t(unsigned int,
- fls(NODE_DATA(0)->node_spanned_pages) - 1
+ flsl(NODE_DATA(0)->node_spanned_pages) - 1
+ PAGE_SHIFT - 2,
32);
#else
@@ -1544,7 +1544,7 @@ static unsigned int __read_mostly xenhea
void __init xenheap_max_mfn(unsigned long mfn)
{
- xenheap_bits = fls(mfn) + PAGE_SHIFT;
+ xenheap_bits = flsl(mfn) + PAGE_SHIFT;
}
void init_xenheap_pages(paddr_t ps, paddr_t pe)
--- unstable.orig/xen/common/xmalloc_tlsf.c 2015-01-22 13:28:41.000000000
+0100
+++ unstable/xen/common/xmalloc_tlsf.c 2015-01-21 08:53:05.000000000 +0100
@@ -138,9 +138,9 @@ static inline void MAPPING_SEARCH(unsign
}
else
{
- t = (1 << (fls(*r) - 1 - MAX_LOG2_SLI)) - 1;
+ t = (1 << (flsl(*r) - 1 - MAX_LOG2_SLI)) - 1;
*r = *r + t;
- *fl = fls(*r) - 1;
+ *fl = flsl(*r) - 1;
*sl = (*r >> (*fl - MAX_LOG2_SLI)) - MAX_SLI;
*fl -= FLI_OFFSET;
/*if ((*fl -= FLI_OFFSET) < 0) // FL will be always >0!
@@ -164,7 +164,7 @@ static inline void MAPPING_INSERT(unsign
}
else
{
- *fl = fls(r) - 1;
+ *fl = flsl(r) - 1;
*sl = (r >> (*fl - MAX_LOG2_SLI)) - MAX_SLI;
*fl -= FLI_OFFSET;
}
--- unstable.orig/xen/include/asm-arm/arm32/bitops.h 2015-01-22
13:28:41.000000000 +0100
+++ unstable/xen/include/asm-arm/arm32/bitops.h 2015-01-21 10:06:01.000000000
+0100
@@ -15,6 +15,8 @@ extern int _test_and_change_bit(int nr,
#define test_and_clear_bit(n,p) _test_and_clear_bit(n,p)
#define test_and_change_bit(n,p) _test_and_change_bit(n,p)
+#define flsl fls
+
/*
* Little endian assembly bitops. nr = 0 -> byte 0 bit 0.
*/
--- unstable.orig/xen/include/asm-arm/arm64/bitops.h 2015-01-22
13:28:41.000000000 +0100
+++ unstable/xen/include/asm-arm/arm64/bitops.h 2015-01-21 08:28:43.000000000
+0100
@@ -32,6 +32,17 @@ static /*__*/always_inline unsigned long
*/
#define ffz(x) __ffs(~(x))
+static inline int flsl(unsigned long x)
+{
+ int ret;
+
+ if (__builtin_constant_p(x))
+ return generic_flsl(x);
+
+ asm("clz\t%0, %1" : "=r" (ret) : "r" (x));
+ return BITS_PER_LONG - ret;
+}
+
/* Based on linux/include/asm-generic/bitops/find.h */
#ifndef find_next_bit
--- unstable.orig/xen/include/asm-arm/bitops.h 2015-01-22 13:28:41.000000000
+0100
+++ unstable/xen/include/asm-arm/bitops.h 2015-01-22 13:30:17.000000000
+0100
@@ -99,46 +99,17 @@ static inline int test_bit(int nr, const
return 1UL & (p[BIT_WORD(nr)] >> (nr & (BITS_PER_WORD-1)));
}
-static inline int constant_fls(int x)
-{
- int r = 32;
-
- if (!x)
- return 0;
- if (!(x & 0xffff0000u)) {
- x <<= 16;
- r -= 16;
- }
- if (!(x & 0xff000000u)) {
- x <<= 8;
- r -= 8;
- }
- if (!(x & 0xf0000000u)) {
- x <<= 4;
- r -= 4;
- }
- if (!(x & 0xc0000000u)) {
- x <<= 2;
- r -= 2;
- }
- if (!(x & 0x80000000u)) {
- x <<= 1;
- r -= 1;
- }
- return r;
-}
-
/*
* On ARMv5 and above those functions can be implemented around
* the clz instruction for much better code efficiency.
*/
-static inline int fls(int x)
+static inline int fls(unsigned int x)
{
int ret;
if (__builtin_constant_p(x))
- return constant_fls(x);
+ return generic_fls(x);
asm("clz\t%0, %1" : "=r" (ret) : "r" (x));
ret = BITS_PER_LONG - ret;
@@ -146,7 +117,8 @@ static inline int fls(int x)
}
-#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })
+#define ffs(x) ({ unsigned int __t = (x); fls(__t & -__t); })
+#define ffsl(x) ({ unsigned long __t = (x); flsl(__t & -__t); })
/**
* find_first_set_bit - find the first set bit in @word
@@ -157,7 +129,7 @@ static inline int fls(int x)
*/
static inline unsigned int find_first_set_bit(unsigned long word)
{
- return ffs(word) - 1;
+ return ffsl(word) - 1;
}
/**
--- unstable.orig/xen/include/asm-x86/bitops.h 2014-09-15 15:42:35.000000000
+0200
+++ unstable/xen/include/asm-x86/bitops.h 2015-01-22 13:30:02.000000000
+0100
@@ -401,7 +401,7 @@ static inline unsigned int find_first_se
*
* This is defined the same way as the libc and compiler builtin ffs routines.
*/
-static inline int ffs(unsigned long x)
+static inline int ffsl(unsigned long x)
{
long r;
@@ -412,13 +412,24 @@ static inline int ffs(unsigned long x)
return (int)r+1;
}
+static inline int ffs(unsigned int x)
+{
+ int r;
+
+ asm ( "bsf %1,%0\n\t"
+ "jnz 1f\n\t"
+ "mov $-1,%0\n"
+ "1:" : "=r" (r) : "rm" (x));
+ return r + 1;
+}
+
/**
* fls - find last bit set
* @x: the word to search
*
* This is defined the same way as ffs.
*/
-static inline int fls(unsigned long x)
+static inline int flsl(unsigned long x)
{
long r;
@@ -429,8 +440,16 @@ static inline int fls(unsigned long x)
return (int)r+1;
}
-#define ffs64 ffs
-#define fls64 fls
+static inline int fls(unsigned int x)
+{
+ int r;
+
+ asm ( "bsr %1,%0\n\t"
+ "jnz 1f\n\t"
+ "mov $-1,%0\n"
+ "1:" : "=r" (r) : "rm" (x));
+ return r + 1;
+}
/**
* hweightN - returns the hamming weight of a N-bit word
--- unstable.orig/xen/include/xen/bitops.h 2015-01-22 13:28:41.000000000
+0100
+++ unstable/xen/include/xen/bitops.h 2015-01-22 13:30:46.000000000 +0100
@@ -70,20 +70,52 @@ static __inline__ int generic_fls(int x)
return r;
}
+#if BITS_PER_LONG == 64
+
+static inline int generic_ffsl(unsigned long x)
+{
+ return !x || (u32)x ? generic_ffs(x) : generic_ffs(x >> 32) + 32;
+}
+
+static inline int generic_flsl(unsigned long x)
+{
+ u32 h = x >> 32;
+
+ return h ? generic_fls(h) + 32 : generic_fls(x);
+}
+
+#else
+# define generic_ffsl generic_ffs
+# define generic_flsl generic_fls
+#endif
+
/*
* Include this here because some architectures need generic_ffs/fls in
* scope
*/
#include <asm/bitops.h>
-
+#if BITS_PER_LONG == 64
+# define fls64 flsl
+# define ffs64 ffsl
+#else
+# ifndef ffs64
+static inline int generic_ffs64(__u64 x)
+{
+ return !x || (__u32)x ? ffs(x) : ffs(x >> 32) + 32;
+}
+# define ffs64 generic_ffs64
+# endif
+# ifndef fls64
static inline int generic_fls64(__u64 x)
{
__u32 h = x >> 32;
- if (h)
- return fls(x) + 32;
- return fls(x);
+
+ return h ? fls(h) + 32 : fls(x);
}
+# define fls64 generic_fls64
+# endif
+#endif
static __inline__ int get_bitmask_order(unsigned int count)
{
Attachment:
fls-ffs.patch _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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