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Commit cb4ede92 authored by Xiao Wang's avatar Xiao Wang Committed by Palmer Dabbelt
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riscv: Avoid code duplication with generic bitops implementation 

There's code duplication between the fallback implementation for bitops
__ffs/__fls/ffs/fls API and the generic C implementation in
include/asm-generic/bitops/. To avoid this duplication, this patch renames
the generic C implementation by adding a "generic_" prefix to them, then we
can use these generic APIs as fallback.
Suggested-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarXiao Wang <xiao.w.wang@intel.com>
Reviewed-by: default avatarCharlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20231112094421.4014931-1-xiao.w.wang@intel.comSigned-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 05d450aa
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Showing with 48 additions and 122 deletions
arch/riscv/include/asm/bitops.h
View file @ cb4ede92
......@@ -22,6 +22,16 @@
#include <asm-generic/bitops/fls.h>
#else
#define __HAVE_ARCH___FFS
#define __HAVE_ARCH___FLS
#define __HAVE_ARCH_FFS
#define __HAVE_ARCH_FLS
#include <asm-generic/bitops/__ffs.h>
#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/ffs.h>
#include <asm-generic/bitops/fls.h>
#include <asm/alternative-macros.h>
#include <asm/hwcap.h>
......@@ -37,8 +47,6 @@
static __always_inline unsigned long variable__ffs(unsigned long word)
{
int num;
asm_volatile_goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
......@@ -52,32 +60,7 @@ static __always_inline unsigned long variable__ffs(unsigned long word)
return word;
legacy:
num = 0;
#if BITS_PER_LONG == 64
if ((word & 0xffffffff) == 0) {
num += 32;
word >>= 32;
}
#endif
if ((word & 0xffff) == 0) {
num += 16;
word >>= 16;
}
if ((word & 0xff) == 0) {
num += 8;
word >>= 8;
}
if ((word & 0xf) == 0) {
num += 4;
word >>= 4;
}
if ((word & 0x3) == 0) {
num += 2;
word >>= 2;
}
if ((word & 0x1) == 0)
num += 1;
return num;
return generic___ffs(word);
}
/**
......@@ -93,8 +76,6 @@ static __always_inline unsigned long variable__ffs(unsigned long word)
static __always_inline unsigned long variable__fls(unsigned long word)
{
int num;
asm_volatile_goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
......@@ -108,32 +89,7 @@ static __always_inline unsigned long variable__fls(unsigned long word)
return BITS_PER_LONG - 1 - word;
legacy:
num = BITS_PER_LONG - 1;
#if BITS_PER_LONG == 64
if (!(word & (~0ul << 32))) {
num -= 32;
word <<= 32;
}
#endif
if (!(word & (~0ul << (BITS_PER_LONG - 16)))) {
num -= 16;
word <<= 16;
}
if (!(word & (~0ul << (BITS_PER_LONG - 8)))) {
num -= 8;
word <<= 8;
}
if (!(word & (~0ul << (BITS_PER_LONG - 4)))) {
num -= 4;
word <<= 4;
}
if (!(word & (~0ul << (BITS_PER_LONG - 2)))) {
num -= 2;
word <<= 2;
}
if (!(word & (~0ul << (BITS_PER_LONG - 1))))
num -= 1;
return num;
return generic___fls(word);
}
/**
......@@ -149,46 +105,23 @@ static __always_inline unsigned long variable__fls(unsigned long word)
static __always_inline int variable_ffs(int x)
{
int r;
if (!x)
return 0;
asm_volatile_goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
if (!x)
return 0;
asm volatile (".option push\n"
".option arch,+zbb\n"
CTZW "%0, %1\n"
".option pop\n"
: "=r" (r) : "r" (x) :);
: "=r" (x) : "r" (x) :);
return r + 1;
return x + 1;
legacy:
r = 1;
if (!(x & 0xffff)) {
x >>= 16;
r += 16;
}
if (!(x & 0xff)) {
x >>= 8;
r += 8;
}
if (!(x & 0xf)) {
x >>= 4;
r += 4;
}
if (!(x & 3)) {
x >>= 2;
r += 2;
}
if (!(x & 1)) {
x >>= 1;
r += 1;
}
return r;
return generic_ffs(x);
}
/**
......@@ -204,46 +137,23 @@ static __always_inline int variable_ffs(int x)
static __always_inline int variable_fls(unsigned int x)
{
int r;
if (!x)
return 0;
asm_volatile_goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
if (!x)
return 0;
asm volatile (".option push\n"
".option arch,+zbb\n"
CLZW "%0, %1\n"
".option pop\n"
: "=r" (r) : "r" (x) :);
: "=r" (x) : "r" (x) :);
return 32 - r;
return 32 - x;
legacy:
r = 32;
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;
return generic_fls(x);
}
/**
......
include/asm-generic/bitops/__ffs.h
View file @ cb4ede92
......@@ -5,12 +5,12 @@
#include <asm/types.h>
/**
* __ffs - find first bit in word.
* generic___ffs - find first bit in word.
* @word: The word to search
*
* Undefined if no bit exists, so code should check against 0 first.
*/
static __always_inline unsigned long __ffs(unsigned long word)
static __always_inline unsigned long generic___ffs(unsigned long word)
{
int num = 0;
......@@ -41,4 +41,8 @@ static __always_inline unsigned long __ffs(unsigned long word)
return num;
}
#ifndef __HAVE_ARCH___FFS
#define __ffs(word) generic___ffs(word)
#endif
#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */
include/asm-generic/bitops/__fls.h
View file @ cb4ede92
......@@ -5,12 +5,12 @@
#include <asm/types.h>
/**
* __fls - find last (most-significant) set bit in a long word
* generic___fls - find last (most-significant) set bit in a long word
* @word: the word to search
*
* Undefined if no set bit exists, so code should check against 0 first.
*/
static __always_inline unsigned long __fls(unsigned long word)
static __always_inline unsigned long generic___fls(unsigned long word)
{
int num = BITS_PER_LONG - 1;
......@@ -41,4 +41,8 @@ static __always_inline unsigned long __fls(unsigned long word)
return num;
}
#ifndef __HAVE_ARCH___FLS
#define __fls(word) generic___fls(word)
#endif
#endif /* _ASM_GENERIC_BITOPS___FLS_H_ */
include/asm-generic/bitops/ffs.h
View file @ cb4ede92
......@@ -3,14 +3,14 @@
#define _ASM_GENERIC_BITOPS_FFS_H_
/**
* ffs - find first bit set
* generic_ffs - find first bit set
* @x: the word to search
*
* This is defined the same way as
* the libc and compiler builtin ffs routines, therefore
* differs in spirit from ffz (man ffs).
*/
static inline int ffs(int x)
static inline int generic_ffs(int x)
{
int r = 1;
......@@ -39,4 +39,8 @@ static inline int ffs(int x)
return r;
}
#ifndef __HAVE_ARCH_FFS
#define ffs(x) generic_ffs(x)
#endif
#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */
include/asm-generic/bitops/fls.h
View file @ cb4ede92
......@@ -3,14 +3,14 @@
#define _ASM_GENERIC_BITOPS_FLS_H_
/**
* fls - find last (most-significant) bit set
* generic_fls - find last (most-significant) bit set
* @x: the word to search
*
* This is defined the same way as ffs.
* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
*/
static __always_inline int fls(unsigned int x)
static __always_inline int generic_fls(unsigned int x)
{
int r = 32;
......@@ -39,4 +39,8 @@ static __always_inline int fls(unsigned int x)
return r;
}
#ifndef __HAVE_ARCH_FLS
#define fls(x) generic_fls(x)
#endif
#endif /* _ASM_GENERIC_BITOPS_FLS_H_ */
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