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riscv: bitops: Use riscv_has_extension_likely

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Use riscv_has_extension_likely() to check for RISCV_ISA_EXT_ZBB,
replacing the use of asm goto with ALTERNATIVE.

The "likely" variant is used to match the behavior of the original
implementation using ALTERNATIVE("j %l[legacy]", "nop", ...).

Signed-off-by: Vivian Wang <wangruikang@iscas.ac.cn>
Link: https://patch.msgid.link/20251020-riscv-altn-helper-wip-v4-4-ef941c87669a@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>
This commit is contained in:
Vivian Wang
2025-11-17 21:19:22 -07:00
committed by Paul Walmsley
parent 8261a9d167
commit 6b85e9ac4a
1 changed files with 8 additions and 24 deletions
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32
arch/riscv/include/asm/bitops.h
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@@ -47,9 +47,8 @@
static __always_inline __attribute_const__ unsigned long variable__ffs(unsigned long word)
{
asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
if (!riscv_has_extension_likely(RISCV_ISA_EXT_ZBB))
return generic___ffs(word);
asm volatile (".option push\n"
".option arch,+zbb\n"
@@ -58,9 +57,6 @@ static __always_inline __attribute_const__ unsigned long variable__ffs(unsigned
: "=r" (word) : "r" (word) :);
return word;
legacy:
return generic___ffs(word);
}
/**
@@ -76,9 +72,8 @@ legacy:
static __always_inline __attribute_const__ unsigned long variable__fls(unsigned long word)
{
asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
if (!riscv_has_extension_likely(RISCV_ISA_EXT_ZBB))
return generic___fls(word);
asm volatile (".option push\n"
".option arch,+zbb\n"
@@ -87,9 +82,6 @@ static __always_inline __attribute_const__ unsigned long variable__fls(unsigned
: "=r" (word) : "r" (word) :);
return BITS_PER_LONG - 1 - word;
legacy:
return generic___fls(word);
}
/**
@@ -105,9 +97,8 @@ legacy:
static __always_inline __attribute_const__ int variable_ffs(int x)
{
asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
if (!riscv_has_extension_likely(RISCV_ISA_EXT_ZBB))
return generic_ffs(x);
if (!x)
return 0;
@@ -119,9 +110,6 @@ static __always_inline __attribute_const__ int variable_ffs(int x)
: "=r" (x) : "r" (x) :);
return x + 1;
legacy:
return generic_ffs(x);
}
/**
@@ -137,9 +125,8 @@ legacy:
static __always_inline int variable_fls(unsigned int x)
{
asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
RISCV_ISA_EXT_ZBB, 1)
: : : : legacy);
if (!riscv_has_extension_likely(RISCV_ISA_EXT_ZBB))
return generic_fls(x);
if (!x)
return 0;
@@ -151,9 +138,6 @@ static __always_inline int variable_fls(unsigned int x)
: "=r" (x) : "r" (x) :);
return 32 - x;
legacy:
return generic_fls(x);
}
/**