diff options
| author | Jisheng Zhang <jszhang@kernel.org> | 2021-05-12 22:55:45 +0800 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2021-05-25 22:56:57 -0700 |
| commit | 37a7a2a10ec525a79d733008bc7fe4ebbca34382 (patch) | |
| tree | c4d7257ecfe7a54eec0286b274de15ae56eb68a7 /arch/riscv/kernel | |
| parent | 8237c5243a614d33fe339bc844f90aa2b393c2a8 (diff) | |
riscv: Turn has_fpu into a static key if FPU=y
The has_fpu check sits at hot code path: switch_to(). Currently, has_fpu
is a bool variable if FPU=y, switch_to() checks it each time, we can
optimize out this check by turning the has_fpu into a static key.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv/kernel')
| -rw-r--r-- | arch/riscv/kernel/cpufeature.c | 4 | ||||
| -rw-r--r-- | arch/riscv/kernel/process.c | 2 | ||||
| -rw-r--r-- | arch/riscv/kernel/signal.c | 4 |
3 files changed, 5 insertions, 5 deletions
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index ac202f44a670..a2848dc36927 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -19,7 +19,7 @@ unsigned long elf_hwcap __read_mostly; static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly; #ifdef CONFIG_FPU -bool has_fpu __read_mostly; +__ro_after_init DEFINE_STATIC_KEY_FALSE(cpu_hwcap_fpu); #endif /** @@ -146,6 +146,6 @@ void riscv_fill_hwcap(void) #ifdef CONFIG_FPU if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D)) - has_fpu = true; + static_branch_enable(&cpu_hwcap_fpu); #endif } diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index f9cd57c9c67d..03ac3aa611f5 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -87,7 +87,7 @@ void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) { regs->status = SR_PIE; - if (has_fpu) { + if (has_fpu()) { regs->status |= SR_FS_INITIAL; /* * Restore the initial value to the FP register diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 65942b3748b4..c2d5ecbe5526 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -90,7 +90,7 @@ static long restore_sigcontext(struct pt_regs *regs, /* sc_regs is structured the same as the start of pt_regs */ err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs)); /* Restore the floating-point state. */ - if (has_fpu) + if (has_fpu()) err |= restore_fp_state(regs, &sc->sc_fpregs); return err; } @@ -143,7 +143,7 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, /* sc_regs is structured the same as the start of pt_regs */ err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); /* Save the floating-point state. */ - if (has_fpu) + if (has_fpu()) err |= save_fp_state(regs, &sc->sc_fpregs); return err; } |