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Subject[PATCH 2/3] riscv: replace has_fpu() with system_supports_fpu()
Date
This is to use the unified cpus_have_{final|const}_cap() instead of
putting static key related here and there.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
arch/riscv/include/asm/cpufeature.h | 5 +++++
arch/riscv/include/asm/switch_to.h | 9 ++-------
arch/riscv/kernel/cpufeature.c | 8 ++------
arch/riscv/kernel/process.c | 2 +-
arch/riscv/kernel/signal.c | 4 ++--
5 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index d80ddd2f3b49..634a653c7fa2 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -91,4 +91,9 @@ static inline void cpus_set_cap(unsigned int num)
}
}

+static inline bool system_supports_fpu(void)
+{
+ return IS_ENABLED(CONFIG_FPU) && !cpus_have_final_cap(RISCV_HAS_NO_FPU);
+}
+
#endif
diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h
index 0a3f4f95c555..362cb18d12d5 100644
--- a/arch/riscv/include/asm/switch_to.h
+++ b/arch/riscv/include/asm/switch_to.h
@@ -8,6 +8,7 @@

#include <linux/jump_label.h>
#include <linux/sched/task_stack.h>
+#include <asm/cpufeature.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/csr.h>
@@ -56,13 +57,7 @@ static inline void __switch_to_aux(struct task_struct *prev,
fstate_restore(next, task_pt_regs(next));
}

-extern struct static_key_false cpu_hwcap_fpu;
-static __always_inline bool has_fpu(void)
-{
- return static_branch_likely(&cpu_hwcap_fpu);
-}
#else
-static __always_inline bool has_fpu(void) { return false; }
#define fstate_save(task, regs) do { } while (0)
#define fstate_restore(task, regs) do { } while (0)
#define __switch_to_aux(__prev, __next) do { } while (0)
@@ -75,7 +70,7 @@ extern struct task_struct *__switch_to(struct task_struct *,
do { \
struct task_struct *__prev = (prev); \
struct task_struct *__next = (next); \
- if (has_fpu()) \
+ if (system_supports_fpu()) \
__switch_to_aux(__prev, __next); \
((last) = __switch_to(__prev, __next)); \
} while (0)
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 09331abfa70c..da272b399af6 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -19,10 +19,6 @@ unsigned long elf_hwcap __read_mostly;
/* Host ISA bitmap */
static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;

-#ifdef CONFIG_FPU
-__ro_after_init DEFINE_STATIC_KEY_FALSE(cpu_hwcap_fpu);
-#endif
-
DECLARE_BITMAP(cpu_hwcaps, RISCV_NCAPS);
EXPORT_SYMBOL(cpu_hwcaps);

@@ -166,8 +162,8 @@ void __init riscv_fill_hwcap(void)
pr_info("riscv: ELF capabilities %s\n", print_str);

#ifdef CONFIG_FPU
- if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
- static_branch_enable(&cpu_hwcap_fpu);
+ if (!(elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D)))
+ cpus_set_cap(RISCV_HAS_NO_FPU);
#endif
enable_cpu_capabilities();
static_branch_enable(&riscv_const_caps_ready);
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 03ac3aa611f5..ece62392b79f 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 (system_supports_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 c2d5ecbe5526..c236eb777fbc 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 (system_supports_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 (system_supports_fpu())
err |= save_fp_state(regs, &sc->sc_fpregs);
return err;
}
--
2.34.1
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