Messages in this thread Patch in this message | | | From | Alan Kao <> | Subject | [PATCH] riscv: Add support to no-FPU systems | Date | Thu, 21 Jun 2018 09:24:36 +0800 |
| |
This patch adds an option, CONFIG_FPU, so that we can enable/disable floating procedures in kernel.
Signed-off-by: Alan Kao <alankao@andestech.com> Cc: Greentime Hu <greentime@andestech.com> Cc: Zong Li <zong@andestech.com> --- arch/riscv/Kconfig | 4 ++++ arch/riscv/Makefile | 4 ++++ arch/riscv/include/asm/switch_to.h | 4 ++++ arch/riscv/kernel/entry.S | 3 ++- arch/riscv/kernel/process.c | 6 ++++++ arch/riscv/kernel/signal.c | 6 ++++++ 6 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 6debcc4afc72..429d0bf777c9 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -232,6 +232,10 @@ config RISCV_BASE_PMU endmenu +config FPU + bool "FPU support" + default y + endmenu menu "Kernel type" diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 76e958a5414a..2719e768c4dc 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -47,7 +47,11 @@ ifeq ($(CONFIG_RISCV_ISA_C),y) KBUILD_ARCH_C = c endif +ifeq ($(CONFIG_FPU),y) KBUILD_AFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_ARCH_A)fd$(KBUILD_ARCH_C) +else +KBUILD_AFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_ARCH_A)$(KBUILD_ARCH_C) +endif KBUILD_CFLAGS += -march=$(KBUILD_MARCH)$(KBUILD_ARCH_A)$(KBUILD_ARCH_C) KBUILD_CFLAGS += -mno-save-restore diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h index dd6b05bff75b..da0327a74466 100644 --- a/arch/riscv/include/asm/switch_to.h +++ b/arch/riscv/include/asm/switch_to.h @@ -18,6 +18,7 @@ #include <asm/ptrace.h> #include <asm/csr.h> +#ifdef CONFIG_FPU extern void __fstate_save(struct task_struct *save_to); extern void __fstate_restore(struct task_struct *restore_from); @@ -54,6 +55,9 @@ static inline void __switch_to_aux(struct task_struct *prev, fstate_save(prev, regs); fstate_restore(next, task_pt_regs(next)); } +#else +#define __switch_to_aux(__prev, __next) +#endif extern struct task_struct *__switch_to(struct task_struct *, struct task_struct *); diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 9aaf6c986771..89867c9aa4f5 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -357,6 +357,7 @@ ENTRY(__switch_to) ret ENDPROC(__switch_to) +#ifdef CONFIG_FPU ENTRY(__fstate_save) li a2, TASK_THREAD_F0 add a0, a0, a2 @@ -442,7 +443,7 @@ ENTRY(__fstate_restore) csrc sstatus, t1 ret ENDPROC(__fstate_restore) - +#endif .section ".rodata" /* Exception vector table */ diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index cb209139ba53..a817046e478a 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -83,7 +83,11 @@ void show_regs(struct pt_regs *regs) void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) { +#ifdef CONFIG_FPU regs->sstatus = SR_SPIE /* User mode, irqs on */ | SR_FS_INITIAL; +#else + regs->sstatus = SR_SPIE | SR_FS_OFF; +#endif regs->sepc = pc; regs->sp = sp; set_fs(USER_DS); @@ -101,7 +105,9 @@ void flush_thread(void) int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { +#ifdef CONFIG_FPU fstate_save(src, task_pt_regs(src)); +#endif *dst = *src; return 0; } diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 718d0c984ef0..0f659c9ef465 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -37,6 +37,7 @@ struct rt_sigframe { struct ucontext uc; }; +#ifdef CONFIG_FPU static long restore_d_state(struct pt_regs *regs, struct __riscv_d_ext_state __user *state) { @@ -53,6 +54,7 @@ static long save_d_state(struct pt_regs *regs, fstate_save(current, regs); return __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); } +#endif static long restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) @@ -63,6 +65,7 @@ static long restore_sigcontext(struct pt_regs *regs, err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs)); if (unlikely(err)) return err; +#ifdef CONFIG_FPU /* Restore the floating-point state. */ err = restore_d_state(regs, &sc->sc_fpregs.d); if (unlikely(err)) @@ -76,6 +79,7 @@ static long restore_sigcontext(struct pt_regs *regs, if (value != 0) return -EINVAL; } +#endif return err; } @@ -127,11 +131,13 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, size_t i; /* sc_regs is structured the same as the start of pt_regs */ err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); +#ifdef CONFIG_FPU /* Save the floating-point state. */ err |= save_d_state(regs, &sc->sc_fpregs.d); /* We support no other extension state at this time. */ for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++) err |= __put_user(0, &sc->sc_fpregs.q.reserved[i]); +#endif return err; } -- 2.17.0
| |