diff options
| author | Palmer Dabbelt <palmer@sifive.com> | 2018-10-22 17:38:26 -0700 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@sifive.com> | 2018-10-22 17:38:26 -0700 |
| commit | 4e4101cfefd382176b05356c5ef112561ae10384 (patch) | |
| tree | b60173dc3824f7da801b33d5d1d172c4a6f9e41f /arch/riscv/include | |
| parent | aef53f97b505ff94190ce3a06dcd0ded6cf5c0ca (diff) | |
| parent | 9411ec60c23d868124d9c1b1d491937aebe07afa (diff) | |
| download | linux-4e4101cfefd382176b05356c5ef112561ae10384.tar.bz2 | |
riscv: Add support to no-FPU systems
This patchset adds an option, CONFIG_FPU, to enable/disable floating-
point support within the kernel. The kernel's new behavior will be as
follows:
* with CONFIG_FPU=y
All FPU codes are reserved. If no FPU is found during booting, a
global flag will be set, and those functions will be bypassed with
condition check to that flag.
* with CONFIG_FPU=n
No floating-point instructions in kernel and all related settings
are excluded.
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv/include')
| -rw-r--r-- | arch/riscv/include/asm/switch_to.h | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h index dd6b05bff75b..733559083f24 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); @@ -55,6 +56,14 @@ static inline void __switch_to_aux(struct task_struct *prev, fstate_restore(next, task_pt_regs(next)); } +extern bool has_fpu; +#else +#define has_fpu 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) +#endif + extern struct task_struct *__switch_to(struct task_struct *, struct task_struct *); @@ -62,7 +71,8 @@ extern struct task_struct *__switch_to(struct task_struct *, do { \ struct task_struct *__prev = (prev); \ struct task_struct *__next = (next); \ - __switch_to_aux(__prev, __next); \ + if (has_fpu) \ + __switch_to_aux(__prev, __next); \ ((last) = __switch_to(__prev, __next)); \ } while (0) |