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| author | Alan Kao <alankao@andestech.com> | 2018-10-09 04:18:34 +0200 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@sifive.com> | 2018-10-23 02:02:23 +0200 |
| commit | 9411ec60c23d868124d9c1b1d491937aebe07afa (patch) | |
| tree | b099a760ac5b284dd79281ded728e35ec30d2e77 /arch/riscv/kernel/signal.c | |
| parent | Allow to disable FPU support (diff) | |
| download | linux-9411ec60c23d868124d9c1b1d491937aebe07afa.tar.xz linux-9411ec60c23d868124d9c1b1d491937aebe07afa.zip | |
Auto-detect whether a FPU exists
We expect that a kernel with CONFIG_FPU=y can still support no-FPU
machines. To do so, the kernel should first examine the existence of a
FPU, then do nothing if a FPU does exist; otherwise, it should
disable/bypass all FPU-related functions.
In this patch, a new global variable, has_fpu, is created and determined
when parsing the hardware capability from device tree during booting.
This variable is used in those FPU-related functions.
Signed-off-by: Alan Kao <alankao@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Cc: Vincent Chen <vincentc@andestech.com>
Cc: Zong Li <zong@andestech.com>
Cc: Nick Hu <nickhu@andestech.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv/kernel/signal.c')
| -rw-r--r-- | arch/riscv/kernel/signal.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 2450b824d799..f9b5e7e352ef 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -98,7 +98,8 @@ 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. */ - err |= restore_fp_state(regs, &sc->sc_fpregs); + if (has_fpu) + err |= restore_fp_state(regs, &sc->sc_fpregs); return err; } @@ -150,7 +151,8 @@ 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. */ - err |= save_fp_state(regs, &sc->sc_fpregs); + if (has_fpu) + err |= save_fp_state(regs, &sc->sc_fpregs); return err; } |