Messages in this thread | | | Date | Wed, 12 Jul 2017 12:07:51 +0100 | From | James Hogan <> | Subject | Re: [PATCH 16/17] RISC-V: User-facing API |
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On Tue, Jul 11, 2017 at 06:31:29PM -0700, Palmer Dabbelt wrote: > diff --git a/arch/riscv/include/asm/unistd.h b/arch/riscv/include/asm/unistd.h > new file mode 100644 > index 000000000000..9f250ed007cd > --- /dev/null > +++ b/arch/riscv/include/asm/unistd.h > @@ -0,0 +1,16 @@ > +/* > + * Copyright (C) 2012 Regents of the University of California > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * as published by the Free Software Foundation, version 2. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#define __ARCH_HAVE_MMU > +#define __ARCH_WANT_SYS_CLONE > +#include <uapi/asm/unistd.h>
It might be worth keeping arch/risc/include/uapi/asm/unistd.h around, even if it only includes asm-generic/unistd.h, as it'll only get added again the next time a syscall is deprecated from the default list in order to add the appropriate __ARCH_WANT_RENAMEAT-like define, but yeh no big deal.
> diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c > new file mode 100644 > index 000000000000..ba3e80712797 > --- /dev/null > +++ b/arch/riscv/kernel/ptrace.c > @@ -0,0 +1,125 @@
> +static int riscv_gpr_get(struct task_struct *target, > + const struct user_regset *regset, > + unsigned int pos, unsigned int count, > + void *kbuf, void __user *ubuf) > +{ > + struct pt_regs *regs; > + > + regs = task_pt_regs(target); > + return user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs, 0, -1); > +} > + > +static int riscv_gpr_set(struct task_struct *target, > + const struct user_regset *regset, > + unsigned int pos, unsigned int count, > + const void *kbuf, const void __user *ubuf) > +{ > + int ret; > + struct pt_regs *regs; > + > + regs = task_pt_regs(target); > + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, ®s, 0, -1); > + return ret; > +}
This is looking much safer now (the caller at least seems to always check pos + count is in range).
> diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c > new file mode 100644 > index 000000000000..e0a1b89583ef > --- /dev/null > +++ b/arch/riscv/kernel/signal.c > @@ -0,0 +1,289 @@
> +static long setup_sigcontext(struct rt_sigframe __user *frame, > + struct pt_regs *regs) > +{ > + struct sigcontext __user *sc = &frame->uc.uc_mcontext; > + long err; > + 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)); > + /* 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]);
How should userland determine how to interpret sc_fpregs? It looks like you couldn't add f or q state without using one of these reserved fields, so why not just specify a field up front to say which fp format (if any) to interpret?
That would allow userland wanting to interpret it to safely check that field in a forward and backward compatible way without assuming a specific format is in use.
Cheers James [unhandled content-type:application/pgp-signature] | |