| Message ID | 20230224170118.16766-13-andy.chiu@sifive.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | riscv: Add vector ISA support | expand |
On Fri, Feb 24, 2023 at 05:01:11PM +0000, Andy Chiu wrote: > In order to let kernel/user locate and identify an extension context on > the existing sigframe, we are going to utilize reserved space of fp and > encode the information there. And since the sigcontext has already > preserved a space for fp context w or w/o CONFIG_FPU, we move those > reserved words checking/setting routine back into generic code. > > This commit also undone an additional logical change carried by the > refactor commit 007f5c3589578 > ("Refactor FPU code in signal setup/return procedures"). Originally we > did not restore fp context if restoring of gpr have failed. And it was > fine on the other side. In such way the kernel could keep the regfiles > intact, and potentially react at the failing point of restore. > > Signed-off-by: Andy Chiu <andy.chiu@sifive.com> > --- > @@ -90,11 +66,29 @@ static long restore_sigcontext(struct pt_regs *regs, > struct sigcontext __user *sc) > { > long err; > + size_t i; > + > /* sc_regs is structured the same as the start of pt_regs */ > err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs)); > + if (unlikely(err)) > + return err; > /* Restore the floating-point state. */ Please preserve the newline after return from where you moved this from. > - if (has_fpu()) > - err |= restore_fp_state(regs, &sc->sc_fpregs); > + if (has_fpu()) { > + err = restore_fp_state(regs, &sc->sc_fpregs); > + if (unlikely(err)) > + return err; > + } > @@ -145,11 +139,16 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, > { > 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. */ > if (has_fpu()) > err |= save_fp_state(regs, &sc->sc_fpregs); > + /* 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]); > return err; And one before the return here would not go amiss. Those are nitpick bits though, so: Acked-by: Conor Dooley <conor.dooley@microchip.com> Cheers, Conor.
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index bfb2afa4135f..0c8be5404a73 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -38,26 +38,13 @@ static long restore_fp_state(struct pt_regs *regs, { long err; struct __riscv_d_ext_state __user *state = &sc_fpregs->d; - size_t i; err = __copy_from_user(¤t->thread.fstate, state, sizeof(*state)); if (unlikely(err)) return err; fstate_restore(current, regs); - - /* We support no other extension state at this time. */ - for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { - u32 value; - - err = __get_user(value, &sc_fpregs->q.reserved[i]); - if (unlikely(err)) - break; - if (value != 0) - return -EINVAL; - } - - return err; + return 0; } static long save_fp_state(struct pt_regs *regs, @@ -65,20 +52,9 @@ static long save_fp_state(struct pt_regs *regs, { long err; struct __riscv_d_ext_state __user *state = &sc_fpregs->d; - size_t i; fstate_save(current, regs); err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); - if (unlikely(err)) - return err; - - /* We support no other extension state at this time. */ - for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { - err = __put_user(0, &sc_fpregs->q.reserved[i]); - if (unlikely(err)) - break; - } - return err; } #else @@ -90,11 +66,29 @@ static long restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { long err; + size_t i; + /* sc_regs is structured the same as the start of pt_regs */ err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs)); + if (unlikely(err)) + return err; /* Restore the floating-point state. */ - if (has_fpu()) - err |= restore_fp_state(regs, &sc->sc_fpregs); + if (has_fpu()) { + err = restore_fp_state(regs, &sc->sc_fpregs); + if (unlikely(err)) + return err; + } + + /* We support no other extension state at this time. */ + for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++) { + u32 value; + + err = __get_user(value, &sc->sc_fpregs.q.reserved[i]); + if (unlikely(err)) + break; + if (value != 0) + return -EINVAL; + } return err; } @@ -145,11 +139,16 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, { 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. */ if (has_fpu()) err |= save_fp_state(regs, &sc->sc_fpregs); + /* 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]); return err; }
In order to let kernel/user locate and identify an extension context on the existing sigframe, we are going to utilize reserved space of fp and encode the information there. And since the sigcontext has already preserved a space for fp context w or w/o CONFIG_FPU, we move those reserved words checking/setting routine back into generic code. This commit also undone an additional logical change carried by the refactor commit 007f5c3589578 ("Refactor FPU code in signal setup/return procedures"). Originally we did not restore fp context if restoring of gpr have failed. And it was fine on the other side. In such way the kernel could keep the regfiles intact, and potentially react at the failing point of restore. Signed-off-by: Andy Chiu <andy.chiu@sifive.com> --- arch/riscv/kernel/signal.c | 53 +++++++++++++++++++------------------- 1 file changed, 26 insertions(+), 27 deletions(-)