Messages in this thread | | | Date | Sun, 15 May 2022 18:39:06 +0800 | Subject | Re: [PATCH V10 14/22] LoongArch: Add signal handling support | From | WANG Xuerui <> |
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Hi,
On 5/14/22 16:03, Huacai Chen wrote: > Add ucontext/sigcontext definition and signal handling support for > LoongArch. > > Cc: Eric Biederman <ebiederm@xmission.com> > Cc: Al Viro <viro@zeniv.linux.org.uk> > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> > --- > arch/loongarch/include/uapi/asm/sigcontext.h | 63 ++ > arch/loongarch/include/uapi/asm/signal.h | 13 + > arch/loongarch/include/uapi/asm/ucontext.h | 35 ++ > arch/loongarch/kernel/signal.c | 568 +++++++++++++++++++ > 4 files changed, 679 insertions(+) > create mode 100644 arch/loongarch/include/uapi/asm/sigcontext.h > create mode 100644 arch/loongarch/include/uapi/asm/signal.h > create mode 100644 arch/loongarch/include/uapi/asm/ucontext.h > create mode 100644 arch/loongarch/kernel/signal.c > > diff --git a/arch/loongarch/include/uapi/asm/sigcontext.h b/arch/loongarch/include/uapi/asm/sigcontext.h > new file mode 100644 > index 000000000000..efeb8b3f8236 > --- /dev/null > +++ b/arch/loongarch/include/uapi/asm/sigcontext.h > @@ -0,0 +1,63 @@ > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ > +/* > + * Author: Hanlu Li <lihanlu@loongson.cn> > + * Huacai Chen <chenhuacai@loongson.cn> > + * > + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited > + */ > +#ifndef _UAPI_ASM_SIGCONTEXT_H > +#define _UAPI_ASM_SIGCONTEXT_H > + > +#include <linux/types.h> > +#include <linux/posix_types.h> > + > +/* FP context was used */ > +#define USED_FP (1 << 0) > +/* Load/Store access flags for address error */ > +#define ADRERR_RD (1 << 30) > +#define ADRERR_WR (1 << 31) I've searched GitHub globally, and my local glibc checkout, for usages of these 3 constants, and there seems to be none; please consider removing these if doable. We don't want cruft in uapi right from the beginning. > + > +struct sigcontext { > + __u64 sc_pc; > + __u64 sc_regs[32]; > + __u32 sc_flags; > + __u64 sc_extcontext[0] __attribute__((__aligned__(16))); > +}; > + > +#define CONTEXT_INFO_ALIGN 16 > +struct _ctxinfo { > + __u32 magic; > + __u32 size; > + __u64 padding; /* padding to 16 bytes */ > +}; > + > +/* FPU context */ > +#define FPU_CTX_MAGIC 0x46505501 > +#define FPU_CTX_ALIGN 8 > +struct fpu_context { > + __u64 regs[32]; > + __u64 fcc; > + __u32 fcsr; > +}; The 3 structs above should already see usage downstream (glibc and other low-level friends), so they probably shouldn't be touched by now. At least I can't see problems. > + > +/* LSX context */ > +#define LSX_CTX_MAGIC 0x53580001 > +#define LSX_CTX_ALIGN 16 > +struct lsx_context { > + __u64 regs[2*32]; > + __u64 fcc; > + __u32 fcsr; > + __u32 vcsr; > +}; > + > +/* LASX context */ > +#define LASX_CTX_MAGIC 0x41535801 > +#define LASX_CTX_ALIGN 32 > +struct lasx_context { > + __u64 regs[4*32]; > + __u64 fcc; > + __u32 fcsr; > + __u32 vcsr; > +}; Do we want to freeze the LSX/LASX layout this early, before any detail of said extension are published? We'll need to update kernel later anyway, so I'd recommend leaving them out for the initial bring-up. > + > +#endif /* _UAPI_ASM_SIGCONTEXT_H */ > diff --git a/arch/loongarch/include/uapi/asm/signal.h b/arch/loongarch/include/uapi/asm/signal.h > new file mode 100644 > index 000000000000..992d965aa13f > --- /dev/null > +++ b/arch/loongarch/include/uapi/asm/signal.h > @@ -0,0 +1,13 @@ > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ > +/* > + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited > + */ > +#ifndef _UAPI_ASM_SIGNAL_H > +#define _UAPI_ASM_SIGNAL_H > + > +#define MINSIGSTKSZ 4096 > +#define SIGSTKSZ 16384
I've checked this set of values is also the choice for arch/alpha and arch/sparc, and that the Loongson devs are aware of the LWN article [1] about x86's story around insufficient signal stack size. So I'd approve this.
[1]: https://lwn.net/Articles/874846/
> + > +#include <asm-generic/signal.h> > + > +#endif > diff --git a/arch/loongarch/include/uapi/asm/ucontext.h b/arch/loongarch/include/uapi/asm/ucontext.h > new file mode 100644 > index 000000000000..12577e22b1c7 > --- /dev/null > +++ b/arch/loongarch/include/uapi/asm/ucontext.h > @@ -0,0 +1,35 @@ > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ > +#ifndef __LOONGARCH_UAPI_ASM_UCONTEXT_H > +#define __LOONGARCH_UAPI_ASM_UCONTEXT_H > + > +/** > + * struct ucontext - user context structure > + * @uc_flags: > + * @uc_link: > + * @uc_stack: > + * @uc_mcontext: holds basic processor state > + * @uc_sigmask: > + * @uc_extcontext: holds extended processor state Document the other fields? ;-) > + */ > +struct ucontext { > + unsigned long uc_flags; > + struct ucontext *uc_link; > + stack_t uc_stack; > + sigset_t uc_sigmask; > + /* There's some padding here to allow sigset_t to be expanded in the > + * future. Though this is unlikely, other architectures put uc_sigmask > + * at the end of this structure and explicitly state it can be > + * expanded, so we didn't want to box ourselves in here. */ > + __u8 __unused[1024 / 8 - sizeof(sigset_t)]; > + /* We can't put uc_sigmask at the end of this structure because we need > + * to be able to expand sigcontext in the future. For example, the > + * vector ISA extension will almost certainly add ISA state. We want > + * to ensure all user-visible ISA state can be saved and restored via a > + * ucontext, so we're putting this at the end in order to allow for > + * infinite extensibility. Since we know this will be extended and we > + * assume sigset_t won't be extended an extreme amount, we're > + * prioritizing this. */ > + struct sigcontext uc_mcontext; > +}; This is in turn copied from arch/riscv (who got it from arch/arm64, thanks to both arches!), so we shouldn't be too bad future-proof-wise. But do we want an attribution to arch/riscv too, like they did for arch/arm64? (Stating that you referred to arch/riscv for inspiration.) > + > +#endif /* __LOONGARCH_UAPI_ASM_UCONTEXT_H */ > diff --git a/arch/loongarch/kernel/signal.c b/arch/loongarch/kernel/signal.c > new file mode 100644 > index 000000000000..489e169e1d13 > --- /dev/null > +++ b/arch/loongarch/kernel/signal.c > @@ -0,0 +1,568 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Author: Hanlu Li <lihanlu@loongson.cn> > + * Huacai Chen <chenhuacai@loongson.cn> > + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited > + * > + * Derived from MIPS: > + * Copyright (C) 1991, 1992 Linus Torvalds > + * Copyright (C) 1994 - 2000 Ralf Baechle > + * Copyright (C) 1999, 2000 Silicon Graphics, Inc. > + * Copyright (C) 2014, Imagination Technologies Ltd. > + */ > +#include <linux/audit.h> > +#include <linux/cache.h> > +#include <linux/context_tracking.h> > +#include <linux/irqflags.h> > +#include <linux/sched.h> > +#include <linux/mm.h> > +#include <linux/personality.h> > +#include <linux/smp.h> > +#include <linux/kernel.h> > +#include <linux/signal.h> > +#include <linux/errno.h> > +#include <linux/wait.h> > +#include <linux/ptrace.h> > +#include <linux/unistd.h> > +#include <linux/compiler.h> > +#include <linux/syscalls.h> > +#include <linux/uaccess.h> > + > +#include <asm/asm.h> > +#include <asm/cacheflush.h> > +#include <asm/cpu-features.h> > +#include <asm/fpu.h> > +#include <asm/ucontext.h> > +#include <asm/vdso.h> > + > +#ifdef DEBUG_SIG > +# define DEBUGP(fmt, args...) printk("%s: " fmt, __func__, ##args) > +#else > +# define DEBUGP(fmt, args...) > +#endif > + > +/* Make sure we will not lose FPU ownership */ > +#define lock_fpu_owner() ({ preempt_disable(); pagefault_disable(); }) > +#define unlock_fpu_owner() ({ pagefault_enable(); preempt_enable(); }) > + > +/* Assembly functions to move context to/from the FPU */ > +extern asmlinkage int > +_save_fp_context(void __user *fpregs, void __user *fcc, void __user *csr); > +extern asmlinkage int > +_restore_fp_context(void __user *fpregs, void __user *fcc, void __user *csr); > + > +struct rt_sigframe { > + struct siginfo rs_info; > + struct ucontext rs_uctx; > +}; > + > +struct _ctx_layout { > + struct _ctxinfo *addr; > + unsigned int size; > +}; > + > +struct extctx_layout { > + unsigned long size; > + unsigned int flags; > + struct _ctx_layout fpu; > + struct _ctx_layout lsx; > + struct _ctx_layout lasx; > + struct _ctx_layout end; > +}; > + > +static void __user *get_ctx_through_ctxinfo(struct _ctxinfo *info) > +{ > + return (void __user *)((char *)info + sizeof(struct _ctxinfo)); > +} > + > +/* > + * Thread saved context copy to/from a signal context presumed to be on the > + * user stack, and therefore accessed with appropriate macros from uaccess.h. > + */ > +static int copy_fpu_to_sigcontext(struct fpu_context __user *ctx) > +{ > + int i; > + int err = 0; > + uint64_t __user *regs = (uint64_t *)&ctx->regs; > + uint64_t __user *fcc = &ctx->fcc; > + uint32_t __user *fcsr = &ctx->fcsr; > + > + for (i = 0; i < NUM_FPU_REGS; i++) { > + err |= > + __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 0), > + ®s[i]); > + } > + err |= __put_user(current->thread.fpu.fcc, fcc); > + err |= __put_user(current->thread.fpu.fcsr, fcsr); > + > + return err; > +} > + > +static int copy_fpu_from_sigcontext(struct fpu_context __user *ctx) > +{ > + int i; > + int err = 0; > + u64 fpr_val; > + uint64_t __user *regs = (uint64_t *)&ctx->regs; > + uint64_t __user *fcc = &ctx->fcc; > + uint32_t __user *fcsr = &ctx->fcsr; > + > + for (i = 0; i < NUM_FPU_REGS; i++) { > + err |= __get_user(fpr_val, ®s[i]); > + set_fpr64(¤t->thread.fpu.fpr[i], 0, fpr_val); > + } > + err |= __get_user(current->thread.fpu.fcc, fcc); > + err |= __get_user(current->thread.fpu.fcsr, fcsr); > + > + return err; > +} > + > +/* > + * Wrappers for the assembly _{save,restore}_fp_context functions. > + */ > +static int save_hw_fpu_context(struct fpu_context __user *ctx) > +{ > + uint64_t __user *regs = (uint64_t *)&ctx->regs; > + uint64_t __user *fcc = &ctx->fcc; > + uint32_t __user *fcsr = &ctx->fcsr; > + > + return _save_fp_context(regs, fcc, fcsr); > +} > + > +static int restore_hw_fpu_context(struct fpu_context __user *ctx) > +{ > + uint64_t __user *regs = (uint64_t *)&ctx->regs; > + uint64_t __user *fcc = &ctx->fcc; > + uint32_t __user *fcsr = &ctx->fcsr; > + > + return _restore_fp_context(regs, fcc, fcsr); > +} > + > +int fpcsr_pending(unsigned int __user *fpcsr) Is "fpcsr" just "fcsr"? > +{ > + int err, sig = 0; > + unsigned int csr, enabled; > + > + err = __get_user(csr, fpcsr); > + enabled = ((csr & FPU_CSR_ALL_E) << 24); > + /* > + * If the signal handler set some FPU exceptions, clear it and > + * send SIGFPE. > + */ > + if (csr & enabled) { > + csr &= ~enabled; > + err |= __put_user(csr, fpcsr); > + sig = SIGFPE; > + } > + return err ?: sig; > +} > + > +/* > + * Helper routines > + */ > +static int protected_save_fpu_context(struct extctx_layout *extctx) > +{ > + int err = 0; > + struct _ctxinfo __user *info = extctx->fpu.addr; > + struct fpu_context __user *fpu_ctx = (struct fpu_context *)get_ctx_through_ctxinfo(info); > + uint64_t __user *regs = (uint64_t *)&fpu_ctx->regs; > + uint64_t __user *fcc = &fpu_ctx->fcc; > + uint32_t __user *fcsr = &fpu_ctx->fcsr; > + > + while (1) { > + lock_fpu_owner(); > + if (is_fpu_owner()) > + err = save_hw_fpu_context(fpu_ctx); > + else > + err = copy_fpu_to_sigcontext(fpu_ctx); > + unlock_fpu_owner(); > + > + err |= __put_user(FPU_CTX_MAGIC, &info->magic); > + err |= __put_user(extctx->fpu.size, &info->size); > + > + if (likely(!err)) > + break; > + /* Touch the FPU context and try again */ > + err = __put_user(0, ®s[0]) | > + __put_user(0, ®s[31]) | > + __put_user(0, fcc) | > + __put_user(0, fcsr); > + if (err) > + return err; /* really bad sigcontext */ > + } > + > + return err; > +} > + > +static int protected_restore_fpu_context(struct extctx_layout *extctx) > +{ > + int err = 0, sig = 0, tmp __maybe_unused; > + struct _ctxinfo __user *info = extctx->fpu.addr; > + struct fpu_context __user *fpu_ctx = (struct fpu_context *)get_ctx_through_ctxinfo(info); > + uint64_t __user *regs = (uint64_t *)&fpu_ctx->regs; > + uint64_t __user *fcc = &fpu_ctx->fcc; > + uint32_t __user *fcsr = &fpu_ctx->fcsr; > + > + err = sig = fpcsr_pending(fcsr); > + if (err < 0) > + return err; > + > + while (1) { > + lock_fpu_owner(); > + if (is_fpu_owner()) > + err = restore_hw_fpu_context(fpu_ctx); > + else > + err = copy_fpu_from_sigcontext(fpu_ctx); > + unlock_fpu_owner(); > + > + if (likely(!err)) > + break; > + /* Touch the FPU context and try again */ > + err = __get_user(tmp, ®s[0]) | > + __get_user(tmp, ®s[31]) | > + __get_user(tmp, fcc) | > + __get_user(tmp, fcsr); > + if (err) > + break; /* really bad sigcontext */ > + } > + > + return err ?: sig; > +} > + > +static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, > + struct extctx_layout *extctx) > +{ > + int i, err = 0; > + struct _ctxinfo __user *info; > + > + err |= __put_user(regs->csr_era, &sc->sc_pc); > + err |= __put_user(extctx->flags, &sc->sc_flags); > + > + err |= __put_user(0, &sc->sc_regs[0]); > + for (i = 1; i < 32; i++) > + err |= __put_user(regs->regs[i], &sc->sc_regs[i]); > + > + if (extctx->fpu.addr) > + err |= protected_save_fpu_context(extctx); > + > + /* Set the "end" magic */ > + info = (struct _ctxinfo *)extctx->end.addr; > + err |= __put_user(0, &info->magic); > + err |= __put_user(0, &info->size); > + > + return err; > +} > + > +static int parse_extcontext(struct sigcontext __user *sc, struct extctx_layout *extctx) > +{ > + int err = 0; > + unsigned int magic, size; > + struct _ctxinfo __user *info = (struct _ctxinfo __user *)&sc->sc_extcontext; > + > + while(1) { > + err |= __get_user(magic, &info->magic); > + err |= __get_user(size, &info->size); > + if (err) > + return err; > + > + switch (magic) { > + case 0: /* END */ > + goto done; > + > + case FPU_CTX_MAGIC: > + if (size < (sizeof(struct _ctxinfo) + > + sizeof(struct fpu_context))) > + goto invalid; > + extctx->fpu.addr = info; > + break; > + > + default: > + goto invalid; > + } > + > + info = (struct _ctxinfo *)((char *)info + size); > + } > + > +done: > + return 0; > + > +invalid: > + return -EINVAL; > +} > + > +static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) > +{ > + int i, err = 0; > + struct extctx_layout extctx; > + > + memset(&extctx, 0, sizeof(struct extctx_layout)); > + > + err = __get_user(extctx.flags, &sc->sc_flags); > + if (err) > + goto bad; > + > + err = parse_extcontext(sc, &extctx); > + if (err) > + goto bad; > + > + conditional_used_math(extctx.flags & USED_FP); > + > + /* > + * The signal handler may have used FPU; give it up if the program > + * doesn't want it following sigreturn. > + */ > + if (!(extctx.flags & USED_FP)) > + lose_fpu(0); > + > + /* Always make any pending restarted system calls return -EINTR */ > + current->restart_block.fn = do_no_restart_syscall; > + > + err |= __get_user(regs->csr_era, &sc->sc_pc); > + for (i = 1; i < 32; i++) > + err |= __get_user(regs->regs[i], &sc->sc_regs[i]); > + > + if (extctx.fpu.addr) > + err |= protected_restore_fpu_context(&extctx); > + > +bad: > + return err; > +} > + > +static unsigned int handle_flags(void) > +{ > + unsigned int flags = 0; > + > + flags |= used_math() ? USED_FP : 0; > + > + switch (current->thread.error_code) { > + case 1: > + flags |= ADRERR_RD; > + break; > + case 2: > + flags |= ADRERR_WR; > + break; > + } > + > + return flags; > +} > + > +static unsigned long extframe_alloc(struct extctx_layout *extctx, > + struct _ctx_layout *layout, > + size_t size, unsigned int align, unsigned long base) > +{ > + unsigned long new_base = base - size; > + > + new_base = round_down(new_base, (align < 16 ? 16 : align)); > + new_base -= sizeof(struct _ctxinfo); > + > + layout->addr = (void *)new_base; > + layout->size = (unsigned int)(base - new_base); > + extctx->size += layout->size; > + > + return new_base; > +} > + > +static unsigned long setup_extcontext(struct extctx_layout *extctx, unsigned long sp) > +{ > + unsigned long new_sp = sp; > + > + memset(extctx, 0, sizeof(struct extctx_layout)); > + > + extctx->flags = handle_flags(); > + > + /* Grow down, alloc "end" context info first. */ > + new_sp -= sizeof(struct _ctxinfo); > + extctx->end.addr = (void *)new_sp; > + extctx->end.size = (unsigned int)sizeof(struct _ctxinfo); > + extctx->size += extctx->end.size; > + > + if (extctx->flags & USED_FP) { > + if (cpu_has_fpu) > + new_sp = extframe_alloc(extctx, &extctx->fpu, > + sizeof(struct fpu_context), FPU_CTX_ALIGN, new_sp); > + } > + > + return new_sp; > +} > + > +void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, > + struct extctx_layout *extctx) > +{ > + unsigned long sp; > + > + /* Default to using normal stack */ > + sp = regs->regs[3]; > + > + /* > + * If we are on the alternate signal stack and would overflow it, don't. > + * Return an always-bogus address instead so we will die with SIGSEGV. > + */ > + if (on_sig_stack(sp) && > + !likely(on_sig_stack(sp - sizeof(struct rt_sigframe)))) > + return (void __user __force *)(-1UL); > + > + sp = sigsp(sp, ksig); > + sp = round_down(sp, 16); > + sp = setup_extcontext(extctx, sp); > + sp -= sizeof(struct rt_sigframe); > + > + if (!IS_ALIGNED(sp, 16)) > + BUG(); > + > + return (void __user *)sp; > +} > + > +/* > + * Atomically swap in the new signal mask, and wait for a signal. > + */ > + > +asmlinkage long sys_rt_sigreturn(void) > +{ > + int sig; > + sigset_t set; > + struct pt_regs *regs; > + struct rt_sigframe __user *frame; > + > + regs = current_pt_regs(); > + frame = (struct rt_sigframe __user *)regs->regs[3]; > + if (!access_ok(frame, sizeof(*frame))) > + goto badframe; > + if (__copy_from_user(&set, &frame->rs_uctx.uc_sigmask, sizeof(set))) > + goto badframe; > + > + set_current_blocked(&set); > + > + sig = restore_sigcontext(regs, &frame->rs_uctx.uc_mcontext); > + if (sig < 0) > + goto badframe; > + else if (sig) > + force_sig(sig); > + > + regs->regs[0] = 0; /* No syscall restarting */ > + if (restore_altstack(&frame->rs_uctx.uc_stack)) > + goto badframe; > + > + return regs->regs[4]; > + > +badframe: > + force_sig(SIGSEGV); > + return 0; > +} > + > +static int setup_rt_frame(void *sig_return, struct ksignal *ksig, > + struct pt_regs *regs, sigset_t *set) > +{ > + int err = 0; > + struct extctx_layout extctx; > + struct rt_sigframe __user *frame; > + > + frame = get_sigframe(ksig, regs, &extctx); > + if (!access_ok(frame, sizeof(*frame) + extctx.size)) > + return -EFAULT; > + > + /* Create siginfo. */ > + err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info); > + > + /* Create the ucontext. */ > + err |= __put_user(0, &frame->rs_uctx.uc_flags); > + err |= __put_user(NULL, &frame->rs_uctx.uc_link); > + err |= __save_altstack(&frame->rs_uctx.uc_stack, regs->regs[3]); > + err |= setup_sigcontext(regs, &frame->rs_uctx.uc_mcontext, &extctx); > + err |= __copy_to_user(&frame->rs_uctx.uc_sigmask, set, sizeof(*set)); > + > + if (err) > + return -EFAULT; > + > + /* > + * Arguments to signal handler: > + * > + * a0 = signal number > + * a1 = pointer to siginfo > + * a2 = pointer to ucontext > + * > + * c0_era point to the signal handler, $r3 (sp) points to > + * the struct rt_sigframe. > + */ > + regs->regs[4] = ksig->sig; > + regs->regs[5] = (unsigned long) &frame->rs_info; > + regs->regs[6] = (unsigned long) &frame->rs_uctx; > + regs->regs[3] = (unsigned long) frame; > + regs->regs[1] = (unsigned long) sig_return; > + regs->csr_era = (unsigned long) ksig->ka.sa.sa_handler; > + > + DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n", > + current->comm, current->pid, > + frame, regs->csr_era, regs->regs[1]); > + > + return 0; > +} > + > +static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) > +{ > + int ret; > + sigset_t *oldset = sigmask_to_save(); > + void *vdso = current->mm->context.vdso; > + > + /* Are we from a system call? */ > + if (regs->regs[0]) { > + switch (regs->regs[4]) { > + case -ERESTART_RESTARTBLOCK: > + case -ERESTARTNOHAND: > + regs->regs[4] = -EINTR; > + break; > + case -ERESTARTSYS: > + if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { > + regs->regs[4] = -EINTR; > + break; > + } > + fallthrough; > + case -ERESTARTNOINTR: > + regs->regs[4] = regs->orig_a0; > + regs->csr_era -= 4; > + } > + > + regs->regs[0] = 0; /* Don't deal with this again. */ > + } > + > + rseq_signal_deliver(ksig, regs); > + > + ret = setup_rt_frame(vdso + current->thread.vdso->offset_sigreturn, ksig, regs, oldset); > + > + signal_setup_done(ret, ksig, 0); > +} > + > +void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) > +{ > + struct ksignal ksig; > + > + if (has_signal && get_signal(&ksig)) { > + /* Whee! Actually deliver the signal. */ > + handle_signal(&ksig, regs); > + return; > + } > + > + /* Are we from a system call? */ > + if (regs->regs[0]) { > + switch (regs->regs[4]) { > + case -ERESTARTNOHAND: > + case -ERESTARTSYS: > + case -ERESTARTNOINTR: > + regs->regs[4] = regs->orig_a0; > + regs->csr_era -= 4; > + break; > + > + case -ERESTART_RESTARTBLOCK: > + regs->regs[4] = regs->orig_a0; > + regs->regs[11] = __NR_restart_syscall; > + regs->csr_era -= 4; > + break; > + } > + regs->regs[0] = 0; /* Don't deal with this again. */ > + } > + > + /* > + * If there's no signal to deliver, we just put the saved sigmask > + * back > + */ > + restore_saved_sigmask(); > +}
This patch looks reasonably good, with the comments addressed (revised or replied in case you want to keep as-is):
Reviewed-by: WANG Xuerui <git@xen0n.name>
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