From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/riscv/kernel/signal.c | 478 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 478 insertions(+) create mode 100644 arch/riscv/kernel/signal.c (limited to 'arch/riscv/kernel/signal.c') diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c new file mode 100644 index 0000000000..21a4d0e111 --- /dev/null +++ b/arch/riscv/kernel/signal.c @@ -0,0 +1,478 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2009 Sunplus Core Technology Co., Ltd. + * Chen Liqin + * Lennox Wu + * Copyright (C) 2012 Regents of the University of California + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include + +unsigned long signal_minsigstksz __ro_after_init; + +extern u32 __user_rt_sigreturn[2]; +static size_t riscv_v_sc_size __ro_after_init; + +#define DEBUG_SIG 0 + +struct rt_sigframe { + struct siginfo info; + struct ucontext uc; +#ifndef CONFIG_MMU + u32 sigreturn_code[2]; +#endif +}; + +#ifdef CONFIG_FPU +static long restore_fp_state(struct pt_regs *regs, + union __riscv_fp_state __user *sc_fpregs) +{ + long err; + struct __riscv_d_ext_state __user *state = &sc_fpregs->d; + + err = __copy_from_user(¤t->thread.fstate, state, sizeof(*state)); + if (unlikely(err)) + return err; + + fstate_restore(current, regs); + return 0; +} + +static long save_fp_state(struct pt_regs *regs, + union __riscv_fp_state __user *sc_fpregs) +{ + long err; + struct __riscv_d_ext_state __user *state = &sc_fpregs->d; + + fstate_save(current, regs); + err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); + return err; +} +#else +#define save_fp_state(task, regs) (0) +#define restore_fp_state(task, regs) (0) +#endif + +#ifdef CONFIG_RISCV_ISA_V + +static long save_v_state(struct pt_regs *regs, void __user **sc_vec) +{ + struct __riscv_ctx_hdr __user *hdr; + struct __sc_riscv_v_state __user *state; + void __user *datap; + long err; + + hdr = *sc_vec; + /* Place state to the user's signal context space after the hdr */ + state = (struct __sc_riscv_v_state __user *)(hdr + 1); + /* Point datap right after the end of __sc_riscv_v_state */ + datap = state + 1; + + /* datap is designed to be 16 byte aligned for better performance */ + WARN_ON(unlikely(!IS_ALIGNED((unsigned long)datap, 16))); + + riscv_v_vstate_save(current, regs); + /* Copy everything of vstate but datap. */ + err = __copy_to_user(&state->v_state, ¤t->thread.vstate, + offsetof(struct __riscv_v_ext_state, datap)); + /* Copy the pointer datap itself. */ + err |= __put_user(datap, &state->v_state.datap); + /* Copy the whole vector content to user space datap. */ + err |= __copy_to_user(datap, current->thread.vstate.datap, riscv_v_vsize); + /* Copy magic to the user space after saving all vector conetext */ + err |= __put_user(RISCV_V_MAGIC, &hdr->magic); + err |= __put_user(riscv_v_sc_size, &hdr->size); + if (unlikely(err)) + return err; + + /* Only progress the sv_vec if everything has done successfully */ + *sc_vec += riscv_v_sc_size; + return 0; +} + +/* + * Restore Vector extension context from the user's signal frame. This function + * assumes a valid extension header. So magic and size checking must be done by + * the caller. + */ +static long __restore_v_state(struct pt_regs *regs, void __user *sc_vec) +{ + long err; + struct __sc_riscv_v_state __user *state = sc_vec; + void __user *datap; + + /* Copy everything of __sc_riscv_v_state except datap. */ + err = __copy_from_user(¤t->thread.vstate, &state->v_state, + offsetof(struct __riscv_v_ext_state, datap)); + if (unlikely(err)) + return err; + + /* Copy the pointer datap itself. */ + err = __get_user(datap, &state->v_state.datap); + if (unlikely(err)) + return err; + /* + * Copy the whole vector content from user space datap. Use + * copy_from_user to prevent information leak. + */ + err = copy_from_user(current->thread.vstate.datap, datap, riscv_v_vsize); + if (unlikely(err)) + return err; + + riscv_v_vstate_restore(current, regs); + + return err; +} +#else +#define save_v_state(task, regs) (0) +#define __restore_v_state(task, regs) (0) +#endif + +static long restore_sigcontext(struct pt_regs *regs, + struct sigcontext __user *sc) +{ + void __user *sc_ext_ptr = &sc->sc_extdesc.hdr; + __u32 rsvd; + long err; + /* 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 (unlikely(err)) + return err; + } + + /* Check the reserved word before extensions parsing */ + err = __get_user(rsvd, &sc->sc_extdesc.reserved); + if (unlikely(err)) + return err; + if (unlikely(rsvd)) + return -EINVAL; + + while (!err) { + __u32 magic, size; + struct __riscv_ctx_hdr __user *head = sc_ext_ptr; + + err |= __get_user(magic, &head->magic); + err |= __get_user(size, &head->size); + if (unlikely(err)) + return err; + + sc_ext_ptr += sizeof(*head); + switch (magic) { + case END_MAGIC: + if (size != END_HDR_SIZE) + return -EINVAL; + + return 0; + case RISCV_V_MAGIC: + if (!has_vector() || !riscv_v_vstate_query(regs) || + size != riscv_v_sc_size) + return -EINVAL; + + err = __restore_v_state(regs, sc_ext_ptr); + break; + default: + return -EINVAL; + } + sc_ext_ptr = (void __user *)head + size; + } + return err; +} + +static size_t get_rt_frame_size(bool cal_all) +{ + struct rt_sigframe __user *frame; + size_t frame_size; + size_t total_context_size = 0; + + frame_size = sizeof(*frame); + + if (has_vector()) { + if (cal_all || riscv_v_vstate_query(task_pt_regs(current))) + total_context_size += riscv_v_sc_size; + } + /* + * Preserved a __riscv_ctx_hdr for END signal context header if an + * extension uses __riscv_extra_ext_header + */ + if (total_context_size) + total_context_size += sizeof(struct __riscv_ctx_hdr); + + frame_size += total_context_size; + + frame_size = round_up(frame_size, 16); + return frame_size; +} + +SYSCALL_DEFINE0(rt_sigreturn) +{ + struct pt_regs *regs = current_pt_regs(); + struct rt_sigframe __user *frame; + struct task_struct *task; + sigset_t set; + size_t frame_size = get_rt_frame_size(false); + + /* Always make any pending restarted system calls return -EINTR */ + current->restart_block.fn = do_no_restart_syscall; + + frame = (struct rt_sigframe __user *)regs->sp; + + if (!access_ok(frame, frame_size)) + goto badframe; + + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto badframe; + + set_current_blocked(&set); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + if (restore_altstack(&frame->uc.uc_stack)) + goto badframe; + + regs->cause = -1UL; + + return regs->a0; + +badframe: + task = current; + if (show_unhandled_signals) { + pr_info_ratelimited( + "%s[%d]: bad frame in %s: frame=%p pc=%p sp=%p\n", + task->comm, task_pid_nr(task), __func__, + frame, (void *)regs->epc, (void *)regs->sp); + } + force_sig(SIGSEGV); + return 0; +} + +static long setup_sigcontext(struct rt_sigframe __user *frame, + struct pt_regs *regs) +{ + struct sigcontext __user *sc = &frame->uc.uc_mcontext; + struct __riscv_ctx_hdr __user *sc_ext_ptr = &sc->sc_extdesc.hdr; + long err; + + /* 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); + /* Save the vector state. */ + if (has_vector() && riscv_v_vstate_query(regs)) + err |= save_v_state(regs, (void __user **)&sc_ext_ptr); + /* Write zero to fp-reserved space and check it on restore_sigcontext */ + err |= __put_user(0, &sc->sc_extdesc.reserved); + /* And put END __riscv_ctx_hdr at the end. */ + err |= __put_user(END_MAGIC, &sc_ext_ptr->magic); + err |= __put_user(END_HDR_SIZE, &sc_ext_ptr->size); + + return err; +} + +static inline void __user *get_sigframe(struct ksignal *ksig, + struct pt_regs *regs, size_t framesize) +{ + unsigned long sp; + /* Default to using normal stack */ + sp = regs->sp; + + /* + * 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 - framesize))) + return (void __user __force *)(-1UL); + + /* This is the X/Open sanctioned signal stack switching. */ + sp = sigsp(sp, ksig) - framesize; + + /* Align the stack frame. */ + sp &= ~0xfUL; + + return (void __user *)sp; +} + +static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, + struct pt_regs *regs) +{ + struct rt_sigframe __user *frame; + long err = 0; + unsigned long __maybe_unused addr; + size_t frame_size = get_rt_frame_size(false); + + frame = get_sigframe(ksig, regs, frame_size); + if (!access_ok(frame, frame_size)) + return -EFAULT; + + err |= copy_siginfo_to_user(&frame->info, &ksig->info); + + /* Create the ucontext. */ + err |= __put_user(0, &frame->uc.uc_flags); + err |= __put_user(NULL, &frame->uc.uc_link); + err |= __save_altstack(&frame->uc.uc_stack, regs->sp); + err |= setup_sigcontext(frame, regs); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + if (err) + return -EFAULT; + + /* Set up to return from userspace. */ +#ifdef CONFIG_MMU + regs->ra = (unsigned long)VDSO_SYMBOL( + current->mm->context.vdso, rt_sigreturn); +#else + /* + * For the nommu case we don't have a VDSO. Instead we push two + * instructions to call the rt_sigreturn syscall onto the user stack. + */ + if (copy_to_user(&frame->sigreturn_code, __user_rt_sigreturn, + sizeof(frame->sigreturn_code))) + return -EFAULT; + + addr = (unsigned long)&frame->sigreturn_code; + /* Make sure the two instructions are pushed to icache. */ + flush_icache_range(addr, addr + sizeof(frame->sigreturn_code)); + + regs->ra = addr; +#endif /* CONFIG_MMU */ + + /* + * Set up registers for signal handler. + * Registers that we don't modify keep the value they had from + * user-space at the time we took the signal. + * We always pass siginfo and mcontext, regardless of SA_SIGINFO, + * since some things rely on this (e.g. glibc's debug/segfault.c). + */ + regs->epc = (unsigned long)ksig->ka.sa.sa_handler; + regs->sp = (unsigned long)frame; + regs->a0 = ksig->sig; /* a0: signal number */ + regs->a1 = (unsigned long)(&frame->info); /* a1: siginfo pointer */ + regs->a2 = (unsigned long)(&frame->uc); /* a2: ucontext pointer */ + +#if DEBUG_SIG + pr_info("SIG deliver (%s:%d): sig=%d pc=%p ra=%p sp=%p\n", + current->comm, task_pid_nr(current), ksig->sig, + (void *)regs->epc, (void *)regs->ra, frame); +#endif + + return 0; +} + +static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) +{ + sigset_t *oldset = sigmask_to_save(); + int ret; + + /* Are we from a system call? */ + if (regs->cause == EXC_SYSCALL) { + /* Avoid additional syscall restarting via ret_from_exception */ + regs->cause = -1UL; + /* If so, check system call restarting.. */ + switch (regs->a0) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + regs->a0 = -EINTR; + break; + + case -ERESTARTSYS: + if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { + regs->a0 = -EINTR; + break; + } + fallthrough; + case -ERESTARTNOINTR: + regs->a0 = regs->orig_a0; + regs->epc -= 0x4; + break; + } + } + + rseq_signal_deliver(ksig, regs); + + /* Set up the stack frame */ + if (is_compat_task()) + ret = compat_setup_rt_frame(ksig, oldset, regs); + else + ret = setup_rt_frame(ksig, oldset, regs); + + signal_setup_done(ret, ksig, 0); +} + +void arch_do_signal_or_restart(struct pt_regs *regs) +{ + struct ksignal ksig; + + if (get_signal(&ksig)) { + /* Actually deliver the signal */ + handle_signal(&ksig, regs); + return; + } + + /* Did we come from a system call? */ + if (regs->cause == EXC_SYSCALL) { + /* Avoid additional syscall restarting via ret_from_exception */ + regs->cause = -1UL; + + /* Restart the system call - no handlers present */ + switch (regs->a0) { + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + regs->a0 = regs->orig_a0; + regs->epc -= 0x4; + break; + case -ERESTART_RESTARTBLOCK: + regs->a0 = regs->orig_a0; + regs->a7 = __NR_restart_syscall; + regs->epc -= 0x4; + break; + } + } + + /* + * If there is no signal to deliver, we just put the saved + * sigmask back. + */ + restore_saved_sigmask(); +} + +void init_rt_signal_env(void); +void __init init_rt_signal_env(void) +{ + riscv_v_sc_size = sizeof(struct __riscv_ctx_hdr) + + sizeof(struct __sc_riscv_v_state) + riscv_v_vsize; + /* + * Determine the stack space required for guaranteed signal delivery. + * The signal_minsigstksz will be populated into the AT_MINSIGSTKSZ entry + * in the auxiliary array at process startup. + */ + signal_minsigstksz = get_rt_frame_size(true); +} + +#ifdef CONFIG_DYNAMIC_SIGFRAME +bool sigaltstack_size_valid(size_t ss_size) +{ + return ss_size > get_rt_frame_size(false); +} +#endif /* CONFIG_DYNAMIC_SIGFRAME */ -- cgit v1.2.3