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-rw-r--r--arch/riscv/kernel/signal.c478
1 files changed, 478 insertions, 0 deletions
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 <liqin.chen@sunplusct.com>
+ * Lennox Wu <lennox.wu@sunplusct.com>
+ * Copyright (C) 2012 Regents of the University of California
+ */
+
+#include <linux/compat.h>
+#include <linux/signal.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/resume_user_mode.h>
+#include <linux/linkage.h>
+#include <linux/entry-common.h>
+
+#include <asm/ucontext.h>
+#include <asm/vdso.h>
+#include <asm/signal.h>
+#include <asm/signal32.h>
+#include <asm/switch_to.h>
+#include <asm/vector.h>
+#include <asm/csr.h>
+#include <asm/cacheflush.h>
+
+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(&current->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, &current->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, &current->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(&current->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 */
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