Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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 */