1 files changed, 252 insertions, 84 deletions

diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 17ba190e84a5..501e66debf69 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -6,18 +6,27 @@
  * 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/tracehook.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
 
@@ -35,26 +44,13 @@ 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(&current->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,
@@ -62,52 +58,189 @@ 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, &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)));
+
+	get_cpu_vector_context();
+	riscv_v_vstate_save(&current->thread.vstate, regs);
+	put_cpu_vector_context();
+
+	/* 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((__force void *)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;
 
-	/* 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;
-	}
+	/* 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_set_restore(current, regs);
 
 	return err;
 }
 #else
-#define save_fp_state(task, regs) (0)
-#define restore_fp_state(task, regs) (0)
+#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 (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, sizeof(*frame)))
+	if (!access_ok(frame, frame_size))
 		goto badframe;
 
 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
@@ -121,6 +254,8 @@ SYSCALL_DEFINE0(rt_sigreturn)
 	if (restore_altstack(&frame->uc.uc_stack))
 		goto badframe;
 
+	regs->cause = -1UL;
+
 	return regs->a0;
 
 badframe:
@@ -139,12 +274,23 @@ 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)
+	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;
 }
 
@@ -176,9 +322,11 @@ static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
 {
 	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, sizeof(*frame));
-	if (!access_ok(frame, sizeof(*frame)))
+	frame = get_sigframe(ksig, regs, frame_size);
+	if (!access_ok(frame, frame_size))
 		return -EFAULT;
 
 	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
@@ -204,7 +352,12 @@ static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
 	if (copy_to_user(&frame->sigreturn_code, __user_rt_sigreturn,
 			 sizeof(frame->sigreturn_code)))
 		return -EFAULT;
-	regs->ra = (unsigned long)&frame->sigreturn_code;
+
+	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 */
 
 	/*
@@ -234,87 +387,102 @@ 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 */
-	ret = setup_rt_frame(ksig, oldset, regs);
+	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);
 }
 
-static void do_signal(struct pt_regs *regs)
+void arch_do_signal_or_restart(struct pt_regs *regs)
 {
+	unsigned long continue_addr = 0, restart_addr = 0;
+	int retval = 0;
 	struct ksignal ksig;
+	bool syscall = (regs->cause == EXC_SYSCALL);
 
-	if (get_signal(&ksig)) {
-		/* Actually deliver the signal */
-		handle_signal(&ksig, regs);
-		return;
-	}
+	/* If we were from a system call, check for system call restarting */
+	if (syscall) {
+		continue_addr = regs->epc;
+		restart_addr = continue_addr - 4;
+		retval = regs->a0;
 
-	/* 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) {
+		/*
+		 * Prepare for system call restart. We do this here so that a
+		 * debugger will see the already changed PC.
+		 */
+		switch (retval) {
 		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;
+			regs->a0 = regs->orig_a0;
+			regs->epc = restart_addr;
 			break;
 		}
 	}
 
 	/*
+	 * Get the signal to deliver. When running under ptrace, at this point
+	 * the debugger may change all of our registers.
+	 */
+	if (get_signal(&ksig)) {
+		/*
+		 * Depending on the signal settings, we may need to revert the
+		 * decision to restart the system call, but skip this if a
+		 * debugger has chosen to restart at a different PC.
+		 */
+		if (regs->epc == restart_addr &&
+		    (retval == -ERESTARTNOHAND ||
+		     retval == -ERESTART_RESTARTBLOCK ||
+		     (retval == -ERESTARTSYS &&
+		      !(ksig.ka.sa.sa_flags & SA_RESTART)))) {
+			regs->a0 = -EINTR;
+			regs->epc = continue_addr;
+		}
+
+		/* Actually deliver the signal */
+		handle_signal(&ksig, regs);
+		return;
+	}
+
+	/*
+	 * Handle restarting a different system call. As above, if a debugger
+	 * has chosen to restart at a different PC, ignore the restart.
+	 */
+	if (syscall && regs->epc == restart_addr && retval == -ERESTART_RESTARTBLOCK)
+		regs->a7 = __NR_restart_syscall;
+
+	/*
 	 * If there is no signal to deliver, we just put the saved
 	 * sigmask back.
 	 */
 	restore_saved_sigmask();
 }
 
-/*
- * notification of userspace execution resumption
- * - triggered by the _TIF_WORK_MASK flags
- */
-asmlinkage __visible void do_notify_resume(struct pt_regs *regs,
-					   unsigned long thread_info_flags)
+void init_rt_signal_env(void);
+void __init init_rt_signal_env(void)
 {
-	/* Handle pending signal delivery */
-	if (thread_info_flags & _TIF_SIGPENDING)
-		do_signal(regs);
+	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);
+}
 
-	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
-		clear_thread_flag(TIF_NOTIFY_RESUME);
-		tracehook_notify_resume(regs);
-	}
+#ifdef CONFIG_DYNAMIC_SIGFRAME
+bool sigaltstack_size_valid(size_t ss_size)
+{
+	return ss_size > get_rt_frame_size(false);
 }
+#endif /* CONFIG_DYNAMIC_SIGFRAME */