Adding upstream version 6.1.76.upstream/6.1.76upstream

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

1 files changed, 589 insertions, 0 deletions

diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c
new file mode 100644
index 000000000..8bc0ddaa6
--- /dev/null
+++ b/arch/parisc/kernel/signal.c
@@ -0,0 +1,589 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  PA-RISC architecture-specific signal handling support.
+ *
+ *  Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
+ *  Copyright (C) 2000 Linuxcare, Inc.
+ *  Copyright (C) 2000-2022 Helge Deller <deller@gmx.de>
+ *  Copyright (C) 2022 John David Anglin <dave.anglin@bell.net>
+ *
+ *  Based on the ia64, i386, and alpha versions.
+ */
+
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/mm.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/resume_user_mode.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/compat.h>
+#include <linux/elf.h>
+#include <asm/ucontext.h>
+#include <asm/rt_sigframe.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+#include <asm/asm-offsets.h>
+#include <asm/vdso.h>
+
+#ifdef CONFIG_COMPAT
+#include "signal32.h"
+#endif
+
+#define DEBUG_SIG 0 
+#define DEBUG_SIG_LEVEL 2
+
+#if DEBUG_SIG
+#define DBG(LEVEL, ...) \
+        ((DEBUG_SIG_LEVEL >= LEVEL) \
+	? printk(__VA_ARGS__) : (void) 0)
+#else
+#define DBG(LEVEL, ...)
+#endif
+	
+/* gcc will complain if a pointer is cast to an integer of different
+ * size.  If you really need to do this (and we do for an ELF32 user
+ * application in an ELF64 kernel) then you have to do a cast to an
+ * integer of the same size first.  The A() macro accomplishes
+ * this. */
+#define A(__x)	((unsigned long)(__x))
+
+/*
+ * Do a signal return - restore sigcontext.
+ */
+
+static long
+restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
+{
+	long err = 0;
+
+	err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
+	err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
+	err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
+	err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
+	err |= __get_user(regs->sar, &sc->sc_sar);
+	DBG(2, "%s: iaoq is %#lx / %#lx\n",
+			__func__, regs->iaoq[0], regs->iaoq[1]);
+	DBG(2, "%s: r28 is %ld\n", __func__, regs->gr[28]);
+	return err;
+}
+
+void
+sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
+{
+	struct rt_sigframe __user *frame;
+	sigset_t set;
+	unsigned long usp = (regs->gr[30] & ~(0x01UL));
+	unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
+#ifdef CONFIG_64BIT
+	struct compat_rt_sigframe __user * compat_frame;
+	
+	if (is_compat_task())
+		sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
+#endif
+
+	current->restart_block.fn = do_no_restart_syscall;
+
+	/* Unwind the user stack to get the rt_sigframe structure. */
+	frame = (struct rt_sigframe __user *)
+		(usp - sigframe_size);
+	DBG(2, "%s: frame is %p pid %d\n", __func__, frame, task_pid_nr(current));
+
+	regs->orig_r28 = 1; /* no restarts for sigreturn */
+
+#ifdef CONFIG_64BIT
+	compat_frame = (struct compat_rt_sigframe __user *)frame;
+	
+	if (is_compat_task()) {
+		if (get_compat_sigset(&set, &compat_frame->uc.uc_sigmask))
+			goto give_sigsegv;
+	} else
+#endif
+	{
+		if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+			goto give_sigsegv;
+	}
+		
+	set_current_blocked(&set);
+
+	/* Good thing we saved the old gr[30], eh? */
+#ifdef CONFIG_64BIT
+	if (is_compat_task()) {
+		DBG(1, "%s: compat_frame->uc.uc_mcontext 0x%p\n",
+				__func__, &compat_frame->uc.uc_mcontext);
+// FIXME: Load upper half from register file
+		if (restore_sigcontext32(&compat_frame->uc.uc_mcontext, 
+					&compat_frame->regs, regs))
+			goto give_sigsegv;
+		DBG(1, "%s: usp %#08lx stack 0x%p\n",
+				__func__, usp, &compat_frame->uc.uc_stack);
+		if (compat_restore_altstack(&compat_frame->uc.uc_stack))
+			goto give_sigsegv;
+	} else
+#endif
+	{
+		DBG(1, "%s: frame->uc.uc_mcontext 0x%p\n",
+				__func__, &frame->uc.uc_mcontext);
+		if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
+			goto give_sigsegv;
+		DBG(1, "%s: usp %#08lx stack 0x%p\n",
+				__func__, usp, &frame->uc.uc_stack);
+		if (restore_altstack(&frame->uc.uc_stack))
+			goto give_sigsegv;
+	}
+		
+
+
+	/* If we are on the syscall path IAOQ will not be restored, and
+	 * if we are on the interrupt path we must not corrupt gr31.
+	 */
+	if (in_syscall)
+		regs->gr[31] = regs->iaoq[0];
+
+	return;
+
+give_sigsegv:
+	DBG(1, "%s: Sending SIGSEGV\n", __func__);
+	force_sig(SIGSEGV);
+	return;
+}
+
+/*
+ * Set up a signal frame.
+ */
+
+static inline void __user *
+get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
+{
+	/*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
+	  don't use the parameter it doesn't matter */
+
+	DBG(1, "%s: ka = %#lx, sp = %#lx, frame_size = %zu\n",
+			__func__, (unsigned long)ka, sp, frame_size);
+	
+	/* Align alternate stack and reserve 64 bytes for the signal
+	   handler's frame marker.  */
+	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
+		sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
+
+	DBG(1, "%s: Returning sp = %#lx\n", __func__, (unsigned long)sp);
+	return (void __user *) sp; /* Stacks grow up.  Fun. */
+}
+
+static long
+setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
+		 
+{
+	unsigned long flags = 0;
+	long err = 0;
+
+	if (on_sig_stack((unsigned long) sc))
+		flags |= PARISC_SC_FLAG_ONSTACK;
+	if (in_syscall) {
+		flags |= PARISC_SC_FLAG_IN_SYSCALL;
+		/* regs->iaoq is undefined in the syscall return path */
+		err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
+		err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
+		err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
+		err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
+		DBG(1, "%s: iaoq %#lx / %#lx (in syscall)\n",
+			__func__, regs->gr[31], regs->gr[31]+4);
+	} else {
+		err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
+		err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
+		DBG(1, "%s: iaoq %#lx / %#lx (not in syscall)\n",
+			__func__, regs->iaoq[0], regs->iaoq[1]);
+	}
+
+	err |= __put_user(flags, &sc->sc_flags);
+	err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
+	err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
+	err |= __put_user(regs->sar, &sc->sc_sar);
+	DBG(1, "%s: r28 is %ld\n", __func__, regs->gr[28]);
+
+	return err;
+}
+
+static long
+setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
+	       int in_syscall)
+{
+	struct rt_sigframe __user *frame;
+	unsigned long rp, usp;
+	unsigned long haddr, sigframe_size;
+	unsigned long start;
+	int err = 0;
+#ifdef CONFIG_64BIT
+	struct compat_rt_sigframe __user * compat_frame;
+#endif
+	
+	usp = (regs->gr[30] & ~(0x01UL));
+	sigframe_size = PARISC_RT_SIGFRAME_SIZE;
+#ifdef CONFIG_64BIT
+	if (is_compat_task()) {
+		/* The gcc alloca implementation leaves garbage in the upper 32 bits of sp */
+		usp = (compat_uint_t)usp;
+		sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
+	}
+#endif
+	frame = get_sigframe(&ksig->ka, usp, sigframe_size);
+
+	DBG(1, "%s: frame %p info %p\n", __func__, frame, &ksig->info);
+
+	start = (unsigned long) frame;
+	if (start >= TASK_SIZE_MAX - sigframe_size)
+		return -EFAULT;
+	
+#ifdef CONFIG_64BIT
+
+	compat_frame = (struct compat_rt_sigframe __user *)frame;
+	
+	if (is_compat_task()) {
+		DBG(1, "%s: frame->info = 0x%p\n", __func__, &compat_frame->info);
+		err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
+		err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
+		DBG(1, "%s: frame->uc = 0x%p\n", __func__, &compat_frame->uc);
+		DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
+			__func__, &compat_frame->uc.uc_mcontext);
+		err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext, 
+					&compat_frame->regs, regs, in_syscall);
+		err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
+					 sizeof(compat_sigset_t));
+	} else
+#endif
+	{	
+		DBG(1, "%s: frame->info = 0x%p\n", __func__, &frame->info);
+		err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+		err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
+		DBG(1, "%s: frame->uc = 0x%p\n", __func__, &frame->uc);
+		DBG(1, "%s: frame->uc.uc_mcontext = 0x%p\n",
+			__func__, &frame->uc.uc_mcontext);
+		err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
+		/* FIXME: Should probably be converted as well for the compat case */
+		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+	}
+	
+	if (err)
+		return -EFAULT;
+
+#ifdef CONFIG_64BIT
+	if (!is_compat_task())
+		rp = VDSO64_SYMBOL(current, sigtramp_rt);
+	else
+#endif
+		rp = VDSO32_SYMBOL(current, sigtramp_rt);
+
+	if (in_syscall)
+		rp += 4*4; /* skip 4 instructions and start at ldi 1,%r25 */
+
+	haddr = A(ksig->ka.sa.sa_handler);
+	/* The sa_handler may be a pointer to a function descriptor */
+#ifdef CONFIG_64BIT
+	if (is_compat_task()) {
+#endif
+		if (haddr & PA_PLABEL_FDESC) {
+			Elf32_Fdesc fdesc;
+			Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
+
+			err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
+
+			if (err)
+				return -EFAULT;
+
+			haddr = fdesc.addr;
+			regs->gr[19] = fdesc.gp;
+		}
+#ifdef CONFIG_64BIT
+	} else {
+		Elf64_Fdesc fdesc;
+		Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
+		
+		err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
+		
+		if (err)
+			return -EFAULT;
+		
+		haddr = fdesc.addr;
+		regs->gr[19] = fdesc.gp;
+		DBG(1, "%s: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
+		     __func__, haddr, regs->gr[19], in_syscall);
+	}
+#endif
+
+	/* The syscall return path will create IAOQ values from r31.
+	 */
+	if (in_syscall) {
+		regs->gr[31] = haddr;
+#ifdef CONFIG_64BIT
+		if (!test_thread_flag(TIF_32BIT))
+			sigframe_size |= 1; /* XXX ???? */
+#endif
+	} else {
+		unsigned long psw = USER_PSW;
+#ifdef CONFIG_64BIT
+		if (!test_thread_flag(TIF_32BIT))
+			psw |= PSW_W;
+#endif
+
+		/* If we are singlestepping, arrange a trap to be delivered
+		   when we return to userspace. Note the semantics -- we
+		   should trap before the first insn in the handler is
+		   executed. Ref:
+			http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
+		 */
+		if (pa_psw(current)->r) {
+			pa_psw(current)->r = 0;
+			psw |= PSW_R;
+			mtctl(-1, 0);
+		}
+
+		regs->gr[0] = psw;
+		regs->iaoq[0] = haddr | PRIV_USER;
+		regs->iaoq[1] = regs->iaoq[0] + 4;
+	}
+
+	regs->gr[2]  = rp;			/* userland return pointer */
+	regs->gr[26] = ksig->sig;               /* signal number */
+	
+#ifdef CONFIG_64BIT
+	if (is_compat_task()) {
+		regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
+		regs->gr[24] = A(&compat_frame->uc);   /* ucontext pointer */
+	} else
+#endif
+	{		
+		regs->gr[25] = A(&frame->info); /* siginfo pointer */
+		regs->gr[24] = A(&frame->uc);   /* ucontext pointer */
+	}
+	
+	DBG(1, "%s: making sigreturn frame: %#lx + %#lx = %#lx\n", __func__,
+	       regs->gr[30], sigframe_size,
+	       regs->gr[30] + sigframe_size);
+	/* Raise the user stack pointer to make a proper call frame. */
+	regs->gr[30] = (A(frame) + sigframe_size);
+
+
+	DBG(1, "%s: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
+	       __func__, current->comm, current->pid, frame, regs->gr[30],
+	       regs->iaoq[0], regs->iaoq[1], rp);
+
+	return 0;
+}
+
+/*
+ * OK, we're invoking a handler.
+ */	
+
+static void
+handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
+{
+	int ret;
+	sigset_t *oldset = sigmask_to_save();
+
+	DBG(1, "%s: sig=%d, ka=%p, info=%p, oldset=%p, regs=%p\n",
+	       __func__, ksig->sig, &ksig->ka, &ksig->info, oldset, regs);
+	
+	/* Set up the stack frame */
+	ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
+
+	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
+			  test_thread_flag(TIF_BLOCKSTEP));
+
+	DBG(1, "%s: Exit (success), regs->gr[28] = %ld\n",
+		__func__, regs->gr[28]);
+}
+
+/*
+ * Check how the syscall number gets loaded into %r20 within
+ * the delay branch in userspace and adjust as needed.
+ */
+
+static void check_syscallno_in_delay_branch(struct pt_regs *regs)
+{
+	u32 opcode, source_reg;
+	u32 __user *uaddr;
+	int err;
+
+	/* Usually we don't have to restore %r20 (the system call number)
+	 * because it gets loaded in the delay slot of the branch external
+	 * instruction via the ldi instruction.
+	 * In some cases a register-to-register copy instruction might have
+	 * been used instead, in which case we need to copy the syscall
+	 * number into the source register before returning to userspace.
+	 */
+
+	/* A syscall is just a branch, so all we have to do is fiddle the
+	 * return pointer so that the ble instruction gets executed again.
+	 */
+	regs->gr[31] -= 8; /* delayed branching */
+
+	/* Get assembler opcode of code in delay branch */
+	uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
+	err = get_user(opcode, uaddr);
+	if (err)
+		return;
+
+	/* Check if delay branch uses "ldi int,%r20" */
+	if ((opcode & 0xffff0000) == 0x34140000)
+		return;	/* everything ok, just return */
+
+	/* Check if delay branch uses "nop" */
+	if (opcode == INSN_NOP)
+		return;
+
+	/* Check if delay branch uses "copy %rX,%r20" */
+	if ((opcode & 0xffe0ffff) == 0x08000254) {
+		source_reg = (opcode >> 16) & 31;
+		regs->gr[source_reg] = regs->gr[20];
+		return;
+	}
+
+	pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
+		current->comm, task_pid_nr(current), opcode);
+}
+
+static inline void
+syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
+{
+	if (regs->orig_r28)
+		return;
+	regs->orig_r28 = 1; /* no more restarts */
+
+	DBG(1, "%s:  orig_r28 = %ld  pid %d  r20 %ld\n",
+		__func__, regs->orig_r28, task_pid_nr(current), regs->gr[20]);
+
+	/* Check the return code */
+	switch (regs->gr[28]) {
+	case -ERESTART_RESTARTBLOCK:
+	case -ERESTARTNOHAND:
+		DBG(1, "%s: ERESTARTNOHAND: returning -EINTR\n", __func__);
+		regs->gr[28] = -EINTR;
+		break;
+	case -ERESTARTSYS:
+		if (!(ka->sa.sa_flags & SA_RESTART)) {
+			DBG(1, "%s: ERESTARTSYS: putting -EINTR pid %d\n",
+				__func__, task_pid_nr(current));
+			regs->gr[28] = -EINTR;
+			break;
+		}
+		fallthrough;
+	case -ERESTARTNOINTR:
+		DBG(1, "%s: %ld\n", __func__, regs->gr[28]);
+		check_syscallno_in_delay_branch(regs);
+		break;
+	}
+}
+
+static inline void
+insert_restart_trampoline(struct pt_regs *regs)
+{
+	if (regs->orig_r28)
+		return;
+	regs->orig_r28 = 1; /* no more restarts */
+
+	DBG(2, "%s: gr28 = %ld pid %d\n",
+		__func__, regs->gr[28], task_pid_nr(current));
+
+	switch (regs->gr[28]) {
+	case -ERESTART_RESTARTBLOCK: {
+		/* Restart the system call - no handlers present */
+		unsigned int *usp = (unsigned int *)regs->gr[30];
+		unsigned long rp;
+		long err = 0;
+
+		/* check that we don't exceed the stack */
+		if (A(&usp[0]) >= TASK_SIZE_MAX - 5 * sizeof(int))
+			return;
+
+		/* Call trampoline in vdso to restart the syscall
+		 * with __NR_restart_syscall.
+		 * Original return addresses are on stack like this:
+		 *
+		 *  0: <return address (orig r31)>
+		 *  4: <2nd half for 64-bit>
+		 */
+#ifdef CONFIG_64BIT
+		if (!is_compat_task()) {
+			err |= put_user(regs->gr[31] >> 32, &usp[0]);
+			err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
+			rp = VDSO64_SYMBOL(current, restart_syscall);
+		} else
+#endif
+		{
+			err |= put_user(regs->gr[31], &usp[0]);
+			rp = VDSO32_SYMBOL(current, restart_syscall);
+		}
+		WARN_ON(err);
+
+		regs->gr[31] = rp;
+		DBG(1, "%s: ERESTART_RESTARTBLOCK\n", __func__);
+		return;
+	}
+	case -EINTR:
+		/* ok, was handled before and should be returned. */
+		break;
+	case -ERESTARTNOHAND:
+	case -ERESTARTSYS:
+	case -ERESTARTNOINTR:
+		DBG(1, "%s: Type %ld\n", __func__, regs->gr[28]);
+		check_syscallno_in_delay_branch(regs);
+		return;
+	default:
+		break;
+	}
+}
+
+/*
+ * We need to be able to restore the syscall arguments (r21-r26) to
+ * restart syscalls.  Thus, the syscall path should save them in the
+ * pt_regs structure (it's okay to do so since they are caller-save
+ * registers).  As noted below, the syscall number gets restored for
+ * us due to the magic of delayed branching.
+ */
+static void do_signal(struct pt_regs *regs, long in_syscall)
+{
+	struct ksignal ksig;
+	int restart_syscall;
+	bool has_handler;
+
+	has_handler = get_signal(&ksig);
+
+	restart_syscall = 0;
+	if (in_syscall)
+		restart_syscall = 1;
+
+	if (has_handler) {
+		/* Restart a system call if necessary. */
+		if (restart_syscall)
+			syscall_restart(regs, &ksig.ka);
+
+		handle_signal(&ksig, regs, in_syscall);
+		DBG(1, "%s: Handled signal pid %d\n",
+			__func__, task_pid_nr(current));
+		return;
+	}
+
+	/* Do we need to restart the system call? */
+	if (restart_syscall)
+		insert_restart_trampoline(regs);
+	
+	DBG(1, "%s: Exit (not delivered), regs->gr[28] = %ld  orig_r28 = %ld  pid %d\n",
+		__func__, regs->gr[28], regs->orig_r28, task_pid_nr(current));
+
+	restore_saved_sigmask();
+}
+
+void do_notify_resume(struct pt_regs *regs, long in_syscall)
+{
+	if (test_thread_flag(TIF_SIGPENDING) ||
+	    test_thread_flag(TIF_NOTIFY_SIGNAL))
+		do_signal(regs, in_syscall);
+
+	if (test_thread_flag(TIF_NOTIFY_RESUME))
+		resume_user_mode_work(regs);
+}