Adding upstream version 4.19.249.upstream/4.19.249

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

1 files changed, 412 insertions, 0 deletions

diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
new file mode 100644
index 000000000..9a960829a
--- /dev/null
+++ b/arch/ia64/kernel/signal.c
@@ -0,0 +1,412 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Architecture-specific signal handling support.
+ *
+ * Copyright (C) 1999-2004 Hewlett-Packard Co
+ *	David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * Derived from i386 and Alpha versions.
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/smp.h>
+#include <linux/stddef.h>
+#include <linux/tty.h>
+#include <linux/binfmts.h>
+#include <linux/unistd.h>
+#include <linux/wait.h>
+
+#include <asm/intrinsics.h>
+#include <linux/uaccess.h>
+#include <asm/rse.h>
+#include <asm/sigcontext.h>
+
+#include "sigframe.h"
+
+#define DEBUG_SIG	0
+#define STACK_ALIGN	16		/* minimal alignment for stack pointer */
+
+#if _NSIG_WORDS > 1
+# define PUT_SIGSET(k,u)	__copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
+# define GET_SIGSET(k,u)	__copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
+#else
+# define PUT_SIGSET(k,u)	__put_user((k)->sig[0], &(u)->sig[0])
+# define GET_SIGSET(k,u)	__get_user((k)->sig[0], &(u)->sig[0])
+#endif
+
+static long
+restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
+{
+	unsigned long ip, flags, nat, um, cfm, rsc;
+	long err;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	/* restore scratch that always needs gets updated during signal delivery: */
+	err  = __get_user(flags, &sc->sc_flags);
+	err |= __get_user(nat, &sc->sc_nat);
+	err |= __get_user(ip, &sc->sc_ip);			/* instruction pointer */
+	err |= __get_user(cfm, &sc->sc_cfm);
+	err |= __get_user(um, &sc->sc_um);			/* user mask */
+	err |= __get_user(rsc, &sc->sc_ar_rsc);
+	err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
+	err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
+	err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
+	err |= __get_user(scr->pt.pr, &sc->sc_pr);		/* predicates */
+	err |= __get_user(scr->pt.b0, &sc->sc_br[0]);		/* b0 (rp) */
+	err |= __get_user(scr->pt.b6, &sc->sc_br[6]);		/* b6 */
+	err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8);	/* r1 */
+	err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8);	/* r8-r11 */
+	err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8);	/* r12-r13 */
+	err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8);	/* r15 */
+
+	scr->pt.cr_ifs = cfm | (1UL << 63);
+	scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
+
+	/* establish new instruction pointer: */
+	scr->pt.cr_iip = ip & ~0x3UL;
+	ia64_psr(&scr->pt)->ri = ip & 0x3;
+	scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
+
+	scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
+
+	if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
+		/* Restore most scratch-state only when not in syscall. */
+		err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);		/* ar.ccv */
+		err |= __get_user(scr->pt.b7, &sc->sc_br[7]);			/* b7 */
+		err |= __get_user(scr->pt.r14, &sc->sc_gr[14]);			/* r14 */
+		err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
+		err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8);	/* r2-r3 */
+		err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8);	/* r16-r31 */
+	}
+
+	if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
+		struct ia64_psr *psr = ia64_psr(&scr->pt);
+
+		err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
+		psr->mfh = 0;	/* drop signal handler's fph contents... */
+		preempt_disable();
+		if (psr->dfh)
+			ia64_drop_fpu(current);
+		else {
+			/* We already own the local fph, otherwise psr->dfh wouldn't be 0.  */
+			__ia64_load_fpu(current->thread.fph);
+			ia64_set_local_fpu_owner(current);
+		}
+		preempt_enable();
+	}
+	return err;
+}
+
+long
+ia64_rt_sigreturn (struct sigscratch *scr)
+{
+	extern char ia64_strace_leave_kernel, ia64_leave_kernel;
+	struct sigcontext __user *sc;
+	sigset_t set;
+	long retval;
+
+	sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
+
+	/*
+	 * When we return to the previously executing context, r8 and r10 have already
+	 * been setup the way we want them.  Indeed, if the signal wasn't delivered while
+	 * in a system call, we must not touch r8 or r10 as otherwise user-level state
+	 * could be corrupted.
+	 */
+	retval = (long) &ia64_leave_kernel;
+	if (test_thread_flag(TIF_SYSCALL_TRACE)
+	    || test_thread_flag(TIF_SYSCALL_AUDIT))
+		/*
+		 * strace expects to be notified after sigreturn returns even though the
+		 * context to which we return may not be in the middle of a syscall.
+		 * Thus, the return-value that strace displays for sigreturn is
+		 * meaningless.
+		 */
+		retval = (long) &ia64_strace_leave_kernel;
+
+	if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
+		goto give_sigsegv;
+
+	if (GET_SIGSET(&set, &sc->sc_mask))
+		goto give_sigsegv;
+
+	set_current_blocked(&set);
+
+	if (restore_sigcontext(sc, scr))
+		goto give_sigsegv;
+
+#if DEBUG_SIG
+	printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
+	       current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
+#endif
+	if (restore_altstack(&sc->sc_stack))
+		goto give_sigsegv;
+	return retval;
+
+  give_sigsegv:
+	force_sig(SIGSEGV, current);
+	return retval;
+}
+
+/*
+ * This does just the minimum required setup of sigcontext.
+ * Specifically, it only installs data that is either not knowable at
+ * the user-level or that gets modified before execution in the
+ * trampoline starts.  Everything else is done at the user-level.
+ */
+static long
+setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
+{
+	unsigned long flags = 0, ifs, cfm, nat;
+	long err = 0;
+
+	ifs = scr->pt.cr_ifs;
+
+	if (on_sig_stack((unsigned long) sc))
+		flags |= IA64_SC_FLAG_ONSTACK;
+	if ((ifs & (1UL << 63)) == 0)
+		/* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
+		flags |= IA64_SC_FLAG_IN_SYSCALL;
+	cfm = ifs & ((1UL << 38) - 1);
+	ia64_flush_fph(current);
+	if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
+		flags |= IA64_SC_FLAG_FPH_VALID;
+		err = __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
+	}
+
+	nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
+
+	err |= __put_user(flags, &sc->sc_flags);
+	err |= __put_user(nat, &sc->sc_nat);
+	err |= PUT_SIGSET(mask, &sc->sc_mask);
+	err |= __put_user(cfm, &sc->sc_cfm);
+	err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
+	err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
+	err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat);		/* ar.unat */
+	err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);		/* ar.fpsr */
+	err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
+	err |= __put_user(scr->pt.pr, &sc->sc_pr);			/* predicates */
+	err |= __put_user(scr->pt.b0, &sc->sc_br[0]);			/* b0 (rp) */
+	err |= __put_user(scr->pt.b6, &sc->sc_br[6]);			/* b6 */
+	err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8);		/* r1 */
+	err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8);		/* r8-r11 */
+	err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8);	/* r12-r13 */
+	err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8);		/* r15 */
+	err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
+
+	if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
+		/* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
+		err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);		/* ar.ccv */
+		err |= __put_user(scr->pt.b7, &sc->sc_br[7]);			/* b7 */
+		err |= __put_user(scr->pt.r14, &sc->sc_gr[14]);			/* r14 */
+		err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
+		err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8);		/* r2-r3 */
+		err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8);	/* r16-r31 */
+	}
+	return err;
+}
+
+/*
+ * Check whether the register-backing store is already on the signal stack.
+ */
+static inline int
+rbs_on_sig_stack (unsigned long bsp)
+{
+	return (bsp - current->sas_ss_sp < current->sas_ss_size);
+}
+
+static long
+setup_frame(struct ksignal *ksig, sigset_t *set, struct sigscratch *scr)
+{
+	extern char __kernel_sigtramp[];
+	unsigned long tramp_addr, new_rbs = 0, new_sp;
+	struct sigframe __user *frame;
+	long err;
+
+	new_sp = scr->pt.r12;
+	tramp_addr = (unsigned long) __kernel_sigtramp;
+	if (ksig->ka.sa.sa_flags & SA_ONSTACK) {
+		int onstack = sas_ss_flags(new_sp);
+
+		if (onstack == 0) {
+			new_sp = current->sas_ss_sp + current->sas_ss_size;
+			/*
+			 * We need to check for the register stack being on the
+			 * signal stack separately, because it's switched
+			 * separately (memory stack is switched in the kernel,
+			 * register stack is switched in the signal trampoline).
+			 */
+			if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
+				new_rbs = ALIGN(current->sas_ss_sp,
+						sizeof(long));
+		} else if (onstack == SS_ONSTACK) {
+			unsigned long check_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.
+			 */
+			check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN;
+			if (!likely(on_sig_stack(check_sp))) {
+				force_sigsegv(ksig->sig, current);
+				return 1;
+			}
+		}
+	}
+	frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) {
+		force_sigsegv(ksig->sig, current);
+		return 1;
+	}
+
+	err  = __put_user(ksig->sig, &frame->arg0);
+	err |= __put_user(&frame->info, &frame->arg1);
+	err |= __put_user(&frame->sc, &frame->arg2);
+	err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
+	err |= __put_user(0, &frame->sc.sc_loadrs);	/* initialize to zero */
+	err |= __put_user(ksig->ka.sa.sa_handler, &frame->handler);
+
+	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+
+	err |= __save_altstack(&frame->sc.sc_stack, scr->pt.r12);
+	err |= setup_sigcontext(&frame->sc, set, scr);
+
+	if (unlikely(err)) {
+		force_sigsegv(ksig->sig, current);
+		return 1;
+	}
+
+	scr->pt.r12 = (unsigned long) frame - 16;	/* new stack pointer */
+	scr->pt.ar_fpsr = FPSR_DEFAULT;			/* reset fpsr for signal handler */
+	scr->pt.cr_iip = tramp_addr;
+	ia64_psr(&scr->pt)->ri = 0;			/* start executing in first slot */
+	ia64_psr(&scr->pt)->be = 0;			/* force little-endian byte-order */
+	/*
+	 * Force the interruption function mask to zero.  This has no effect when a
+	 * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is
+	 * ignored), but it has the desirable effect of making it possible to deliver a
+	 * signal with an incomplete register frame (which happens when a mandatory RSE
+	 * load faults).  Furthermore, it has no negative effect on the getting the user's
+	 * dirty partition preserved, because that's governed by scr->pt.loadrs.
+	 */
+	scr->pt.cr_ifs = (1UL << 63);
+
+	/*
+	 * Note: this affects only the NaT bits of the scratch regs (the ones saved in
+	 * pt_regs), which is exactly what we want.
+	 */
+	scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
+
+#if DEBUG_SIG
+	printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n",
+	       current->comm, current->pid, ksig->sig, scr->pt.r12, frame->sc.sc_ip, frame->handler);
+#endif
+	return 0;
+}
+
+static long
+handle_signal (struct ksignal *ksig, struct sigscratch *scr)
+{
+	int ret = setup_frame(ksig, sigmask_to_save(), scr);
+
+	if (!ret)
+		signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
+
+	return ret;
+}
+
+/*
+ * Note that `init' is a special process: it doesn't get signals it doesn't want to
+ * handle.  Thus you cannot kill init even with a SIGKILL even by mistake.
+ */
+void
+ia64_do_signal (struct sigscratch *scr, long in_syscall)
+{
+	long restart = in_syscall;
+	long errno = scr->pt.r8;
+	struct ksignal ksig;
+
+	/*
+	 * This only loops in the rare cases of handle_signal() failing, in which case we
+	 * need to push through a forced SIGSEGV.
+	 */
+	while (1) {
+		get_signal(&ksig);
+
+		/*
+		 * get_signal_to_deliver() may have run a debugger (via notify_parent())
+		 * and the debugger may have modified the state (e.g., to arrange for an
+		 * inferior call), thus it's important to check for restarting _after_
+		 * get_signal_to_deliver().
+		 */
+		if ((long) scr->pt.r10 != -1)
+			/*
+			 * A system calls has to be restarted only if one of the error codes
+			 * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned.  If r10
+			 * isn't -1 then r8 doesn't hold an error code and we don't need to
+			 * restart the syscall, so we can clear the "restart" flag here.
+			 */
+			restart = 0;
+
+		if (ksig.sig <= 0)
+			break;
+
+		if (unlikely(restart)) {
+			switch (errno) {
+			      case ERESTART_RESTARTBLOCK:
+			      case ERESTARTNOHAND:
+				scr->pt.r8 = EINTR;
+				/* note: scr->pt.r10 is already -1 */
+				break;
+
+			      case ERESTARTSYS:
+				if ((ksig.ka.sa.sa_flags & SA_RESTART) == 0) {
+					scr->pt.r8 = EINTR;
+					/* note: scr->pt.r10 is already -1 */
+					break;
+				}
+			      case ERESTARTNOINTR:
+				ia64_decrement_ip(&scr->pt);
+				restart = 0; /* don't restart twice if handle_signal() fails... */
+			}
+		}
+
+		/*
+		 * Whee!  Actually deliver the signal.  If the delivery failed, we need to
+		 * continue to iterate in this loop so we can deliver the SIGSEGV...
+		 */
+		if (handle_signal(&ksig, scr))
+			return;
+	}
+
+	/* Did we come from a system call? */
+	if (restart) {
+		/* Restart the system call - no handlers present */
+		if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
+		    || errno == ERESTART_RESTARTBLOCK)
+		{
+			/*
+			 * Note: the syscall number is in r15 which is saved in
+			 * pt_regs so all we need to do here is adjust ip so that
+			 * the "break" instruction gets re-executed.
+			 */
+			ia64_decrement_ip(&scr->pt);
+			if (errno == ERESTART_RESTARTBLOCK)
+				scr->pt.r15 = __NR_restart_syscall;
+		}
+	}
+
+	/* if there's no signal to deliver, we just put the saved sigmask
+	 * back */
+	restore_saved_sigmask();
+}