v4.19.13 snapshot.
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
new file mode 100644
index 0000000..22f0824
--- /dev/null
+++ b/arch/s390/kernel/signal.c
@@ -0,0 +1,541 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 1999, 2006
+ * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
+ *
+ * Based on Intel version
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
+ */
+
+#include <linux/sched.h>
+#include <linux/sched/task_stack.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/unistd.h>
+#include <linux/stddef.h>
+#include <linux/tty.h>
+#include <linux/personality.h>
+#include <linux/binfmts.h>
+#include <linux/tracehook.h>
+#include <linux/syscalls.h>
+#include <linux/compat.h>
+#include <asm/ucontext.h>
+#include <linux/uaccess.h>
+#include <asm/lowcore.h>
+#include <asm/switch_to.h>
+#include "entry.h"
+
+/*
+ * Layout of an old-style signal-frame:
+ * -----------------------------------------
+ * | save area (_SIGNAL_FRAMESIZE) |
+ * -----------------------------------------
+ * | struct sigcontext |
+ * | oldmask |
+ * | _sigregs * |
+ * -----------------------------------------
+ * | _sigregs with |
+ * | _s390_regs_common |
+ * | _s390_fp_regs |
+ * -----------------------------------------
+ * | int signo |
+ * -----------------------------------------
+ * | _sigregs_ext with |
+ * | gprs_high 64 byte (opt) |
+ * | vxrs_low 128 byte (opt) |
+ * | vxrs_high 256 byte (opt) |
+ * | reserved 128 byte (opt) |
+ * -----------------------------------------
+ * | __u16 svc_insn |
+ * -----------------------------------------
+ * The svc_insn entry with the sigreturn system call opcode does not
+ * have a fixed position and moves if gprs_high or vxrs exist.
+ * Future extensions will be added to _sigregs_ext.
+ */
+struct sigframe
+{
+ __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
+ struct sigcontext sc;
+ _sigregs sregs;
+ int signo;
+ _sigregs_ext sregs_ext;
+ __u16 svc_insn; /* Offset of svc_insn is NOT fixed! */
+};
+
+/*
+ * Layout of an rt signal-frame:
+ * -----------------------------------------
+ * | save area (_SIGNAL_FRAMESIZE) |
+ * -----------------------------------------
+ * | svc __NR_rt_sigreturn 2 byte |
+ * -----------------------------------------
+ * | struct siginfo |
+ * -----------------------------------------
+ * | struct ucontext_extended with |
+ * | unsigned long uc_flags |
+ * | struct ucontext *uc_link |
+ * | stack_t uc_stack |
+ * | _sigregs uc_mcontext with |
+ * | _s390_regs_common |
+ * | _s390_fp_regs |
+ * | sigset_t uc_sigmask |
+ * | _sigregs_ext uc_mcontext_ext |
+ * | gprs_high 64 byte (opt) |
+ * | vxrs_low 128 byte (opt) |
+ * | vxrs_high 256 byte (opt)|
+ * | reserved 128 byte (opt) |
+ * -----------------------------------------
+ * Future extensions will be added to _sigregs_ext.
+ */
+struct rt_sigframe
+{
+ __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
+ __u16 svc_insn;
+ struct siginfo info;
+ struct ucontext_extended uc;
+};
+
+/* Store registers needed to create the signal frame */
+static void store_sigregs(void)
+{
+ save_access_regs(current->thread.acrs);
+ save_fpu_regs();
+}
+
+/* Load registers after signal return */
+static void load_sigregs(void)
+{
+ restore_access_regs(current->thread.acrs);
+}
+
+/* Returns non-zero on fault. */
+static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
+{
+ _sigregs user_sregs;
+
+ /* Copy a 'clean' PSW mask to the user to avoid leaking
+ information about whether PER is currently on. */
+ user_sregs.regs.psw.mask = PSW_USER_BITS |
+ (regs->psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
+ user_sregs.regs.psw.addr = regs->psw.addr;
+ memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs));
+ memcpy(&user_sregs.regs.acrs, current->thread.acrs,
+ sizeof(user_sregs.regs.acrs));
+ fpregs_store(&user_sregs.fpregs, ¤t->thread.fpu);
+ if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs)))
+ return -EFAULT;
+ return 0;
+}
+
+static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
+{
+ _sigregs user_sregs;
+
+ /* Alwys make any pending restarted system call return -EINTR */
+ current->restart_block.fn = do_no_restart_syscall;
+
+ if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
+ return -EFAULT;
+
+ if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
+ return -EINVAL;
+
+ /* Test the floating-point-control word. */
+ if (test_fp_ctl(user_sregs.fpregs.fpc))
+ return -EINVAL;
+
+ /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
+ regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
+ (user_sregs.regs.psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
+ /* Check for invalid user address space control. */
+ if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
+ regs->psw.mask = PSW_ASC_PRIMARY |
+ (regs->psw.mask & ~PSW_MASK_ASC);
+ /* Check for invalid amode */
+ if (regs->psw.mask & PSW_MASK_EA)
+ regs->psw.mask |= PSW_MASK_BA;
+ regs->psw.addr = user_sregs.regs.psw.addr;
+ memcpy(®s->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
+ memcpy(¤t->thread.acrs, &user_sregs.regs.acrs,
+ sizeof(current->thread.acrs));
+
+ fpregs_load(&user_sregs.fpregs, ¤t->thread.fpu);
+
+ clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
+ return 0;
+}
+
+/* Returns non-zero on fault. */
+static int save_sigregs_ext(struct pt_regs *regs,
+ _sigregs_ext __user *sregs_ext)
+{
+ __u64 vxrs[__NUM_VXRS_LOW];
+ int i;
+
+ /* Save vector registers to signal stack */
+ if (MACHINE_HAS_VX) {
+ for (i = 0; i < __NUM_VXRS_LOW; i++)
+ vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1);
+ if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
+ sizeof(sregs_ext->vxrs_low)) ||
+ __copy_to_user(&sregs_ext->vxrs_high,
+ current->thread.fpu.vxrs + __NUM_VXRS_LOW,
+ sizeof(sregs_ext->vxrs_high)))
+ return -EFAULT;
+ }
+ return 0;
+}
+
+static int restore_sigregs_ext(struct pt_regs *regs,
+ _sigregs_ext __user *sregs_ext)
+{
+ __u64 vxrs[__NUM_VXRS_LOW];
+ int i;
+
+ /* Restore vector registers from signal stack */
+ if (MACHINE_HAS_VX) {
+ if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
+ sizeof(sregs_ext->vxrs_low)) ||
+ __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW,
+ &sregs_ext->vxrs_high,
+ sizeof(sregs_ext->vxrs_high)))
+ return -EFAULT;
+ for (i = 0; i < __NUM_VXRS_LOW; i++)
+ *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i];
+ }
+ return 0;
+}
+
+SYSCALL_DEFINE0(sigreturn)
+{
+ struct pt_regs *regs = task_pt_regs(current);
+ struct sigframe __user *frame =
+ (struct sigframe __user *) regs->gprs[15];
+ sigset_t set;
+
+ if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
+ goto badframe;
+ set_current_blocked(&set);
+ save_fpu_regs();
+ if (restore_sigregs(regs, &frame->sregs))
+ goto badframe;
+ if (restore_sigregs_ext(regs, &frame->sregs_ext))
+ goto badframe;
+ load_sigregs();
+ return regs->gprs[2];
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+SYSCALL_DEFINE0(rt_sigreturn)
+{
+ struct pt_regs *regs = task_pt_regs(current);
+ struct rt_sigframe __user *frame =
+ (struct rt_sigframe __user *)regs->gprs[15];
+ sigset_t set;
+
+ if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
+ goto badframe;
+ set_current_blocked(&set);
+ if (restore_altstack(&frame->uc.uc_stack))
+ goto badframe;
+ save_fpu_regs();
+ if (restore_sigregs(regs, &frame->uc.uc_mcontext))
+ goto badframe;
+ if (restore_sigregs_ext(regs, &frame->uc.uc_mcontext_ext))
+ goto badframe;
+ load_sigregs();
+ return regs->gprs[2];
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+/*
+ * Determine which stack to use..
+ */
+static inline void __user *
+get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
+{
+ unsigned long sp;
+
+ /* Default to using normal stack */
+ sp = regs->gprs[15];
+
+ /* Overflow on alternate signal stack gives SIGSEGV. */
+ if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
+ return (void __user *) -1UL;
+
+ /* This is the X/Open sanctioned signal stack switching. */
+ if (ka->sa.sa_flags & SA_ONSTACK) {
+ if (! sas_ss_flags(sp))
+ sp = current->sas_ss_sp + current->sas_ss_size;
+ }
+
+ return (void __user *)((sp - frame_size) & -8ul);
+}
+
+static int setup_frame(int sig, struct k_sigaction *ka,
+ sigset_t *set, struct pt_regs * regs)
+{
+ struct sigframe __user *frame;
+ struct sigcontext sc;
+ unsigned long restorer;
+ size_t frame_size;
+
+ /*
+ * gprs_high are only present for a 31-bit task running on
+ * a 64-bit kernel (see compat_signal.c) but the space for
+ * gprs_high need to be allocated if vector registers are
+ * included in the signal frame on a 31-bit system.
+ */
+ frame_size = sizeof(*frame) - sizeof(frame->sregs_ext);
+ if (MACHINE_HAS_VX)
+ frame_size += sizeof(frame->sregs_ext);
+ frame = get_sigframe(ka, regs, frame_size);
+ if (frame == (void __user *) -1UL)
+ return -EFAULT;
+
+ /* Set up backchain. */
+ if (__put_user(regs->gprs[15], (addr_t __user *) frame))
+ return -EFAULT;
+
+ /* Create struct sigcontext on the signal stack */
+ memcpy(&sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE);
+ sc.sregs = (_sigregs __user __force *) &frame->sregs;
+ if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc)))
+ return -EFAULT;
+
+ /* Store registers needed to create the signal frame */
+ store_sigregs();
+
+ /* Create _sigregs on the signal stack */
+ if (save_sigregs(regs, &frame->sregs))
+ return -EFAULT;
+
+ /* Place signal number on stack to allow backtrace from handler. */
+ if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
+ return -EFAULT;
+
+ /* Create _sigregs_ext on the signal stack */
+ if (save_sigregs_ext(regs, &frame->sregs_ext))
+ return -EFAULT;
+
+ /* Set up to return from userspace. If provided, use a stub
+ already in userspace. */
+ if (ka->sa.sa_flags & SA_RESTORER) {
+ restorer = (unsigned long) ka->sa.sa_restorer;
+ } else {
+ /* Signal frame without vector registers are short ! */
+ __u16 __user *svc = (void __user *) frame + frame_size - 2;
+ if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
+ return -EFAULT;
+ restorer = (unsigned long) svc;
+ }
+
+ /* Set up registers for signal handler */
+ regs->gprs[14] = restorer;
+ regs->gprs[15] = (unsigned long) frame;
+ /* Force default amode and default user address space control. */
+ regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
+ (PSW_USER_BITS & PSW_MASK_ASC) |
+ (regs->psw.mask & ~PSW_MASK_ASC);
+ regs->psw.addr = (unsigned long) ka->sa.sa_handler;
+
+ regs->gprs[2] = sig;
+ regs->gprs[3] = (unsigned long) &frame->sc;
+
+ /* We forgot to include these in the sigcontext.
+ To avoid breaking binary compatibility, they are passed as args. */
+ if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
+ sig == SIGTRAP || sig == SIGFPE) {
+ /* set extra registers only for synchronous signals */
+ regs->gprs[4] = regs->int_code & 127;
+ regs->gprs[5] = regs->int_parm_long;
+ regs->gprs[6] = current->thread.last_break;
+ }
+ return 0;
+}
+
+static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
+ struct pt_regs *regs)
+{
+ struct rt_sigframe __user *frame;
+ unsigned long uc_flags, restorer;
+ size_t frame_size;
+
+ frame_size = sizeof(struct rt_sigframe) - sizeof(_sigregs_ext);
+ /*
+ * gprs_high are only present for a 31-bit task running on
+ * a 64-bit kernel (see compat_signal.c) but the space for
+ * gprs_high need to be allocated if vector registers are
+ * included in the signal frame on a 31-bit system.
+ */
+ uc_flags = 0;
+ if (MACHINE_HAS_VX) {
+ frame_size += sizeof(_sigregs_ext);
+ uc_flags |= UC_VXRS;
+ }
+ frame = get_sigframe(&ksig->ka, regs, frame_size);
+ if (frame == (void __user *) -1UL)
+ return -EFAULT;
+
+ /* Set up backchain. */
+ if (__put_user(regs->gprs[15], (addr_t __user *) frame))
+ return -EFAULT;
+
+ /* Set up to return from userspace. If provided, use a stub
+ already in userspace. */
+ if (ksig->ka.sa.sa_flags & SA_RESTORER) {
+ restorer = (unsigned long) ksig->ka.sa.sa_restorer;
+ } else {
+ __u16 __user *svc = &frame->svc_insn;
+ if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
+ return -EFAULT;
+ restorer = (unsigned long) svc;
+ }
+
+ /* Create siginfo on the signal stack */
+ if (copy_siginfo_to_user(&frame->info, &ksig->info))
+ return -EFAULT;
+
+ /* Store registers needed to create the signal frame */
+ store_sigregs();
+
+ /* Create ucontext on the signal stack. */
+ if (__put_user(uc_flags, &frame->uc.uc_flags) ||
+ __put_user(NULL, &frame->uc.uc_link) ||
+ __save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
+ save_sigregs(regs, &frame->uc.uc_mcontext) ||
+ __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) ||
+ save_sigregs_ext(regs, &frame->uc.uc_mcontext_ext))
+ return -EFAULT;
+
+ /* Set up registers for signal handler */
+ regs->gprs[14] = restorer;
+ regs->gprs[15] = (unsigned long) frame;
+ /* Force default amode and default user address space control. */
+ regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
+ (PSW_USER_BITS & PSW_MASK_ASC) |
+ (regs->psw.mask & ~PSW_MASK_ASC);
+ regs->psw.addr = (unsigned long) ksig->ka.sa.sa_handler;
+
+ regs->gprs[2] = ksig->sig;
+ regs->gprs[3] = (unsigned long) &frame->info;
+ regs->gprs[4] = (unsigned long) &frame->uc;
+ regs->gprs[5] = current->thread.last_break;
+ return 0;
+}
+
+static void handle_signal(struct ksignal *ksig, sigset_t *oldset,
+ struct pt_regs *regs)
+{
+ int ret;
+
+ /* Set up the stack frame */
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+ ret = setup_rt_frame(ksig, oldset, regs);
+ else
+ ret = setup_frame(ksig->sig, &ksig->ka, oldset, regs);
+
+ signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
+}
+
+/*
+ * 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.
+ *
+ * Note that we go through the signals twice: once to check the signals that
+ * the kernel can handle, and then we build all the user-level signal handling
+ * stack-frames in one go after that.
+ */
+void do_signal(struct pt_regs *regs)
+{
+ struct ksignal ksig;
+ sigset_t *oldset = sigmask_to_save();
+
+ /*
+ * Get signal to deliver. When running under ptrace, at this point
+ * the debugger may change all our registers, including the system
+ * call information.
+ */
+ current->thread.system_call =
+ test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
+
+ if (get_signal(&ksig)) {
+ /* Whee! Actually deliver the signal. */
+ if (current->thread.system_call) {
+ regs->int_code = current->thread.system_call;
+ /* Check for system call restarting. */
+ switch (regs->gprs[2]) {
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ regs->gprs[2] = -EINTR;
+ break;
+ case -ERESTARTSYS:
+ if (!(ksig.ka.sa.sa_flags & SA_RESTART)) {
+ regs->gprs[2] = -EINTR;
+ break;
+ }
+ /* fallthrough */
+ case -ERESTARTNOINTR:
+ regs->gprs[2] = regs->orig_gpr2;
+ regs->psw.addr =
+ __rewind_psw(regs->psw,
+ regs->int_code >> 16);
+ break;
+ }
+ }
+ /* No longer in a system call */
+ clear_pt_regs_flag(regs, PIF_SYSCALL);
+ rseq_signal_deliver(&ksig, regs);
+ if (is_compat_task())
+ handle_signal32(&ksig, oldset, regs);
+ else
+ handle_signal(&ksig, oldset, regs);
+ return;
+ }
+
+ /* No handlers present - check for system call restart */
+ clear_pt_regs_flag(regs, PIF_SYSCALL);
+ if (current->thread.system_call) {
+ regs->int_code = current->thread.system_call;
+ switch (regs->gprs[2]) {
+ case -ERESTART_RESTARTBLOCK:
+ /* Restart with sys_restart_syscall */
+ regs->int_code = __NR_restart_syscall;
+ /* fallthrough */
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ /* Restart system call with magic TIF bit. */
+ regs->gprs[2] = regs->orig_gpr2;
+ set_pt_regs_flag(regs, PIF_SYSCALL);
+ if (test_thread_flag(TIF_SINGLE_STEP))
+ clear_pt_regs_flag(regs, PIF_PER_TRAP);
+ break;
+ }
+ }
+
+ /*
+ * If there's no signal to deliver, we just put the saved sigmask back.
+ */
+ restore_saved_sigmask();
+}
+
+void do_notify_resume(struct pt_regs *regs)
+{
+ clear_thread_flag(TIF_NOTIFY_RESUME);
+ tracehook_notify_resume(regs);
+ rseq_handle_notify_resume(NULL, regs);
+}