[PATCH 10/19] csky: Signal handling

From: Guo Ren
Date: Sun Mar 18 2018 - 15:58:44 EST

Signed-off-by: Guo Ren <ren_guo@xxxxxxxxx>
---
arch/csky/include/uapi/asm/sigcontext.h | 33 +++
arch/csky/include/uapi/asm/signal.h | 164 ++++++++++++++
arch/csky/kernel/signal.c | 379 ++++++++++++++++++++++++++++++++
3 files changed, 576 insertions(+)
create mode 100644 arch/csky/include/uapi/asm/sigcontext.h
create mode 100644 arch/csky/include/uapi/asm/signal.h
create mode 100644 arch/csky/kernel/signal.c

diff --git a/arch/csky/include/uapi/asm/sigcontext.h b/arch/csky/include/uapi/asm/sigcontext.h
new file mode 100644
index 0000000..8ef0ce8
--- /dev/null
+++ b/arch/csky/include/uapi/asm/sigcontext.h
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+#ifndef _ASM_CSKY_SIGCONTEXT_H
+#define _ASM_CSKY_SIGCONTEXT_H
+
+struct sigcontext {
+ unsigned long sc_mask; /* old sigmask */
+ unsigned long sc_usp; /* old user stack pointer */
+ unsigned long sc_a0;
+ unsigned long sc_a1;
+ unsigned long sc_a2;
+ unsigned long sc_a3;
+ // ABIV2: r4 ~ r13; ABIV1: r6 ~ r14, r1.
+ unsigned long sc_regs[10];
+ unsigned long sc_r15;
+#if (__CSKY__ == 2) /* config CPU=cskyv2(ck800) */
+ // r16 ~ r31;
+ unsigned long sc_exregs[16];
+ unsigned long sc_rhi;
+ unsigned long sc_rlo;
+#endif
+ unsigned long sc_sr;
+ unsigned long sc_pc;
+ /* fpu */
+ unsigned long sc_fcr;
+ unsigned long sc_fsr; /* Nothing in CPU_CSKYV2 */
+ unsigned long sc_fesr;
+ unsigned long sc_feinst1; /* Nothing in CPU_CSKYV2 */
+ unsigned long sc_feinst2; /* Nothing in CPU_CSKYV2 */
+ unsigned long sc_fpregs[32];
+};
+
+#endif /* _ASM_CSKY_SIGCONTEXT_H */
diff --git a/arch/csky/include/uapi/asm/signal.h b/arch/csky/include/uapi/asm/signal.h
new file mode 100644
index 0000000..3bc0004
--- /dev/null
+++ b/arch/csky/include/uapi/asm/signal.h
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+#ifndef __ASM_CSKY_SIGNAL_H
+#define __ASM_CSKY_SIGNAL_H
+
+#define __ARCH_HAS_SA_RESTORER
+#include <linux/types.h>
+
+/* Avoid too many header ordering problems. */
+struct siginfo;
+
+#ifdef __KERNEL__
+
+/* Most things should be clean enough to redefine this at will, if care
+ is taken to make libc match. */
+
+#define _NSIG 64
+#define _NSIG_BPW 32
+#define _NSIG_WORDS (_NSIG / _NSIG_BPW)
+
+typedef unsigned long old_sigset_t; /* at least 32 bits */
+
+typedef struct {
+ unsigned long sig[_NSIG_WORDS];
+} sigset_t;
+
+#else
+
+/* Here we must cater to libcs that poke about in kernel headers. */
+
+#define NSIG 32
+typedef unsigned long sigset_t;
+
+#endif /* __KERNEL__ */
+
+#define SIGHUP 1
+#define SIGINT 2
+#define SIGQUIT 3
+#define SIGILL 4
+#define SIGTRAP 5
+#define SIGABRT 6
+#define SIGIOT 6
+#define SIGBUS 7
+#define SIGFPE 8
+#define SIGKILL 9
+#define SIGUSR1 10
+#define SIGSEGV 11
+#define SIGUSR2 12
+#define SIGPIPE 13
+#define SIGALRM 14
+#define SIGTERM 15
+#define SIGSTKFLT 16
+#define SIGCHLD 17
+#define SIGCONT 18
+#define SIGSTOP 19
+#define SIGTSTP 20
+#define SIGTTIN 21
+#define SIGTTOU 22
+#define SIGURG 23
+#define SIGXCPU 24
+#define SIGXFSZ 25
+#define SIGVTALRM 26
+#define SIGPROF 27
+#define SIGWINCH 28
+#define SIGIO 29
+#define SIGPOLL SIGIO
+/*
+#define SIGLOST 29
+*/
+#define SIGPWR 30
+#define SIGSYS 31
+#define SIGUNUSED 31
+
+/* These should not be considered constants from userland. */
+#define SIGRTMIN 32
+#define SIGRTMAX (_NSIG-1)
+
+/*
+ * SA_FLAGS values:
+ *
+ * SA_ONSTACK indicates that a registered stack_t will be used.
+ * SA_INTERRUPT is a no-op, but left due to historical reasons. Use the
+ * SA_RESTART flag to get restarting signals (which were the default long ago)
+ * SA_NOCLDSTOP flag to turn off SIGCHLD when children stop.
+ * SA_RESETHAND clears the handler when the signal is delivered.
+ * SA_NOCLDWAIT flag on SIGCHLD to inhibit zombies.
+ * SA_NODEFER prevents the current signal from being masked in the handler.
+ *
+ * SA_ONESHOT and SA_NOMASK are the historical Linux names for the Single
+ * Unix names RESETHAND and NODEFER respectively.
+ */
+#define SA_NOCLDSTOP 0x00000001
+#define SA_NOCLDWAIT 0x00000002 /* not supported yet */
+#define SA_SIGINFO 0x00000004
+#define SA_ONSTACK 0x08000000
+#define SA_RESTART 0x10000000
+#define SA_NODEFER 0x40000000
+#define SA_RESETHAND 0x80000000
+
+#define SA_NOMASK SA_NODEFER
+#define SA_ONESHOT SA_RESETHAND
+#define SA_INTERRUPT 0x20000000 /* dummy -- ignored */
+
+/*
+ * sigaltstack controls
+ */
+#define SS_ONSTACK 1
+#define SS_DISABLE 2
+
+#define MINSIGSTKSZ 2048
+#define SIGSTKSZ 8192
+
+#include <asm-generic/signal-defs.h>
+
+#ifdef __KERNEL__
+
+/*
+ * These values of sa_flags are used only by the kernel as part of the
+ * irq handling routines.
+ *
+ * SA_INTERRUPT is also used by the irq handling routines.
+ * SA_SHIRQ is for shared interrupt support on PCI and EISA.
+ */
+#define SA_PROBE SA_ONESHOT
+#define SA_SAMPLE_RANDOM SA_RESTART
+#define SA_SHIRQ 0x04000000
+#endif
+
+#define SIG_BLOCK 0 /* for blocking signals */
+#define SIG_UNBLOCK 1 /* for unblocking signals */
+#define SIG_SETMASK 2 /* for setting the signal mask */
+
+#ifndef __KERNEL__
+
+/* Here we must cater to libcs that poke about in kernel headers. */
+
+struct sigaction {
+ union {
+ __sighandler_t _sa_handler;
+ void (*_sa_sigaction)(int, struct siginfo *, void *);
+ } _u;
+ sigset_t sa_mask;
+ unsigned long sa_flags;
+ void (*sa_restorer)(void);
+};
+
+#define sa_handler _u._sa_handler
+#define sa_sigaction _u._sa_sigaction
+
+#endif /* __KERNEL__ */
+
+typedef struct sigaltstack {
+ void *ss_sp;
+ int ss_flags;
+ size_t ss_size;
+} stack_t;
+
+#ifdef __KERNEL__
+
+#include <asm/sigcontext.h>
+#define ptrace_signal_deliver() do{}while(0)
+#endif /* __KERNEL__ */
+
+#endif
diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
new file mode 100644
index 0000000..ce27972
--- /dev/null
+++ b/arch/csky/kernel/signal.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/syscalls.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/ptrace.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/highuid.h>
+#include <linux/personality.h>
+#include <linux/tty.h>
+#include <linux/binfmts.h>
+#include <linux/tracehook.h>
+#include <linux/freezer.h>
+#include <linux/uaccess.h>
+
+#include <asm/setup.h>
+#include <asm/pgtable.h>
+#include <asm/traps.h>
+#include <asm/ucontext.h>
+#include <asm/vdso.h>
+
+#include <abi/regdef.h>
+#ifdef CONFIG_CPU_HAS_FPU
+#include <abi/fpu.h>
+#endif
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+struct rt_sigframe
+{
+ int sig;
+ struct siginfo *pinfo;
+ void *puc;
+ struct siginfo info;
+ struct ucontext uc;
+};
+
+static inline int
+restore_sigframe(struct pt_regs *regs, struct sigcontext *usc, int *pr2)
+{
+ int err = 0;
+ int i = 0;
+ unsigned long usp;
+
+ /* Always make any pending restarted system calls return -EINTR */
+ current_thread_info()->task->restart_block.fn = do_no_restart_syscall;
+
+ /* restore passed registers */
+ err |= __get_user(regs->a0, &usc->sc_a0);
+ err |= __get_user(regs->a1, &usc->sc_a1);
+ err |= __get_user(regs->a2, &usc->sc_a2);
+ err |= __get_user(regs->a3, &usc->sc_a3);
+ for(i = 0; i < 10; i++)
+ err |= __get_user(regs->regs[i], &usc->sc_regs[i]);
+
+ err |= __get_user(regs->r15, &usc->sc_r15);
+#if defined(__CSKYABIV2__)
+ for(i = 0; i < 16; i++)
+ {
+ err |= __get_user(regs->exregs[i], &usc->sc_exregs[i]);
+ }
+ err |= __get_user(regs->rhi, &usc->sc_rhi);
+ err |= __get_user(regs->rlo, &usc->sc_rlo);
+#endif
+ err |= __get_user(regs->sr, &usc->sc_sr);
+ err |= __get_user(regs->pc, &usc->sc_pc);
+ err |= __get_user(usp, &usc->sc_usp);
+ wrusp(usp);
+
+#ifdef CONFIG_CPU_HAS_FPU
+ err |= restore_fpu_state(usc);
+#endif
+ *pr2 = regs->a0;
+ return err;
+}
+
+asmlinkage int
+do_rt_sigreturn(void)
+{
+ unsigned long usp = rdusp();
+ struct rt_sigframe *frame = (struct rt_sigframe *)usp;
+ sigset_t set;
+ int a0;
+ struct pt_regs *regs = current_pt_regs();
+
+ if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
+ goto badframe;
+ if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ goto badframe;
+
+ sigdelsetmask(&set, ~_BLOCKABLE);
+ spin_lock_irq(&current->sighand->siglock);
+ current->blocked = set;
+ recalc_sigpending( );
+ spin_unlock_irq(&current->sighand->siglock);
+
+ if (restore_sigframe(regs, &frame->uc.uc_mcontext, &a0))
+ goto badframe;
+
+ return a0;
+
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+/*
+ * Set up a signal frame.
+ */
+
+static inline int setup_sigframe(struct sigcontext *sc, struct pt_regs *regs,
+ unsigned long mask)
+{
+ int err = 0;
+ int i = 0;
+
+ err |= __put_user(mask, &sc->sc_mask);
+ err |= __put_user(rdusp(), &sc->sc_usp);
+ err |= __put_user(regs->a0, &sc->sc_a0);
+ err |= __put_user(regs->a1, &sc->sc_a1);
+ err |= __put_user(regs->a2, &sc->sc_a2);
+ err |= __put_user(regs->a3, &sc->sc_a3);
+ for(i = 0; i < 10; i++)
+ {
+ err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
+ }
+ err |= __put_user(regs->r15, &sc->sc_r15);
+#if defined(__CSKYABIV2__)
+ for(i = 0; i < 16; i++)
+ {
+ err |= __put_user(regs->exregs[i], &sc->sc_exregs[i]);
+ }
+ err |= __put_user(regs->rhi, &sc->sc_rhi);
+ err |= __put_user(regs->rlo, &sc->sc_rlo);
+#endif
+ err |= __put_user(regs->sr, &sc->sc_sr);
+ err |= __put_user(regs->pc, &sc->sc_pc);
+
+#ifdef CONFIG_CPU_HAS_FPU
+ err |= save_fpu_state(sc, regs);
+#endif
+
+ return err;
+}
+
+static inline void *
+get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
+{
+ unsigned long usp;
+
+ /* Default to using normal stack. */
+ usp = rdusp();
+
+ /* This is the X/Open sanctioned signal stack switching. */
+ if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(usp)) {
+ if (!on_sig_stack(usp))
+ usp = current->sas_ss_sp + current->sas_ss_size;
+ }
+ return (void *)((usp - frame_size) & -8UL);
+}
+
+static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
+ sigset_t *set, struct pt_regs *regs)
+{
+ struct rt_sigframe *frame;
+ int err = 0;
+
+ struct csky_vdso *vdso = current->mm->context.vdso;
+
+ frame = get_sigframe(ka, regs, sizeof(*frame));
+ if (!frame)
+ return 1;
+
+ err |= __put_user(sig, &frame->sig);
+ err |= __put_user(&frame->info, &frame->pinfo);
+ err |= __put_user(&frame->uc, &frame->puc);
+ err |= copy_siginfo_to_user(&frame->info, info);
+
+ /* Create the ucontext. */
+ err |= __put_user(0, &frame->uc.uc_flags);
+ err |= __put_user(0, &frame->uc.uc_link);
+ err |= __put_user((void *)current->sas_ss_sp,
+ &frame->uc.uc_stack.ss_sp);
+ err |= __put_user(sas_ss_flags(rdusp()),
+ &frame->uc.uc_stack.ss_flags);
+ err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+ err |= setup_sigframe(&frame->uc.uc_mcontext, regs, 0);
+ err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ if (err)
+ goto give_sigsegv;
+
+ /* Set up registers for signal handler */
+ wrusp ((unsigned long) frame);
+ regs->pc = (unsigned long) ka->sa.sa_handler;
+ regs->r15 = (unsigned long)vdso->rt_signal_retcode;
+
+adjust_stack:
+ regs->a0 = sig; /* first arg is signo */
+ regs->a1 = (unsigned long)(&(frame->info)); /* second arg is (siginfo_t*) */
+ regs->a2 = (unsigned long)(&(frame->uc));/* third arg pointer to ucontext */
+ return err;
+
+give_sigsegv:
+ if (sig == SIGSEGV)
+ ka->sa.sa_handler = SIG_DFL;
+ force_sig(SIGSEGV, current);
+ goto adjust_stack;
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+static int
+handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
+ sigset_t *oldset, struct pt_regs *regs)
+{
+ struct task_struct *tsk = current;
+ int ret;
+
+ /* set up the stack frame, regardless of SA_SIGINFO, and pass info anyway. */
+ ret = setup_rt_frame(sig, ka, info, oldset, regs);
+
+ if (ret != 0) {
+ force_sigsegv(sig, tsk);
+ return ret;
+ }
+
+ /* Block the signal if we were successful. */
+ spin_lock_irq(&current->sighand->siglock);
+ sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
+ if (!(ka->sa.sa_flags & SA_NODEFER))
+ sigaddset(&current->blocked, sig);
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+
+ return 0;
+}
+
+/*
+ * 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.
+ */
+static void do_signal(struct pt_regs *regs, int syscall)
+{
+ unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
+ struct ksignal ksig;
+
+ /*
+ * We want the common case to go fast, which
+ * is why we may in certain cases get here from
+ * kernel mode. Just return without doing anything
+ * if so.
+ */
+ if (!user_mode(regs))
+ return;
+
+ current->thread.esp0 = (unsigned long)regs;
+
+ /*
+ * If we were from a system call, check for system call restarting...
+ */
+ if (syscall) {
+ continue_addr = regs->pc;
+#if defined(__CSKYABIV2__)
+ restart_addr = continue_addr - 4;
+#else
+ restart_addr = continue_addr - 2;
+#endif
+ retval = regs->a0;
+
+ /*
+ * Prepare for system call restart. We do this here so that a
+ * debugger will see the already changed.
+ */
+ switch (retval) {
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ regs->a0 = regs->orig_a0;
+ regs->pc = restart_addr;
+ break;
+ case -ERESTART_RESTARTBLOCK:
+ regs->a0 = -EINTR;
+ break;
+ }
+ }
+
+ if (try_to_freeze())
+ goto no_signal;
+
+ /*
+ * Get the signal to deliver. When running under ptrace, at this
+ * point the debugger may change all our registers ...
+ */
+ if (get_signal(&ksig)) {
+ sigset_t *oldset;
+
+ /*
+ * 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->pc == restart_addr) {
+ if (retval == -ERESTARTNOHAND
+ || (retval == -ERESTARTSYS
+ && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
+ regs->a0 = -EINTR;
+ regs->pc = continue_addr;
+ }
+ }
+
+ if (test_thread_flag(TIF_RESTORE_SIGMASK))
+ oldset = &current->saved_sigmask;
+ else
+ oldset = &current->blocked;
+ /* Whee! Actually deliver the signal. */
+ if (handle_signal(ksig.sig, &ksig.ka, &ksig.info, oldset, regs) == 0) {
+ /*
+ * A signal was successfully delivered; the saved
+ * sigmask will have been stored in the signal frame,
+ * and will be restored by sigreturn, so we can simply
+ * clear the TIF_RESTORE_SIGMASK flag.
+ */
+ if (test_thread_flag(TIF_RESTORE_SIGMASK))
+ clear_thread_flag(TIF_RESTORE_SIGMASK);
+ }
+ return;
+ }
+
+no_signal:
+ if (syscall) {
+ /*
+ * Handle restarting a different system call. As above,
+ * if a debugger has chosen to restart at a different PC,
+ * ignore the restart.
+ */
+ if (retval == -ERESTART_RESTARTBLOCK
+ && regs->pc == continue_addr) {
+#if defined(__CSKYABIV2__)
+ regs->regs[3] = __NR_restart_syscall;
+ regs->pc -= 4;
+#else
+ regs->regs[9] = __NR_restart_syscall;
+ regs->pc -= 2;
+#endif
+ }
+
+ /* If there's no signal to deliver, we just put the saved sigmask
+ * back.
+ */
+ if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
+ clear_thread_flag(TIF_RESTORE_SIGMASK);
+ sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
+ }
+ }
+}
+
+asmlinkage void
+do_notify_resume(unsigned int thread_flags, struct pt_regs *regs, int syscall)
+{
+ if (thread_flags & _TIF_SIGPENDING)
+ do_signal(regs, syscall);
+
+ if (thread_flags & _TIF_NOTIFY_RESUME) {
+ clear_thread_flag(TIF_NOTIFY_RESUME);
+ tracehook_notify_resume(regs);
+ }
+}
--
2.7.4