diff options
Diffstat (limited to 'arch/sh/kernel/signal_32.c')
| -rw-r--r-- | arch/sh/kernel/signal_32.c | 510 |
1 files changed, 510 insertions, 0 deletions
diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c new file mode 100644 index 000000000..c46c0020f --- /dev/null +++ b/arch/sh/kernel/signal_32.c @@ -0,0 +1,510 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/arch/sh/kernel/signal.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson + * + * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima + * + */ +#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/elf.h> +#include <linux/personality.h> +#include <linux/binfmts.h> +#include <linux/io.h> +#include <linux/tracehook.h> +#include <asm/ucontext.h> +#include <linux/uaccess.h> +#include <asm/pgtable.h> +#include <asm/cacheflush.h> +#include <asm/syscalls.h> +#include <asm/fpu.h> + +struct fdpic_func_descriptor { + unsigned long text; + unsigned long GOT; +}; + +/* + * The following define adds a 64 byte gap between the signal + * stack frame and previous contents of the stack. This allows + * frame unwinding in a function epilogue but only if a frame + * pointer is used in the function. This is necessary because + * current gcc compilers (<4.3) do not generate unwind info on + * SH for function epilogues. + */ +#define UNWINDGUARD 64 + +/* + * Do a signal return; undo the signal stack. + */ + +#define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */ +#if defined(CONFIG_CPU_SH2) +#define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */ +#else +#define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */ +#endif +#define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */ + +struct sigframe +{ + struct sigcontext sc; + unsigned long extramask[_NSIG_WORDS-1]; + u16 retcode[8]; +}; + +struct rt_sigframe +{ + struct siginfo info; + struct ucontext uc; + u16 retcode[8]; +}; + +#ifdef CONFIG_SH_FPU +static inline int restore_sigcontext_fpu(struct sigcontext __user *sc) +{ + struct task_struct *tsk = current; + + if (!(boot_cpu_data.flags & CPU_HAS_FPU)) + return 0; + + set_used_math(); + return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0], + sizeof(long)*(16*2+2)); +} + +static inline int save_sigcontext_fpu(struct sigcontext __user *sc, + struct pt_regs *regs) +{ + struct task_struct *tsk = current; + + if (!(boot_cpu_data.flags & CPU_HAS_FPU)) + return 0; + + if (!used_math()) + return __put_user(0, &sc->sc_ownedfp); + + if (__put_user(1, &sc->sc_ownedfp)) + return -EFAULT; + + /* This will cause a "finit" to be triggered by the next + attempted FPU operation by the 'current' process. + */ + clear_used_math(); + + unlazy_fpu(tsk, regs); + return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu, + sizeof(long)*(16*2+2)); +} +#endif /* CONFIG_SH_FPU */ + +static int +restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p) +{ + unsigned int err = 0; + +#define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) + COPY(regs[1]); + COPY(regs[2]); COPY(regs[3]); + COPY(regs[4]); COPY(regs[5]); + COPY(regs[6]); COPY(regs[7]); + COPY(regs[8]); COPY(regs[9]); + COPY(regs[10]); COPY(regs[11]); + COPY(regs[12]); COPY(regs[13]); + COPY(regs[14]); COPY(regs[15]); + COPY(gbr); COPY(mach); + COPY(macl); COPY(pr); + COPY(sr); COPY(pc); +#undef COPY + +#ifdef CONFIG_SH_FPU + if (boot_cpu_data.flags & CPU_HAS_FPU) { + int owned_fp; + struct task_struct *tsk = current; + + regs->sr |= SR_FD; /* Release FPU */ + clear_fpu(tsk, regs); + clear_used_math(); + err |= __get_user (owned_fp, &sc->sc_ownedfp); + if (owned_fp) + err |= restore_sigcontext_fpu(sc); + } +#endif + + regs->tra = -1; /* disable syscall checks */ + err |= __get_user(*r0_p, &sc->sc_regs[0]); + return err; +} + +asmlinkage int sys_sigreturn(void) +{ + struct pt_regs *regs = current_pt_regs(); + struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15]; + sigset_t set; + int r0; + + /* Always make any pending restarted system calls return -EINTR */ + current->restart_block.fn = do_no_restart_syscall; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + + if (__get_user(set.sig[0], &frame->sc.oldmask) + || (_NSIG_WORDS > 1 + && __copy_from_user(&set.sig[1], &frame->extramask, + sizeof(frame->extramask)))) + goto badframe; + + set_current_blocked(&set); + + if (restore_sigcontext(regs, &frame->sc, &r0)) + goto badframe; + return r0; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +asmlinkage int sys_rt_sigreturn(void) +{ + struct pt_regs *regs = current_pt_regs(); + struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15]; + sigset_t set; + int r0; + + /* Always make any pending restarted system calls return -EINTR */ + current->restart_block.fn = do_no_restart_syscall; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto badframe; + + set_current_blocked(&set); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) + goto badframe; + + if (restore_altstack(&frame->uc.uc_stack)) + goto badframe; + + return r0; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +/* + * Set up a signal frame. + */ + +static int +setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, + unsigned long mask) +{ + int err = 0; + +#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) + COPY(regs[0]); COPY(regs[1]); + COPY(regs[2]); COPY(regs[3]); + COPY(regs[4]); COPY(regs[5]); + COPY(regs[6]); COPY(regs[7]); + COPY(regs[8]); COPY(regs[9]); + COPY(regs[10]); COPY(regs[11]); + COPY(regs[12]); COPY(regs[13]); + COPY(regs[14]); COPY(regs[15]); + COPY(gbr); COPY(mach); + COPY(macl); COPY(pr); + COPY(sr); COPY(pc); +#undef COPY + +#ifdef CONFIG_SH_FPU + err |= save_sigcontext_fpu(sc, regs); +#endif + + /* non-iBCS2 extensions.. */ + err |= __put_user(mask, &sc->oldmask); + + return err; +} + +/* + * Determine which stack to use.. + */ +static inline void __user * +get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) +{ + if (ka->sa.sa_flags & SA_ONSTACK) { + if (sas_ss_flags(sp) == 0) + sp = current->sas_ss_sp + current->sas_ss_size; + } + + return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul); +} + +/* These symbols are defined with the addresses in the vsyscall page. + See vsyscall-trapa.S. */ +extern void __kernel_sigreturn(void); +extern void __kernel_rt_sigreturn(void); + +static int setup_frame(struct ksignal *ksig, sigset_t *set, + struct pt_regs *regs) +{ + struct sigframe __user *frame; + int err = 0, sig = ksig->sig; + + frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + return -EFAULT; + + err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); + + if (_NSIG_WORDS > 1) + err |= __copy_to_user(frame->extramask, &set->sig[1], + sizeof(frame->extramask)); + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + if (ksig->ka.sa.sa_flags & SA_RESTORER) { + regs->pr = (unsigned long) ksig->ka.sa.sa_restorer; +#ifdef CONFIG_VSYSCALL + } else if (likely(current->mm->context.vdso)) { + regs->pr = VDSO_SYM(&__kernel_sigreturn); +#endif + } else { + /* Generate return code (system call to sigreturn) */ + err |= __put_user(MOVW(7), &frame->retcode[0]); + err |= __put_user(TRAP_NOARG, &frame->retcode[1]); + err |= __put_user(OR_R0_R0, &frame->retcode[2]); + err |= __put_user(OR_R0_R0, &frame->retcode[3]); + err |= __put_user(OR_R0_R0, &frame->retcode[4]); + err |= __put_user(OR_R0_R0, &frame->retcode[5]); + err |= __put_user(OR_R0_R0, &frame->retcode[6]); + err |= __put_user((__NR_sigreturn), &frame->retcode[7]); + regs->pr = (unsigned long) frame->retcode; + flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); + } + + if (err) + return -EFAULT; + + /* Set up registers for signal handler */ + regs->regs[15] = (unsigned long) frame; + regs->regs[4] = sig; /* Arg for signal handler */ + regs->regs[5] = 0; + regs->regs[6] = (unsigned long) &frame->sc; + + if (current->personality & FDPIC_FUNCPTRS) { + struct fdpic_func_descriptor __user *funcptr = + (struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler; + + err |= __get_user(regs->pc, &funcptr->text); + err |= __get_user(regs->regs[12], &funcptr->GOT); + } else + regs->pc = (unsigned long)ksig->ka.sa.sa_handler; + + if (err) + return -EFAULT; + + pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", + current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); + + return 0; +} + +static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, + struct pt_regs *regs) +{ + struct rt_sigframe __user *frame; + int err = 0, sig = ksig->sig; + + frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + return -EFAULT; + + err |= copy_siginfo_to_user(&frame->info, &ksig->info); + + /* Create the ucontext. */ + err |= __put_user(0, &frame->uc.uc_flags); + err |= __put_user(NULL, &frame->uc.uc_link); + err |= __save_altstack(&frame->uc.uc_stack, regs->regs[15]); + err |= setup_sigcontext(&frame->uc.uc_mcontext, + regs, set->sig[0]); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + if (ksig->ka.sa.sa_flags & SA_RESTORER) { + regs->pr = (unsigned long) ksig->ka.sa.sa_restorer; +#ifdef CONFIG_VSYSCALL + } else if (likely(current->mm->context.vdso)) { + regs->pr = VDSO_SYM(&__kernel_rt_sigreturn); +#endif + } else { + /* Generate return code (system call to rt_sigreturn) */ + err |= __put_user(MOVW(7), &frame->retcode[0]); + err |= __put_user(TRAP_NOARG, &frame->retcode[1]); + err |= __put_user(OR_R0_R0, &frame->retcode[2]); + err |= __put_user(OR_R0_R0, &frame->retcode[3]); + err |= __put_user(OR_R0_R0, &frame->retcode[4]); + err |= __put_user(OR_R0_R0, &frame->retcode[5]); + err |= __put_user(OR_R0_R0, &frame->retcode[6]); + err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]); + regs->pr = (unsigned long) frame->retcode; + flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); + } + + if (err) + return -EFAULT; + + /* Set up registers for signal handler */ + regs->regs[15] = (unsigned long) frame; + regs->regs[4] = sig; /* Arg for signal handler */ + regs->regs[5] = (unsigned long) &frame->info; + regs->regs[6] = (unsigned long) &frame->uc; + + if (current->personality & FDPIC_FUNCPTRS) { + struct fdpic_func_descriptor __user *funcptr = + (struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler; + + err |= __get_user(regs->pc, &funcptr->text); + err |= __get_user(regs->regs[12], &funcptr->GOT); + } else + regs->pc = (unsigned long)ksig->ka.sa.sa_handler; + + if (err) + return -EFAULT; + + pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", + current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); + + return 0; +} + +static inline void +handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs, + struct sigaction *sa) +{ + /* If we're not from a syscall, bail out */ + if (regs->tra < 0) + return; + + /* check for system call restart.. */ + switch (regs->regs[0]) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + no_system_call_restart: + regs->regs[0] = -EINTR; + break; + + case -ERESTARTSYS: + if (!(sa->sa_flags & SA_RESTART)) + goto no_system_call_restart; + /* fallthrough */ + case -ERESTARTNOINTR: + regs->regs[0] = save_r0; + regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); + break; + } +} + +/* + * OK, we're invoking a handler + */ +static void +handle_signal(struct ksignal *ksig, struct pt_regs *regs, unsigned int save_r0) +{ + sigset_t *oldset = sigmask_to_save(); + 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, oldset, regs); + + signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); +} + +/* + * 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, unsigned int save_r0) +{ + 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; + + if (get_signal(&ksig)) { + handle_syscall_restart(save_r0, regs, &ksig.ka.sa); + + /* Whee! Actually deliver the signal. */ + handle_signal(&ksig, regs, save_r0); + return; + } + + /* Did we come from a system call? */ + if (regs->tra >= 0) { + /* Restart the system call - no handlers present */ + if (regs->regs[0] == -ERESTARTNOHAND || + regs->regs[0] == -ERESTARTSYS || + regs->regs[0] == -ERESTARTNOINTR) { + regs->regs[0] = save_r0; + regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); + } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) { + regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); + regs->regs[3] = __NR_restart_syscall; + } + } + + /* + * If there's no signal to deliver, we just put the saved sigmask + * back. + */ + restore_saved_sigmask(); +} + +asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, + unsigned long thread_info_flags) +{ + /* deal with pending signal delivery */ + if (thread_info_flags & _TIF_SIGPENDING) + do_signal(regs, save_r0); + + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + } +} |