diff options
Diffstat (limited to 'arch/um/kernel/signal.c')
| -rw-r--r-- | arch/um/kernel/signal.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/arch/um/kernel/signal.c b/arch/um/kernel/signal.c new file mode 100644 index 000000000..ae4658f57 --- /dev/null +++ b/arch/um/kernel/signal.c @@ -0,0 +1,141 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) + */ + +#include <linux/module.h> +#include <linux/ptrace.h> +#include <linux/sched.h> +#include <linux/ftrace.h> +#include <asm/siginfo.h> +#include <asm/signal.h> +#include <asm/unistd.h> +#include <frame_kern.h> +#include <kern_util.h> +#include <os.h> + +EXPORT_SYMBOL(block_signals); +EXPORT_SYMBOL(unblock_signals); + +void block_signals_trace(void) +{ + block_signals(); + if (current_thread_info()) + trace_hardirqs_off(); +} + +void unblock_signals_trace(void) +{ + if (current_thread_info()) + trace_hardirqs_on(); + unblock_signals(); +} + +void um_trace_signals_on(void) +{ + if (current_thread_info()) + trace_hardirqs_on(); +} + +void um_trace_signals_off(void) +{ + if (current_thread_info()) + trace_hardirqs_off(); +} + +/* + * OK, we're invoking a handler + */ +static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) +{ + sigset_t *oldset = sigmask_to_save(); + int singlestep = 0; + unsigned long sp; + int err; + + if (test_thread_flag(TIF_SINGLESTEP) && (current->ptrace & PT_PTRACED)) + singlestep = 1; + + /* Did we come from a system call? */ + if (PT_REGS_SYSCALL_NR(regs) >= 0) { + /* If so, check system call restarting.. */ + switch (PT_REGS_SYSCALL_RET(regs)) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + PT_REGS_SYSCALL_RET(regs) = -EINTR; + break; + + case -ERESTARTSYS: + if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { + PT_REGS_SYSCALL_RET(regs) = -EINTR; + break; + } + fallthrough; + case -ERESTARTNOINTR: + PT_REGS_RESTART_SYSCALL(regs); + PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs); + break; + } + } + + sp = PT_REGS_SP(regs); + if ((ksig->ka.sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0)) + sp = current->sas_ss_sp + current->sas_ss_size; + +#ifdef CONFIG_ARCH_HAS_SC_SIGNALS + if (!(ksig->ka.sa.sa_flags & SA_SIGINFO)) + err = setup_signal_stack_sc(sp, ksig, regs, oldset); + else +#endif + err = setup_signal_stack_si(sp, ksig, regs, oldset); + + signal_setup_done(err, ksig, singlestep); +} + +void do_signal(struct pt_regs *regs) +{ + struct ksignal ksig; + int handled_sig = 0; + + while (get_signal(&ksig)) { + handled_sig = 1; + /* Whee! Actually deliver the signal. */ + handle_signal(&ksig, regs); + } + + /* Did we come from a system call? */ + if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) { + /* Restart the system call - no handlers present */ + switch (PT_REGS_SYSCALL_RET(regs)) { + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs); + PT_REGS_RESTART_SYSCALL(regs); + break; + case -ERESTART_RESTARTBLOCK: + PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall; + PT_REGS_RESTART_SYSCALL(regs); + break; + } + } + + /* + * This closes a way to execute a system call on the host. If + * you set a breakpoint on a system call instruction and singlestep + * from it, the tracing thread used to PTRACE_SINGLESTEP the process + * rather than PTRACE_SYSCALL it, allowing the system call to execute + * on the host. The tracing thread will check this flag and + * PTRACE_SYSCALL if necessary. + */ + if (test_thread_flag(TIF_SINGLESTEP)) + current->thread.singlestep_syscall = + is_syscall(PT_REGS_IP(¤t->thread.regs)); + + /* + * if there's no signal to deliver, we just put the saved sigmask + * back + */ + if (!handled_sig) + restore_saved_sigmask(); +} |