cregit-Linux how code gets into the kernel

Release 4.11 arch/avr32/kernel/signal.c

/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * Based on linux/arch/sh/kernel/signal.c
 *  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/tracehook.h>

#include <linux/uaccess.h>
#include <asm/ucontext.h>
#include <asm/syscalls.h>


struct rt_sigframe
{
	
struct siginfo info;
	
struct ucontext uc;
	
unsigned long retcode;
};


static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { int err = 0; #define COPY(x) err |= __get_user(regs->x, &sc->x) COPY(sr); COPY(pc); COPY(lr); COPY(sp); COPY(r12); COPY(r11); COPY(r10); COPY(r9); COPY(r8); COPY(r7); COPY(r6); COPY(r5); COPY(r4); COPY(r3); COPY(r2); COPY(r1); COPY(r0); #undef COPY /* * Don't allow anyone to pretend they're running in supervisor * mode or something... */ err |= !valid_user_regs(regs); return err; }

Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen129100.00%1100.00%
Total129100.00%1100.00%


asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) { struct rt_sigframe __user *frame; sigset_t set; /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; frame = (struct rt_sigframe __user *)regs->sp; pr_debug("SIG return: frame = %p\n", frame); 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)) goto badframe; if (restore_altstack(&frame->uc.uc_stack)) goto badframe; pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n", regs->pc, regs->lr, regs->sp); return regs->r12; badframe: force_sig(SIGSEGV, current); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen13784.57%116.67%
Martin Koegler148.64%116.67%
Al Viro95.56%233.33%
Andrew Lutomirski10.62%116.67%
Oleg Nesterov10.62%116.67%
Total162100.00%6100.00%


static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) { int err = 0; #define COPY(x) err |= __put_user(regs->x, &sc->x) COPY(sr); COPY(pc); COPY(lr); COPY(sp); COPY(r12); COPY(r11); COPY(r10); COPY(r9); COPY(r8); COPY(r7); COPY(r6); COPY(r5); COPY(r4); COPY(r3); COPY(r2); COPY(r1); COPY(r0); #undef COPY return err; }

Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen120100.00%1100.00%
Total120100.00%1100.00%


static inline void __user * get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize) { unsigned long sp = sigsp(regs->sp, ksig); return (void __user *)((sp - framesize) & ~3); }

Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen4586.54%150.00%
Richard Weinberger713.46%150.00%
Total52100.00%2100.00%


static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) { struct rt_sigframe __user *frame; int err = 0; frame = get_sigframe(ksig, regs, sizeof(*frame)); err = -EFAULT; if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) goto out; /* * Set up the return code: * * mov r8, __NR_rt_sigreturn * scall * * Note: This will blow up since we're using a non-executable * stack. Better use SA_RESTORER. */ #if __NR_rt_sigreturn > 127 # error __NR_rt_sigreturn must be < 127 to fit in a short mov #endif err = __put_user(0x3008d733 | (__NR_rt_sigreturn << 20), &frame->retcode); err |= copy_siginfo_to_user(&frame->info, &ksig->info); /* Set up 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->sp); err |= setup_sigcontext(&frame->uc.uc_mcontext, regs); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); if (err) goto out; regs->r12 = ksig->sig; regs->r11 = (unsigned long) &frame->info; regs->r10 = (unsigned long) &frame->uc; regs->sp = (unsigned long) frame; if (ksig->ka.sa.sa_flags & SA_RESTORER) regs->lr = (unsigned long)ksig->ka.sa.sa_restorer; else { printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n", current->comm, current->pid); regs->lr = (unsigned long) &frame->retcode; } pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n", current->comm, current->pid, ksig->sig, regs->sp, regs->pc, ksig->ka.sa.sa_handler, regs->lr); regs->pc = (unsigned long)ksig->ka.sa.sa_handler; out: return err; }

Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen33693.33%133.33%
Richard Weinberger226.11%133.33%
Al Viro20.56%133.33%
Total360100.00%3100.00%


static inline void setup_syscall_restart(struct pt_regs *regs) { if (regs->r12 == -ERESTART_RESTARTBLOCK) regs->r8 = __NR_restart_syscall; else regs->r12 = regs->r12_orig; regs->pc -= 2; }

Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen4197.62%150.00%
Eric W. Biedermann12.38%150.00%
Total42100.00%2100.00%


static inline void handle_signal(struct ksignal *ksig, struct pt_regs *regs, int syscall) { int ret; /* * Set up the stack frame */ ret = setup_rt_frame(ksig, sigmask_to_save(), regs); /* * Check that the resulting registers are sane */ ret |= !valid_user_regs(regs); /* * Block the signal if we were successful. */ signal_setup_done(ret, ksig, 0); }

Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen4378.18%116.67%
Richard Weinberger610.91%116.67%
Al Viro59.09%350.00%
Matt Fleming11.82%116.67%
Total55100.00%6100.00%

/* * 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. */
static void do_signal(struct pt_regs *regs, int syscall) { 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; get_signal(&ksig); if (syscall) { switch (regs->r12) { case -ERESTART_RESTARTBLOCK: case -ERESTARTNOHAND: if (ksig.sig > 0) { regs->r12 = -EINTR; break; } /* fall through */ case -ERESTARTSYS: if (ksig.sig > 0 && !(ksig.ka.sa.sa_flags & SA_RESTART)) { regs->r12 = -EINTR; break; } /* fall through */ case -ERESTARTNOINTR: setup_syscall_restart(regs); } } if (!ksig.sig) { /* No signal to deliver -- put the saved sigmask back */ restore_saved_sigmask(); return; } handle_signal(&ksig, regs, syscall); }

Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen12083.33%120.00%
Richard Weinberger1711.81%120.00%
Al Viro64.17%240.00%
Eric W. Biedermann10.69%120.00%
Total144100.00%5100.00%


asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti) { int syscall = 0; if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR) syscall = 1; if (ti->flags & _TIF_SIGPENDING) do_signal(regs, syscall); if (ti->flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); } }

Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen4764.38%133.33%
David Howells2027.40%133.33%
Al Viro68.22%133.33%
Total73100.00%3100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Håvard Skinnemoen105789.35%15.26%
Richard Weinberger524.40%210.53%
Al Viro282.37%736.84%
David Howells231.94%210.53%
Martin Koegler141.18%15.26%
Jaswinder Singh Rajput30.25%15.26%
Eric W. Biedermann20.17%15.26%
Linus Torvalds10.08%15.26%
Andrew Lutomirski10.08%15.26%
Matt Fleming10.08%15.26%
Oleg Nesterov10.08%15.26%
Total1183100.00%19100.00%
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