cregit-Linux how code gets into the kernel

Release 4.14 arch/unicore32/kernel/signal.c

/*
 * linux/arch/unicore32/kernel/signal.c
 *
 * Code specific to PKUnity SoC and UniCore ISA
 *
 * Copyright (C) 2001-2010 GUAN Xue-tao
 *
 * 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/errno.h>
#include <linux/signal.h>
#include <linux/personality.h>
#include <linux/uaccess.h>
#include <linux/tracehook.h>
#include <linux/elf.h>
#include <linux/unistd.h>

#include <asm/cacheflush.h>
#include <asm/ucontext.h>

/*
 * For UniCore syscalls, we encode the syscall number into the instruction.
 */

#define SWI_SYS_SIGRETURN	(0xff000000) 
/* error number for new abi */

#define SWI_SYS_RT_SIGRETURN	(0xff000000 | (__NR_rt_sigreturn))

#define SWI_SYS_RESTART		(0xff000000 | (__NR_restart_syscall))


#define KERN_SIGRETURN_CODE	(KUSER_VECPAGE_BASE + 0x00000500)

#define KERN_RESTART_CODE	(KERN_SIGRETURN_CODE + sizeof(sigreturn_codes))


const unsigned long sigreturn_codes[3] = {
	SWI_SYS_SIGRETURN, SWI_SYS_RT_SIGRETURN,
};


const unsigned long syscall_restart_code[2] = {
	SWI_SYS_RESTART,	/* swi  __NR_restart_syscall */
	0x69efc004,		/* ldr  pc, [sp], #4 */
};

/*
 * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
 */

struct sigframe {
	
struct ucontext uc;
	
unsigned long retcode[2];
};


struct rt_sigframe {
	
struct siginfo info;
	
struct sigframe sig;
};


static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) { sigset_t set; int err; err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); if (err == 0) set_current_blocked(&set); err |= __get_user(regs->UCreg_00, &sf->uc.uc_mcontext.regs.UCreg_00); err |= __get_user(regs->UCreg_01, &sf->uc.uc_mcontext.regs.UCreg_01); err |= __get_user(regs->UCreg_02, &sf->uc.uc_mcontext.regs.UCreg_02); err |= __get_user(regs->UCreg_03, &sf->uc.uc_mcontext.regs.UCreg_03); err |= __get_user(regs->UCreg_04, &sf->uc.uc_mcontext.regs.UCreg_04); err |= __get_user(regs->UCreg_05, &sf->uc.uc_mcontext.regs.UCreg_05); err |= __get_user(regs->UCreg_06, &sf->uc.uc_mcontext.regs.UCreg_06); err |= __get_user(regs->UCreg_07, &sf->uc.uc_mcontext.regs.UCreg_07); err |= __get_user(regs->UCreg_08, &sf->uc.uc_mcontext.regs.UCreg_08); err |= __get_user(regs->UCreg_09, &sf->uc.uc_mcontext.regs.UCreg_09); err |= __get_user(regs->UCreg_10, &sf->uc.uc_mcontext.regs.UCreg_10); err |= __get_user(regs->UCreg_11, &sf->uc.uc_mcontext.regs.UCreg_11); err |= __get_user(regs->UCreg_12, &sf->uc.uc_mcontext.regs.UCreg_12); err |= __get_user(regs->UCreg_13, &sf->uc.uc_mcontext.regs.UCreg_13); err |= __get_user(regs->UCreg_14, &sf->uc.uc_mcontext.regs.UCreg_14); err |= __get_user(regs->UCreg_15, &sf->uc.uc_mcontext.regs.UCreg_15); err |= __get_user(regs->UCreg_16, &sf->uc.uc_mcontext.regs.UCreg_16); err |= __get_user(regs->UCreg_17, &sf->uc.uc_mcontext.regs.UCreg_17); err |= __get_user(regs->UCreg_18, &sf->uc.uc_mcontext.regs.UCreg_18); err |= __get_user(regs->UCreg_19, &sf->uc.uc_mcontext.regs.UCreg_19); err |= __get_user(regs->UCreg_20, &sf->uc.uc_mcontext.regs.UCreg_20); err |= __get_user(regs->UCreg_21, &sf->uc.uc_mcontext.regs.UCreg_21); err |= __get_user(regs->UCreg_22, &sf->uc.uc_mcontext.regs.UCreg_22); err |= __get_user(regs->UCreg_23, &sf->uc.uc_mcontext.regs.UCreg_23); err |= __get_user(regs->UCreg_24, &sf->uc.uc_mcontext.regs.UCreg_24); err |= __get_user(regs->UCreg_25, &sf->uc.uc_mcontext.regs.UCreg_25); err |= __get_user(regs->UCreg_26, &sf->uc.uc_mcontext.regs.UCreg_26); err |= __get_user(regs->UCreg_fp, &sf->uc.uc_mcontext.regs.UCreg_fp); err |= __get_user(regs->UCreg_ip, &sf->uc.uc_mcontext.regs.UCreg_ip); err |= __get_user(regs->UCreg_sp, &sf->uc.uc_mcontext.regs.UCreg_sp); err |= __get_user(regs->UCreg_lr, &sf->uc.uc_mcontext.regs.UCreg_lr); err |= __get_user(regs->UCreg_pc, &sf->uc.uc_mcontext.regs.UCreg_pc); err |= __get_user(regs->UCreg_asr, &sf->uc.uc_mcontext.regs.UCreg_asr); err |= !valid_user_regs(regs); return err; }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao72599.86%150.00%
Matt Fleming10.14%150.00%
Total726100.00%2100.00%


asmlinkage int __sys_rt_sigreturn(struct pt_regs *regs) { struct rt_sigframe __user *frame; /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; /* * Since we stacked the signal on a 64-bit boundary, * then 'sp' should be word aligned here. If it's * not, then the user is trying to mess with us. */ if (regs->UCreg_sp & 7) goto badframe; frame = (struct rt_sigframe __user *)regs->UCreg_sp; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (restore_sigframe(regs, &frame->sig)) goto badframe; if (restore_altstack(&frame->sig.uc.uc_stack)) goto badframe; return regs->UCreg_00; badframe: force_sig(SIGSEGV, current); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao11698.31%133.33%
Andrew Lutomirski10.85%133.33%
Al Viro10.85%133.33%
Total118100.00%3100.00%


static int setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) { int err = 0; err |= __put_user(regs->UCreg_00, &sf->uc.uc_mcontext.regs.UCreg_00); err |= __put_user(regs->UCreg_01, &sf->uc.uc_mcontext.regs.UCreg_01); err |= __put_user(regs->UCreg_02, &sf->uc.uc_mcontext.regs.UCreg_02); err |= __put_user(regs->UCreg_03, &sf->uc.uc_mcontext.regs.UCreg_03); err |= __put_user(regs->UCreg_04, &sf->uc.uc_mcontext.regs.UCreg_04); err |= __put_user(regs->UCreg_05, &sf->uc.uc_mcontext.regs.UCreg_05); err |= __put_user(regs->UCreg_06, &sf->uc.uc_mcontext.regs.UCreg_06); err |= __put_user(regs->UCreg_07, &sf->uc.uc_mcontext.regs.UCreg_07); err |= __put_user(regs->UCreg_08, &sf->uc.uc_mcontext.regs.UCreg_08); err |= __put_user(regs->UCreg_09, &sf->uc.uc_mcontext.regs.UCreg_09); err |= __put_user(regs->UCreg_10, &sf->uc.uc_mcontext.regs.UCreg_10); err |= __put_user(regs->UCreg_11, &sf->uc.uc_mcontext.regs.UCreg_11); err |= __put_user(regs->UCreg_12, &sf->uc.uc_mcontext.regs.UCreg_12); err |= __put_user(regs->UCreg_13, &sf->uc.uc_mcontext.regs.UCreg_13); err |= __put_user(regs->UCreg_14, &sf->uc.uc_mcontext.regs.UCreg_14); err |= __put_user(regs->UCreg_15, &sf->uc.uc_mcontext.regs.UCreg_15); err |= __put_user(regs->UCreg_16, &sf->uc.uc_mcontext.regs.UCreg_16); err |= __put_user(regs->UCreg_17, &sf->uc.uc_mcontext.regs.UCreg_17); err |= __put_user(regs->UCreg_18, &sf->uc.uc_mcontext.regs.UCreg_18); err |= __put_user(regs->UCreg_19, &sf->uc.uc_mcontext.regs.UCreg_19); err |= __put_user(regs->UCreg_20, &sf->uc.uc_mcontext.regs.UCreg_20); err |= __put_user(regs->UCreg_21, &sf->uc.uc_mcontext.regs.UCreg_21); err |= __put_user(regs->UCreg_22, &sf->uc.uc_mcontext.regs.UCreg_22); err |= __put_user(regs->UCreg_23, &sf->uc.uc_mcontext.regs.UCreg_23); err |= __put_user(regs->UCreg_24, &sf->uc.uc_mcontext.regs.UCreg_24); err |= __put_user(regs->UCreg_25, &sf->uc.uc_mcontext.regs.UCreg_25); err |= __put_user(regs->UCreg_26, &sf->uc.uc_mcontext.regs.UCreg_26); err |= __put_user(regs->UCreg_fp, &sf->uc.uc_mcontext.regs.UCreg_fp); err |= __put_user(regs->UCreg_ip, &sf->uc.uc_mcontext.regs.UCreg_ip); err |= __put_user(regs->UCreg_sp, &sf->uc.uc_mcontext.regs.UCreg_sp); err |= __put_user(regs->UCreg_lr, &sf->uc.uc_mcontext.regs.UCreg_lr); err |= __put_user(regs->UCreg_pc, &sf->uc.uc_mcontext.regs.UCreg_pc); err |= __put_user(regs->UCreg_asr, &sf->uc.uc_mcontext.regs.UCreg_asr); err |= __put_user(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no); err |= __put_user(current->thread.error_code, &sf->uc.uc_mcontext.error_code); err |= __put_user(current->thread.address, &sf->uc.uc_mcontext.fault_address); err |= __put_user(set->sig[0], &sf->uc.uc_mcontext.oldmask); err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); return err; }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao790100.00%1100.00%
Total790100.00%1100.00%


static inline void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) { unsigned long sp = regs->UCreg_sp; void __user *frame; /* * This is the X/Open sanctioned signal stack switching. */ if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) sp = current->sas_ss_sp + current->sas_ss_size; /* * ATPCS B01 mandates 8-byte alignment */ frame = (void __user *)((sp - framesize) & ~7); /* * Check that we can actually write to the signal frame. */ if (!access_ok(VERIFY_WRITE, frame, framesize)) frame = NULL; return frame; }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao103100.00%1100.00%
Total103100.00%1100.00%


static int setup_return(struct pt_regs *regs, struct k_sigaction *ka, unsigned long __user *rc, void __user *frame, int usig) { unsigned long handler = (unsigned long)ka->sa.sa_handler; unsigned long retcode; unsigned long asr = regs->UCreg_asr & ~PSR_f; unsigned int idx = 0; if (ka->sa.sa_flags & SA_SIGINFO) idx += 1; if (__put_user(sigreturn_codes[idx], rc) || __put_user(sigreturn_codes[idx+1], rc+1)) return 1; retcode = KERN_SIGRETURN_CODE + (idx << 2); regs->UCreg_00 = usig; regs->UCreg_sp = (unsigned long)frame; regs->UCreg_lr = retcode; regs->UCreg_pc = handler; regs->UCreg_asr = asr; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao155100.00%1100.00%
Total155100.00%1100.00%


static int setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) { struct sigframe __user *frame = get_sigframe(&ksig->ka, regs, sizeof(*frame)); int err = 0; if (!frame) return 1; /* * Set uc.uc_flags to a value which sc.trap_no would never have. */ err |= __put_user(0x5ac3c35a, &frame->uc.uc_flags); err |= setup_sigframe(frame, regs, set); if (err == 0) err |= setup_return(regs, &ksig->ka, frame->retcode, frame, ksig->sig); return err; }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao10190.18%133.33%
Richard Weinberger87.14%133.33%
Guenter Roeck32.68%133.33%
Total112100.00%3100.00%


static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) { struct rt_sigframe __user *frame = get_sigframe(&ksig->ka, regs, sizeof(*frame)); int err = 0; if (!frame) return 1; err |= copy_siginfo_to_user(&frame->info, &ksig->info); err |= __put_user(0, &frame->sig.uc.uc_flags); err |= __put_user(NULL, &frame->sig.uc.uc_link); err |= __save_altstack(&frame->sig.uc.uc_stack, regs->UCreg_sp); err |= setup_sigframe(&frame->sig, regs, set); if (err == 0) err |= setup_return(regs, &ksig->ka, frame->sig.retcode, frame, ksig->sig); if (err == 0) { /* * For realtime signals we must also set the second and third * arguments for the signal handler. */ regs->UCreg_01 = (unsigned long)&frame->info; regs->UCreg_02 = (unsigned long)&frame->sig.uc; } return err; }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao18691.18%125.00%
Richard Weinberger115.39%125.00%
Al Viro41.96%125.00%
Guenter Roeck31.47%125.00%
Total204100.00%4100.00%


static inline void setup_syscall_restart(struct pt_regs *regs) { regs->UCreg_00 = regs->UCreg_ORIG_00; regs->UCreg_pc -= 4; }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao26100.00%1100.00%
Total26100.00%1100.00%

/* * OK, we're invoking a handler */
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs, int syscall) { struct thread_info *thread = current_thread_info(); sigset_t *oldset = sigmask_to_save(); int usig = ksig->sig; int ret; /* * If we were from a system call, check for system call restarting... */ if (syscall) { switch (regs->UCreg_00) { case -ERESTART_RESTARTBLOCK: case -ERESTARTNOHAND: regs->UCreg_00 = -EINTR; break; case -ERESTARTSYS: if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { regs->UCreg_00 = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: setup_syscall_restart(regs); } } /* * 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); /* * Check that the resulting registers are actually sane. */ ret |= !valid_user_regs(regs); signal_setup_done(ret, ksig, 0); }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao14385.12%116.67%
Richard Weinberger158.93%116.67%
Al Viro84.76%350.00%
Matt Fleming21.19%116.67%
Total168100.00%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. * * 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) { 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_signal(&ksig, regs, syscall); return; } /* * No signal to deliver to the process - restart the syscall. */ if (syscall) { if (regs->UCreg_00 == -ERESTART_RESTARTBLOCK) { u32 __user *usp; regs->UCreg_sp -= 4; usp = (u32 __user *)regs->UCreg_sp; if (put_user(regs->UCreg_pc, usp) == 0) { regs->UCreg_pc = KERN_RESTART_CODE; } else { regs->UCreg_sp += 4; force_sigsegv(0, current); } } if (regs->UCreg_00 == -ERESTARTNOHAND || regs->UCreg_00 == -ERESTARTSYS || regs->UCreg_00 == -ERESTARTNOINTR) { setup_syscall_restart(regs); } } /* If there's no signal to deliver, we just put the saved * sigmask back. */ restore_saved_sigmask(); }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao14993.12%120.00%
Richard Weinberger63.75%120.00%
Al Viro42.50%240.00%
Guenter Roeck10.62%120.00%
Total160100.00%5100.00%


asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, 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); } }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao49100.00%1100.00%
Total49100.00%1100.00%

/* * Copy signal return handlers into the vector page, and * set sigreturn to be a pointer to these. */
void __init early_signal_init(void) { memcpy((void *)kuser_vecpage_to_vectors(KERN_SIGRETURN_CODE), sigreturn_codes, sizeof(sigreturn_codes)); memcpy((void *)kuser_vecpage_to_vectors(KERN_RESTART_CODE), syscall_restart_code, sizeof(syscall_restart_code)); /* Need not to flush icache, since early_trap_init will do it last. */ }

Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao47100.00%1100.00%
Total47100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Guan Xuetao270497.55%19.09%
Richard Weinberger401.44%19.09%
Al Viro170.61%654.55%
Guenter Roeck70.25%19.09%
Matt Fleming30.11%19.09%
Andrew Lutomirski10.04%19.09%
Total2772100.00%11100.00%
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