Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * OpenRISC signal.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Linux architectural port borrowing liberally from similar works of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  * others.  All original copyrights apply as per the original source
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  * declaration.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  * Modifications for the OpenRISC architecture:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/smp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/signal.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include <linux/wait.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #include <linux/ptrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) #include <linux/unistd.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include <linux/stddef.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) #include <linux/tracehook.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #include <asm/processor.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #include <asm/syscall.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) #include <asm/ucontext.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) #define DEBUG_SIG 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) struct rt_sigframe {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	struct siginfo info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 	struct ucontext uc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	unsigned char retcode[16];	/* trampoline code */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) static int restore_sigcontext(struct pt_regs *regs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 			      struct sigcontext __user *sc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	int err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	/* Always make any pending restarted system calls return -EINTR */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	current->restart_block.fn = do_no_restart_syscall;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	 * Restore the regs from &sc->regs.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	 * (sc is already checked since the sigframe was
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	 *  checked in sys_sigreturn previously)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	err |= __copy_from_user(regs, sc->regs.gpr, 32 * sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	err |= __copy_from_user(&regs->pc, &sc->regs.pc, sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	err |= __copy_from_user(&regs->sr, &sc->regs.sr, sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	/* make sure the SM-bit is cleared so user-mode cannot fool us */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	regs->sr &= ~SPR_SR_SM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	regs->orig_gpr11 = -1;	/* Avoid syscall restart checks */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 	/* TODO: the other ports use regs->orig_XX to disable syscall checks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	 * after this completes, but we don't use that mechanism. maybe we can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	 * use it now ?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	sigset_t set;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	 * Since we stacked the signal on a dword boundary,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	 * then frame should be dword aligned here.  If it's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	 * not, then the user is trying to mess with us.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	if (((unsigned long)frame) & 3)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 		goto badframe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	if (!access_ok(frame, sizeof(*frame)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 		goto badframe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		goto badframe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	set_current_blocked(&set);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 		goto badframe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	if (restore_altstack(&frame->uc.uc_stack))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 		goto badframe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	return regs->gpr[11];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) badframe:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	force_sig(SIGSEGV);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)  * Set up a signal frame.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	int err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	/* copy the regs */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	/* There should be no need to save callee-saved registers here...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	 * ...but we save them anyway.  Revisit this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	err |= __copy_to_user(sc->regs.gpr, regs, 32 * sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	err |= __copy_to_user(&sc->regs.pc, &regs->pc, sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	err |= __copy_to_user(&sc->regs.sr, &regs->sr, sizeof(unsigned long));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) static inline unsigned long align_sigframe(unsigned long sp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	return sp & ~3UL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127)  * Work out where the signal frame should go.  It's either on the user stack
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128)  * or the alternate stack.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) static inline void __user *get_sigframe(struct ksignal *ksig,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 					struct pt_regs *regs, size_t frame_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	unsigned long sp = regs->sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	/* redzone */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	sp -= STACK_FRAME_OVERHEAD;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	sp = sigsp(sp, ksig);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	sp = align_sigframe(sp - frame_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	return (void __user *)sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) /* grab and setup a signal frame.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)  * basically we stack a lot of state info, and arrange for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)  * user-mode program to return to the kernel using either a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)  * trampoline which performs the syscall sigreturn, or a provided
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149)  * user-mode trampoline.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 			  struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	struct rt_sigframe __user *frame;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	unsigned long return_ip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	int err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	frame = get_sigframe(ksig, regs, sizeof(*frame));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	if (!access_ok(frame, sizeof(*frame)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 		return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	/* Create siginfo.  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 		err |= copy_siginfo_to_user(&frame->info, &ksig->info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	/* Create the ucontext.  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	err |= __put_user(0, &frame->uc.uc_flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	err |= __put_user(NULL, &frame->uc.uc_link);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 		return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	/* trampoline - the desired return ip is the retcode itself */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	return_ip = (unsigned long)&frame->retcode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	/* This is:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 		l.ori r11,r0,__NR_sigreturn
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 		l.sys 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	err |= __put_user(0xa960,             (short __user *)(frame->retcode + 0));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	err |= __put_user(__NR_rt_sigreturn,  (short __user *)(frame->retcode + 2));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 	err |= __put_user(0x20000001, (unsigned long __user *)(frame->retcode + 4));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	err |= __put_user(0x15000000, (unsigned long __user *)(frame->retcode + 8));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 		return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	/* Set up registers for signal handler */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	regs->pc = (unsigned long)ksig->ka.sa.sa_handler; /* what we enter NOW */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	regs->gpr[9] = (unsigned long)return_ip;     /* what we enter LATER */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	regs->gpr[3] = (unsigned long)ksig->sig;           /* arg 1: signo */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	regs->gpr[4] = (unsigned long)&frame->info;  /* arg 2: (siginfo_t*) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	regs->gpr[5] = (unsigned long)&frame->uc;    /* arg 3: ucontext */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 	/* actually move the usp to reflect the stacked frame */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	regs->sp = (unsigned long)frame;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) static inline void
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) handle_signal(struct ksignal *ksig, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216)  * Note that 'init' is a special process: it doesn't get signals it doesn't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217)  * want to handle. Thus you cannot kill init even with a SIGKILL even by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218)  * mistake.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220)  * Also note that the regs structure given here as an argument, is the latest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221)  * pushed pt_regs. It may or may not be the same as the first pushed registers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222)  * when the initial usermode->kernelmode transition took place. Therefore
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223)  * we can use user_mode(regs) to see if we came directly from kernel or user
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224)  * mode below.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) int do_signal(struct pt_regs *regs, int syscall)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 	struct ksignal ksig;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 	unsigned long continue_addr = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 	unsigned long restart_addr = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 	unsigned long retval = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 	int restart = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 	if (syscall) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 		continue_addr = regs->pc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 		restart_addr = continue_addr - 4;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 		retval = regs->gpr[11];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 		 * Setup syscall restart here so that a debugger will
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 		 * see the already changed PC.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 		switch (retval) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 		case -ERESTART_RESTARTBLOCK:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 			restart = -2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 			fallthrough;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 		case -ERESTARTNOHAND:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 		case -ERESTARTSYS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 		case -ERESTARTNOINTR:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 			restart++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 			regs->gpr[11] = regs->orig_gpr11;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 			regs->pc = restart_addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	 * Get the signal to deliver.  During the call to get_signal the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 	 * debugger may change all our registers so we may need to revert
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	 * the decision to restart the syscall; specifically, if the PC is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	 * changed, don't restart the syscall.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	if (get_signal(&ksig)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 		if (unlikely(restart) && regs->pc == restart_addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 			if (retval == -ERESTARTNOHAND ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 			    retval == -ERESTART_RESTARTBLOCK
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 			    || (retval == -ERESTARTSYS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 			        && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 				/* No automatic restart */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 				regs->gpr[11] = -EINTR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 				regs->pc = continue_addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 		handle_signal(&ksig, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 		/* no handler */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 		restore_saved_sigmask();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 		 * Restore pt_regs PC as syscall restart will be handled by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 		 * kernel without return to userspace
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 		if (unlikely(restart) && regs->pc == restart_addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 			regs->pc = continue_addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 			return restart;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) asmlinkage int
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 		if (likely(thread_flags & _TIF_NEED_RESCHED)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 			schedule();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 			if (unlikely(!user_mode(regs)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 				return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 			local_irq_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 			if (thread_flags & _TIF_SIGPENDING) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 				int restart = do_signal(regs, syscall);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 				if (unlikely(restart)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 					/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 					 * Restart without handlers.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 					 * Deal with it without leaving
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 					 * the kernel space.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 					 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 					return restart;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 				}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 				syscall = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 			} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 				tracehook_notify_resume(regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 		local_irq_disable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 		thread_flags = current_thread_info()->flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	} while (thread_flags & _TIF_WORK_MASK);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) }