[PATCH] m32r: employ new kernel API/ABI

We, Linux/M32R project members, decided to change the kernel API/ABI.  This
modification is not small, but if we don't change it now, perhaps we have
no chance to change them hereafter.

* Why change the m32r kernel API/ABI?
- The m32r port has many old-style syscall interfaces,
  because we made m32r port refering to the other traditional archs.
  Some old syscalls are no longer used or can be safely removed
  by upgrading the GNU C library.
- To make the m32r kernel more secure, it is preferable to prevent
  stack region from being executed. (e.g. stack overflow)

* API/ABI changes
- include/asm-m32r/unistd.h: Upgrade to the new kernel API.
- arch/m32r/entry.S: Minimum update to the new ABI.
- Don't use UID16 syscalls.
- To make stack noexecutable:
  1) Don't use trampoline for signal handlers for kernel space (cf. sparc64):
    sys_signal: remove.
    sys_sigaction, sys_rt_sigaction: use glibc's restorer.
  2) Don't generate trampoline code by GCC in userspace:
    Support non-executable stack by the m32r gcc.
    --> done (for gcc-3.4.3/gcc-4.0)

* New userland
- This modification does *not* keep backward compatibility.
  So we have been prepared new userland, based on the new API/ABI.
  Already, more than 200 new Debian deb binary packages are available
  on the Linux/M32R site:
  http://debian.linux-m32r.org/dists/04_ordovician/ (for this new ABI)
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/m32r/Kconfig

@@ -14,7 +14,7 @@ config SBUS
 
 config UID16
 	bool
-	default y
+	default n
 
 config GENERIC_ISA_DMA
 	bool

arch/m32r/kernel/entry.S

@@ -725,25 +725,25 @@ ENTRY(sys_call_table)
 	.long sys_time
 	.long sys_mknod
 	.long sys_chmod			/* 15 */
-	.long sys_lchown
+	.long sys_ni_syscall		/* lchown16 syscall holder */
 	.long sys_ni_syscall		/* old break syscall holder */
-	.long sys_stat
+	.long sys_ni_syscall		/* old stat syscall holder */
 	.long sys_lseek
 	.long sys_getpid		/* 20 */
 	.long sys_mount
 	.long sys_oldumount
-	.long sys_setuid
-	.long sys_getuid
+	.long sys_ni_syscall		/* setuid16 syscall holder */
+	.long sys_ni_syscall		/* getuid16 syscall holder */
 	.long sys_stime			/* 25 */
 	.long sys_ptrace
 	.long sys_alarm
-	.long sys_fstat
+	.long sys_ni_syscall		/* old fstat syscall holder */
 	.long sys_pause
 	.long sys_utime			/* 30 */
-	.long sys_cacheflush		/* for M32R */ /* old stty syscall holder */
+	.long sys_ni_syscall		/* old stty syscall holder */
 	.long sys_cachectl		/* for M32R */ /* old gtty syscall holder */
 	.long sys_access
-	.long sys_nice
+	.long sys_ni_syscall		/* nice	syscall holder */
 	.long sys_ni_syscall		/* 35  -  old ftime syscall holder */
 	.long sys_sync
 	.long sys_kill
@@ -755,17 +755,17 @@ ENTRY(sys_call_table)
 	.long sys_times
 	.long sys_ni_syscall		/* old prof syscall holder */
 	.long sys_brk			/* 45 */
-	.long sys_setgid
-	.long sys_getgid
-	.long sys_signal
-	.long sys_geteuid
-	.long sys_getegid		/* 50 */
+	.long sys_ni_syscall		/* setgid16 syscall holder */
+	.long sys_getgid		/* will be unused */
+	.long sys_ni_syscall		/* signal syscall holder */
+	.long sys_ni_syscall		/* geteuid16  syscall holder */
+	.long sys_ni_syscall		/* 50 - getegid16 syscall holder */
 	.long sys_acct
 	.long sys_umount		/* recycled never used phys() */
 	.long sys_ni_syscall		/* old lock syscall holder */
 	.long sys_ioctl
-	.long sys_fcntl			/* 55 */
-	.long sys_ni_syscall		/* old mpx syscall holder */
+	.long sys_fcntl			/* 55 - will be unused */
+	.long sys_ni_syscall		/* mpx syscall holder */
 	.long sys_setpgid
 	.long sys_ni_syscall		/* old ulimit syscall holder */
 	.long sys_ni_syscall		/* sys_olduname */
@@ -776,41 +776,41 @@ ENTRY(sys_call_table)
 	.long sys_getppid
 	.long sys_getpgrp		/* 65 */
 	.long sys_setsid
-	.long sys_sigaction
-	.long sys_sgetmask
-	.long sys_ssetmask
-	.long sys_setreuid		/* 70 */
-	.long sys_setregid
-	.long sys_sigsuspend
-	.long sys_sigpending
+	.long sys_ni_syscall		/* sigaction syscall holder */
+	.long sys_ni_syscall		/* sgetmask syscall holder */
+	.long sys_ni_syscall		/* ssetmask syscall holder */
+	.long sys_ni_syscall		/* 70 - setreuid16 syscall holder */
+	.long sys_ni_syscall		/* setregid16 syscall holder */
+	.long sys_ni_syscall		/* sigsuspend syscall holder */
+	.long sys_ni_syscall		/* sigpending syscall holder */
 	.long sys_sethostname
 	.long sys_setrlimit		/* 75 */
-	.long sys_getrlimit
+	.long sys_getrlimit/*will be unused*/
 	.long sys_getrusage
 	.long sys_gettimeofday
 	.long sys_settimeofday
-	.long sys_getgroups		/* 80 */
-	.long sys_setgroups
+	.long sys_ni_syscall		/* 80 - getgroups16 syscall holder */
+	.long sys_ni_syscall		/* setgroups16 syscall holder */
 	.long sys_ni_syscall		/* sys_oldselect */
 	.long sys_symlink
-	.long sys_lstat
+	.long sys_ni_syscall		/* old lstat syscall holder */
 	.long sys_readlink		/* 85 */
 	.long sys_uselib
 	.long sys_swapon
 	.long sys_reboot
-	.long old_readdir
+	.long sys_ni_syscall		/* readdir syscall holder */
 	.long sys_ni_syscall		/* 90 - old_mmap syscall holder */
 	.long sys_munmap
 	.long sys_truncate
 	.long sys_ftruncate
 	.long sys_fchmod
-	.long sys_fchown		/* 95 */
+	.long sys_ni_syscall		/* 95 - fchwon16  syscall holder */
 	.long sys_getpriority
 	.long sys_setpriority
 	.long sys_ni_syscall		/* old profil syscall holder */
 	.long sys_statfs
 	.long sys_fstatfs		/* 100 */
-	.long sys_ni_syscall		/* ioperm */
+	.long sys_ni_syscall		/* ioperm syscall holder */
 	.long sys_socketcall
 	.long sys_syslog
 	.long sys_setitimer
@@ -818,37 +818,37 @@ ENTRY(sys_call_table)
 	.long sys_newstat
 	.long sys_newlstat
 	.long sys_newfstat
-	.long sys_uname
-	.long sys_ni_syscall		/* 110  -  iopl */
+	.long sys_ni_syscall		/* old uname syscall holder */
+	.long sys_ni_syscall		/* 110  -  iopl syscall holder */
 	.long sys_vhangup
-	.long sys_ni_syscall		/* for idle */
-	.long sys_ni_syscall		/* for vm86old */
+	.long sys_ni_syscall		/* idle syscall holder */
+	.long sys_ni_syscall		/* vm86old syscall holder */
 	.long sys_wait4
 	.long sys_swapoff		/* 115 */
 	.long sys_sysinfo
 	.long sys_ipc
 	.long sys_fsync
-	.long sys_sigreturn
+	.long sys_ni_syscall		/* sigreturn syscall holder */
 	.long sys_clone			/* 120 */
 	.long sys_setdomainname
 	.long sys_newuname
-	.long sys_ni_syscall		/* sys_modify_ldt */
+	.long sys_ni_syscall		/* modify_ldt syscall holder */
 	.long sys_adjtimex
 	.long sys_mprotect		/* 125 */
-	.long sys_sigprocmask
-	.long sys_ni_syscall		/* sys_create_module */
+	.long sys_ni_syscall		/* sigprocmask syscall holder */
+	.long sys_ni_syscall		/* create_module syscall holder */
 	.long sys_init_module
 	.long sys_delete_module
-	.long sys_ni_syscall		/* 130 sys_get_kernel_syms */
+	.long sys_ni_syscall		/* 130 - get_kernel_syms */
 	.long sys_quotactl
 	.long sys_getpgid
 	.long sys_fchdir
 	.long sys_bdflush
 	.long sys_sysfs			/* 135 */
 	.long sys_personality
-	.long sys_ni_syscall		/* for afs_syscall */
-	.long sys_setfsuid
-	.long sys_setfsgid
+	.long sys_ni_syscall		/* afs_syscall syscall holder */
+	.long sys_ni_syscall		/* setfsuid16 syscall holder */
+	.long sys_ni_syscall		/* setfsgid16 syscall holder */
 	.long sys_llseek		/* 140 */
 	.long sys_getdents
 	.long sys_select
@@ -873,10 +873,10 @@ ENTRY(sys_call_table)
 	.long sys_sched_rr_get_interval
 	.long sys_nanosleep
 	.long sys_mremap
-	.long sys_setresuid
-	.long sys_getresuid		/* 165 */
-	.long sys_tas			/* vm86 */
-	.long sys_ni_syscall		/* sys_query_module */
+	.long sys_ni_syscall		/* setresuid16 syscall holder */
+	.long sys_ni_syscall		/* 165 - getresuid16 syscall holder */
+	.long sys_tas			/* vm86 syscall holder */
+	.long sys_ni_syscall		/* query_module syscall holder */
 	.long sys_poll
 	.long sys_nfsservctl
 	.long sys_setresgid		/* 170 */
@@ -891,7 +891,7 @@ ENTRY(sys_call_table)
 	.long sys_rt_sigsuspend
 	.long sys_pread64		/* 180 */
 	.long sys_pwrite64
-	.long sys_chown
+	.long sys_ni_syscall		/* chown16 syscall holder */
 	.long sys_getcwd
 	.long sys_capget
 	.long sys_capset		/* 185 */

arch/m32r/kernel/signal.c

@@ -33,32 +33,6 @@
 
 int do_signal(struct pt_regs *, sigset_t *);
 
-/*
- * Atomically swap in the new signal mask, and wait for a signal.
- */
-asmlinkage int
-sys_sigsuspend(old_sigset_t mask, unsigned long r1,
-	       unsigned long r2, unsigned long r3, unsigned long r4,
-	       unsigned long r5, unsigned long r6, struct pt_regs regs)
-{
-	sigset_t saveset;
-
-	mask &= _BLOCKABLE;
-	spin_lock_irq(&current->sighand->siglock);
-	saveset = current->blocked;
-	siginitset(&current->blocked, mask);
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
-
-	regs.r0 = -EINTR;
-	while (1) {
-		current->state = TASK_INTERRUPTIBLE;
-		schedule();
-		if (do_signal(&regs, &saveset))
-			return regs.r0;
-	}
-}
-
 asmlinkage int
 sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize,
 		  unsigned long r2, unsigned long r3, unsigned long r4,
@@ -89,38 +63,6 @@ sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize,
 	}
 }
 
-asmlinkage int
-sys_sigaction(int sig, const struct old_sigaction __user *act,
-	      struct old_sigaction __user *oact)
-{
-	struct k_sigaction new_ka, old_ka;
-	int ret;
-
-	if (act) {
-		old_sigset_t mask;
-		if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
-		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
-		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
-			return -EFAULT;
-		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
-		__get_user(mask, &act->sa_mask);
-		siginitset(&new_ka.sa.sa_mask, mask);
-	}
-
-	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
-
-	if (!ret && oact) {
-		if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
-		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
-		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
-			return -EFAULT;
-		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
-		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
-	}
-
-	return ret;
-}
-
 asmlinkage int
 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 		unsigned long r2, unsigned long r3, unsigned long r4,
@@ -134,26 +76,14 @@ sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  * Do a signal return; undo the signal stack.
  */
 
-struct sigframe
-{
-//	char *pretcode;
-	int sig;
-	struct sigcontext sc;
-//	struct _fpstate fpstate;
-	unsigned long extramask[_NSIG_WORDS-1];
-	char retcode[4];
-};
-
 struct rt_sigframe
 {
-//	char *pretcode;
 	int sig;
 	struct siginfo *pinfo;
 	void *puc;
 	struct siginfo info;
 	struct ucontext uc;
 //	struct _fpstate fpstate;
-	char retcode[8];
 };
 
 static int
@@ -207,38 +137,6 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
 	return err;
 }
 
-asmlinkage int
-sys_sigreturn(unsigned long r0, unsigned long r1,
-	      unsigned long r2, unsigned long r3, unsigned long r4,
-	      unsigned long r5, unsigned long r6, struct pt_regs regs)
-{
-	struct sigframe __user *frame = (struct sigframe __user *)regs.spu;
-	sigset_t set;
-	int result;
-
-	if (verify_area(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;
-
-	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
-
-	if (restore_sigcontext(&regs, &frame->sc, &result))
-		goto badframe;
-	return result;
-
-badframe:
-	force_sig(SIGSEGV, current);
-	return 0;
-}
-
 asmlinkage int
 sys_rt_sigreturn(unsigned long r0, unsigned long r1,
 		 unsigned long r2, unsigned long r3, unsigned long r4,
@@ -342,71 +240,6 @@ get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 	return (void __user *)((sp - frame_size) & -8ul);
 }
 
-static void setup_frame(int sig, struct k_sigaction *ka,
-			sigset_t *set, struct pt_regs *regs)
-{
-	struct sigframe __user *frame;
-	int err = 0;
-	int signal;
-
-	frame = get_sigframe(ka, regs->spu, sizeof(*frame));
-
-	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
-		goto give_sigsegv;
-
-	signal = current_thread_info()->exec_domain
-		&& current_thread_info()->exec_domain->signal_invmap
-		&& sig < 32
-		? current_thread_info()->exec_domain->signal_invmap[sig]
-		: sig;
-
-	err |= __put_user(signal, &frame->sig);
-	if (err)
-		goto give_sigsegv;
-
-	err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
-	if (err)
-		goto give_sigsegv;
-
-	if (_NSIG_WORDS > 1) {
-		err |= __copy_to_user(frame->extramask, &set->sig[1],
-				      sizeof(frame->extramask));
-		if (err)
-			goto give_sigsegv;
-	}
-
-	if (ka->sa.sa_flags & SA_RESTORER)
-		regs->lr = (unsigned long)ka->sa.sa_restorer;
-	else {
-		/* This is : ldi r7, #__NR_sigreturn ; trap #2 */
-		unsigned long code = 0x670010f2 | (__NR_sigreturn << 16);
-
-		regs->lr = (unsigned long)frame->retcode;
-		err |= __put_user(code, (long __user *)(frame->retcode+0));
-		if (err)
-			goto give_sigsegv;
-		flush_cache_sigtramp((unsigned long)frame->retcode);
-	}
-
-	/* Set up registers for signal handler */
-	regs->spu = (unsigned long)frame;
-	regs->r0 = signal;	/* Arg for signal handler */
-	regs->r1 = (unsigned long)&frame->sc;
-	regs->bpc = (unsigned long)ka->sa.sa_handler;
-
-	set_fs(USER_DS);
-
-#if DEBUG_SIG
-	printk("SIG deliver (%s:%d): sp=%p pc=%p\n",
-		current->comm, current->pid, frame, regs->pc);
-#endif
-
-	return;
-
-give_sigsegv:
-	force_sigsegv(sig, current);
-}
-
 static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 			   sigset_t *set, struct pt_regs *regs)
 {
@@ -448,20 +281,7 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 		goto give_sigsegv;
 
 	/* Set up to return from userspace.  */
-	if (ka->sa.sa_flags & SA_RESTORER)
-		regs->lr = (unsigned long)ka->sa.sa_restorer;
-	else {
-		/* This is : ldi r7, #__NR_rt_sigreturn ; trap #2 */
-		unsigned long code1 = 0x97f00000 | (__NR_rt_sigreturn);
-		unsigned long code2 = 0x10f2f000;
-
-		regs->lr = (unsigned long)frame->retcode;
-		err |= __put_user(code1, (long __user *)(frame->retcode+0));
-		err |= __put_user(code2, (long __user *)(frame->retcode+4));
-		if (err)
-			goto give_sigsegv;
-		flush_cache_sigtramp((unsigned long)frame->retcode);
-	}
+	regs->lr = (unsigned long)ka->sa.sa_restorer;
 
 	/* Set up registers for signal handler */
 	regs->spu = (unsigned long)frame;
@@ -519,10 +339,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 	}
 
 	/* Set up the stack frame */
-	if (ka->sa.sa_flags & SA_SIGINFO)
-		setup_rt_frame(sig, ka, info, oldset, regs);
-	else
-		setup_frame(sig, ka, oldset, regs);
+	setup_rt_frame(sig, ka, info, oldset, regs);
 
 	if (!(ka->sa.sa_flags & SA_NODEFER)) {
 		spin_lock_irq(&current->sighand->siglock);