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m68k: sanitize copy_thread(), fork/vfork/clone wrappers, switch to generic fork/vfork

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-10-21 16:41:46 -04:00
parent dfe09ae0e5
commit 20ecc91c32
4 changed files with 46 additions and 71 deletions
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2
arch/m68k/include/asm/unistd.h
View File

@ -32,6 +32,8 @@
#define __ARCH_WANT_SYS_RT_SIGACTION
#define __ARCH_WANT_SYS_RT_SIGSUSPEND
#define __ARCH_WANT_SYS_EXECVE
#define __ARCH_WANT_SYS_FORK
#define __ARCH_WANT_SYS_VFORK
/*
* "Conditional" syscalls

23
arch/m68k/kernel/entry.S
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@ -44,34 +44,29 @@
.globl system_call, buserr, trap, resume
.globl sys_call_table
.globl sys_fork, sys_clone, sys_vfork
.globl __sys_fork, __sys_clone, __sys_vfork
.globl ret_from_interrupt, bad_interrupt
.globl auto_irqhandler_fixup
.globl user_irqvec_fixup
.text
ENTRY(sys_fork)
ENTRY(__sys_fork)
SAVE_SWITCH_STACK
pea %sp@(SWITCH_STACK_SIZE)
jbsr m68k_fork
addql #4,%sp
RESTORE_SWITCH_STACK
jbsr sys_fork
lea %sp@(24),%sp
rts
ENTRY(sys_clone)
ENTRY(__sys_clone)
SAVE_SWITCH_STACK
pea %sp@(SWITCH_STACK_SIZE)
jbsr m68k_clone
addql #4,%sp
RESTORE_SWITCH_STACK
lea %sp@(28),%sp
rts
ENTRY(sys_vfork)
ENTRY(__sys_vfork)
SAVE_SWITCH_STACK
pea %sp@(SWITCH_STACK_SIZE)
jbsr m68k_vfork
addql #4,%sp
RESTORE_SWITCH_STACK
jbsr sys_vfork
lea %sp@(24),%sp
rts
ENTRY(sys_sigreturn)

86
arch/m68k/kernel/process.c
View File

@ -136,57 +136,36 @@ void flush_thread(void)
}
/*
* "m68k_fork()".. By the time we get here, the
* non-volatile registers have also been saved on the
* stack. We do some ugly pointer stuff here.. (see
* also copy_thread)
* Why not generic sys_clone, you ask? m68k passes all arguments on stack.
* And we need all registers saved, which means a bunch of stuff pushed
* on top of pt_regs, which means that sys_clone() arguments would be
* buried. We could, of course, copy them, but it's too costly for no
* good reason - generic clone() would have to copy them *again* for
* do_fork() anyway. So in this case it's actually better to pass pt_regs *
* and extract arguments for do_fork() from there. Eventually we might
* go for calling do_fork() directly from the wrapper, but only after we
* are finished with do_fork() prototype conversion.
*/
asmlinkage int m68k_fork(struct pt_regs *regs)
{
#ifdef CONFIG_MMU
return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
#else
return -EINVAL;
#endif
}
asmlinkage int m68k_vfork(struct pt_regs *regs)
{
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
NULL, NULL);
}
asmlinkage int m68k_clone(struct pt_regs *regs)
{
unsigned long clone_flags;
unsigned long newsp;
int __user *parent_tidptr, *child_tidptr;
/* syscall2 puts clone_flags in d1 and usp in d2 */
clone_flags = regs->d1;
newsp = regs->d2;
parent_tidptr = (int __user *)regs->d3;
child_tidptr = (int __user *)regs->d4;
if (!newsp)
newsp = rdusp();
return do_fork(clone_flags, newsp, regs, 0,
parent_tidptr, child_tidptr);
/* regs will be equal to current_pt_regs() */
return do_fork(regs->d1, regs->d2, regs, 0,
(int __user *)regs->d3, (int __user *)regs->d4);
}
int copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long arg,
struct task_struct * p, struct pt_regs * regs)
struct task_struct * p, struct pt_regs * unused)
{
struct pt_regs * childregs;
struct switch_stack *childstack;
struct fork_frame {
struct switch_stack sw;
struct pt_regs regs;
} *frame;
childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
childstack = ((struct switch_stack *) childregs) - 1;
frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
p->thread.usp = usp;
p->thread.ksp = (unsigned long)childstack;
p->thread.esp0 = (unsigned long)childregs;
p->thread.ksp = (unsigned long)frame;
p->thread.esp0 = (unsigned long)&frame->regs;
/*
* Must save the current SFC/DFC value, NOT the value when
@ -194,25 +173,24 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
*/
p->thread.fs = get_fs().seg;
if (unlikely(!regs)) {
if (unlikely(p->flags & PF_KTHREAD)) {
/* kernel thread */
memset(childstack, 0,
sizeof(struct switch_stack) + sizeof(struct pt_regs));
childregs->sr = PS_S;
childstack->a3 = usp; /* function */
childstack->d7 = arg;
childstack->retpc = (unsigned long)ret_from_kernel_thread;
memset(frame, 0, sizeof(struct fork_frame));
frame->regs.sr = PS_S;
frame->sw.a3 = usp; /* function */
frame->sw.d7 = arg;
frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
p->thread.usp = 0;
return 0;
}
*childregs = *regs;
childregs->d0 = 0;
*childstack = ((struct switch_stack *) regs)[-1];
childstack->retpc = (unsigned long)ret_from_fork;
memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
sizeof(struct fork_frame));
frame->regs.d0 = 0;
frame->sw.retpc = (unsigned long)ret_from_fork;
p->thread.usp = usp ?: rdusp();
if (clone_flags & CLONE_SETTLS)
task_thread_info(p)->tp_value = regs->d5;
task_thread_info(p)->tp_value = frame->regs.d5;
#ifdef CONFIG_FPU
if (!FPU_IS_EMU) {

6
arch/m68k/kernel/syscalltable.S
View File

@ -22,7 +22,7 @@ ALIGN
ENTRY(sys_call_table)
.long sys_restart_syscall /* 0 - old "setup()" system call, used for restarting */
.long sys_exit
.long sys_fork
.long __sys_fork
.long sys_read
.long sys_write
.long sys_open /* 5 */
@ -140,7 +140,7 @@ ENTRY(sys_call_table)
.long sys_ipc
.long sys_fsync
.long sys_sigreturn
.long sys_clone /* 120 */
.long __sys_clone /* 120 */
.long sys_setdomainname
.long sys_newuname
.long sys_cacheflush /* modify_ldt for i386 */
@ -210,7 +210,7 @@ ENTRY(sys_call_table)
.long sys_sendfile
.long sys_ni_syscall /* streams1 */
.long sys_ni_syscall /* streams2 */
.long sys_vfork /* 190 */
.long __sys_vfork /* 190 */
.long sys_getrlimit
.long sys_mmap2
.long sys_truncate64