summaryrefslogtreecommitdiff
path: root/arch/m68k/kernel
diff options
context:
space:
mode:
authorAl Viro <viro@zeniv.linux.org.uk>2012-10-21 16:41:46 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2012-11-28 22:44:46 -0500
commit20ecc91c3230b747cd13d9a2f43a45f6445a3906 (patch)
tree3892c3eafe47e78f153549158c24d26cf1b7ecc8 /arch/m68k/kernel
parentdfe09ae0e5fe40679af05b1ba810d469844c97b3 (diff)
m68k: sanitize copy_thread(), fork/vfork/clone wrappers, switch to generic fork/vfork
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/m68k/kernel')
-rw-r--r--arch/m68k/kernel/entry.S23
-rw-r--r--arch/m68k/kernel/process.c86
-rw-r--r--arch/m68k/kernel/syscalltable.S6
3 files changed, 44 insertions, 71 deletions
diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S
index 45b2f293f8cf..a78f5649e8de 100644
--- a/arch/m68k/kernel/entry.S
+++ b/arch/m68k/kernel/entry.S
@@ -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)
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index c51bb172e14d..aa9b11000273 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -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) {
diff --git a/arch/m68k/kernel/syscalltable.S b/arch/m68k/kernel/syscalltable.S
index 4fc2e29b771b..c30da5b3f2db 100644
--- a/arch/m68k/kernel/syscalltable.S
+++ b/arch/m68k/kernel/syscalltable.S
@@ -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