From 533e6903bea0440816a0f517b0845ccea4cc7917 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 16 Sep 2012 12:05:09 -0400
Subject: m68k: split ret_from_fork(), simplify kernel_thread()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/m68k/kernel/process.c | 84 +++++++++++++---------------------------------
1 file changed, 24 insertions(+), 60 deletions(-)
(limited to 'arch/m68k/kernel/process.c')
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index c488e3cfab5..b3d4760c975 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -34,6 +34,7 @@
asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
/*
@@ -120,51 +121,6 @@ void show_regs(struct pt_regs * regs)
printk("USP: %08lx\n", rdusp());
}
-/*
- * Create a kernel thread
- */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
- int pid;
- mm_segment_t fs;
-
- fs = get_fs();
- set_fs (KERNEL_DS);
-
- {
- register long retval __asm__ ("d0");
- register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
-
- retval = __NR_clone;
- __asm__ __volatile__
- ("clrl %%d2\n\t"
- "trap #0\n\t" /* Linux/m68k system call */
- "tstl %0\n\t" /* child or parent */
- "jne 1f\n\t" /* parent - jump */
-#ifdef CONFIG_MMU
- "lea %%sp@(%c7),%6\n\t" /* reload current */
- "movel %6@,%6\n\t"
-#endif
- "movel %3,%%sp@-\n\t" /* push argument */
- "jsr %4@\n\t" /* call fn */
- "movel %0,%%d1\n\t" /* pass exit value */
- "movel %2,%%d0\n\t" /* exit */
- "trap #0\n"
- "1:"
- : "+d" (retval)
- : "i" (__NR_clone), "i" (__NR_exit),
- "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
- "i" (-THREAD_SIZE)
- : "d2");
-
- pid = retval;
- }
-
- set_fs (fs);
- return pid;
-}
-EXPORT_SYMBOL(kernel_thread);
-
void flush_thread(void)
{
current->thread.fs = __USER_DS;
@@ -216,30 +172,18 @@ asmlinkage int m68k_clone(struct pt_regs *regs)
}
int copy_thread(unsigned long clone_flags, unsigned long usp,
- unsigned long unused,
+ unsigned long arg,
struct task_struct * p, struct pt_regs * regs)
{
struct pt_regs * childregs;
- struct switch_stack * childstack, *stack;
- unsigned long *retp;
+ struct switch_stack *childstack;
childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
-
- *childregs = *regs;
- childregs->d0 = 0;
-
- retp = ((unsigned long *) regs);
- stack = ((struct switch_stack *) retp) - 1;
-
childstack = ((struct switch_stack *) childregs) - 1;
- *childstack = *stack;
- childstack->retpc = (unsigned long)ret_from_fork;
p->thread.usp = usp;
p->thread.ksp = (unsigned long)childstack;
-
- if (clone_flags & CLONE_SETTLS)
- task_thread_info(p)->tp_value = regs->d5;
+ p->thread.esp0 = (unsigned long)childregs;
/*
* Must save the current SFC/DFC value, NOT the value when
@@ -247,6 +191,26 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
*/
p->thread.fs = get_fs().seg;
+ if (unlikely(!regs)) {
+ /* 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;
+ p->thread.usp = 0;
+ return 0;
+ }
+ *childregs = *regs;
+ childregs->d0 = 0;
+
+ *childstack = ((struct switch_stack *) regs)[-1];
+ childstack->retpc = (unsigned long)ret_from_fork;
+
+ if (clone_flags & CLONE_SETTLS)
+ task_thread_info(p)->tp_value = regs->d5;
+
#ifdef CONFIG_FPU
if (!FPU_IS_EMU) {
/* Copy the current fpu state */
--
cgit v1.2.3-70-g09d2
From d878d6dacee2c862f02da20f7fa3e2c0e8820e71 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 16 Sep 2012 12:06:34 -0400
Subject: m68k: switch to generic sys_execve()/kernel_execve()
The tricky part here is that task_pt_regs() on m68k works *only* for
process inside do_signal(). However, we need something much simpler -
pt_regs of a process inside do_signal() may be at different offsets
from the stack bottom, depending on the way we'd entered the kernel,
but for a task inside sys_execve() it *is* at constant offset.
Moreover, for a kernel thread about to become a userland process the
same location is also fine - setting sp to that will leave the kernel
stack pointer at the very bottom of the kernel stack when we finally
switch to userland.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/m68k/include/asm/ptrace.h | 2 ++
arch/m68k/include/asm/unistd.h | 2 ++
arch/m68k/kernel/entry.S | 5 +++++
arch/m68k/kernel/process.c | 20 --------------------
arch/m68k/kernel/sys_m68k.c | 17 -----------------
5 files changed, 9 insertions(+), 37 deletions(-)
(limited to 'arch/m68k/kernel/process.c')
diff --git a/arch/m68k/include/asm/ptrace.h b/arch/m68k/include/asm/ptrace.h
index 65322b17b6c..5e08b597f01 100644
--- a/arch/m68k/include/asm/ptrace.h
+++ b/arch/m68k/include/asm/ptrace.h
@@ -85,6 +85,8 @@ struct switch_stack {
#define user_mode(regs) (!((regs)->sr & PS_S))
#define instruction_pointer(regs) ((regs)->pc)
#define profile_pc(regs) instruction_pointer(regs)
+#define current_pt_regs() \
+ (struct pt_regs *)((char *)current_thread_info() + THREAD_SIZE) - 1
#define arch_has_single_step() (1)
diff --git a/arch/m68k/include/asm/unistd.h b/arch/m68k/include/asm/unistd.h
index 045cfd6a9e3..c702ad71679 100644
--- a/arch/m68k/include/asm/unistd.h
+++ b/arch/m68k/include/asm/unistd.h
@@ -382,6 +382,8 @@
#define __ARCH_WANT_SYS_SIGPROCMASK
#define __ARCH_WANT_SYS_RT_SIGACTION
#define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_KERNEL_EXECVE
/*
* "Conditional" syscalls
diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S
index 8a01f580a02..946cb018775 100644
--- a/arch/m68k/kernel/entry.S
+++ b/arch/m68k/kernel/entry.S
@@ -122,6 +122,11 @@ ENTRY(ret_from_kernel_thread)
movel %d0,(%sp)
jra sys_exit
+ENTRY(ret_from_kernel_execve)
+ movel 4(%sp), %sp
+ GET_CURRENT(%d0)
+ jra ret_from_exception
+
#if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
#ifdef TRAP_DBG_INTERRUPT
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index b3d4760c975..4e54b4c0308 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -298,26 +298,6 @@ int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
EXPORT_SYMBOL(dump_fpu);
#endif /* CONFIG_FPU */
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys_execve(const char __user *name,
- const char __user *const __user *argv,
- const char __user *const __user *envp)
-{
- int error;
- char * filename;
- struct pt_regs *regs = (struct pt_regs *) &name;
-
- filename = getname(name);
- error = PTR_ERR(filename);
- if (IS_ERR(filename))
- return error;
- error = do_execve(filename, argv, envp, regs);
- putname(filename);
- return error;
-}
-
unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c
index 9a5932ec368..3a480b3df0d 100644
--- a/arch/m68k/kernel/sys_m68k.c
+++ b/arch/m68k/kernel/sys_m68k.c
@@ -549,23 +549,6 @@ asmlinkage int sys_getpagesize(void)
return PAGE_SIZE;
}
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
- const char *const argv[],
- const char *const envp[])
-{
- register long __res asm ("%d0") = __NR_execve;
- register long __a asm ("%d1") = (long)(filename);
- register long __b asm ("%d2") = (long)(argv);
- register long __c asm ("%d3") = (long)(envp);
- asm volatile ("trap #0" : "+d" (__res)
- : "d" (__a), "d" (__b), "d" (__c));
- return __res;
-}
-
asmlinkage unsigned long sys_get_thread_area(void)
{
return current_thread_info()->tp_value;
--
cgit v1.2.3-70-g09d2