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score: switch to generic kernel_thread()/kernel_execve()

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-10-15 15:26:11 -04:00
parent ddffeb8c4d
commit 1856ab6db1
5 changed files with 23 additions and 72 deletions
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2
arch/score/Kconfig
View File

@ -13,6 +13,8 @@ config SCORE
select GENERIC_CLOCKEVENTS
select HAVE_MOD_ARCH_SPECIFIC
select MODULES_USE_ELF_REL
select GENERIC_KERNEL_THREAD
select GENERIC_KERNEL_EXECVE
choice
prompt "System type"

1
arch/score/include/asm/processor.h
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@ -13,7 +13,6 @@ struct task_struct;
*/
extern void (*cpu_wait)(void);
extern long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
extern unsigned long thread_saved_pc(struct task_struct *tsk);
extern void start_thread(struct pt_regs *regs,
unsigned long pc, unsigned long sp);

7
arch/score/kernel/entry.S
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@ -278,6 +278,13 @@ need_resched:
nop
#endif
ENTRY(ret_from_kernel_thread)
bl schedule_tail # r4=struct task_struct *prev
nop
mv r4, r13
brl r12
j syscall_exit
ENTRY(ret_from_fork)
bl schedule_tail # r4=struct task_struct *prev

55
arch/score/kernel/process.c
View File

@ -60,6 +60,7 @@ void __noreturn cpu_idle(void)
}
void ret_from_fork(void);
void ret_from_kernel_thread(void);
void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
{
@ -86,29 +87,27 @@ void flush_thread(void) {}
* set up the kernel stack and exception frames for a new process
*/
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 thread_info *ti = task_thread_info(p);
struct pt_regs *childregs = task_pt_regs(p);
p->set_child_tid = NULL;
p->clear_child_tid = NULL;
*childregs = *regs;
childregs->regs[7] = 0; /* Clear error flag */
childregs->regs[4] = 0; /* Child gets zero as return value */
regs->regs[4] = p->pid;
if (childregs->cp0_psr & 0x8) { /* test kernel fork or user fork */
childregs->regs[0] = usp; /* user fork */
p->thread.reg0 = (unsigned long) childregs;
if (unlikely(!regs)) {
memset(childregs, 0, sizeof(struct pt_regs));
p->thread->reg12 = usp;
p->thread->reg13 = arg;
p->thread.reg3 = (unsigned long) ret_from_kernel_thread;
} else {
childregs->regs[28] = (unsigned long) ti; /* kernel fork */
childregs->regs[0] = (unsigned long) childregs;
*childregs = *regs;
childregs->regs[7] = 0; /* Clear error flag */
childregs->regs[4] = 0; /* Child gets zero as return value */
childregs->regs[0] = usp; /* user fork */
regs->regs[4] = p->pid; /* WTF? */
p->thread.reg3 = (unsigned long) ret_from_fork;
}
p->thread.reg0 = (unsigned long) childregs;
p->thread.reg3 = (unsigned long) ret_from_fork;
p->thread.cp0_psr = 0;
return 0;
@ -120,32 +119,6 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
return 1;
}
static void __noreturn
kernel_thread_helper(void *unused0, int (*fn)(void *),
void *arg, void *unused1)
{
do_exit(fn(arg));
}
/*
* Create a kernel thread.
*/
long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(&regs, 0, sizeof(regs));
regs.regs[6] = (unsigned long) arg;
regs.regs[5] = (unsigned long) fn;
regs.cp0_epc = (unsigned long) kernel_thread_helper;
regs.cp0_psr = (regs.cp0_psr & ~(0x1|0x4|0x8)) | \
((regs.cp0_psr & 0x3) << 2);
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, \
0, &regs, 0, NULL, NULL);
}
unsigned long thread_saved_pc(struct task_struct *tsk)
{
return task_pt_regs(tsk)->cp0_epc;

30
arch/score/kernel/sys_score.c
View File

@ -107,33 +107,3 @@ score_execve(struct pt_regs *regs)
putname(filename);
return error;
}
/*
* Do a system call from kernel instead of calling sys_execve so we
* end up with proper pt_regs.
*/
asmlinkage
int kernel_execve(const char *filename,
const char *const argv[],
const char *const envp[])
{
register unsigned long __r4 asm("r4") = (unsigned long) filename;
register unsigned long __r5 asm("r5") = (unsigned long) argv;
register unsigned long __r6 asm("r6") = (unsigned long) envp;
register unsigned long __r7 asm("r7");
__asm__ __volatile__ (" \n"
"ldi r27, %5 \n"
"syscall \n"
"mv %0, r4 \n"
"mv %1, r7 \n"
: "=&r" (__r4), "=r" (__r7)
: "r" (__r4), "r" (__r5), "r" (__r6), "i" (__NR_execve)
: "r8", "r9", "r10", "r11", "r22", "r23", "r24", "r25",
"r26", "r27", "memory");
if (__r7 == 0)
return __r4;
return -__r4;
}