diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm/include/asm/processor.h | 5 | ||||
| -rw-r--r-- | arch/arm/kernel/entry-common.S | 12 | ||||
| -rw-r--r-- | arch/arm/kernel/process.c | 75 |
4 files changed, 26 insertions, 67 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 2f88d8d97701..a949eec22861 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -49,6 +49,7 @@ config ARM select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN + select GENERIC_KERNEL_THREAD help The ARM series is a line of low-power-consumption RISC chip designs licensed by ARM Ltd and targeted at embedded applications and diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h index 99afa7498260..06e7d509eaac 100644 --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -85,11 +85,6 @@ unsigned long get_wchan(struct task_struct *p); #define cpu_relax() barrier() #endif -/* - * Create a new kernel thread - */ -extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); - #define task_pt_regs(p) \ ((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1) diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 978eac57e04a..9a48b7a577e7 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -91,6 +91,18 @@ ENTRY(ret_from_fork) b ret_slow_syscall ENDPROC(ret_from_fork) +ENTRY(ret_from_kernel_thread) + UNWIND(.fnstart) + UNWIND(.cantunwind) + bl schedule_tail + mov r0, r4 + adr lr, BSYM(1f) @ kernel threads should not exit + mov pc, r5 +1: bl do_exit + nop + UNWIND(.fnend) +ENDPROC(ret_from_kernel_thread) + .equ NR_syscalls,0 #define CALL(x) .equ NR_syscalls,NR_syscalls+1 #include "calls.S" diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 693b744fd572..c10e4395bc47 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -373,6 +373,7 @@ void release_thread(struct task_struct *dead_task) } asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); +asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread"); int copy_thread(unsigned long clone_flags, unsigned long stack_start, @@ -381,13 +382,20 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start, struct thread_info *thread = task_thread_info(p); struct pt_regs *childregs = task_pt_regs(p); - *childregs = *regs; - childregs->ARM_r0 = 0; - childregs->ARM_sp = stack_start; - memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); + + if (likely(regs)) { + *childregs = *regs; + childregs->ARM_r0 = 0; + childregs->ARM_sp = stack_start; + thread->cpu_context.pc = (unsigned long)ret_from_fork; + } else { + thread->cpu_context.r4 = stk_sz; + thread->cpu_context.r5 = stack_start; + thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread; + childregs->ARM_cpsr = SVC_MODE; + } thread->cpu_context.sp = (unsigned long)childregs; - thread->cpu_context.pc = (unsigned long)ret_from_fork; clear_ptrace_hw_breakpoint(p); @@ -423,63 +431,6 @@ int dump_fpu (struct pt_regs *regs, struct user_fp *fp) } EXPORT_SYMBOL(dump_fpu); -/* - * Shuffle the argument into the correct register before calling the - * thread function. r4 is the thread argument, r5 is the pointer to - * the thread function, and r6 points to the exit function. - */ -extern void kernel_thread_helper(void); -asm( ".pushsection .text\n" -" .align\n" -" .type kernel_thread_helper, #function\n" -"kernel_thread_helper:\n" -#ifdef CONFIG_TRACE_IRQFLAGS -" bl trace_hardirqs_on\n" -#endif -" msr cpsr_c, r7\n" -" mov r0, r4\n" -" mov lr, r6\n" -" mov pc, r5\n" -" .size kernel_thread_helper, . - kernel_thread_helper\n" -" .popsection"); - -#ifdef CONFIG_ARM_UNWIND -extern void kernel_thread_exit(long code); -asm( ".pushsection .text\n" -" .align\n" -" .type kernel_thread_exit, #function\n" -"kernel_thread_exit:\n" -" .fnstart\n" -" .cantunwind\n" -" bl do_exit\n" -" nop\n" -" .fnend\n" -" .size kernel_thread_exit, . - kernel_thread_exit\n" -" .popsection"); -#else -#define kernel_thread_exit do_exit -#endif - -/* - * Create a kernel thread. - */ -pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) -{ - struct pt_regs regs; - - memset(®s, 0, sizeof(regs)); - - regs.ARM_r4 = (unsigned long)arg; - regs.ARM_r5 = (unsigned long)fn; - regs.ARM_r6 = (unsigned long)kernel_thread_exit; - regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE; - regs.ARM_pc = (unsigned long)kernel_thread_helper; - regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT; - - return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); -} -EXPORT_SYMBOL(kernel_thread); - unsigned long get_wchan(struct task_struct *p) { struct stackframe frame; |
