score: switch to generic kernel_thread()/kernel_execve() (1856ab6d) · Commits · 戴 / test

arch/score/Kconfig

+2 −0

Original line number	Diff line number	Diff line
		@@ -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"

arch/score/include/asm/processor.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -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);

arch/score/kernel/entry.S

+7 −0

Original line number	Diff line number	Diff line
		@@ -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

arch/score/kernel/process.c

+14 −41

Original line number	Diff line number	Diff line
		@@ -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;

		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;
		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 */
		} else {
		childregs->regs[28] = (unsigned long) ti; /* kernel fork */
		childregs->regs[0] = (unsigned long) childregs;
		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;

arch/score/kernel/sys_score.c

+0 −30

Original line number	Diff line number	Diff line
		@@ -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;
		}

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