From: Al Viro Date: Tue, 9 Oct 2012 20:27:45 +0000 (-0400) Subject: mips: switch to generic kernel_thread() X-Git-Tag: firefly_0821_release~3680^2~1355^2~54^2~16^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8f54bcacbc39f883bde2210cf2754e5d198f55a4;p=firefly-linux-kernel-4.4.55.git mips: switch to generic kernel_thread() Signed-off-by: Al Viro --- diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index dba9390d37cf..ede301f9c88b 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -40,6 +40,7 @@ config MIPS select HAVE_MOD_ARCH_SPECIFIC select MODULES_USE_ELF_REL select MODULES_USE_ELF_RELA if 64BIT + select GENERIC_KERNEL_THREAD menu "Machine selection" diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h index 5e33fabe354d..d28c41e0887c 100644 --- a/arch/mips/include/asm/processor.h +++ b/arch/mips/include/asm/processor.h @@ -310,8 +310,6 @@ struct task_struct; /* Free all resources held by a thread. */ #define release_thread(thread) do { } while(0) -extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags); - extern unsigned long thread_saved_pc(struct task_struct *tsk); /* diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S index a6c133212003..aab6997b8f47 100644 --- a/arch/mips/kernel/entry.S +++ b/arch/mips/kernel/entry.S @@ -65,6 +65,13 @@ need_resched: b need_resched #endif +FEXPORT(ret_from_kernel_thread) + jal schedule_tail # a0 = struct task_struct *prev + move a0, s1 + jal s0 + li a0, 0 + j sys_exit + FEXPORT(ret_from_fork) jal schedule_tail # a0 = struct task_struct *prev diff --git a/arch/mips/kernel/mips_ksyms.c b/arch/mips/kernel/mips_ksyms.c index 3fc1691110dc..2d9304c2b54c 100644 --- a/arch/mips/kernel/mips_ksyms.c +++ b/arch/mips/kernel/mips_ksyms.c @@ -32,8 +32,6 @@ EXPORT_SYMBOL(memset); EXPORT_SYMBOL(memcpy); EXPORT_SYMBOL(memmove); -EXPORT_SYMBOL(kernel_thread); - /* * Functions that operate on entire pages. Mostly used by memory management. */ diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index e9a5fd7277f4..d13720ac656f 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -84,6 +84,7 @@ void __noreturn cpu_idle(void) } asmlinkage void ret_from_fork(void); +asmlinkage void ret_from_kernel_thread(void); void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) { @@ -113,7 +114,7 @@ void flush_thread(void) } int copy_thread(unsigned long clone_flags, unsigned long usp, - unsigned long unused, struct task_struct *p, struct pt_regs *regs) + unsigned long arg, struct task_struct *p, struct pt_regs *regs) { struct thread_info *ti = task_thread_info(p); struct pt_regs *childregs; @@ -136,19 +137,30 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, childregs = (struct pt_regs *) childksp - 1; /* Put the stack after the struct pt_regs. */ childksp = (unsigned long) childregs; + p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); + if (unlikely(p->flags & PF_KTHREAD)) { + unsigned long status = p->thread.cp0_status; + memset(childregs, 0, sizeof(struct pt_regs)); + ti->addr_limit = KERNEL_DS; + p->thread.reg16 = usp; /* fn */ + p->thread.reg17 = arg; + p->thread.reg29 = childksp; + p->thread.reg31 = (unsigned long) ret_from_kernel_thread; +#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) + status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | + ((status & (ST0_KUC | ST0_IEC)) << 2); +#else + status |= ST0_EXL; +#endif + childregs->cp0_status = status; + return 0; + } *childregs = *regs; childregs->regs[7] = 0; /* Clear error flag */ - childregs->regs[2] = 0; /* Child gets zero as return value */ + childregs->regs[29] = usp; + ti->addr_limit = USER_DS; - if (childregs->cp0_status & ST0_CU0) { - childregs->regs[28] = (unsigned long) ti; - childregs->regs[29] = childksp; - ti->addr_limit = KERNEL_DS; - } else { - childregs->regs[29] = usp; - ti->addr_limit = USER_DS; - } p->thread.reg29 = (unsigned long) childregs; p->thread.reg31 = (unsigned long) ret_from_fork; @@ -156,7 +168,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, * New tasks lose permission to use the fpu. This accelerates context * switching for most programs since they don't use the fpu. */ - p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); #ifdef CONFIG_MIPS_MT_SMTC @@ -221,35 +232,6 @@ int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr) return 1; } -/* - * Create a kernel thread - */ -static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *)) -{ - do_exit(fn(arg)); -} - -long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) -{ - struct pt_regs regs; - - memset(®s, 0, sizeof(regs)); - - regs.regs[4] = (unsigned long) arg; - regs.regs[5] = (unsigned long) fn; - regs.cp0_epc = (unsigned long) kernel_thread_helper; - regs.cp0_status = read_c0_status(); -#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) - regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | - ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2); -#else - regs.cp0_status |= ST0_EXL; -#endif - - /* Ok, create the new process.. */ - return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); -} - /* * */