From 0500871f21b237b2bea2d9db405eadf78e5aab05 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 2 Jan 2018 15:12:01 +0000 Subject: Construct init thread stack in the linker script rather than by union Construct the init thread stack in the linker script rather than doing it by means of a union so that ia64's init_task.c can be got rid of. The following symbols are then made available from INIT_TASK_DATA() linker script macro: init_thread_union init_stack INIT_TASK_DATA() also expands the region to THREAD_SIZE to accommodate the size of the init stack. init_thread_union is given its own section so that it can be placed into the stack space in the right order. I'm assuming that the ia64 ordering is correct and that the task_struct is first and the thread_info second. Signed-off-by: David Howells Tested-by: Tony Luck Tested-by: Will Deacon (arm64) Tested-by: Palmer Dabbelt Acked-by: Thomas Gleixner --- include/asm-generic/vmlinux.lds.h | 4 ++++ include/linux/init_task.h | 3 +++ include/linux/sched.h | 9 +++++++++ 3 files changed, 16 insertions(+) (limited to 'include') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index ee8b707d9fa9..a564b83bf013 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -268,7 +268,11 @@ #define INIT_TASK_DATA(align) \ . = ALIGN(align); \ VMLINUX_SYMBOL(__start_init_task) = .; \ + VMLINUX_SYMBOL(init_thread_union) = .; \ + VMLINUX_SYMBOL(init_stack) = .; \ *(.data..init_task) \ + *(.data..init_thread_info) \ + . = VMLINUX_SYMBOL(__start_init_task) + THREAD_SIZE; \ VMLINUX_SYMBOL(__end_init_task) = .; /* diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 6a532629c983..30a89b99a5af 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -304,5 +304,8 @@ extern struct cred init_cred; /* Attach to the init_task data structure for proper alignment */ #define __init_task_data __attribute__((__section__(".data..init_task"))) +/* Attach to the thread_info data structure for proper alignment */ +#define __init_thread_info __attribute__((__section__(".data..init_thread_info"))) + #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index d2588263a989..68a504f6e474 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1446,12 +1446,21 @@ extern void ia64_set_curr_task(int cpu, struct task_struct *p); void yield(void); union thread_union { +#ifndef CONFIG_ARCH_TASK_STRUCT_ON_STACK + struct task_struct task; +#endif #ifndef CONFIG_THREAD_INFO_IN_TASK struct thread_info thread_info; #endif unsigned long stack[THREAD_SIZE/sizeof(long)]; }; +#ifndef CONFIG_THREAD_INFO_IN_TASK +extern struct thread_info init_thread_info; +#endif + +extern unsigned long init_stack[THREAD_SIZE / sizeof(unsigned long)]; + #ifdef CONFIG_THREAD_INFO_IN_TASK static inline struct thread_info *task_thread_info(struct task_struct *task) { -- cgit v1.2.1