Commit b40fa75e authored by Jinyang He's avatar Jinyang He Committed by Huacai Chen
Browse files

LoongArch: Remove unused kernel stack padding 



The current LoongArch kernel stack is padded as if obeying the MIPS o32
calling convention (32 bytes), signifying the port's MIPS lineage but no
longer making sense. Remove the padding for clarity.

Reviewed-by: default avatarWANG Xuerui <git@xen0n.name>
Signed-off-by: default avatarJinyang He <hejinyang@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 247f34f7

arch/loongarch/include/asm/processor.h

+1 −1
Original line number Diff line number Diff line
@@ -191,7 +191,7 @@ static inline void flush_thread(void) 
unsigned long __get_wchan(struct task_struct *p);



#define __KSTK_TOS(tsk) ((unsigned long)task_stack_page(tsk) + \

			 THREAD_SIZE - 32 - sizeof(struct pt_regs))

			 THREAD_SIZE - sizeof(struct pt_regs))

#define task_pt_regs(tsk) ((struct pt_regs *)__KSTK_TOS(tsk))

#define KSTK_EIP(tsk) (task_pt_regs(tsk)->csr_era)

#define KSTK_ESP(tsk) (task_pt_regs(tsk)->regs[3])

arch/loongarch/include/asm/ptrace.h

+1 −1
Original line number Diff line number Diff line
@@ -133,7 +133,7 @@ static inline void die_if_kernel(const char *str, struct pt_regs *regs) 
#define current_pt_regs()						\

({									\

	unsigned long sp = (unsigned long)__builtin_frame_address(0);	\

	(struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1 - 32) - 1;	\

	(struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1) - 1;		\

})



/* Helpers for working with the user stack pointer */

arch/loongarch/kernel/head.S

+1 −2
Original line number Diff line number Diff line
@@ -84,10 +84,9 @@ SYM_CODE_START(kernel_entry) # kernel entry point 


	la.pcrel	tp, init_thread_union

	/* Set the SP after an empty pt_regs.  */

	PTR_LI		sp, (_THREAD_SIZE - 32 - PT_SIZE)

	PTR_LI		sp, (_THREAD_SIZE - PT_SIZE)

	PTR_ADD		sp, sp, tp

	set_saved_sp	sp, t0, t1

	PTR_ADDI	sp, sp, -4 * SZREG	# init stack pointer



	bl		start_kernel

	ASM_BUG()

arch/loongarch/kernel/process.c

+2 −2
Original line number Diff line number Diff line
@@ -129,7 +129,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 
	unsigned long clone_flags = args->flags;

	struct pt_regs *childregs, *regs = current_pt_regs();



	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;

	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE;



	/* set up new TSS. */

	childregs = (struct pt_regs *) childksp - 1;
@@ -236,7 +236,7 @@ bool in_task_stack(unsigned long stack, struct task_struct *task, 
			struct stack_info *info)

{

	unsigned long begin = (unsigned long)task_stack_page(task);

	unsigned long end = begin + THREAD_SIZE - 32;

	unsigned long end = begin + THREAD_SIZE;



	if (stack < begin || stack >= end)

		return false;

arch/loongarch/kernel/switch.S

+1 −1
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ SYM_FUNC_START(__switch_to) 
	move	tp, a2

	cpu_restore_nonscratch a1



	li.w		t0, _THREAD_SIZE - 32

	li.w		t0, _THREAD_SIZE

	PTR_ADD		t0, t0, tp

	set_saved_sp	t0, t1, t2