From 3240dd57e533da94998029af6e17008a1806c665 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 27 Feb 2015 10:59:31 +0530 Subject: [PATCH] ARC: Fix thread_saved_pc() The old implementation assumed that SP at the time of __switch_to() is right above pt_regs which is almost certainly not the case as there will be some stack build up between entry into kernel and leading up to __switch_to Signed-off-by: Vineet Gupta --- arch/arc/include/asm/processor.h | 5 ++--- arch/arc/kernel/process.c | 23 ----------------------- 2 files changed, 2 insertions(+), 26 deletions(-) diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h index 88398caa3989..52312cb5dbe2 100644 --- a/arch/arc/include/asm/processor.h +++ b/arch/arc/include/asm/processor.h @@ -47,9 +47,6 @@ struct thread_struct { /* Forward declaration, a strange C thing */ struct task_struct; -/* Return saved PC of a blocked thread */ -unsigned long thread_saved_pc(struct task_struct *t); - #define task_pt_regs(p) \ ((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1) @@ -86,6 +83,8 @@ unsigned long thread_saved_pc(struct task_struct *t); #define TSK_K_BLINK(tsk) TSK_K_REG(tsk, 4) #define TSK_K_FP(tsk) TSK_K_REG(tsk, 0) +#define thread_saved_pc(tsk) TSK_K_BLINK(tsk) + extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp); diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c index fdd89715d2d3..98c00a2d4dd9 100644 --- a/arch/arc/kernel/process.c +++ b/arch/arc/kernel/process.c @@ -192,29 +192,6 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) return 0; } -/* - * API: expected by schedular Code: If thread is sleeping where is that. - * What is this good for? it will be always the scheduler or ret_from_fork. - * So we hard code that anyways. - */ -unsigned long thread_saved_pc(struct task_struct *t) -{ - struct pt_regs *regs = task_pt_regs(t); - unsigned long blink = 0; - - /* - * If the thread being queried for in not itself calling this, then it - * implies it is not executing, which in turn implies it is sleeping, - * which in turn implies it got switched OUT by the schedular. - * In that case, it's kernel mode blink can reliably retrieved as per - * the picture above (right above pt_regs). - */ - if (t != current && t->state != TASK_RUNNING) - blink = *((unsigned int *)regs - 1); - - return blink; -} - int elf_check_arch(const struct elf32_hdr *x) { unsigned int eflags;