Commit 3240dd57 authored by Vineet Gupta's avatar Vineet Gupta

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: default avatarVineet Gupta <vgupta@synopsys.com>
parent 13648b01
...@@ -47,9 +47,6 @@ struct thread_struct { ...@@ -47,9 +47,6 @@ struct thread_struct {
/* Forward declaration, a strange C thing */ /* Forward declaration, a strange C thing */
struct task_struct; struct task_struct;
/* Return saved PC of a blocked thread */
unsigned long thread_saved_pc(struct task_struct *t);
#define task_pt_regs(p) \ #define task_pt_regs(p) \
((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1) ((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1)
...@@ -86,6 +83,8 @@ unsigned long thread_saved_pc(struct task_struct *t); ...@@ -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_BLINK(tsk) TSK_K_REG(tsk, 4)
#define TSK_K_FP(tsk) TSK_K_REG(tsk, 0) #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, extern void start_thread(struct pt_regs * regs, unsigned long pc,
unsigned long usp); unsigned long usp);
......
...@@ -192,29 +192,6 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) ...@@ -192,29 +192,6 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
return 0; 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) int elf_check_arch(const struct elf32_hdr *x)
{ {
unsigned int eflags; unsigned int eflags;
......
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