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android_kernel_oneplus_msm8998/arch/ia64/include/asm/thread_info.h
Linus Torvalds 50d3f7d55a UPSTREAM: Clarify naming of thread info/stack allocators 
We've had the thread info allocated together with the thread stack for
most architectures for a long time (since the thread_info was split off
from the task struct), but that is about to change.

But the patches that move the thread info to be off-stack (and a part of
the task struct instead) made it clear how confused the allocator and
freeing functions are.

Because the common case was that we share an allocation with the thread
stack and the thread_info, the two pointers were identical.  That
identity then meant that we would have things like

	ti = alloc_thread_info_node(tsk, node);
	...
	tsk->stack = ti;

which certainly _worked_ (since stack and thread_info have the same
value), but is rather confusing: why are we assigning a thread_info to
the stack? And if we move the thread_info away, the "confusing" code
just gets to be entirely bogus.

So remove all this confusion, and make it clear that we are doing the
stack allocation by renaming and clarifying the function names to be
about the stack.  The fact that the thread_info then shares the
allocation is an implementation detail, and not really about the
allocation itself.

This is a pure renaming and type fix: we pass in the same pointer, it's
just that we clarify what the pointer means.

The ia64 code that actually only has one single allocation (for all of
task_struct, thread_info and kernel thread stack) now looks a bit odd,
but since "tsk->stack" is actually not even used there, that oddity
doesn't matter.  It would be a separate thing to clean that up, I
intentionally left the ia64 changes as a pure brute-force renaming and
type change.

Acked-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Bug: 38331309
Change-Id: I870b5476fc900c9145134f9dd3ed18a32a490162
(cherry picked from commit b235beea9e996a4d36fed6cfef4801a3e7d7a9a5)
Signed-off-by: Zubin Mithra <zsm@google.com>
2017-08-09 15:23:22 +01:00

152 lines
5.3 KiB
C
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/*
* Copyright (C) 2002-2003 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*/
#ifndef _ASM_IA64_THREAD_INFO_H
#define _ASM_IA64_THREAD_INFO_H
#ifndef ASM_OFFSETS_C
#include <asm/asm-offsets.h>
#endif
#include <asm/processor.h>
#include <asm/ptrace.h>
#ifndef __ASSEMBLY__
/*
* On IA-64, we want to keep the task structure and kernel stack together, so they can be
* mapped by a single TLB entry and so they can be addressed by the "current" pointer
* without having to do pointer masking.
*/
struct thread_info {
struct task_struct *task; /* XXX not really needed, except for dup_task_struct() */
__u32 flags; /* thread_info flags (see TIF_*) */
__u32 cpu; /* current CPU */
__u32 last_cpu; /* Last CPU thread ran on */
__u32 status; /* Thread synchronous flags */
mm_segment_t addr_limit; /* user-level address space limit */
int preempt_count; /* 0=premptable, <0=BUG; will also serve as bh-counter */
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
__u64 ac_stamp;
__u64 ac_leave;
__u64 ac_stime;
__u64 ac_utime;
#endif
};
#define THREAD_SIZE KERNEL_STACK_SIZE
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
.flags = 0, \
.cpu = 0, \
.addr_limit = KERNEL_DS, \
.preempt_count = INIT_PREEMPT_COUNT, \
}
#ifndef ASM_OFFSETS_C
/* how to get the thread information struct from C */
#define current_thread_info() ((struct thread_info *) ((char *) current + IA64_TASK_SIZE))
#define alloc_thread_stack_node(tsk, node) \
((unsigned long *) ((char *) (tsk) + IA64_TASK_SIZE))
#define task_thread_info(tsk) ((struct thread_info *) ((char *) (tsk) + IA64_TASK_SIZE))
#else
#define current_thread_info() ((struct thread_info *) 0)
#define alloc_thread_stack_node(tsk, node) ((unsigned long *) 0)
#define task_thread_info(tsk) ((struct thread_info *) 0)
#endif
#define free_thread_stack(ti) /* nothing */
#define task_stack_page(tsk) ((void *)(tsk))
#define __HAVE_THREAD_FUNCTIONS
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
#define setup_thread_stack(p, org) \
*task_thread_info(p) = *task_thread_info(org); \
task_thread_info(p)->ac_stime = 0; \
task_thread_info(p)->ac_utime = 0; \
task_thread_info(p)->task = (p);
#else
#define setup_thread_stack(p, org) \
*task_thread_info(p) = *task_thread_info(org); \
task_thread_info(p)->task = (p);
#endif
#define end_of_stack(p) (unsigned long *)((void *)(p) + IA64_RBS_OFFSET)
#define alloc_task_struct_node(node) \
({ \
struct page *page = alloc_pages_node(node, GFP_KERNEL | __GFP_COMP, \
KERNEL_STACK_SIZE_ORDER); \
struct task_struct *ret = page ? page_address(page) : NULL; \
\
ret; \
})
#define free_task_struct(tsk) free_pages((unsigned long) (tsk), KERNEL_STACK_SIZE_ORDER)
#endif /* !__ASSEMBLY */
/*
* thread information flags
* - these are process state flags that various assembly files may need to access
* - pending work-to-be-done flags are in least-significant 16 bits, other flags
* in top 16 bits
*/
#define TIF_SIGPENDING 0 /* signal pending */
#define TIF_NEED_RESCHED 1 /* rescheduling necessary */
#define TIF_SYSCALL_TRACE 2 /* syscall trace active */
#define TIF_SYSCALL_AUDIT 3 /* syscall auditing active */
#define TIF_SINGLESTEP 4 /* restore singlestep on return to user mode */
#define TIF_NOTIFY_RESUME 6 /* resumption notification requested */
#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
#define TIF_MCA_INIT 18 /* this task is processing MCA or INIT */
#define TIF_DB_DISABLED 19 /* debug trap disabled for fsyscall */
#define TIF_RESTORE_RSE 21 /* user RBS is newer than kernel RBS */
#define TIF_POLLING_NRFLAG 22 /* idle is polling for TIF_NEED_RESCHED */
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
#define _TIF_SYSCALL_TRACEAUDIT (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_MCA_INIT (1 << TIF_MCA_INIT)
#define _TIF_DB_DISABLED (1 << TIF_DB_DISABLED)
#define _TIF_RESTORE_RSE (1 << TIF_RESTORE_RSE)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
/* "work to do on user-return" bits */
#define TIF_ALLWORK_MASK (_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SYSCALL_AUDIT|\
_TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE)
/* like TIF_ALLWORK_BITS but sans TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT */
#define TIF_WORK_MASK (TIF_ALLWORK_MASK&~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT))
#define TS_RESTORE_SIGMASK 2 /* restore signal mask in do_signal() */
#ifndef __ASSEMBLY__
#define HAVE_SET_RESTORE_SIGMASK 1
static inline void set_restore_sigmask(void)
{
struct thread_info *ti = current_thread_info();
ti->status |= TS_RESTORE_SIGMASK;
WARN_ON(!test_bit(TIF_SIGPENDING, &ti->flags));
}
static inline void clear_restore_sigmask(void)
{
current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
}
static inline bool test_restore_sigmask(void)
{
return current_thread_info()->status & TS_RESTORE_SIGMASK;
}
static inline bool test_and_clear_restore_sigmask(void)
{
struct thread_info *ti = current_thread_info();
if (!(ti->status & TS_RESTORE_SIGMASK))
return false;
ti->status &= ~TS_RESTORE_SIGMASK;
return true;
}
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_IA64_THREAD_INFO_H */
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