![Chris Metcalf](/assets/img/avatar_default.png)
This change is a prerequisite change for TASK_ISOLATION but also
stands on its own for readability and maintainability. The existing
tile do_work_pending() was called in a loop from assembly on
the slow path; this change moves the loop into C code as well.
For the x86 version see commit c5c46f59e4
("x86/entry: Add new,
comprehensible entry and exit handlers written in C").
This change exposes a pre-existing bug on the older tilepro platform;
the singlestep processing is done last, but on tilepro (unlike tilegx)
we enable interrupts while doing that processing, so we could in
theory miss a signal or other asynchronous event. A future change
could fix this by breaking the singlestep work into a "prepare"
step done in the main loop, and a "trigger" step done after exiting
the loop. Since this change is intended as purely a restructuring
change, we call out the bug explicitly now, but don't yet fix it.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
198 lines
6.3 KiB
C
198 lines
6.3 KiB
C
/*
|
|
* Copyright (C) 2002 David Howells (dhowells@redhat.com)
|
|
* Copyright 2010 Tilera Corporation. All Rights Reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation, version 2.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
|
|
* NON INFRINGEMENT. See the GNU General Public License for
|
|
* more details.
|
|
*/
|
|
|
|
#ifndef _ASM_TILE_THREAD_INFO_H
|
|
#define _ASM_TILE_THREAD_INFO_H
|
|
|
|
#include <asm/processor.h>
|
|
#include <asm/page.h>
|
|
#ifndef __ASSEMBLY__
|
|
|
|
/*
|
|
* Low level task data that assembly code needs immediate access to.
|
|
* The structure is placed at the bottom of the supervisor stack.
|
|
*/
|
|
struct thread_info {
|
|
struct task_struct *task; /* main task structure */
|
|
unsigned long flags; /* low level flags */
|
|
unsigned long status; /* thread-synchronous flags */
|
|
__u32 homecache_cpu; /* CPU we are homecached on */
|
|
__u32 cpu; /* current CPU */
|
|
int preempt_count; /* 0 => preemptable,
|
|
<0 => BUG */
|
|
|
|
mm_segment_t addr_limit; /* thread address space
|
|
(KERNEL_DS or USER_DS) */
|
|
struct single_step_state *step_state; /* single step state
|
|
(if non-zero) */
|
|
int align_ctl; /* controls unaligned access */
|
|
#ifdef __tilegx__
|
|
unsigned long unalign_jit_tmp[4]; /* temp r0..r3 storage */
|
|
void __user *unalign_jit_base; /* unalign fixup JIT base */
|
|
#endif
|
|
bool in_backtrace; /* currently doing backtrace? */
|
|
};
|
|
|
|
/*
|
|
* macros/functions for gaining access to the thread information structure.
|
|
*/
|
|
#define INIT_THREAD_INFO(tsk) \
|
|
{ \
|
|
.task = &tsk, \
|
|
.flags = 0, \
|
|
.cpu = 0, \
|
|
.preempt_count = INIT_PREEMPT_COUNT, \
|
|
.addr_limit = KERNEL_DS, \
|
|
.step_state = NULL, \
|
|
.align_ctl = 0, \
|
|
}
|
|
|
|
#define init_thread_info (init_thread_union.thread_info)
|
|
#define init_stack (init_thread_union.stack)
|
|
|
|
#endif /* !__ASSEMBLY__ */
|
|
|
|
#if PAGE_SIZE < 8192
|
|
#define THREAD_SIZE_ORDER (13 - PAGE_SHIFT)
|
|
#else
|
|
#define THREAD_SIZE_ORDER (0)
|
|
#endif
|
|
#define THREAD_SIZE_PAGES (1 << THREAD_SIZE_ORDER)
|
|
|
|
#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
|
|
#define LOG2_THREAD_SIZE (PAGE_SHIFT + THREAD_SIZE_ORDER)
|
|
|
|
#define STACK_WARN (THREAD_SIZE/8)
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
void arch_release_thread_info(struct thread_info *info);
|
|
|
|
/* How to get the thread information struct from C. */
|
|
register unsigned long stack_pointer __asm__("sp");
|
|
|
|
#define current_thread_info() \
|
|
((struct thread_info *)(stack_pointer & -THREAD_SIZE))
|
|
|
|
/* Sit on a nap instruction until interrupted. */
|
|
extern void smp_nap(void);
|
|
|
|
/* Enable interrupts racelessly and nap forever: helper for arch_cpu_idle(). */
|
|
extern void _cpu_idle(void);
|
|
|
|
#else /* __ASSEMBLY__ */
|
|
|
|
/*
|
|
* How to get the thread information struct from assembly.
|
|
* Note that we use different macros since different architectures
|
|
* have different semantics in their "mm" instruction and we would
|
|
* like to guarantee that the macro expands to exactly one instruction.
|
|
*/
|
|
#ifdef __tilegx__
|
|
#define EXTRACT_THREAD_INFO(reg) mm reg, zero, LOG2_THREAD_SIZE, 63
|
|
#else
|
|
#define GET_THREAD_INFO(reg) mm reg, sp, zero, LOG2_THREAD_SIZE, 31
|
|
#endif
|
|
|
|
#endif /* !__ASSEMBLY__ */
|
|
|
|
/*
|
|
* Thread information flags that various assembly files may need to access.
|
|
* Keep flags accessed frequently in low bits, particular since it makes
|
|
* it easier to build constants in assembly.
|
|
*/
|
|
#define TIF_SIGPENDING 0 /* signal pending */
|
|
#define TIF_NEED_RESCHED 1 /* rescheduling necessary */
|
|
#define TIF_SINGLESTEP 2 /* restore singlestep on return to
|
|
user mode */
|
|
#define TIF_ASYNC_TLB 3 /* got an async TLB fault in kernel */
|
|
#define TIF_SYSCALL_TRACE 4 /* syscall trace active */
|
|
#define TIF_SYSCALL_AUDIT 5 /* syscall auditing active */
|
|
#define TIF_SECCOMP 6 /* secure computing */
|
|
#define TIF_MEMDIE 7 /* OOM killer at work */
|
|
#define TIF_NOTIFY_RESUME 8 /* callback before returning to user */
|
|
#define TIF_SYSCALL_TRACEPOINT 9 /* syscall tracepoint instrumentation */
|
|
#define TIF_POLLING_NRFLAG 10 /* idle is polling for TIF_NEED_RESCHED */
|
|
#define TIF_NOHZ 11 /* in adaptive nohz mode */
|
|
|
|
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
|
|
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
|
|
#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
|
|
#define _TIF_ASYNC_TLB (1<<TIF_ASYNC_TLB)
|
|
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
|
|
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
|
|
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
|
|
#define _TIF_MEMDIE (1<<TIF_MEMDIE)
|
|
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
|
|
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
|
|
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
|
|
#define _TIF_NOHZ (1<<TIF_NOHZ)
|
|
|
|
/* Work to do as we loop to exit to user space. */
|
|
#define _TIF_WORK_MASK \
|
|
(_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
|
|
_TIF_ASYNC_TLB | _TIF_NOTIFY_RESUME)
|
|
|
|
/* Work to do on any return to user space. */
|
|
#define _TIF_ALLWORK_MASK \
|
|
(_TIF_WORK_MASK | _TIF_SINGLESTEP | _TIF_NOHZ)
|
|
|
|
/* Work to do at syscall entry. */
|
|
#define _TIF_SYSCALL_ENTRY_WORK \
|
|
(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ)
|
|
|
|
/* Work to do at syscall exit. */
|
|
#define _TIF_SYSCALL_EXIT_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT)
|
|
|
|
/*
|
|
* Thread-synchronous status.
|
|
*
|
|
* This is different from the flags in that nobody else
|
|
* ever touches our thread-synchronous status, so we don't
|
|
* have to worry about atomic accesses.
|
|
*/
|
|
#ifdef __tilegx__
|
|
#define TS_COMPAT 0x0001 /* 32-bit compatibility mode */
|
|
#endif
|
|
#define TS_RESTORE_SIGMASK 0x0008 /* 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_TILE_THREAD_INFO_H */
|