f39224a8c1
We weren't using the recommended sequence for putting the CPU into nap mode. When I changed the idle loop, for some reason 7447A cpus started hanging when we put them into nap mode. Changing to the recommended sequence fixes that. The complexity here is that the recommended sequence is a loop that keeps putting the cpu back into nap mode. Clearly we need some way to break out of the loop when an interrupt (external interrupt, decrementer, performance monitor) occurs. Here we use a bit in the thread_info struct to indicate that we need this, and the exception entry code notices this and arranges for the exception to return to the value in the link register, thus breaking out of the loop. We use a new `local_flags' field in the thread_info which we can alter without needing to use an atomic update sequence. The PPC970 has the same recommended sequence, so we do the same thing there too. This also fixes a bug in the kernel stack overflow handling code on 32-bit, since it was causing a value that we needed in a register to get trashed. Signed-off-by: Paul Mackerras <paulus@samba.org>
157 lines
4.7 KiB
C
157 lines
4.7 KiB
C
/* thread_info.h: PowerPC low-level thread information
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* adapted from the i386 version by Paul Mackerras
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*
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* Copyright (C) 2002 David Howells (dhowells@redhat.com)
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* - Incorporating suggestions made by Linus Torvalds and Dave Miller
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*/
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#ifndef _ASM_POWERPC_THREAD_INFO_H
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#define _ASM_POWERPC_THREAD_INFO_H
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#ifdef __KERNEL__
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/* We have 8k stacks on ppc32 and 16k on ppc64 */
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#ifdef CONFIG_PPC64
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#define THREAD_SHIFT 14
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#else
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#define THREAD_SHIFT 13
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#endif
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#define THREAD_SIZE (1 << THREAD_SHIFT)
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#ifndef __ASSEMBLY__
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#include <linux/config.h>
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#include <linux/cache.h>
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#include <asm/processor.h>
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#include <asm/page.h>
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#include <linux/stringify.h>
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/*
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* low level task data.
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*/
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struct thread_info {
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struct task_struct *task; /* main task structure */
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struct exec_domain *exec_domain; /* execution domain */
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int cpu; /* cpu we're on */
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int preempt_count; /* 0 => preemptable,
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<0 => BUG */
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struct restart_block restart_block;
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unsigned long local_flags; /* private flags for thread */
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/* low level flags - has atomic operations done on it */
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unsigned long flags ____cacheline_aligned_in_smp;
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};
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/*
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* macros/functions for gaining access to the thread information structure
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*
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* preempt_count needs to be 1 initially, until the scheduler is functional.
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*/
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.task = &tsk, \
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.exec_domain = &default_exec_domain, \
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.cpu = 0, \
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.preempt_count = 1, \
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.restart_block = { \
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.fn = do_no_restart_syscall, \
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}, \
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.flags = 0, \
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}
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#define init_thread_info (init_thread_union.thread_info)
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#define init_stack (init_thread_union.stack)
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/* thread information allocation */
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#if THREAD_SHIFT >= PAGE_SHIFT
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#define THREAD_ORDER (THREAD_SHIFT - PAGE_SHIFT)
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#ifdef CONFIG_DEBUG_STACK_USAGE
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#define alloc_thread_info(tsk) \
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((struct thread_info *)__get_free_pages(GFP_KERNEL | \
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__GFP_ZERO, THREAD_ORDER))
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#else
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#define alloc_thread_info(tsk) \
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((struct thread_info *)__get_free_pages(GFP_KERNEL, THREAD_ORDER))
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#endif
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#define free_thread_info(ti) free_pages((unsigned long)ti, THREAD_ORDER)
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#else /* THREAD_SHIFT < PAGE_SHIFT */
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#ifdef CONFIG_DEBUG_STACK_USAGE
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#define alloc_thread_info(tsk) kzalloc(THREAD_SIZE, GFP_KERNEL)
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#else
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#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
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#endif
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#define free_thread_info(ti) kfree(ti)
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#endif /* THREAD_SHIFT < PAGE_SHIFT */
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/* how to get the thread information struct from C */
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static inline struct thread_info *current_thread_info(void)
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{
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register unsigned long sp asm("r1");
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/* gcc4, at least, is smart enough to turn this into a single
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* rlwinm for ppc32 and clrrdi for ppc64 */
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return (struct thread_info *)(sp & ~(THREAD_SIZE-1));
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}
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#endif /* __ASSEMBLY__ */
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#define PREEMPT_ACTIVE 0x10000000
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/*
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* thread information flag bit numbers
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*/
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#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
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#define TIF_NOTIFY_RESUME 1 /* resumption notification requested */
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#define TIF_SIGPENDING 2 /* signal pending */
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#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
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#define TIF_POLLING_NRFLAG 4 /* true if poll_idle() is polling
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TIF_NEED_RESCHED */
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#define TIF_32BIT 5 /* 32 bit binary */
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#define TIF_RUNLATCH 6 /* Is the runlatch enabled? */
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#define TIF_ABI_PENDING 7 /* 32/64 bit switch needed */
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#define TIF_SYSCALL_AUDIT 8 /* syscall auditing active */
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#define TIF_SINGLESTEP 9 /* singlestepping active */
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#define TIF_MEMDIE 10
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#define TIF_SECCOMP 11 /* secure computing */
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#define TIF_RESTOREALL 12 /* Restore all regs (implies NOERROR) */
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#define TIF_NOERROR 14 /* Force successful syscall return */
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#define TIF_RESTORE_SIGMASK 15 /* Restore signal mask in do_signal */
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/* as above, but as bit values */
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#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
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#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
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#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
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#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
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#define _TIF_32BIT (1<<TIF_32BIT)
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#define _TIF_RUNLATCH (1<<TIF_RUNLATCH)
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#define _TIF_ABI_PENDING (1<<TIF_ABI_PENDING)
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#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
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#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
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#define _TIF_SECCOMP (1<<TIF_SECCOMP)
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#define _TIF_RESTOREALL (1<<TIF_RESTOREALL)
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#define _TIF_NOERROR (1<<TIF_NOERROR)
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#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
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#define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
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#define _TIF_USER_WORK_MASK (_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \
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_TIF_NEED_RESCHED | _TIF_RESTORE_SIGMASK)
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#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR)
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/* Bits in local_flags */
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/* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
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#define TLF_NAPPING 0 /* idle thread enabled NAP mode */
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#define _TLF_NAPPING (1 << TLF_NAPPING)
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_THREAD_INFO_H */
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