719d1cd867
The hvlpevent_queue (formally ItLpQueue) has a member called xInUseWord which is used for serialising access to the queue. Because it's a word (ie. 32 bit) there's a custom 32-bit version of test_and_set_bit() or thereabouts in ItLpQueue.c. The xInUseWord is not shared with they hypervisor, so we can replace it with a spinlock and remove the custom code. There is also another locking mechanism (ItLpQueueInProcess). This is redundant because it's only manipulated while the lock's held. Remove it. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
81 lines
2.8 KiB
C
81 lines
2.8 KiB
C
/*
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* ItLpQueue.h
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* Copyright (C) 2001 Mike Corrigan IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _ITLPQUEUE_H
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#define _ITLPQUEUE_H
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/*
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* This control block defines the simple LP queue structure that is
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* shared between the hypervisor (PLIC) and the OS in order to send
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* events to an LP.
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*/
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#include <asm/types.h>
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#include <asm/ptrace.h>
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struct HvLpEvent;
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#define ITMaxLpQueues 8
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#define NotUsed 0 // Queue will not be used by PLIC
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#define DedicatedIo 1 // Queue dedicated to IO processor specified
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#define DedicatedLp 2 // Queue dedicated to LP specified
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#define Shared 3 // Queue shared for both IO and LP
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#define LpEventStackSize 4096
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#define LpEventMaxSize 256
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#define LpEventAlign 64
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struct hvlpevent_queue {
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/*
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* The xSlicCurEventPtr is the pointer to the next event stack entry
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* that will become valid. The OS must peek at this entry to determine
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* if it is valid. PLIC will set the valid indicator as the very last
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* store into that entry.
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*
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* When the OS has completed processing of the event then it will mark
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* the event as invalid so that PLIC knows it can store into that event
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* location again.
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*
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* If the event stack fills and there are overflow events, then PLIC
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* will set the xPlicOverflowIntPending flag in which case the OS will
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* have to fetch the additional LP events once they have drained the
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* event stack.
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*
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* The first 16-bytes are known by both the OS and PLIC. The remainder
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* of the cache line is for use by the OS.
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*/
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u8 xPlicOverflowIntPending;// 0x00 Overflow events are pending
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u8 xPlicStatus; // 0x01 DedicatedIo or DedicatedLp or NotUsed
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u16 xSlicLogicalProcIndex; // 0x02 Logical Proc Index for correlation
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u8 xPlicRsvd[12]; // 0x04
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char *xSlicCurEventPtr; // 0x10
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char *xSlicLastValidEventPtr; // 0x18
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char *xSlicEventStackPtr; // 0x20
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u8 xIndex; // 0x28 unique sequential index.
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u8 xSlicRsvd[3]; // 0x29-2b
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spinlock_t lock;
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};
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extern struct hvlpevent_queue hvlpevent_queue;
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extern int hvlpevent_is_pending(void);
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extern void process_hvlpevents(struct pt_regs *);
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extern void setup_hvlpevent_queue(void);
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#endif /* _ITLPQUEUE_H */
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