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f007cacffc
This changes the writeX family of functions to have a sync instruction before the MMIO store rather than after, because the generally expected behaviour is that the device receiving the MMIO store can be guaranteed to see the effects of any preceding writes to normal memory. To preserve ordering between writeX and readX, and to preserve ordering between preceding stores and the readX, the readX family of functions have had an sync added before the load. Although writeX followed by spin_unlock is not officially guaranteed to keep the writeX inside the spin-locked region unless an mmiowb() is used, there are currently drivers that depend on the previous behaviour on powerpc, which was that the mmiowb wasn't actually required. Therefore we have a per-cpu flag that is set by writeX, cleared by __raw_spin_lock and mmiowb, and tested by __raw_spin_unlock. If it is set, __raw_spin_unlock does a sync and clears it. This changes both 32-bit and 64-bit readX/writeX. 32-bit already has a sync in __raw_spin_unlock (since lwsync doesn't exist on 32-bit), and thus doesn't need the per-cpu flag. Tested on G5 (PPC970) and POWER5. Signed-off-by: Paul Mackerras <paulus@samba.org>
110 lines
3.4 KiB
C
110 lines
3.4 KiB
C
/*
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* include/asm-powerpc/paca.h
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*
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* This control block defines the PACA which defines the processor
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* specific data for each logical processor on the system.
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* There are some pointers defined that are utilized by PLIC.
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*
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* C 2001 PPC 64 Team, IBM Corp
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _ASM_POWERPC_PACA_H
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#define _ASM_POWERPC_PACA_H
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#ifdef __KERNEL__
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#include <asm/types.h>
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#include <asm/lppaca.h>
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#include <asm/mmu.h>
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register struct paca_struct *local_paca asm("r13");
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#define get_paca() local_paca
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#define get_lppaca() (get_paca()->lppaca_ptr)
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struct task_struct;
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/*
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* Defines the layout of the paca.
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*
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* This structure is not directly accessed by firmware or the service
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* processor except for the first two pointers that point to the
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* lppaca area and the ItLpRegSave area for this CPU. The lppaca
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* object is currently contained within the PACA but it doesn't need
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* to be.
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*/
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struct paca_struct {
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/*
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* Because hw_cpu_id, unlike other paca fields, is accessed
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* routinely from other CPUs (from the IRQ code), we stick to
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* read-only (after boot) fields in the first cacheline to
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* avoid cacheline bouncing.
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*/
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/*
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* MAGIC: These first two pointers can't be moved - they're
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* accessed by the firmware
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*/
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struct lppaca *lppaca_ptr; /* Pointer to LpPaca for PLIC */
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#ifdef CONFIG_PPC_ISERIES
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void *reg_save_ptr; /* Pointer to LpRegSave for PLIC */
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#endif /* CONFIG_PPC_ISERIES */
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/*
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* MAGIC: the spinlock functions in arch/powerpc/lib/locks.c
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* load lock_token and paca_index with a single lwz
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* instruction. They must travel together and be properly
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* aligned.
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*/
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u16 lock_token; /* Constant 0x8000, used in locks */
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u16 paca_index; /* Logical processor number */
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u64 kernel_toc; /* Kernel TOC address */
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u64 stab_real; /* Absolute address of segment table */
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u64 stab_addr; /* Virtual address of segment table */
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void *emergency_sp; /* pointer to emergency stack */
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u64 data_offset; /* per cpu data offset */
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s16 hw_cpu_id; /* Physical processor number */
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u8 cpu_start; /* At startup, processor spins until */
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/* this becomes non-zero. */
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/*
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* Now, starting in cacheline 2, the exception save areas
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*/
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/* used for most interrupts/exceptions */
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u64 exgen[10] __attribute__((aligned(0x80)));
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u64 exmc[10]; /* used for machine checks */
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u64 exslb[10]; /* used for SLB/segment table misses
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* on the linear mapping */
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mm_context_t context;
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u16 vmalloc_sllp;
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u16 slb_cache[SLB_CACHE_ENTRIES];
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u16 slb_cache_ptr;
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/*
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* then miscellaneous read-write fields
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*/
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struct task_struct *__current; /* Pointer to current */
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u64 kstack; /* Saved Kernel stack addr */
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u64 stab_rr; /* stab/slb round-robin counter */
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u64 saved_r1; /* r1 save for RTAS calls */
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u64 saved_msr; /* MSR saved here by enter_rtas */
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u8 proc_enabled; /* irq soft-enable flag */
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u8 io_sync; /* writel() needs spin_unlock sync */
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/* Stuff for accurate time accounting */
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u64 user_time; /* accumulated usermode TB ticks */
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u64 system_time; /* accumulated system TB ticks */
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u64 startpurr; /* PURR/TB value snapshot */
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};
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extern struct paca_struct paca[];
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void setup_boot_paca(void);
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_PACA_H */
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