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Diffstat (limited to 'arch/tile/include/asm/system.h')
| -rw-r--r-- | arch/tile/include/asm/system.h | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/arch/tile/include/asm/system.h b/arch/tile/include/asm/system.h new file mode 100644 index 00000000000..d6ca7f816c8 --- /dev/null +++ b/arch/tile/include/asm/system.h @@ -0,0 +1,220 @@ +/* + * 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_SYSTEM_H +#define _ASM_TILE_SYSTEM_H + +#ifndef __ASSEMBLY__ + +#include <linux/types.h> +#include <linux/irqflags.h> + +/* NOTE: we can't include <linux/ptrace.h> due to #include dependencies. */ +#include <asm/ptrace.h> + +#include <arch/chip.h> +#include <arch/sim_def.h> +#include <arch/spr_def.h> + +/* + * read_barrier_depends - Flush all pending reads that subsequents reads + * depend on. + * + * No data-dependent reads from memory-like regions are ever reordered + * over this barrier. All reads preceding this primitive are guaranteed + * to access memory (but not necessarily other CPUs' caches) before any + * reads following this primitive that depend on the data return by + * any of the preceding reads. This primitive is much lighter weight than + * rmb() on most CPUs, and is never heavier weight than is + * rmb(). + * + * These ordering constraints are respected by both the local CPU + * and the compiler. + * + * Ordering is not guaranteed by anything other than these primitives, + * not even by data dependencies. See the documentation for + * memory_barrier() for examples and URLs to more information. + * + * For example, the following code would force ordering (the initial + * value of "a" is zero, "b" is one, and "p" is "&a"): + * + * <programlisting> + * CPU 0 CPU 1 + * + * b = 2; + * memory_barrier(); + * p = &b; q = p; + * read_barrier_depends(); + * d = *q; + * </programlisting> + * + * because the read of "*q" depends on the read of "p" and these + * two reads are separated by a read_barrier_depends(). However, + * the following code, with the same initial values for "a" and "b": + * + * <programlisting> + * CPU 0 CPU 1 + * + * a = 2; + * memory_barrier(); + * b = 3; y = b; + * read_barrier_depends(); + * x = a; + * </programlisting> + * + * does not enforce ordering, since there is no data dependency between + * the read of "a" and the read of "b". Therefore, on some CPUs, such + * as Alpha, "y" could be set to 3 and "x" to 0. Use rmb() + * in cases like this where there are no data dependencies. + */ + +#define read_barrier_depends() do { } while (0) + +#define __sync() __insn_mf() + +#if CHIP_HAS_SPLIT_CYCLE() +#define get_cycles_low() __insn_mfspr(SPR_CYCLE_LOW) +#else +#define get_cycles_low() __insn_mfspr(SPR_CYCLE) /* just get all 64 bits */ +#endif + +/* Fence to guarantee visibility of stores to incoherent memory. */ +static inline void +mb_incoherent(void) +{ + __insn_mf(); + +#if !CHIP_HAS_MF_WAITS_FOR_VICTIMS() + { + int __mb_incoherent(void); +#if CHIP_HAS_TILE_WRITE_PENDING() + const unsigned long WRITE_TIMEOUT_CYCLES = 400; + unsigned long start = get_cycles_low(); + do { + if (__insn_mfspr(SPR_TILE_WRITE_PENDING) == 0) + return; + } while ((get_cycles_low() - start) < WRITE_TIMEOUT_CYCLES); +#endif /* CHIP_HAS_TILE_WRITE_PENDING() */ + (void) __mb_incoherent(); + } +#endif /* CHIP_HAS_MF_WAITS_FOR_VICTIMS() */ +} + +#define fast_wmb() __sync() +#define fast_rmb() __sync() +#define fast_mb() __sync() +#define fast_iob() mb_incoherent() + +#define wmb() fast_wmb() +#define rmb() fast_rmb() +#define mb() fast_mb() +#define iob() fast_iob() + +#ifdef CONFIG_SMP +#define smp_mb() mb() +#define smp_rmb() rmb() +#define smp_wmb() wmb() +#define smp_read_barrier_depends() read_barrier_depends() +#else +#define smp_mb() barrier() +#define smp_rmb() barrier() +#define smp_wmb() barrier() +#define smp_read_barrier_depends() do { } while (0) +#endif + +#define set_mb(var, value) \ + do { var = value; mb(); } while (0) + +#include <linux/irqflags.h> + +/* + * Pause the DMA engine and static network before task switching. + */ +#define prepare_arch_switch(next) _prepare_arch_switch(next) +void _prepare_arch_switch(struct task_struct *next); + + +/* + * switch_to(n) should switch tasks to task nr n, first + * checking that n isn't the current task, in which case it does nothing. + * The number of callee-saved registers saved on the kernel stack + * is defined here for use in copy_thread() and must agree with __switch_to(). + */ +#endif /* !__ASSEMBLY__ */ +#define CALLEE_SAVED_FIRST_REG 30 +#define CALLEE_SAVED_REGS_COUNT 24 /* r30 to r52, plus an empty to align */ +#ifndef __ASSEMBLY__ +struct task_struct; +#define switch_to(prev, next, last) ((last) = _switch_to((prev), (next))) +extern struct task_struct *_switch_to(struct task_struct *prev, + struct task_struct *next); + +/* + * On SMP systems, when the scheduler does migration-cost autodetection, + * it needs a way to flush as much of the CPU's caches as possible: + * + * TODO: fill this in! + */ +static inline void sched_cacheflush(void) +{ +} + +#define arch_align_stack(x) (x) + +/* + * Is the kernel doing fixups of unaligned accesses? If <0, no kernel + * intervention occurs and SIGBUS is delivered with no data address + * info. If 0, the kernel single-steps the instruction to discover + * the data address to provide with the SIGBUS. If 1, the kernel does + * a fixup. + */ +extern int unaligned_fixup; + +/* Is the kernel printing on each unaligned fixup? */ +extern int unaligned_printk; + +/* Number of unaligned fixups performed */ +extern unsigned int unaligned_fixup_count; + +/* User-level DMA management functions */ +void grant_dma_mpls(void); +void restrict_dma_mpls(void); + + +/* Invoke the simulator "syscall" mechanism (see arch/tile/kernel/entry.S). */ +extern int _sim_syscall(int syscall_num, ...); +#define sim_syscall(syscall_num, ...) \ + _sim_syscall(SIM_CONTROL_SYSCALL + \ + ((syscall_num) << _SIM_CONTROL_OPERATOR_BITS), \ + ## __VA_ARGS__) + +/* + * Kernel threads can check to see if they need to migrate their + * stack whenever they return from a context switch; for user + * threads, we defer until they are returning to user-space. + */ +#define finish_arch_switch(prev) do { \ + if (unlikely((prev)->state == TASK_DEAD)) \ + __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_EXIT | \ + ((prev)->pid << _SIM_CONTROL_OPERATOR_BITS)); \ + __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_SWITCH | \ + (current->pid << _SIM_CONTROL_OPERATOR_BITS)); \ + if (current->mm == NULL && !kstack_hash && \ + current_thread_info()->homecache_cpu != smp_processor_id()) \ + homecache_migrate_kthread(); \ +} while (0) + +#endif /* !__ASSEMBLY__ */ + +#endif /* _ASM_TILE_SYSTEM_H */ |