projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 867e359b CM |
1 | /* |
| 2 | * Copyright 2010 Tilera Corporation. All Rights Reserved. | |
| 3 | * | |
| 4 | * This program is free software; you can redistribute it and/or | |
| 5 | * modify it under the terms of the GNU General Public License | |
| 6 | * as published by the Free Software Foundation, version 2. | |
| 7 | * | |
| 8 | * This program is distributed in the hope that it will be useful, but | |
| 9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
| 11 | * NON INFRINGEMENT. See the GNU General Public License for | |
| 12 | * more details. | |
| 13 | */ | |
| 14 | ||
| 15 | #ifndef _ASM_TILE_PERCPU_H | |
| 16 | #define _ASM_TILE_PERCPU_H | |
| 17 | ||
| f862eefe CM |
18 | register unsigned long my_cpu_offset_reg asm("tp"); |
| 19 | ||
| 20 | #ifdef CONFIG_PREEMPT | |
| 21 | /* | |
| 22 | * For full preemption, we can't just use the register variable | |
| 23 | * directly, since we need barrier() to hazard against it, causing the | |
| 24 | * compiler to reload anything computed from a previous "tp" value. | |
| 25 | * But we also don't want to use volatile asm, since we'd like the | |
| 26 | * compiler to be able to cache the value across multiple percpu reads. | |
| 27 | * So we use a fake stack read as a hazard against barrier(). | |
| 28 | * The 'U' constraint is like 'm' but disallows postincrement. | |
| 29 | */ | |
| 30 | static inline unsigned long __my_cpu_offset(void) | |
| 31 | { | |
| 32 | unsigned long tp; | |
| 33 | register unsigned long *sp asm("sp"); | |
| 34 | asm("move %0, tp" : "=r" (tp) : "U" (*sp)); | |
| 35 | return tp; | |
| 36 | } | |
| 37 | #define __my_cpu_offset __my_cpu_offset() | |
| 38 | #else | |
| 39 | /* | |
| 40 | * We don't need to hazard against barrier() since "tp" doesn't ever | |
| 41 | * change with PREEMPT_NONE, and with PREEMPT_VOLUNTARY it only | |
| 42 | * changes at function call points, at which we are already re-reading | |
| 43 | * the value of "tp" due to "my_cpu_offset_reg" being a global variable. | |
| 44 | */ | |
| 45 | #define __my_cpu_offset my_cpu_offset_reg | |
| 46 | #endif | |
| 47 | ||
| 48 | #define set_my_cpu_offset(tp) (my_cpu_offset_reg = (tp)) | |
| 867e359b CM |
49 | |
| 50 | #include <asm-generic/percpu.h> | |
| 51 | ||
| 52 | #endif /* _ASM_TILE_PERCPU_H */ |