Jeremy Fitzhardinge | 9ca3610 | 2006-12-07 02:14:02 +0100 | [diff] [blame] | 1 | /* |
| 2 | Per-processor Data Areas |
| 3 | Jeremy Fitzhardinge <jeremy@goop.org> 2006 |
| 4 | Based on asm-x86_64/pda.h by Andi Kleen. |
| 5 | */ |
| 6 | #ifndef _I386_PDA_H |
| 7 | #define _I386_PDA_H |
| 8 | |
| 9 | #include <linux/stddef.h> |
| 10 | |
| 11 | struct i386_pda |
| 12 | { |
| 13 | struct i386_pda *_pda; /* pointer to self */ |
Jeremy Fitzhardinge | b2938f8 | 2006-12-07 02:14:03 +0100 | [diff] [blame^] | 14 | |
| 15 | int cpu_number; |
Jeremy Fitzhardinge | 9ca3610 | 2006-12-07 02:14:02 +0100 | [diff] [blame] | 16 | }; |
| 17 | |
| 18 | extern struct i386_pda *_cpu_pda[]; |
| 19 | |
| 20 | #define cpu_pda(i) (_cpu_pda[i]) |
| 21 | |
| 22 | #define pda_offset(field) offsetof(struct i386_pda, field) |
| 23 | |
| 24 | extern void __bad_pda_field(void); |
| 25 | |
| 26 | /* This variable is never instantiated. It is only used as a stand-in |
| 27 | for the real per-cpu PDA memory, so that gcc can understand what |
| 28 | memory operations the inline asms() below are performing. This |
| 29 | eliminates the need to make the asms volatile or have memory |
| 30 | clobbers, so gcc can readily analyse them. */ |
| 31 | extern struct i386_pda _proxy_pda; |
| 32 | |
| 33 | #define pda_to_op(op,field,val) \ |
| 34 | do { \ |
| 35 | typedef typeof(_proxy_pda.field) T__; \ |
| 36 | if (0) { T__ tmp__; tmp__ = (val); } \ |
| 37 | switch (sizeof(_proxy_pda.field)) { \ |
| 38 | case 1: \ |
| 39 | asm(op "b %1,%%gs:%c2" \ |
| 40 | : "+m" (_proxy_pda.field) \ |
| 41 | :"ri" ((T__)val), \ |
| 42 | "i"(pda_offset(field))); \ |
| 43 | break; \ |
| 44 | case 2: \ |
| 45 | asm(op "w %1,%%gs:%c2" \ |
| 46 | : "+m" (_proxy_pda.field) \ |
| 47 | :"ri" ((T__)val), \ |
| 48 | "i"(pda_offset(field))); \ |
| 49 | break; \ |
| 50 | case 4: \ |
| 51 | asm(op "l %1,%%gs:%c2" \ |
| 52 | : "+m" (_proxy_pda.field) \ |
| 53 | :"ri" ((T__)val), \ |
| 54 | "i"(pda_offset(field))); \ |
| 55 | break; \ |
| 56 | default: __bad_pda_field(); \ |
| 57 | } \ |
| 58 | } while (0) |
| 59 | |
| 60 | #define pda_from_op(op,field) \ |
| 61 | ({ \ |
| 62 | typeof(_proxy_pda.field) ret__; \ |
| 63 | switch (sizeof(_proxy_pda.field)) { \ |
| 64 | case 1: \ |
| 65 | asm(op "b %%gs:%c1,%0" \ |
| 66 | : "=r" (ret__) \ |
| 67 | : "i" (pda_offset(field)), \ |
| 68 | "m" (_proxy_pda.field)); \ |
| 69 | break; \ |
| 70 | case 2: \ |
| 71 | asm(op "w %%gs:%c1,%0" \ |
| 72 | : "=r" (ret__) \ |
| 73 | : "i" (pda_offset(field)), \ |
| 74 | "m" (_proxy_pda.field)); \ |
| 75 | break; \ |
| 76 | case 4: \ |
| 77 | asm(op "l %%gs:%c1,%0" \ |
| 78 | : "=r" (ret__) \ |
| 79 | : "i" (pda_offset(field)), \ |
| 80 | "m" (_proxy_pda.field)); \ |
| 81 | break; \ |
| 82 | default: __bad_pda_field(); \ |
| 83 | } \ |
| 84 | ret__; }) |
| 85 | |
| 86 | /* Return a pointer to a pda field */ |
| 87 | #define pda_addr(field) \ |
| 88 | ((typeof(_proxy_pda.field) *)((unsigned char *)read_pda(_pda) + \ |
| 89 | pda_offset(field))) |
| 90 | |
| 91 | #define read_pda(field) pda_from_op("mov",field) |
| 92 | #define write_pda(field,val) pda_to_op("mov",field,val) |
| 93 | #define add_pda(field,val) pda_to_op("add",field,val) |
| 94 | #define sub_pda(field,val) pda_to_op("sub",field,val) |
| 95 | #define or_pda(field,val) pda_to_op("or",field,val) |
| 96 | |
| 97 | #endif /* _I386_PDA_H */ |