diff options
| -rw-r--r-- | arch/i386/kernel/head.S | 2 | ||||
| -rw-r--r-- | include/asm-i386/pda.h | 95 | ||||
| -rw-r--r-- | include/asm-i386/segment.h | 5 |
3 files changed, 100 insertions, 2 deletions
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S index b1f1df11fcc..4a83384c5a6 100644 --- a/arch/i386/kernel/head.S +++ b/arch/i386/kernel/head.S @@ -585,7 +585,7 @@ ENTRY(cpu_gdt_table) .quad 0x004092000000ffff /* 0xc8 APM DS data */ .quad 0x00c0920000000000 /* 0xd0 - ESPFIX SS */ - .quad 0x0000000000000000 /* 0xd8 - unused */ + .quad 0x0000000000000000 /* 0xd8 - PDA */ .quad 0x0000000000000000 /* 0xe0 - unused */ .quad 0x0000000000000000 /* 0xe8 - unused */ .quad 0x0000000000000000 /* 0xf0 - unused */ diff --git a/include/asm-i386/pda.h b/include/asm-i386/pda.h new file mode 100644 index 00000000000..4c39ccb1305 --- /dev/null +++ b/include/asm-i386/pda.h @@ -0,0 +1,95 @@ +/* + Per-processor Data Areas + Jeremy Fitzhardinge <jeremy@goop.org> 2006 + Based on asm-x86_64/pda.h by Andi Kleen. + */ +#ifndef _I386_PDA_H +#define _I386_PDA_H + +#include <linux/stddef.h> + +struct i386_pda +{ + struct i386_pda *_pda; /* pointer to self */ +}; + +extern struct i386_pda *_cpu_pda[]; + +#define cpu_pda(i) (_cpu_pda[i]) + +#define pda_offset(field) offsetof(struct i386_pda, field) + +extern void __bad_pda_field(void); + +/* This variable is never instantiated. It is only used as a stand-in + for the real per-cpu PDA memory, so that gcc can understand what + memory operations the inline asms() below are performing. This + eliminates the need to make the asms volatile or have memory + clobbers, so gcc can readily analyse them. */ +extern struct i386_pda _proxy_pda; + +#define pda_to_op(op,field,val) \ + do { \ + typedef typeof(_proxy_pda.field) T__; \ + if (0) { T__ tmp__; tmp__ = (val); } \ + switch (sizeof(_proxy_pda.field)) { \ + case 1: \ + asm(op "b %1,%%gs:%c2" \ + : "+m" (_proxy_pda.field) \ + :"ri" ((T__)val), \ + "i"(pda_offset(field))); \ + break; \ + case 2: \ + asm(op "w %1,%%gs:%c2" \ + : "+m" (_proxy_pda.field) \ + :"ri" ((T__)val), \ + "i"(pda_offset(field))); \ + break; \ + case 4: \ + asm(op "l %1,%%gs:%c2" \ + : "+m" (_proxy_pda.field) \ + :"ri" ((T__)val), \ + "i"(pda_offset(field))); \ + break; \ + default: __bad_pda_field(); \ + } \ + } while (0) + +#define pda_from_op(op,field) \ + ({ \ + typeof(_proxy_pda.field) ret__; \ + switch (sizeof(_proxy_pda.field)) { \ + case 1: \ + asm(op "b %%gs:%c1,%0" \ + : "=r" (ret__) \ + : "i" (pda_offset(field)), \ + "m" (_proxy_pda.field)); \ + break; \ + case 2: \ + asm(op "w %%gs:%c1,%0" \ + : "=r" (ret__) \ + : "i" (pda_offset(field)), \ + "m" (_proxy_pda.field)); \ + break; \ + case 4: \ + asm(op "l %%gs:%c1,%0" \ + : "=r" (ret__) \ + : "i" (pda_offset(field)), \ + "m" (_proxy_pda.field)); \ + break; \ + default: __bad_pda_field(); \ + } \ + ret__; }) + +/* Return a pointer to a pda field */ +#define pda_addr(field) \ + ((typeof(_proxy_pda.field) *)((unsigned char *)read_pda(_pda) + \ + pda_offset(field))) + +#define read_pda(field) pda_from_op("mov",field) +#define write_pda(field,val) pda_to_op("mov",field,val) +#define add_pda(field,val) pda_to_op("add",field,val) +#define sub_pda(field,val) pda_to_op("sub",field,val) +#define or_pda(field,val) pda_to_op("or",field,val) + +#endif /* _I386_PDA_H */ diff --git a/include/asm-i386/segment.h b/include/asm-i386/segment.h index b7ab59685ba..5bdda79b6b5 100644 --- a/include/asm-i386/segment.h +++ b/include/asm-i386/segment.h @@ -39,7 +39,7 @@ * 25 - APM BIOS support * * 26 - ESPFIX small SS - * 27 - unused + * 27 - PDA [ per-cpu private data area ] * 28 - unused * 29 - unused * 30 - unused @@ -74,6 +74,9 @@ #define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE + 14) #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8) +#define GDT_ENTRY_PDA (GDT_ENTRY_KERNEL_BASE + 15) +#define __KERNEL_PDA (GDT_ENTRY_PDA * 8) + #define GDT_ENTRY_DOUBLEFAULT_TSS 31 /* |