b91691164b
Suggested by someone I forgot who sorry. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
84 lines
2.8 KiB
C
84 lines
2.8 KiB
C
#ifndef X86_64_PDA_H
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#define X86_64_PDA_H
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#ifndef __ASSEMBLY__
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#include <linux/stddef.h>
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#include <linux/types.h>
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#include <linux/cache.h>
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/* Per processor datastructure. %gs points to it while the kernel runs */
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struct x8664_pda {
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struct task_struct *pcurrent; /* Current process */
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unsigned long data_offset; /* Per cpu data offset from linker address */
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struct x8664_pda *me; /* Pointer to itself */
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unsigned long kernelstack; /* top of kernel stack for current */
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unsigned long oldrsp; /* user rsp for system call */
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unsigned long irqrsp; /* Old rsp for interrupts. */
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int irqcount; /* Irq nesting counter. Starts with -1 */
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int cpunumber; /* Logical CPU number */
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char *irqstackptr; /* top of irqstack */
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unsigned int __softirq_pending;
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unsigned int __nmi_count; /* number of NMI on this CPUs */
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struct mm_struct *active_mm;
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int mmu_state;
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unsigned apic_timer_irqs;
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} ____cacheline_aligned_in_smp;
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#define IRQSTACK_ORDER 2
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#define IRQSTACKSIZE (PAGE_SIZE << IRQSTACK_ORDER)
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extern struct x8664_pda cpu_pda[];
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/*
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* There is no fast way to get the base address of the PDA, all the accesses
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* have to mention %fs/%gs. So it needs to be done this Torvaldian way.
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*/
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#define sizeof_field(type,field) (sizeof(((type *)0)->field))
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#define typeof_field(type,field) typeof(((type *)0)->field)
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extern void __bad_pda_field(void);
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#define pda_offset(field) offsetof(struct x8664_pda, field)
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#define pda_to_op(op,field,val) do { \
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switch (sizeof_field(struct x8664_pda, field)) { \
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case 2: \
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asm volatile(op "w %0,%%gs:%P1"::"r" (val),"i"(pda_offset(field)):"memory"); break; \
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case 4: \
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asm volatile(op "l %0,%%gs:%P1"::"r" (val),"i"(pda_offset(field)):"memory"); break; \
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case 8: \
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asm volatile(op "q %0,%%gs:%P1"::"r" (val),"i"(pda_offset(field)):"memory"); break; \
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default: __bad_pda_field(); \
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} \
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} while (0)
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/*
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* AK: PDA read accesses should be neither volatile nor have an memory clobber.
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* Unfortunately removing them causes all hell to break lose currently.
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*/
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#define pda_from_op(op,field) ({ \
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typedef typeof_field(struct x8664_pda, field) T__; T__ ret__; \
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switch (sizeof_field(struct x8664_pda, field)) { \
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case 2: \
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asm volatile(op "w %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
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case 4: \
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asm volatile(op "l %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
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case 8: \
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asm volatile(op "q %%gs:%P1,%0":"=r" (ret__):"i"(pda_offset(field)):"memory"); break;\
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default: __bad_pda_field(); \
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} \
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ret__; })
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#define read_pda(field) pda_from_op("mov",field)
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#define write_pda(field,val) pda_to_op("mov",field,val)
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#define add_pda(field,val) pda_to_op("add",field,val)
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#define sub_pda(field,val) pda_to_op("sub",field,val)
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#endif
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#define PDA_STACKOFFSET (5*8)
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#endif
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