30ed1a79f5
Basically the existing percpu ops can be used for this_cpu variants that allow operations also on dynamically allocated percpu data. However, we do not pass a reference to a percpu variable in. Instead a dynamically or statically allocated percpu variable is provided. Preempt, the non preempt and the irqsafe operations generate the same code. It will always be possible to have the requires per cpu atomicness in a single RMW instruction with segment override on x86. 64 bit this_cpu operations are not supported on 32 bit. Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Tejun Heo <tj@kernel.org>
296 lines
10 KiB
C
296 lines
10 KiB
C
#ifndef _ASM_X86_PERCPU_H
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#define _ASM_X86_PERCPU_H
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#ifdef CONFIG_X86_64
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#define __percpu_seg gs
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#define __percpu_mov_op movq
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#else
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#define __percpu_seg fs
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#define __percpu_mov_op movl
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#endif
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#ifdef __ASSEMBLY__
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/*
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* PER_CPU finds an address of a per-cpu variable.
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*
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* Args:
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* var - variable name
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* reg - 32bit register
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*
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* The resulting address is stored in the "reg" argument.
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*
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* Example:
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* PER_CPU(cpu_gdt_descr, %ebx)
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*/
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#ifdef CONFIG_SMP
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#define PER_CPU(var, reg) \
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__percpu_mov_op %__percpu_seg:per_cpu__this_cpu_off, reg; \
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lea per_cpu__##var(reg), reg
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#define PER_CPU_VAR(var) %__percpu_seg:per_cpu__##var
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#else /* ! SMP */
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#define PER_CPU(var, reg) \
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__percpu_mov_op $per_cpu__##var, reg
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#define PER_CPU_VAR(var) per_cpu__##var
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#endif /* SMP */
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#ifdef CONFIG_X86_64_SMP
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#define INIT_PER_CPU_VAR(var) init_per_cpu__##var
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#else
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#define INIT_PER_CPU_VAR(var) per_cpu__##var
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#endif
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#else /* ...!ASSEMBLY */
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#include <linux/kernel.h>
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#include <linux/stringify.h>
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#ifdef CONFIG_SMP
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#define __percpu_arg(x) "%%"__stringify(__percpu_seg)":%P" #x
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#define __my_cpu_offset percpu_read(this_cpu_off)
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#else
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#define __percpu_arg(x) "%P" #x
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#endif
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/*
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* Initialized pointers to per-cpu variables needed for the boot
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* processor need to use these macros to get the proper address
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* offset from __per_cpu_load on SMP.
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*
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* There also must be an entry in vmlinux_64.lds.S
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*/
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#define DECLARE_INIT_PER_CPU(var) \
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extern typeof(per_cpu_var(var)) init_per_cpu_var(var)
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#ifdef CONFIG_X86_64_SMP
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#define init_per_cpu_var(var) init_per_cpu__##var
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#else
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#define init_per_cpu_var(var) per_cpu_var(var)
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#endif
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/* For arch-specific code, we can use direct single-insn ops (they
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* don't give an lvalue though). */
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extern void __bad_percpu_size(void);
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#define percpu_to_op(op, var, val) \
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do { \
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typedef typeof(var) T__; \
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if (0) { \
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T__ tmp__; \
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tmp__ = (val); \
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} \
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switch (sizeof(var)) { \
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case 1: \
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asm(op "b %1,"__percpu_arg(0) \
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: "+m" (var) \
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: "qi" ((T__)(val))); \
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break; \
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case 2: \
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asm(op "w %1,"__percpu_arg(0) \
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: "+m" (var) \
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: "ri" ((T__)(val))); \
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break; \
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case 4: \
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asm(op "l %1,"__percpu_arg(0) \
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: "+m" (var) \
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: "ri" ((T__)(val))); \
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break; \
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case 8: \
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asm(op "q %1,"__percpu_arg(0) \
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: "+m" (var) \
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: "re" ((T__)(val))); \
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break; \
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default: __bad_percpu_size(); \
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} \
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} while (0)
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#define percpu_from_op(op, var, constraint) \
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({ \
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typeof(var) ret__; \
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switch (sizeof(var)) { \
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case 1: \
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asm(op "b "__percpu_arg(1)",%0" \
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: "=q" (ret__) \
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: constraint); \
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break; \
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case 2: \
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asm(op "w "__percpu_arg(1)",%0" \
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: "=r" (ret__) \
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: constraint); \
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break; \
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case 4: \
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asm(op "l "__percpu_arg(1)",%0" \
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: "=r" (ret__) \
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: constraint); \
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break; \
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case 8: \
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asm(op "q "__percpu_arg(1)",%0" \
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: "=r" (ret__) \
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: constraint); \
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break; \
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default: __bad_percpu_size(); \
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} \
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ret__; \
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})
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/*
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* percpu_read() makes gcc load the percpu variable every time it is
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* accessed while percpu_read_stable() allows the value to be cached.
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* percpu_read_stable() is more efficient and can be used if its value
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* is guaranteed to be valid across cpus. The current users include
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* get_current() and get_thread_info() both of which are actually
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* per-thread variables implemented as per-cpu variables and thus
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* stable for the duration of the respective task.
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*/
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#define percpu_read(var) percpu_from_op("mov", per_cpu__##var, \
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"m" (per_cpu__##var))
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#define percpu_read_stable(var) percpu_from_op("mov", per_cpu__##var, \
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"p" (&per_cpu__##var))
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#define percpu_write(var, val) percpu_to_op("mov", per_cpu__##var, val)
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#define percpu_add(var, val) percpu_to_op("add", per_cpu__##var, val)
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#define percpu_sub(var, val) percpu_to_op("sub", per_cpu__##var, val)
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#define percpu_and(var, val) percpu_to_op("and", per_cpu__##var, val)
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#define percpu_or(var, val) percpu_to_op("or", per_cpu__##var, val)
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#define percpu_xor(var, val) percpu_to_op("xor", per_cpu__##var, val)
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#define __this_cpu_read_1(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
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#define __this_cpu_read_2(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
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#define __this_cpu_read_4(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
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#define __this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
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#define __this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val)
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#define __this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val)
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#define __this_cpu_add_1(pcp, val) percpu_to_op("add", (pcp), val)
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#define __this_cpu_add_2(pcp, val) percpu_to_op("add", (pcp), val)
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#define __this_cpu_add_4(pcp, val) percpu_to_op("add", (pcp), val)
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#define __this_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
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#define __this_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
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#define __this_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
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#define __this_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val)
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#define __this_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val)
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#define __this_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val)
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#define __this_cpu_xor_1(pcp, val) percpu_to_op("xor", (pcp), val)
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#define __this_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
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#define __this_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
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#define this_cpu_read_1(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
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#define this_cpu_read_2(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
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#define this_cpu_read_4(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
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#define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
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#define this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val)
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#define this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val)
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#define this_cpu_add_1(pcp, val) percpu_to_op("add", (pcp), val)
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#define this_cpu_add_2(pcp, val) percpu_to_op("add", (pcp), val)
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#define this_cpu_add_4(pcp, val) percpu_to_op("add", (pcp), val)
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#define this_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
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#define this_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
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#define this_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
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#define this_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val)
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#define this_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val)
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#define this_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val)
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#define this_cpu_xor_1(pcp, val) percpu_to_op("xor", (pcp), val)
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#define this_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
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#define this_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
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#define irqsafe_cpu_add_1(pcp, val) percpu_to_op("add", (pcp), val)
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#define irqsafe_cpu_add_2(pcp, val) percpu_to_op("add", (pcp), val)
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#define irqsafe_cpu_add_4(pcp, val) percpu_to_op("add", (pcp), val)
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#define irqsafe_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
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#define irqsafe_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
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#define irqsafe_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
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#define irqsafe_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val)
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#define irqsafe_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val)
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#define irqsafe_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val)
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#define irqsafe_cpu_xor_1(pcp, val) percpu_to_op("xor", (pcp), val)
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#define irqsafe_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
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#define irqsafe_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
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/*
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* Per cpu atomic 64 bit operations are only available under 64 bit.
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* 32 bit must fall back to generic operations.
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*/
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#ifdef CONFIG_X86_64
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#define __this_cpu_read_8(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
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#define __this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val)
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#define __this_cpu_add_8(pcp, val) percpu_to_op("add", (pcp), val)
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#define __this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
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#define __this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
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#define __this_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
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#define this_cpu_read_8(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
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#define this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val)
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#define this_cpu_add_8(pcp, val) percpu_to_op("add", (pcp), val)
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#define this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
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#define this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
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#define this_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
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#define irqsafe_cpu_add_8(pcp, val) percpu_to_op("add", (pcp), val)
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#define irqsafe_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
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#define irqsafe_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
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#define irqsafe_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
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#endif
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/* This is not atomic against other CPUs -- CPU preemption needs to be off */
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#define x86_test_and_clear_bit_percpu(bit, var) \
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({ \
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int old__; \
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asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0" \
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: "=r" (old__), "+m" (per_cpu__##var) \
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: "dIr" (bit)); \
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old__; \
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})
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#include <asm-generic/percpu.h>
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/* We can use this directly for local CPU (faster). */
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DECLARE_PER_CPU(unsigned long, this_cpu_off);
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#endif /* !__ASSEMBLY__ */
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#ifdef CONFIG_SMP
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/*
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* Define the "EARLY_PER_CPU" macros. These are used for some per_cpu
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* variables that are initialized and accessed before there are per_cpu
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* areas allocated.
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*/
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#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
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DEFINE_PER_CPU(_type, _name) = _initvalue; \
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__typeof__(_type) _name##_early_map[NR_CPUS] __initdata = \
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{ [0 ... NR_CPUS-1] = _initvalue }; \
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__typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
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#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
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EXPORT_PER_CPU_SYMBOL(_name)
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#define DECLARE_EARLY_PER_CPU(_type, _name) \
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DECLARE_PER_CPU(_type, _name); \
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extern __typeof__(_type) *_name##_early_ptr; \
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extern __typeof__(_type) _name##_early_map[]
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#define early_per_cpu_ptr(_name) (_name##_early_ptr)
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#define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
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#define early_per_cpu(_name, _cpu) \
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*(early_per_cpu_ptr(_name) ? \
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&early_per_cpu_ptr(_name)[_cpu] : \
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&per_cpu(_name, _cpu))
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#else /* !CONFIG_SMP */
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#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
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DEFINE_PER_CPU(_type, _name) = _initvalue
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#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
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EXPORT_PER_CPU_SYMBOL(_name)
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#define DECLARE_EARLY_PER_CPU(_type, _name) \
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DECLARE_PER_CPU(_type, _name)
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#define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
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#define early_per_cpu_ptr(_name) NULL
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/* no early_per_cpu_map() */
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#endif /* !CONFIG_SMP */
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#endif /* _ASM_X86_PERCPU_H */
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