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-rw-r--r--include/asm-x86/percpu.h26
-rw-r--r--include/asm-x86/setup.h1
2 files changed, 27 insertions, 0 deletions
diff --git a/include/asm-x86/percpu.h b/include/asm-x86/percpu.h
index 912a3a17b9db..4e91ee1e37aa 100644
--- a/include/asm-x86/percpu.h
+++ b/include/asm-x86/percpu.h
@@ -22,6 +22,32 @@
22 22
23DECLARE_PER_CPU(struct x8664_pda, pda); 23DECLARE_PER_CPU(struct x8664_pda, pda);
24 24
25/*
26 * These are supposed to be implemented as a single instruction which
27 * operates on the per-cpu data base segment. x86-64 doesn't have
28 * that yet, so this is a fairly inefficient workaround for the
29 * meantime. The single instruction is atomic with respect to
30 * preemption and interrupts, so we need to explicitly disable
31 * interrupts here to achieve the same effect. However, because it
32 * can be used from within interrupt-disable/enable, we can't actually
33 * disable interrupts; disabling preemption is enough.
34 */
35#define x86_read_percpu(var) \
36 ({ \
37 typeof(per_cpu_var(var)) __tmp; \
38 preempt_disable(); \
39 __tmp = __get_cpu_var(var); \
40 preempt_enable(); \
41 __tmp; \
42 })
43
44#define x86_write_percpu(var, val) \
45 do { \
46 preempt_disable(); \
47 __get_cpu_var(var) = (val); \
48 preempt_enable(); \
49 } while(0)
50
25#else /* CONFIG_X86_64 */ 51#else /* CONFIG_X86_64 */
26 52
27#ifdef __ASSEMBLY__ 53#ifdef __ASSEMBLY__
diff --git a/include/asm-x86/setup.h b/include/asm-x86/setup.h
index 90ab2225e71b..659492624e74 100644
--- a/include/asm-x86/setup.h
+++ b/include/asm-x86/setup.h
@@ -76,6 +76,7 @@ extern unsigned long init_pg_tables_start;
76extern unsigned long init_pg_tables_end; 76extern unsigned long init_pg_tables_end;
77 77
78#else 78#else
79void __init x86_64_init_pda(void);
79void __init x86_64_start_kernel(char *real_mode); 80void __init x86_64_start_kernel(char *real_mode);
80void __init x86_64_start_reservations(char *real_mode_data); 81void __init x86_64_start_reservations(char *real_mode_data);
81 82