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authorAl Viro <viro@zeniv.linux.org.uk>2008-08-18 03:05:42 +0200
committerH. Peter Anvin <hpa@zytor.com>2008-10-23 07:55:20 +0200
commitbb8985586b7a906e116db835c64773b7a7d51663 (patch)
treede93ae58e88cc563d95cc124a73f3930594c6100 /arch/x86/include/asm/percpu.h
parentx86, um: initial part of asm-um move (diff)
downloadlinux-bb8985586b7a906e116db835c64773b7a7d51663.tar.xz
linux-bb8985586b7a906e116db835c64773b7a7d51663.zip
x86, um: ... and asm-x86 move
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/include/asm/percpu.h')
-rw-r--r--arch/x86/include/asm/percpu.h218
1 files changed, 218 insertions, 0 deletions
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
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+++ b/arch/x86/include/asm/percpu.h
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+#ifndef ASM_X86__PERCPU_H
+#define ASM_X86__PERCPU_H
+
+#ifdef CONFIG_X86_64
+#include <linux/compiler.h>
+
+/* Same as asm-generic/percpu.h, except that we store the per cpu offset
+ in the PDA. Longer term the PDA and every per cpu variable
+ should be just put into a single section and referenced directly
+ from %gs */
+
+#ifdef CONFIG_SMP
+#include <asm/pda.h>
+
+#define __per_cpu_offset(cpu) (cpu_pda(cpu)->data_offset)
+#define __my_cpu_offset read_pda(data_offset)
+
+#define per_cpu_offset(x) (__per_cpu_offset(x))
+
+#endif
+#include <asm-generic/percpu.h>
+
+DECLARE_PER_CPU(struct x8664_pda, pda);
+
+/*
+ * These are supposed to be implemented as a single instruction which
+ * operates on the per-cpu data base segment. x86-64 doesn't have
+ * that yet, so this is a fairly inefficient workaround for the
+ * meantime. The single instruction is atomic with respect to
+ * preemption and interrupts, so we need to explicitly disable
+ * interrupts here to achieve the same effect. However, because it
+ * can be used from within interrupt-disable/enable, we can't actually
+ * disable interrupts; disabling preemption is enough.
+ */
+#define x86_read_percpu(var) \
+ ({ \
+ typeof(per_cpu_var(var)) __tmp; \
+ preempt_disable(); \
+ __tmp = __get_cpu_var(var); \
+ preempt_enable(); \
+ __tmp; \
+ })
+
+#define x86_write_percpu(var, val) \
+ do { \
+ preempt_disable(); \
+ __get_cpu_var(var) = (val); \
+ preempt_enable(); \
+ } while(0)
+
+#else /* CONFIG_X86_64 */
+
+#ifdef __ASSEMBLY__
+
+/*
+ * PER_CPU finds an address of a per-cpu variable.
+ *
+ * Args:
+ * var - variable name
+ * reg - 32bit register
+ *
+ * The resulting address is stored in the "reg" argument.
+ *
+ * Example:
+ * PER_CPU(cpu_gdt_descr, %ebx)
+ */
+#ifdef CONFIG_SMP
+#define PER_CPU(var, reg) \
+ movl %fs:per_cpu__##this_cpu_off, reg; \
+ lea per_cpu__##var(reg), reg
+#define PER_CPU_VAR(var) %fs:per_cpu__##var
+#else /* ! SMP */
+#define PER_CPU(var, reg) \
+ movl $per_cpu__##var, reg
+#define PER_CPU_VAR(var) per_cpu__##var
+#endif /* SMP */
+
+#else /* ...!ASSEMBLY */
+
+/*
+ * PER_CPU finds an address of a per-cpu variable.
+ *
+ * Args:
+ * var - variable name
+ * cpu - 32bit register containing the current CPU number
+ *
+ * The resulting address is stored in the "cpu" argument.
+ *
+ * Example:
+ * PER_CPU(cpu_gdt_descr, %ebx)
+ */
+#ifdef CONFIG_SMP
+
+#define __my_cpu_offset x86_read_percpu(this_cpu_off)
+
+/* fs segment starts at (positive) offset == __per_cpu_offset[cpu] */
+#define __percpu_seg "%%fs:"
+
+#else /* !SMP */
+
+#define __percpu_seg ""
+
+#endif /* SMP */
+
+#include <asm-generic/percpu.h>
+
+/* We can use this directly for local CPU (faster). */
+DECLARE_PER_CPU(unsigned long, this_cpu_off);
+
+/* For arch-specific code, we can use direct single-insn ops (they
+ * don't give an lvalue though). */
+extern void __bad_percpu_size(void);
+
+#define percpu_to_op(op, var, val) \
+do { \
+ typedef typeof(var) T__; \
+ if (0) { \
+ T__ tmp__; \
+ tmp__ = (val); \
+ } \
+ switch (sizeof(var)) { \
+ case 1: \
+ asm(op "b %1,"__percpu_seg"%0" \
+ : "+m" (var) \
+ : "ri" ((T__)val)); \
+ break; \
+ case 2: \
+ asm(op "w %1,"__percpu_seg"%0" \
+ : "+m" (var) \
+ : "ri" ((T__)val)); \
+ break; \
+ case 4: \
+ asm(op "l %1,"__percpu_seg"%0" \
+ : "+m" (var) \
+ : "ri" ((T__)val)); \
+ break; \
+ default: __bad_percpu_size(); \
+ } \
+} while (0)
+
+#define percpu_from_op(op, var) \
+({ \
+ typeof(var) ret__; \
+ switch (sizeof(var)) { \
+ case 1: \
+ asm(op "b "__percpu_seg"%1,%0" \
+ : "=r" (ret__) \
+ : "m" (var)); \
+ break; \
+ case 2: \
+ asm(op "w "__percpu_seg"%1,%0" \
+ : "=r" (ret__) \
+ : "m" (var)); \
+ break; \
+ case 4: \
+ asm(op "l "__percpu_seg"%1,%0" \
+ : "=r" (ret__) \
+ : "m" (var)); \
+ break; \
+ default: __bad_percpu_size(); \
+ } \
+ ret__; \
+})
+
+#define x86_read_percpu(var) percpu_from_op("mov", per_cpu__##var)
+#define x86_write_percpu(var, val) percpu_to_op("mov", per_cpu__##var, val)
+#define x86_add_percpu(var, val) percpu_to_op("add", per_cpu__##var, val)
+#define x86_sub_percpu(var, val) percpu_to_op("sub", per_cpu__##var, val)
+#define x86_or_percpu(var, val) percpu_to_op("or", per_cpu__##var, val)
+#endif /* !__ASSEMBLY__ */
+#endif /* !CONFIG_X86_64 */
+
+#ifdef CONFIG_SMP
+
+/*
+ * Define the "EARLY_PER_CPU" macros. These are used for some per_cpu
+ * variables that are initialized and accessed before there are per_cpu
+ * areas allocated.
+ */
+
+#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
+ DEFINE_PER_CPU(_type, _name) = _initvalue; \
+ __typeof__(_type) _name##_early_map[NR_CPUS] __initdata = \
+ { [0 ... NR_CPUS-1] = _initvalue }; \
+ __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map
+
+#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
+ EXPORT_PER_CPU_SYMBOL(_name)
+
+#define DECLARE_EARLY_PER_CPU(_type, _name) \
+ DECLARE_PER_CPU(_type, _name); \
+ extern __typeof__(_type) *_name##_early_ptr; \
+ extern __typeof__(_type) _name##_early_map[]
+
+#define early_per_cpu_ptr(_name) (_name##_early_ptr)
+#define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx])
+#define early_per_cpu(_name, _cpu) \
+ (early_per_cpu_ptr(_name) ? \
+ early_per_cpu_ptr(_name)[_cpu] : \
+ per_cpu(_name, _cpu))
+
+#else /* !CONFIG_SMP */
+#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \
+ DEFINE_PER_CPU(_type, _name) = _initvalue
+
+#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \
+ EXPORT_PER_CPU_SYMBOL(_name)
+
+#define DECLARE_EARLY_PER_CPU(_type, _name) \
+ DECLARE_PER_CPU(_type, _name)
+
+#define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu)
+#define early_per_cpu_ptr(_name) NULL
+/* no early_per_cpu_map() */
+
+#endif /* !CONFIG_SMP */
+
+#endif /* ASM_X86__PERCPU_H */