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authorLinus Torvalds <torvalds@linux-foundation.org>2008-08-15 09:19:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-08-15 09:19:40 -0700
commit024b246ed24492d6c2ee14c34d742b137fce1b94 (patch)
tree428444950025503218c96b03c86f749403626dec /arch/alpha/include/asm/percpu.h
parent9419fc1c957d600093baaea247fef23cca3b4e93 (diff)
alpha: move include/asm-alpha to arch/alpha/include/asm
Sam Ravnborg did the build-test that the direct header file move works, I'm just committing it. This is a pure move: mkdir arch/alpha/include git mv include/asm-alpha arch/alpha/include/asm with no other changes. Requested-and-tested-by: Sam Ravnborg <sam@ravnborg.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/alpha/include/asm/percpu.h')
-rw-r--r--arch/alpha/include/asm/percpu.h78
1 files changed, 78 insertions, 0 deletions
diff --git a/arch/alpha/include/asm/percpu.h b/arch/alpha/include/asm/percpu.h
new file mode 100644
index 00000000000..3495e8e00d7
--- /dev/null
+++ b/arch/alpha/include/asm/percpu.h
@@ -0,0 +1,78 @@
+#ifndef __ALPHA_PERCPU_H
+#define __ALPHA_PERCPU_H
+#include <linux/compiler.h>
+#include <linux/threads.h>
+
+/*
+ * Determine the real variable name from the name visible in the
+ * kernel sources.
+ */
+#define per_cpu_var(var) per_cpu__##var
+
+#ifdef CONFIG_SMP
+
+/*
+ * per_cpu_offset() is the offset that has to be added to a
+ * percpu variable to get to the instance for a certain processor.
+ */
+extern unsigned long __per_cpu_offset[NR_CPUS];
+
+#define per_cpu_offset(x) (__per_cpu_offset[x])
+
+#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
+#ifdef CONFIG_DEBUG_PREEMPT
+#define my_cpu_offset per_cpu_offset(smp_processor_id())
+#else
+#define my_cpu_offset __my_cpu_offset
+#endif
+
+#ifndef MODULE
+#define SHIFT_PERCPU_PTR(var, offset) RELOC_HIDE(&per_cpu_var(var), (offset))
+#define PER_CPU_ATTRIBUTES
+#else
+/*
+ * To calculate addresses of locally defined variables, GCC uses 32-bit
+ * displacement from the GP. Which doesn't work for per cpu variables in
+ * modules, as an offset to the kernel per cpu area is way above 4G.
+ *
+ * This forces allocation of a GOT entry for per cpu variable using
+ * ldq instruction with a 'literal' relocation.
+ */
+#define SHIFT_PERCPU_PTR(var, offset) ({ \
+ extern int simple_identifier_##var(void); \
+ unsigned long __ptr, tmp_gp; \
+ asm ( "br %1, 1f \n\
+ 1: ldgp %1, 0(%1) \n\
+ ldq %0, per_cpu__" #var"(%1)\t!literal" \
+ : "=&r"(__ptr), "=&r"(tmp_gp)); \
+ (typeof(&per_cpu_var(var)))(__ptr + (offset)); })
+
+#define PER_CPU_ATTRIBUTES __used
+
+#endif /* MODULE */
+
+/*
+ * A percpu variable may point to a discarded regions. The following are
+ * established ways to produce a usable pointer from the percpu variable
+ * offset.
+ */
+#define per_cpu(var, cpu) \
+ (*SHIFT_PERCPU_PTR(var, per_cpu_offset(cpu)))
+#define __get_cpu_var(var) \
+ (*SHIFT_PERCPU_PTR(var, my_cpu_offset))
+#define __raw_get_cpu_var(var) \
+ (*SHIFT_PERCPU_PTR(var, __my_cpu_offset))
+
+#else /* ! SMP */
+
+#define per_cpu(var, cpu) (*((void)(cpu), &per_cpu_var(var)))
+#define __get_cpu_var(var) per_cpu_var(var)
+#define __raw_get_cpu_var(var) per_cpu_var(var)
+
+#define PER_CPU_ATTRIBUTES
+
+#endif /* SMP */
+
+#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu_var(name)
+
+#endif /* __ALPHA_PERCPU_H */