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x86: use linker to offset symbols by __per_cpu_load

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Impact: cleanup and bug fix

Use the linker to create symbols for certain per-cpu variables
that are offset by __per_cpu_load.  This allows the removal of
the runtime fixup of the GDT pointer, which fixes a bug with
resume reported by Jiri Slaby.

Reported-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Brian Gerst
2009-02-08 09:58:39 -05:00
committed by Ingo Molnar
parent d3770449d3
commit 2add8e235c
5 changed files with 35 additions and 24 deletions
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22
arch/x86/include/asm/percpu.h
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@@ -34,6 +34,12 @@
#define PER_CPU_VAR(var) per_cpu__##var
#endif /* SMP */
#ifdef CONFIG_X86_64_SMP
#define INIT_PER_CPU_VAR(var) init_per_cpu__##var
#else
#define INIT_PER_CPU_VAR(var) per_cpu__##var
#endif
#else /* ...!ASSEMBLY */
#include <linux/stringify.h>
@@ -45,6 +51,22 @@
#define __percpu_arg(x) "%" #x
#endif
/*
* Initialized pointers to per-cpu variables needed for the boot
* processor need to use these macros to get the proper address
* offset from __per_cpu_load on SMP.
*
* There also must be an entry in vmlinux_64.lds.S
*/
#define DECLARE_INIT_PER_CPU(var) \
extern typeof(per_cpu_var(var)) init_per_cpu_var(var)
#ifdef CONFIG_X86_64_SMP
#define init_per_cpu_var(var) init_per_cpu__##var
#else
#define init_per_cpu_var(var) per_cpu_var(var)
#endif
/* For arch-specific code, we can use direct single-insn ops (they
* don't give an lvalue though). */
extern void __bad_percpu_size(void);