hi all,
i found that in kernel 2.6.22 the implementation of "current" macro
of i386 machines is different from previous versions'. and now it became
this:
[include/asm-i386/current.h]
...
#define __percpu_seg "%%fs:"
#else /* !SMP */
#include <asm-generic/percpu.h>
#define __percpu_seg ""
#endif /* SMP */
...
DECLARE_PER_CPU(struct task_struct *, current_task);
static __always_inline struct task_struct *get_current(void)
{
return x86_read_percpu(current_task);
}
#define current get_current()
...
[include/asm-i386/percpu.h]
...
#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)
...
can anyone tell me how does the code above give me current task_struct
structure? and what about current_thread_info() function? is it useless now?
--
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