Commit 336868af authored by Ard Biesheuvel's avatar Ard Biesheuvel
Browse files

powerpc: smp: remove hack to obtain offset of task_struct::cpu 



Instead of relying on awful hacks to obtain the offset of the cpu field
in struct task_struct, move it back into struct thread_info, which does
not create the same level of circular dependency hell when trying to
include the header file that defines it.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent bcf9033e

arch/powerpc/Makefile

+0 −11
Original line number Diff line number Diff line
@@ -446,17 +446,6 @@ else 
endif

endif



ifdef CONFIG_SMP

ifdef CONFIG_PPC32

prepare: task_cpu_prepare



PHONY += task_cpu_prepare

task_cpu_prepare: prepare0

	$(eval KBUILD_CFLAGS += -D_TASK_CPU=$(shell awk '{if ($$2 == "TASK_CPU") print $$3;}' include/generated/asm-offsets.h))



endif # CONFIG_PPC32

endif # CONFIG_SMP



PHONY += checkbin

# Check toolchain versions:

# - gcc-4.6 is the minimum kernel-wide version so nothing required.

arch/powerpc/include/asm/smp.h

+1 −16
Original line number Diff line number Diff line
@@ -87,22 +87,7 @@ int is_cpu_dead(unsigned int cpu); 
/* 32-bit */

extern int smp_hw_index[];



/*

 * This is particularly ugly: it appears we can't actually get the definition

 * of task_struct here, but we need access to the CPU this task is running on.

 * Instead of using task_struct we're using _TASK_CPU which is extracted from

 * asm-offsets.h by kbuild to get the current processor ID.

 *

 * This also needs to be safeguarded when building asm-offsets.s because at

 * that time _TASK_CPU is not defined yet. It could have been guarded by

 * _TASK_CPU itself, but we want the build to fail if _TASK_CPU is missing

 * when building something else than asm-offsets.s

 */

#ifdef GENERATING_ASM_OFFSETS

#define raw_smp_processor_id()		(0)

#else

#define raw_smp_processor_id()		(*(unsigned int *)((void *)current + _TASK_CPU))

#endif

#define raw_smp_processor_id()		(current_thread_info()->cpu)

#define hard_smp_processor_id() 	(smp_hw_index[smp_processor_id()])



static inline int get_hard_smp_processor_id(int cpu)

arch/powerpc/kernel/asm-offsets.c

+0 −2
Original line number Diff line number Diff line
@@ -9,8 +9,6 @@ 
 * #defines from the assembly-language output.

 */



#define GENERATING_ASM_OFFSETS	/* asm/smp.h */



#include <linux/compat.h>

#include <linux/signal.h>

#include <linux/sched.h>