Commit 01463374 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'cpu-to-thread_info-v5.16-rc1' of... 

Merge tag 'cpu-to-thread_info-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull thread_info update to move 'cpu' back from task_struct from Kees Cook:
 "Cross-architecture update to move task_struct::cpu back into
  thread_info on arm64, x86, s390, powerpc, and riscv. All Acked by arch
  maintainers.

  Quoting Ard Biesheuvel:

     'Move task_struct::cpu back into thread_info

      Keeping CPU in task_struct is problematic for architectures that
      define raw_smp_processor_id() in terms of this field, as it
      requires linux/sched.h to be included, which causes a lot of pain
      in terms of circular dependencies (aka 'header soup')

      This series moves it back into thread_info (where it came from)
      for all architectures that enable THREAD_INFO_IN_TASK, addressing
      the header soup issue as well as some pointless differences in the
      implementations of task_cpu() and set_task_cpu()'"

* tag 'cpu-to-thread_info-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  riscv: rely on core code to keep thread_info::cpu updated
  powerpc: smp: remove hack to obtain offset of task_struct::cpu
  sched: move CPU field back into thread_info if THREAD_INFO_IN_TASK=y
  powerpc: add CPU field to struct thread_info
  s390: add CPU field to struct thread_info
  x86: add CPU field to struct thread_info
  arm64: add CPU field to struct thread_info
parents 03feb7c5 d9f2a53f

arch/arm64/include/asm/thread_info.h

+1 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ struct thread_info { 
	void			*scs_base;

	void			*scs_sp;

#endif

	u32			cpu;

};



#define thread_saved_pc(tsk)	\

arch/arm64/kernel/asm-offsets.c

+1 −1
Original line number Diff line number Diff line
@@ -28,8 +28,8 @@ 
int main(void)

{

  DEFINE(TSK_ACTIVE_MM,		offsetof(struct task_struct, active_mm));

  DEFINE(TSK_CPU,		offsetof(struct task_struct, cpu));

  BLANK();

  DEFINE(TSK_TI_CPU,		offsetof(struct task_struct, thread_info.cpu));

  DEFINE(TSK_TI_FLAGS,		offsetof(struct task_struct, thread_info.flags));

  DEFINE(TSK_TI_PREEMPT,	offsetof(struct task_struct, thread_info.preempt_count));

#ifdef CONFIG_ARM64_SW_TTBR0_PAN

arch/arm64/kernel/head.S

+1 −1
Original line number Diff line number Diff line
@@ -412,7 +412,7 @@ SYM_FUNC_END(__create_page_tables) 
	scs_load \tsk



	adr_l	\tmp1, __per_cpu_offset

	ldr	w\tmp2, [\tsk, #TSK_CPU]

	ldr	w\tmp2, [\tsk, #TSK_TI_CPU]

	ldr	\tmp1, [\tmp1, \tmp2, lsl #3]

	set_this_cpu_offset \tmp1

	.endm

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)