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riscv: Cleanup unnecessary define in asm-offset.c

PATCH In review [email protected] 2 participants 2 messages Jul 12, 2020 – Jul 22, 2020

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RISC-V C-sky architecture
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#0 lore raw

PATCH 1/1 riscv: Cleanup unnecessary define in asm-offset.c

From: Guo Ren <[email protected]>

- TASK_THREAD_SP is duplicated define
- TASK_STACK is no use at all
- Don't worry about thread_info's offset in task_struct, have a look on comment in include/linux/sched.h:

struct task_struct {
	/*
	 * For reasons of header soup (see current_thread_info()), this
	 * must be the first element of task_struct.
	 */
	struct thread_info		thread_info;
Signed-off-by Guo Ren <[email protected]>
---
 arch/riscv/kernel/asm-offsets.c | 3 ---
 arch/riscv/kernel/entry.S       | 5 -----
 2 files changed, 8 deletions(-)
arch/riscv/kernel/asm-offsets.c +0 -3
index 07cb9c1..db20344 100644
@@ -27,9 +27,6 @@ void asm_offsets(void)
 	OFFSET(TASK_THREAD_S9, task_struct, thread.s[9]);
 	OFFSET(TASK_THREAD_S10, task_struct, thread.s[10]);
 	OFFSET(TASK_THREAD_S11, task_struct, thread.s[11]);
-	OFFSET(TASK_THREAD_SP, task_struct, thread.sp);
-	OFFSET(TASK_STACK, task_struct, stack);
-	OFFSET(TASK_TI, task_struct, thread_info);
 	OFFSET(TASK_TI_FLAGS, task_struct, thread_info.flags);
 	OFFSET(TASK_TI_PREEMPT_COUNT, task_struct, thread_info.preempt_count);
 	OFFSET(TASK_TI_KERNEL_SP, task_struct, thread_info.kernel_sp);
arch/riscv/kernel/entry.S +0 -5
index cae7e6d..3e8707e 100644
@@ -389,12 +389,7 @@ ENTRY(__switch_to)
 	lw a4, TASK_TI_CPU(a1)
 	sw a3, TASK_TI_CPU(a1)
 	sw a4, TASK_TI_CPU(a0)
-#if TASK_TI != 0
-#error "TASK_TI != 0: tp will contain a 'struct thread_info', not a 'struct task_struct' so get_current() won't work."
-	addi tp, a1, TASK_TI
-#else
 	move tp, a1
-#endif
 	ret
 ENDPROC(__switch_to)
Signature · 1 line
2.7.4
Reviewed-by on v1 1/1
#1 lore raw
Quoted 39 lines · On Sun, 12 Jul 2020 06:41:49 PDT (-0700), [email protected] wrote:

From: Guo Ren <[email protected]>

- TASK_THREAD_SP is duplicated define
- TASK_STACK is no use at all
- Don't worry about thread_info's offset in task_struct, have a look on comment in include/linux/sched.h:

struct task_struct {
	/*
	 * For reasons of header soup (see current_thread_info()), this
	 * must be the first element of task_struct.
	 */
	struct thread_info		thread_info;
Signed-off-by Guo Ren <[email protected]>
---
 arch/riscv/kernel/asm-offsets.c | 3 ---
 arch/riscv/kernel/entry.S       | 5 -----
 2 files changed, 8 deletions(-)
arch/riscv/kernel/asm-offsets.c +0 -3
index 07cb9c1..db20344 100644
@@ -27,9 +27,6 @@ void asm_offsets(void)
 	OFFSET(TASK_THREAD_S9, task_struct, thread.s[9]);
 	OFFSET(TASK_THREAD_S10, task_struct, thread.s[10]);
 	OFFSET(TASK_THREAD_S11, task_struct, thread.s[11]);
-	OFFSET(TASK_THREAD_SP, task_struct, thread.sp);
-	OFFSET(TASK_STACK, task_struct, stack);
-	OFFSET(TASK_TI, task_struct, thread_info);
 	OFFSET(TASK_TI_FLAGS, task_struct, thread_info.flags);
 	OFFSET(TASK_TI_PREEMPT_COUNT, task_struct, thread_info.preempt_count);
 	OFFSET(TASK_TI_KERNEL_SP, task_struct, thread_info.kernel_sp);
arch/riscv/kernel/entry.S +0 -0
index cae7e6d..3e8707e 100644

arch/riscv/kernel/entry.S ENTRY(__switch_to) · line 397

Quoted 9 lines
arch/riscv/kernel/entry.S +0 -5
@@ -389,12 +389,7 @@ ENTRY(__switch_to)
 	lw a4, TASK_TI_CPU(a1)
 	sw a3, TASK_TI_CPU(a1)
 	sw a4, TASK_TI_CPU(a0)
-#if TASK_TI != 0
-#error "TASK_TI != 0: tp will contain a 'struct thread_info', not a 'struct task_struct' so get_current() won't work."
-	addi tp, a1, TASK_TI
-#else
 	move tp, a1
-#endif

Seems reasonable. That was really there to save anyone who got bit by the conversion to to THREAD_INFO_IN_TASK.

I've added a comment and put this on for-next.

Thanks!

arch/riscv/kernel/entry.S ENTRY(__switch_to) · line 394

Quoted 2 lines
arch/riscv/kernel/entry.S +0 -0
 	ret
 ENDPROC(__switch_to)
Reviewed-by Palmer Dabbelt <[email protected]>