linux-kernel - Re: [PATCH 5/9] RISC-V: Task implementation

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Date:   Thu, 29 Jun 2017 15:52:43 -0700 (PDT)
From:   Palmer Dabbelt <palmer@...belt.com>
To:     tklauser@...tanz.ch
CC:     albert@...ive.com
Subject:     Re: [PATCH 5/9] RISC-V: Task implementation

On Thu, 29 Jun 2017 01:22:23 PDT (-0700), tklauser@...tanz.ch wrote:
> On 2017-06-28 at 20:55:34 +0200, Palmer Dabbelt <palmer@...belt.com> wrote:
> [...]
>> diff --git a/arch/riscv/include/asm/kprobes.h b/arch/riscv/include/asm/kprobes.h
>> new file mode 100644
>> index 000000000000..1190de7a0f74
>> --- /dev/null
>> +++ b/arch/riscv/include/asm/kprobes.h
>> @@ -0,0 +1,22 @@
>> +/*
>> + * Copyright (C) 2017 SiFive
>> + *
>> + *   This program is free software; you can redistribute it and/or
>> + *   modify it under the terms of the GNU General Public License
>> + *   as published by the Free Software Foundation, version 2.
>> + *
>> + *   This program is distributed in the hope that it will be useful,
>> + *   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + *   GNU General Public License for more details.
>> + */
>> +
>> +
>> +#ifndef ASM_RISCV_KPROBES_H
>> +#define ASM_RISCV_KPROBES_H
>> +
>> +#ifdef CONFIG_KPROBES
>> +#error "RISC-V doesn't skpport CONFIG_KPROBES"
>
> Typo: s/skpport/support/

Thanks.

>> +#endif
>> +
>> +#endif
>> diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
>> new file mode 100644
>> index 000000000000..65aa014db9b4
>> --- /dev/null
>> +++ b/arch/riscv/include/asm/processor.h
>> @@ -0,0 +1,102 @@
>> +/*
>> + * Copyright (C) 2012 Regents of the University of California
>> + *
>> + *   This program is free software; you can redistribute it and/or
>> + *   modify it under the terms of the GNU General Public License
>> + *   as published by the Free Software Foundation, version 2.
>> + *
>> + *   This program is distributed in the hope that it will be useful,
>> + *   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + *   GNU General Public License for more details.
>> + */
>> +
>> +#ifndef _ASM_RISCV_PROCESSOR_H
>> +#define _ASM_RISCV_PROCESSOR_H
>> +
>> +#include <linux/const.h>
>> +
>> +#include <asm/ptrace.h>
>> +
>> +/*
>> + * This decides where the kernel will search for a free chunk of vm
>> + * space during mmap's.
>> + */
>> +#define TASK_UNMAPPED_BASE	PAGE_ALIGN(TASK_SIZE >> 1)
>> +
>> +#ifdef __KERNEL__
>> +#define STACK_TOP		TASK_SIZE
>> +#define STACK_TOP_MAX		STACK_TOP
>> +#define STACK_ALIGN		16
>> +#endif /* __KERNEL__ */
>> +
>> +#ifndef __ASSEMBLY__
>> +
>> +struct task_struct;
>> +struct pt_regs;
>> +
>> +/*
>> + * Default implementation of macro that returns current
>> + * instruction pointer ("program counter").
>> + */
>> +#define current_text_addr()	({ __label__ _l; _l: &&_l; })
>> +
>> +/* CPU-specific state of a task */
>> +struct thread_struct {
>> +	/* Callee-saved registers */
>> +	unsigned long ra;
>> +	unsigned long sp;	/* Kernel mode stack */
>> +	unsigned long s[12];	/* s[0]: frame pointer */
>> +	struct __riscv_d_ext_state fstate;
>> +};
>> +
>> +#define INIT_THREAD {					\
>> +	.sp = sizeof(init_stack) + (long)&init_stack,	\
>> +}
>> +
>> +/* Return saved (kernel) PC of a blocked thread. */
>> +#define thread_saved_pc(t)	((t)->thread.ra)
>> +#define thread_saved_sp(t)	((t)->thread.sp)
>> +#define thread_saved_fp(t)	((t)->thread.s[0])
>
> These aren't needed outside of arch-specific code (anymore) and the
> riscv port doesn't seem to be using them, so they can be omitted.

Great.  I've removed them, I'll include that in the v4

  diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
  index 53768048b9de..b62873633bde 100644
  --- a/arch/riscv/include/asm/processor.h
  +++ b/arch/riscv/include/asm/processor.h
  @@ -52,11 +52,6 @@ struct thread_struct {
          .sp = sizeof(init_stack) + (long)&init_stack,   \
   }

  -/* Return saved (kernel) PC of a blocked thread. */
  -#define thread_saved_pc(t)     ((t)->thread.ra)
  -#define thread_saved_sp(t)     ((t)->thread.sp)
  -#define thread_saved_fp(t)     ((t)->thread.s[0])
  -
   #define task_pt_regs(tsk)                                              \
          ((struct pt_regs *)(task_stack_page(tsk) + THREAD_SIZE          \
                              - ALIGN(sizeof(struct pt_regs), STACK_ALIGN)))

Thanks!