Re: m68k ptrace code

Christoph Hellwig
2009-08-05T15:28:12Z

Hi Andreas,

On Mon, May 11, 2009 at 11:32:05AM +0200, Andreas Schwab wrote:
> > Looks good to me, except you also want to nix PTRACE_KILL from your switch
> > so the generic code handles it. Same goes for {PEEK,POKE}{DATA,TEXT} too.
> > Also note that you have to define a PTRACE_SINGLEBLOCK value in
> > asm/ptrace.h (new request code in your ptrace syscall ABI) to make
> > user_enable_block_step() get used by anything.
>
> Thanks for your comments. I have made these changes and verified with
> the ptrace testsuite that the singleblock request works correctly.
> There are a few failures in the testsuite, which I haven't analyzed yet,
> but none are regressions.

Any reason why this has never been commited?

>
> Andreas.
> ---
> >From 2fd8c8e890bb4cff1175a7e37cc8cafbe663ef8a Mon Sep 17 00:00:00 2001
> From: Andreas Schwab <schwab@linux-m68k.org>
> Date: Sun, 10 May 2009 21:14:52 +0200
> Subject: [PATCH] m68k: use generic code for ptrace requests
>
> Remove all but PTRACE_{PEEK,POKE}USR and PTRACE_{GET,SET}{REGS,FPREGS}
> from arch_ptrace and let the rest be handled by generic code. Define
> PTRACE_SINGLEBLOCK to enable singleblock tracing.
>
> Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
> ---
> arch/m68k/include/asm/ptrace.h | 13 +++++++
> arch/m68k/kernel/ptrace.c | 75 +++++++++++----------------------------
> 2 files changed, 34 insertions(+), 54 deletions(-)
>
> diff --git a/arch/m68k/include/asm/ptrace.h b/arch/m68k/include/asm/ptrace.h
> index 8c9194b..eef9309 100644
> --- a/arch/m68k/include/asm/ptrace.h
> +++ b/arch/m68k/include/asm/ptrace.h
> @@ -71,6 +71,8 @@ struct switch_stack {
> #define PTRACE_GETFPREGS 14
> #define PTRACE_SETFPREGS 15
>
> +#define PTRACE_SINGLEBLOCK 33 /* resume execution until next branch */
> +
> #ifdef __KERNEL__
>
> #ifndef PS_S
> @@ -82,6 +84,17 @@ struct switch_stack {
> #define instruction_pointer(regs) ((regs)->pc)
> #define profile_pc(regs) instruction_pointer(regs)
> extern void show_regs(struct pt_regs *);
> +
> +/*
> + * These are defined as per linux/ptrace.h, which see.
> + */
> +#define arch_has_single_step() (1)
> +extern void user_enable_single_step(struct task_struct *);
> +extern void user_disable_single_step(struct task_struct *);
> +
> +#define arch_has_block_step() (1)
> +extern void user_enable_block_step(struct task_struct *);
> +
> #endif /* __KERNEL__ */
> #endif /* __ASSEMBLY__ */
> #endif /* _M68K_PTRACE_H */
> diff --git a/arch/m68k/kernel/ptrace.c b/arch/m68k/kernel/ptrace.c
> index 2075543..bd08420 100644
> --- a/arch/m68k/kernel/ptrace.c
> +++ b/arch/m68k/kernel/ptrace.c
> @@ -35,7 +35,9 @@
> #define SR_MASK 0x001f
>
> /* sets the trace bits. */
> -#define TRACE_BITS 0x8000
> +#define TRACE_BITS 0xC000
> +#define T1_BIT 0x8000
> +#define T0_BIT 0x4000
>
> /* Find the stack offset for a register, relative to thread.esp0. */
> #define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg)
> @@ -118,18 +120,30 @@ void ptrace_disable(struct task_struct *child)
> singlestep_disable(child);
> }
>
> +void user_enable_single_step(struct task_struct *child)
> +{
> + unsigned long tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
> + put_reg(child, PT_SR, tmp | (T1_BIT << 16));
> + set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
> +}
> +
> +void user_enable_block_step(struct task_struct *child)
> +{
> + unsigned long tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
> + put_reg(child, PT_SR, tmp | (T0_BIT << 16));
> +}
> +
> +void user_disable_single_step(struct task_struct *child)
> +{
> + singlestep_disable(child);
> +}
> +
> long arch_ptrace(struct task_struct *child, long request, long addr, long data)
> {
> unsigned long tmp;
> int i, ret = 0;
>
> switch (request) {
> - /* when I and D space are separate, these will need to be fixed. */
> - case PTRACE_PEEKTEXT: /* read word at location addr. */
> - case PTRACE_PEEKDATA:
> - ret = generic_ptrace_peekdata(child, addr, data);
> - break;
> -
> /* read the word at location addr in the USER area. */
> case PTRACE_PEEKUSR:
> if (addr & 3)
> @@ -153,12 +167,6 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
> ret = put_user(tmp, (unsigned long *)data);
> break;
>
> - /* when I and D space are separate, this will have to be fixed. */
> - case PTRACE_POKETEXT: /* write the word at location addr. */
> - case PTRACE_POKEDATA:
> - ret = generic_ptrace_pokedata(child, addr, data);
> - break;
> -
> case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
> if (addr & 3)
> goto out_eio;
> @@ -185,47 +193,6 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
> goto out_eio;
> break;
>
> - case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
> - case PTRACE_CONT: /* restart after signal. */
> - if (!valid_signal(data))
> - goto out_eio;
> -
> - if (request == PTRACE_SYSCALL)
> - set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
> - else
> - clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
> - child->exit_code = data;
> - singlestep_disable(child);
> - wake_up_process(child);
> - break;
> -
> - /*
> - * make the child exit. Best I can do is send it a sigkill.
> - * perhaps it should be put in the status that it wants to
> - * exit.
> - */
> - case PTRACE_KILL:
> - if (child->exit_state == EXIT_ZOMBIE) /* already dead */
> - break;
> - child->exit_code = SIGKILL;
> - singlestep_disable(child);
> - wake_up_process(child);
> - break;
> -
> - case PTRACE_SINGLESTEP: /* set the trap flag. */
> - if (!valid_signal(data))
> - goto out_eio;
> -
> - clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
> - tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
> - put_reg(child, PT_SR, tmp);
> - set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
> -
> - child->exit_code = data;
> - /* give it a chance to run. */
> - wake_up_process(child);
> - break;
> -
> case PTRACE_GETREGS: /* Get all gp regs from the child. */
> for (i = 0; i < 19; i++) {
> tmp = get_reg(child, i);
> --
> 1.6.3
>
>
> --
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
> "And now for something completely different."
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