Re: m68k ptrace code

Andreas Schwab
2009-05-10T19:32:34Z

Christoph Hellwig <hch@lst.de> writes:

> we're trying to get all architectures converted to the new ptrace world
> order where a lot more code is in the common kernel/ptrace.c file
> instead of in the architecture and the boundaries are much cleaner.
> Can you take a look at
>
> http://sourceware.org/systemtap/wiki/utrace/arch/HowTo
>
> and see how feasible it is to convert m68k?

Here's a patch for the first step.

Andreas.
---
>From 6b28b94592f8bb81617a315fcdc7d564ea61740a 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_{SYSCALL,CONT,SINGLESTEP}

This defines user_enable_single_step, user_enable_block_step and
user_disable_single_step so that PTRACE_{SYSCALL,CONT,SINGLESTEP} can be
handled by generic ptrace_request.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
---
arch/m68k/include/asm/ptrace.h | 11 ++++++++
arch/m68k/kernel/ptrace.c | 50 ++++++++++++++++-----------------------
2 files changed, 32 insertions(+), 29 deletions(-)

diff --git a/arch/m68k/include/asm/ptrace.h b/arch/m68k/include/asm/ptrace.h
index 8c9194b..de260e6 100644
--- a/arch/m68k/include/asm/ptrace.h
+++ b/arch/m68k/include/asm/ptrace.h
@@ -82,6 +82,17 @@ 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..2a04cd2 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)
@@ -118,6 +120,24 @@ 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;
@@ -185,20 +205,6 @@ 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
@@ -212,20 +218,6 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
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