Re: m68k ptrace code

Andreas Schwab
2009-05-11T09:32:09Z

Roland McGrath <roland@redhat.com> writes:

> 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.

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