Re: m68k ptrace code

[Andreas Schwab <schwab@linux-m68k.org>]

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


-- 
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."