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Date: Tue, 2 Feb 2010 20:00:42 +0100
From: Christoph Hellwig <hch@....de>
To: roland@...hat.com, oleg@...hat.com, akpm@...ux-foundation.org,
starvik@...s.com, jesper.nilsson@...s.com
Cc: linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org
Subject: [PATCH, RFC 13/14] cris arch-v32: use generic ptrace_resume code
Use the generic ptrace_resume code for PTRACE_SYSCALL, PTRACE_CONT,
PTRACE_KILL and PTRACE_SINGLESTEP. This implies defining
arch_has_single_step in <asm/ptrace.h> and implementing the
user_enable_single_step and user_disable_single_step functions, which
also causes the breakpoint information to be cleared on fork, which
could be considered a bug fix.
Also the TIF_SYSCALL_TRACE thread flag is now cleared on PTRACE_KILL
which it previously wasn't which is consistent with all architectures
using the modern ptrace code.
The way breakpoints are disabled is entirely inconsistent
currently, I tried to make some sense of it, but I suspect all of the
content of ptrace_disable should be moved into user_disable_single_step,
this defintively needs some revisting as the current patch changes
behaviour in not quite designed ways.
Signed-off-by: Christoph Hellwig <hch@....de>
Index: linux-2.6/arch/cris/arch-v32/kernel/ptrace.c
===================================================================
--- linux-2.6.orig/arch/cris/arch-v32/kernel/ptrace.c 2010-02-02 19:23:12.314003057 +0100
+++ linux-2.6/arch/cris/arch-v32/kernel/ptrace.c 2010-02-02 19:25:27.396253967 +0100
@@ -78,6 +78,35 @@ int put_reg(struct task_struct *task, un
return 0;
}
+void user_enable_single_step(struct task_struct *child)
+{
+ unsigned long tmp;
+
+ /*
+ * Set up SPC if not set already (in which case we have no other
+ * choice but to trust it).
+ */
+ if (!get_reg(child, PT_SPC)) {
+ /* In case we're stopped in a delay slot. */
+ tmp = get_reg(child, PT_ERP) & ~1;
+ put_reg(child, PT_SPC, tmp);
+ }
+ tmp = get_reg(child, PT_CCS) | SBIT_USER;
+ put_reg(child, PT_CCS, tmp);
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+ put_reg(child, PT_SPC, 0);
+
+ if (!get_debugreg(child->pid, PT_BP_CTRL)) {
+ unsigned long tmp;
+ /* If no h/w bp configured, disable S bit. */
+ tmp = get_reg(child, PT_CCS) & ~SBIT_USER;
+ put_reg(child, PT_CCS, tmp);
+ }
+}
+
/*
* Called by kernel/ptrace.c when detaching.
*
@@ -89,8 +118,7 @@ ptrace_disable(struct task_struct *child
unsigned long tmp;
/* Deconfigure SPC and S-bit. */
- tmp = get_reg(child, PT_CCS) & ~SBIT_USER;
- put_reg(child, PT_CCS, tmp);
+ user_disable_single_step(child);
put_reg(child, PT_SPC, 0);
/* Deconfigure any watchpoints associated with the child. */
@@ -163,83 +191,6 @@ long arch_ptrace(struct task_struct *chi
ret = 0;
break;
- case PTRACE_SYSCALL:
- case PTRACE_CONT:
- ret = -EIO;
-
- if (!valid_signal(data))
- break;
-
- /* Continue means no single-step. */
- put_reg(child, PT_SPC, 0);
-
- if (!get_debugreg(child->pid, PT_BP_CTRL)) {
- unsigned long tmp;
- /* If no h/w bp configured, disable S bit. */
- tmp = get_reg(child, PT_CCS) & ~SBIT_USER;
- put_reg(child, PT_CCS, tmp);
- }
-
- 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;
-
- /* TODO: make sure any pending breakpoint is killed */
- wake_up_process(child);
- ret = 0;
-
- break;
-
- /* Make the child exit by sending it a sigkill. */
- case PTRACE_KILL:
- ret = 0;
-
- if (child->exit_state == EXIT_ZOMBIE)
- break;
-
- child->exit_code = SIGKILL;
-
- /* Deconfigure single-step and h/w bp. */
- ptrace_disable(child);
-
- /* TODO: make sure any pending breakpoint is killed */
- wake_up_process(child);
- break;
-
- /* Set the trap flag. */
- case PTRACE_SINGLESTEP: {
- unsigned long tmp;
- ret = -EIO;
-
- /* Set up SPC if not set already (in which case we have
- no other choice but to trust it). */
- if (!get_reg(child, PT_SPC)) {
- /* In case we're stopped in a delay slot. */
- tmp = get_reg(child, PT_ERP) & ~1;
- put_reg(child, PT_SPC, tmp);
- }
- tmp = get_reg(child, PT_CCS) | SBIT_USER;
- put_reg(child, PT_CCS, tmp);
-
- if (!valid_signal(data))
- break;
-
- clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
-
- /* TODO: set some clever breakpoint mechanism... */
-
- child->exit_code = data;
- wake_up_process(child);
- ret = 0;
- break;
-
- }
-
/* Get all GP registers from the child. */
case PTRACE_GETREGS: {
int i;
Index: linux-2.6/arch/cris/include/arch-v32/arch/ptrace.h
===================================================================
--- linux-2.6.orig/arch/cris/include/arch-v32/arch/ptrace.h 2010-02-02 19:25:39.092254418 +0100
+++ linux-2.6/arch/cris/include/arch-v32/arch/ptrace.h 2010-02-02 19:25:46.173254455 +0100
@@ -108,6 +108,7 @@ struct switch_stack {
#ifdef __KERNEL__
+#define arch_has_single_step() (1)
#define user_mode(regs) (((regs)->ccs & (1 << (U_CCS_BITNR + CCS_SHIFT))) != 0)
#define instruction_pointer(regs) ((regs)->erp)
extern void show_regs(struct pt_regs *);
--
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