[POWERPC] ptrace shouldn't touch FP exec mode

One of the gratuitous difference between 32 and 64-bit ptrace is
whether you can whack the MSR:FE0 and FE1 bits from ptrace.  This
patch forbids it unconditionally.  In addition, the 64-bit kernels
used to return the exception mode in the MSR on reads, but 32-bit
kernels didn't.  This patch makes it return those bits on both.

Finally, since ptrace-ppc32.h and ptrace-ppc64.h are mostly empty now, and
since the previous patch made ptrace32.c no longer need the MSR_DEBUGCHANGE
definition, we just remove those 2 files and move back the remaining bits
to ptrace.c (they were short lived heh ?).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/ptrace-ppc32.h

-/*
- *    Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration
- *    Extracted from ptrace.c and ptrace32.c
- *
- * This file is subject to the terms and conditions of the GNU General
- * Public License.  See the file README.legal in the main directory of
- * this archive for more details.
- */
-
-#ifndef _POWERPC_PTRACE_PPC32_H
-#define _POWERPC_PTRACE_PPC32_H
-
-/*
- * Set of msr bits that gdb can change on behalf of a process.
- */
-#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
-#define MSR_DEBUGCHANGE	0
-#else
-#define MSR_DEBUGCHANGE	(MSR_SE | MSR_BE)
-#endif
-
-/*
- * Max register writeable via put_reg
- */
-#define PT_MAX_PUT_REG	PT_MQ
-
-/*
- * Munging of MSR on return from get_regs
- *
- * Nothing to do on ppc32
- */
-#define PT_MUNGE_MSR(msr, task)	(msr)
-
-
-#endif /* _POWERPC_PTRACE_PPC32_H */

arch/powerpc/kernel/ptrace-ppc64.h

-/*
- *    Copyright (c) 2002 Stephen Rothwell, IBM Coproration
- *    Extracted from ptrace.c and ptrace32.c
- *
- * This file is subject to the terms and conditions of the GNU General
- * Public License.  See the file README.legal in the main directory of
- * this archive for more details.
- */
-
-#ifndef _POWERPC_PTRACE_PPC64_H
-#define _POWERPC_PTRACE_PPC64_H
-
-/*
- * Set of msr bits that gdb can change on behalf of a process.
- */
-#define MSR_DEBUGCHANGE	(MSR_FE0 | MSR_SE | MSR_BE | MSR_FE1)
-
-/*
- * Max register writeable via put_reg
- */
-#define PT_MAX_PUT_REG	PT_CCR
-
-/*
- * Munging of MSR on return from get_regs
- *
- * Put the correct FP bits in, they might be wrong as a result
- * of our lazy FP restore.
- */
-
-#define PT_MUNGE_MSR(msr, task)	({ (msr) | (task)->thread.fpexc_mode; })
-
-static inline int ptrace_set_debugreg(struct task_struct *task,
-				      unsigned long addr, unsigned long data)
-{
-	/* We only support one DABR and no IABRS at the moment */
-	if (addr > 0)
-		return -EINVAL;
-
-	/* The bottom 3 bits are flags */
-	if ((data & ~0x7UL) >= TASK_SIZE)
-		return -EIO;
-
-	/* Ensure translation is on */
-	if (data && !(data & DABR_TRANSLATION))
-		return -EIO;
-
-	task->thread.dabr = data;
-	return 0;
-}
-
-#endif /* _POWERPC_PTRACE_PPC64_H */

arch/powerpc/kernel/ptrace.c

@@ -35,16 +35,28 @@
 #include <asm/pgtable.h>
 #include <asm/system.h>
 
-#ifdef CONFIG_PPC64
-#include "ptrace-ppc64.h"
+/*
+ * does not yet catch signals sent when the child dies.
+ * in exit.c or in signal.c.
+ */
+
+/*
+ * Set of msr bits that gdb can change on behalf of a process.
+ */
+#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
+#define MSR_DEBUGCHANGE	0
 #else
-#include "ptrace-ppc32.h"
+#define MSR_DEBUGCHANGE	(MSR_SE | MSR_BE)
 #endif
 
 /*
- * does not yet catch signals sent when the child dies.
- * in exit.c or in signal.c.
+ * Max register writeable via put_reg
  */
+#ifdef CONFIG_PPC32
+#define PT_MAX_PUT_REG	PT_MQ
+#else
+#define PT_MAX_PUT_REG	PT_CCR
+#endif
 
 /*
  * Get contents of register REGNO in task TASK.
@@ -58,7 +70,7 @@ unsigned long ptrace_get_reg(struct task_struct *task, int regno)
 
 	if (regno == PT_MSR) {
 		tmp = ((unsigned long *)task->thread.regs)[PT_MSR];
-		return PT_MUNGE_MSR(tmp, task);
+		return tmp | task->thread.fpexc_mode;
 	}
 
 	if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long)))
@@ -274,6 +286,27 @@ static void clear_single_step(struct task_struct *task)
 	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
 }
 
+#ifdef CONFIG_PPC64
+static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
+			       unsigned long data)
+{
+	/* We only support one DABR and no IABRS at the moment */
+	if (addr > 0)
+		return -EINVAL;
+
+	/* The bottom 3 bits are flags */
+	if ((data & ~0x7UL) >= TASK_SIZE)
+		return -EIO;
+
+	/* Ensure translation is on */
+	if (data && !(data & DABR_TRANSLATION))
+		return -EIO;
+
+	task->thread.dabr = data;
+	return 0;
+}
+#endif
+
 /*
  * Called by kernel/ptrace.c when detaching..
  *

arch/powerpc/kernel/ptrace32.c

@@ -33,8 +33,6 @@
 #include <asm/pgtable.h>
 #include <asm/system.h>
 
-#include "ptrace-ppc64.h"
-
 /*
  * does not yet catch signals sent when the child dies.
  * in exit.c or in signal.c.