powerpc: Cleanup ptrace bits

This patch cleans that up a bit by having a ptrace-common.h which contains
really common code (and makes a lot more code common), and ptrace-ppc32.h and
ptrace-ppc64.h files that contain the few remaining different bits.

Quoted 6 lines · Benjamin Herrenschmidt

This patch cleans that up a bit by having a ptrace-common.h which contains
really common code (and makes a lot more code common), and ptrace-ppc32.h and
ptrace-ppc64.h files that contain the few remaining different bits.

Hrm.. we do have a subtle difference in vrregs that I've missed.. I'll respin tomorrow. It looks like we don't store the VRSAVE register at the same place on 32 and 64 bits... yuck. I need to double check tomorrow.

Quoted 4 lines

Hrm.. we do have a subtle difference in vrregs that I've missed.. I'll respin tomorrow. It looks like we don't store the VRSAVE register at the
same place on 32 and 64 bits... yuck. I need to double check tomorrow.

That's bad. We really should have VRSAVE in the same location for both. (wondering if GDB expects it a different locations on 32 vs 64- bits.)

It looks like GDB will expect VRSAVE at offset 33*16 (length 4 bytes) in the area returned by PTRACE_GETVRREGS, for both 32-bit and 64-bit applications:

Quoted 1 line

It looks like GDB will expect VRSAVE at offset 33*16 (length 4

bytes)

Quoted 1 line

in the area returned by PTRACE_GETVRREGS, for both 32-bit and

64-bit

Quoted 1 line

applications:

I have to check exactly what's going on there, it might be correct in both cases, I just remember that the code did something subtely different but it might result in the same thing. I'll double check today.

The powerpc ptrace code has some weirdness, like a ptrace-common.h file that is actually ppc64 only and some of the 32 bits code ifdef'ed inside ptrace.c.

There are also separate implementations for things like get/set_vrregs for 32 and 64 bits which is totally unnecessary.

This patch cleans that up a bit by having a ptrace-common.h which contains really common code (and makes a lot more code common), and ptrace-ppc32.h and ptrace-ppc64.h files that contain the few remaining different bits.

Signed-off-by Benjamin Herrenschmidt <[email protected]>

 arch/powerpc/kernel/ptrace-common.h |   89 +++++++---------
 arch/powerpc/kernel/ptrace-ppc32.h  |  100 ++++++++++++++++++
 arch/powerpc/kernel/ptrace-ppc64.h  |   51 +++++++++
 arch/powerpc/kernel/ptrace.c        |  198  
------------------------------------
 arch/powerpc/kernel/ptrace32.c      |    1
 5 files changed, 197 insertions(+), 242 deletions(-)

Index: linux-cell/arch/powerpc/kernel/ptrace-common.h
===================================================================
--- linux-cell.orig/arch/powerpc/kernel/ptrace-common.h 2007-05-29
13:05:55.000000000 +1000
+++ linux-cell/arch/powerpc/kernel/ptrace-common.h 2007-05-29
16:22:00.000000000 +1000

arch/powerpc/kernel/ptrace-common.h +1 -0

@@ -1,5 +1,6 @@
 /*
  *    Copyright (c) 2002 Stephen Rothwell, IBM Coproration
+ *    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

arch/powerpc/kernel/ptrace-common.h +2 -9

@@ -7,15 +8,8 @@
  * this archive for more details.
  */
 
-#ifndef _PPC64_PTRACE_COMMON_H
-#define _PPC64_PTRACE_COMMON_H
-
-#include <asm/system.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)
+#ifndef _POWERPC_PTRACE_COMMON_H
+#define _POWERPC_PTRACE_COMMON_H
 
 /*
  * Get contents of register REGNO in task TASK.

arch/powerpc/kernel/ptrace-common.h +8 -4

+	if (task->thread.regs == NULL)
+		return -EIO;
+
 	if (regno == PT_MSR) {
 		tmp = ((unsigned long *)task->thread.regs)[PT_MSR];
-		tmp |= task->thread.fpexc_mode;
-	} else if (regno < (sizeof(struct pt_regs) / sizeof(unsigned  
 long))) {
-		tmp = ((unsigned long *)task->thread.regs)[regno];
+		return PT_MUNGE_MSR(tmp, task);
 	}
 
-	return tmp;
+	if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long)))
+		return ((unsigned long *)task->thread.regs)[regno];
+
+	return -EIO;
 }

Do we do some different lazy save/restore on ppc64 than ppc32? I'm trying to understand why the comment isn't (or wasn't) valid for ppc32 as well.

This one doesn't seem to apply against current mainline plus the first patch. The hung in ptrace.c rejects.