[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>

1 files changed, 39 insertions, 6 deletions

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index dd4837c4a68a..75bc744a6217 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/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..
  *