[PATCH] uml: S390 preparation, peekusr/pokeusr defined by subarch

s390 needs to change some parts of arch/um/kernel/ptrace.c.  Thus, the code
regarding PEEKUSER and POKEUSER are shifted to arch/um/sys-<subarch>/ptrace.c.

Also s390 debug registers need to be updated, when singlestepping is switched
on / off.  Thus, setting/resetting of singlestepping is centralized in the new
function set_singlestep(), which also inserts the macro
SUBARCH_SET_SINGLESTEP(mode), if defined.

Finally, s390 has the "ieee_instruction_pointer" in its
registers, which also is allowed to be read via

  ptrace( PTRACE_PEEKUSER, getpid(), PT_IEEE_IP, 0);

To implement this feature, sys_ptrace inserts the macro
SUBARCH_PTRACE_SPECIAL, if defined.

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 44 insertions, 0 deletions

diff --git a/arch/um/sys-x86_64/ptrace.c b/arch/um/sys-x86_64/ptrace.c
index 8c146b2a1e00..b593bb256f2c 100644
--- a/arch/um/sys-x86_64/ptrace.c
+++ b/arch/um/sys-x86_64/ptrace.c
@@ -62,6 +62,27 @@ int putreg(struct task_struct *child, int regno, unsigned long value)
 	return 0;
 }
 
+int poke_user(struct task_struct *child, long addr, long data)
+{
+        if ((addr & 3) || addr < 0)
+                return -EIO;
+
+        if (addr < MAX_REG_OFFSET)
+                return putreg(child, addr, data);
+
+#if 0 /* Need x86_64 debugregs handling */
+        else if((addr >= offsetof(struct user, u_debugreg[0])) &&
+                (addr <= offsetof(struct user, u_debugreg[7]))){
+                addr -= offsetof(struct user, u_debugreg[0]);
+                addr = addr >> 2;
+                if((addr == 4) || (addr == 5)) return -EIO;
+                child->thread.arch.debugregs[addr] = data;
+                return 0;
+        }
+#endif
+        return -EIO;
+}
+
 unsigned long getreg(struct task_struct *child, int regno)
 {
 	unsigned long retval = ~0UL;
@@ -84,6 +105,29 @@ unsigned long getreg(struct task_struct *child, int regno)
 	return retval;
 }
 
+int peek_user(struct task_struct *child, long addr, long data)
+{
+	/* read the word at location addr in the USER area. */
+        unsigned long tmp;
+
+        if ((addr & 3) || addr < 0)
+                return -EIO;
+
+        tmp = 0;  /* Default return condition */
+        if(addr < MAX_REG_OFFSET){
+                tmp = getreg(child, addr);
+        }
+#if 0 /* Need x86_64 debugregs handling */
+        else if((addr >= offsetof(struct user, u_debugreg[0])) &&
+                (addr <= offsetof(struct user, u_debugreg[7]))){
+                addr -= offsetof(struct user, u_debugreg[0]);
+                addr = addr >> 2;
+                tmp = child->thread.arch.debugregs[addr];
+        }
+#endif
+        return put_user(tmp, (unsigned long *) data);
+}
+
 void arch_switch(void)
 {
 /* XXX