[PATCH][BUGFIX] utrace/ia64: Fix syscall_get_set_args_cb() to handle syscalls via syscall()

[Masami Hiramatsu]

Fix syscall_get_set_args_cb() to decode user-stack correctly in case of
syscall() which allocates locals in user-stack. If locals (cfm.sol) exist
on the stack, we have to skip it for getting real systemcall arguments.

And also, fix the number of getting arguments which must be less than
(nr outputs - args->i) instead of nr outputs, because args->i is the
indent number (this means, syscall_get_set_args_cb() get/set arguments
from (i)th to (i+n)th.)

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: David Smith <dsmith@redhat.com>
---
 arch/ia64/kernel/ptrace.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

Index: 2.6-rc/arch/ia64/kernel/ptrace.c
===================================================================
--- 2.6-rc.orig/arch/ia64/kernel/ptrace.c
+++ 2.6-rc/arch/ia64/kernel/ptrace.c
@@ -2189,6 +2189,10 @@ struct syscall_get_set_args {
 	int rw;
 };

+#define CFM_SOF(cfm) ((cfm) & 0x7f)			/* Size of frame */
+#define CFM_SOL(cfm) (((cfm) >> 7) & 0x7f)		/* Size of locals */
+#define CFM_OUT(cfm) (CFM_SOF(cfm) - CFM_SOL(cfm))	/* Size of outputs */
+
 static void syscall_get_set_args_cb(struct unw_frame_info *info, void *data)
 {
 	struct syscall_get_set_args *args = data;
@@ -2205,15 +2209,18 @@ static void syscall_get_set_args_cb(stru

 	count = 0;
 	if (in_syscall(pt))
-		count = min_t(int, args->n, cfm & 0x7f);
+		/* args->i + args->n must be less equal than nr outputs */
+		count = min_t(int, args->n, CFM_OUT(cfm) - args->i);

 	for (i = 0; i < count; i++) {
+		/* Skips dirties and locals */
 		if (args->rw)
-			*ia64_rse_skip_regs(krbs, ndirty + i + args->i) =
+			*ia64_rse_skip_regs(krbs,
+				ndirty + CFM_SOL(cfm) + args->i + i) =
 				args->args[i];
 		else
 			args->args[i] = *ia64_rse_skip_regs(krbs,
-				ndirty + i + args->i);
+				ndirty + CFM_SOL(cfm) + args->i + i);
 	}

 	if (!args->rw) {
-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com