Re: baby memory map notification

[Srinivasa DS <srinivasa at in dot ibm dot com>]

David Smith wrote:
> David Smith wrote:
> > Frank,
> >
> > Here's a stab at baby memory map notification.  It works, with several
> > limitations:
>
> I've checked in a new-and-improved version.  This one:
>
> - works on existing threads and new threads (tracking new vms as they
> get created and deleted)
>
> - you can use .begin probes (you couldn't do that with the last version)
>
> - even works on 32-bit x86 apps running on 64-bit x86_64 kernel
>
> Limitations:
>
> - because of a utrace bug, it won't work on fedora x86 2.6.25 kernels
> (it works fine on fedora x86_64 2.6.25 kernels)
>
> - paths for deleted vma's are currently passed to the callback as NULL
>
> - I haven't tested this against a multi-threaded app yet
>
> - almost all testing has been done on x86_64/f9, so that is where it
> will work best
>
> Everything you need should be checked in, but disabled by default.  To
> enable, define 'DEBUG_TASK_FINDER_VMA'.  With the attached script, you
> can run:
>
> # stap -v -DDEBUG_TASK_FINDER_VMA cat.stp

I tried executing this script on ppc64 system, But later found that 
memory map notification was not implemented on ppc64. So I did few 
changes to make it work for ppc64. Iam attaching my patch here, please 
let me know your comments.

Snapshot of script output
=================
stapio:stp_main_loop:318 nb=12
stapio:stp_main_loop:358 probe_start() returned 0
running...
__stp_tf_vm_cb:47: vm_cb: tsk 30717:1 path /lib/ld-2.5.so, start 
0x0ffc0000, end 0x0ffe0000, offset 0x0
__stp_tf_vm_cb:47: vm_cb: tsk 30717:1 path /lib/ld-2.5.so, start 
0x0ffe0000, end 0x10000000, offset 0x10000
__stp_tf_vm_cb:47: vm_cb: tsk 30717:1 path /bin/cat, start 0x10000000, 
end 0x10010000, offset 0x0
__stp_tf_vm_cb:47: vm_cb: tsk 30717:1 path /bin/cat, start 0x10010000, 
end 0x10020000, offset 0x0
*** /bin/cat begin ***
__stp_utrace_task_finder_target_syscall_exit:772: tsk 30717 found 
mmap(0xf7fc0000), returned 0xf7fc0000
__stp_tf_vm_cb:47: vm_cb: tsk 30717:1 path /etc/ld.so.cache, start 
0xf7fc0000, end 0xf7ff0000, offset 0x0
__stp_utrace_task_finder_target_syscall_exit:772: tsk 30717 found 
mmap(0xfe30000), returned 0xfe30000
__stp_tf_vm_cb:47: vm_cb: tsk 30717:1 path /lib/libc-2.5.so, start 
0x0fe30000, end 0x0ffc0000, offset 0x0
__stp_utrace_task_finder_target_syscall_exit:772: tsk 30717 found 
mmap(0xffa0000), returned 0xffa0000
=======================

Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com>


---
 runtime/syscall.h |   39 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 3 deletions(-)

Index: systemtap/runtime/syscall.h
===================================================================
--- systemtap.orig/runtime/syscall.h
+++ systemtap/runtime/syscall.h
@@ -49,15 +49,29 @@
 # endif
 #endif

+#if defined(__powerpc__)
+#define __MMAP_SYSCALL_NO_PPC64 	90
+#define __MPROTECT_SYSCALL_NO_PPC64	125
+#define __MUNMAP_SYSCALL_NO_PPC64	91
+#define __MREMAP_SYSCALL_NO_PPC64	163
+#define MMAP_SYSCALL_NO(tsk) __MMAP_SYSCALL_NO_PPC64
+#define MPROTECT_SYSCALL_NO(tsk) __MPROTECT_SYSCALL_NO_PPC64
+#define MUNMAP_SYSCALL_NO(tsk) __MUNMAP_SYSCALL_NO_PPC64
+#define MREMAP_SYSCALL_NO(tsk) __MREMAP_SYSCALL_NO_PPC64
+#endif
+
 #if !defined(MMAP_SYSCALL_NO) || !defined(MPROTECT_SYSCALL_NO) \
 	|| !defined(MUNMAP_SYSCALL_NO) || !defined(MREMAP_SYSCALL_NO)
 #error "Unimplemented architecture"
 #endif

-#if defined(__i386__) || defined(__x86_64__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__)
 static inline unsigned long
 __stp_user_syscall_nr(struct pt_regs *regs)
 {
+#if defined(__powerpc__)
+    return regs->gpr[0];
+#else
 #if defined(STAPCONF_X86_UNIREGS)
     return regs->orig_ax;
 #elif defined(__x86_64__)
@@ -65,13 +79,17 @@ __stp_user_syscall_nr(struct pt_regs *re
 #elif defined (__i386__)
     return regs->orig_eax;
 #endif
+#endif
 }
 #endif

-#if defined(__i386__) || defined(__x86_64__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__)
 static inline long *
 __stp_user_syscall_return_value(struct task_struct *task, struct 
pt_regs *regs)
 {
+#if defined(__powerpc__)
+    return &regs->gpr[3];
+#else
 #ifdef CONFIG_IA32_EMULATION
 // This code works, but isn't what we need.  Since
 // __stp_user_syscall_arg() doesn't sign-extend, a value passed in as
@@ -91,14 +109,28 @@ __stp_user_syscall_return_value(struct t
 #elif defined (__i386__)
 	return &regs->eax;
 #endif
+#endif
 }
 #endif

-#if defined(__i386__) || defined(__x86_64__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__)
 static inline long *
 __stp_user_syscall_arg(struct task_struct *task, struct pt_regs *regs,
 		       unsigned int n)
 {
+#if defined(__powerpc__)
+	switch (n) {
+	case 0: return &regs->gpr[3];
+	case 1: return &regs->gpr[4];
+	case 2: return &regs->gpr[5];
+	case 3: return &regs->gpr[6];
+	case 4: return &regs->gpr[7];
+	case 5: return &regs->gpr[8];
+	default:
+		_stp_error("syscall arg > 5");
+		return NULL;
+	}
+#else
 #if defined(__i386__)
 	if (n > 5) {
 		_stp_error("syscall arg > 5");
@@ -154,6 +186,7 @@ __stp_user_syscall_arg(struct task_struc
 		return NULL;
 	}
 #endif /* CONFIG_X86_32 */
+#endif
 }
 #endif