From: Frank Ch. Eigler <fche@elastic.org>
Date: Wed, 23 Dec 2009 02:53:39 +0000 (-0500)
Subject: sdt.h semaphore: use get_user / put_user instead of __access_process_vm.
X-Git-Tag: release-1.1~56^2~1
X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=93c8419165a7c651989cc344364b86695e1f142c;p=systemtap.git

sdt.h semaphore: use get_user / put_user instead of __access_process_vm.

    * translate.cxx (translate_pass): Don't #include <access_blah.>
    * tapsets.cxx, tapset-utrace.cxx: Replace __access_process_vm()
      calls with get_user() / put_user() respectively.
---

diff --git a/tapset-utrace.cxx b/tapset-utrace.cxx
index cc4f28061..e3a6fd5be 100644
--- a/tapset-utrace.cxx
+++ b/tapset-utrace.cxx
@@ -949,14 +949,14 @@ utrace_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->newline(-1) << "}";
 
   // Before writing to the semaphore, we need to check for VM_WRITE access.
-  s.op->newline() << "if (p->sdt_sem_address != 0) {";
+  s.op->newline() << "if (p->sdt_sem_address) {";
   s.op->newline(1) << "size_t sdt_semaphore;";
   // XXX p could get registered to more than one task!
   s.op->newline() << "p->tsk = tsk;";
 
-  s.op->newline() << "if (__access_process_vm (tsk, p->sdt_sem_address, &sdt_semaphore, sizeof (sdt_semaphore), 0) == sizeof (sdt_semaphore)) {";
+  s.op->newline() << "if (get_user (sdt_semaphore, (unsigned short __user *) p->sdt_sem_address) == 0) {";
   s.op->newline(1) << "sdt_semaphore ++;";
-  s.op->newline() << "__access_process_vm (tsk, p->sdt_sem_address, &sdt_semaphore, sizeof (sdt_semaphore), 1);";
+  s.op->newline() << "put_user (sdt_semaphore, (unsigned short __user *) p->sdt_sem_address);";
   s.op->newline(-1) << "}";
   s.op->newline(-1) << "}";
   s.op->newline(-1) << "}";
@@ -1043,18 +1043,14 @@ utrace_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->newline(-1) << "}";
   s.op->newline(-1) << "}";
 
-  s.op->newline() << "if (p->sdt_sem_address) {";
+  s.op->newline() << "if (p->sdt_sem_address && (vm_flags & VM_WRITE)) {";
   s.op->newline(1) << "unsigned short sdt_semaphore = 0;"; // NB: fixed size
-  s.op->newline() << "if (__access_process_vm (tsk, p->sdt_sem_address, &sdt_semaphore, sizeof (sdt_semaphore), 0) == sizeof (sdt_semaphore)) {";
-
-  s.op->newline(1) << "if (vm_flags & VM_WRITE) {";
-  s.op->indent(1);
-  s.op->newline() << "sdt_semaphore ++;";
+  s.op->newline() << "if (get_user (sdt_semaphore, (unsigned short __user *) p->sdt_sem_address) == 0) {";
+  s.op->newline(1) << "sdt_semaphore ++;";
   s.op->newline() << "#ifdef DEBUG_UTRACE";
   s.op->newline() << "_stp_dbug (__FUNCTION__,__LINE__, \"+semaphore %#x @ %#lx\\n\", sdt_semaphore, p->sdt_sem_address);";
   s.op->newline() << "#endif";
-  s.op->newline() << "__access_process_vm (tsk, p->sdt_sem_address, &sdt_semaphore, sizeof (sdt_semaphore), 1);";
-  s.op->newline(-1) << "}";
+  s.op->newline() << "put_user (sdt_semaphore, (unsigned short __user *) p->sdt_sem_address);";
   s.op->newline(-1) << "}";
   s.op->newline(-1) << "}";
   s.op->newline() << "return 0;";
@@ -1134,9 +1130,9 @@ utrace_derived_probe_group::emit_module_exit (systemtap_session& s)
   s.op->newline() << "if (p->sdt_sem_address) {";
   s.op->newline(1) << "size_t sdt_semaphore;";
   // XXX p could get registered to more than one task!
-  s.op->newline() << "if (__access_process_vm (p->tsk, p->sdt_sem_address, &sdt_semaphore, sizeof (sdt_semaphore), 0) == sizeof (sdt_semaphore)) {";
+  s.op->newline() << "if (get_user (sdt_semaphore, (unsigned short __user *) p->sdt_sem_address) == 0) {";
   s.op->newline(1) << "sdt_semaphore --;";
-  s.op->newline() << "__access_process_vm (p->tsk, p->sdt_sem_address, &sdt_semaphore, sizeof (sdt_semaphore), 1);";
+  s.op->newline() << "put_user (sdt_semaphore, (unsigned short __user *) p->sdt_sem_address);";
   s.op->newline(-1) << "}";
   s.op->newline(-1) << "}";
   s.op->newline(-1) << "}";
diff --git a/tapsets.cxx b/tapsets.cxx
index e14cc496b..bac477610 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -4869,11 +4869,11 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s)
 
   s.op->newline() << "if (sdt_sem_address[spec_index]) {";
   s.op->newline(1) << "unsigned short sdt_semaphore = 0;"; // NB: fixed size
-  s.op->newline() << "if ( __access_process_vm (tsk, sdt_sem_address[spec_index], &sdt_semaphore, sizeof (sdt_semaphore), 0)) {";
+  s.op->newline() << "if (get_user (sdt_semaphore, (unsigned short __user*) sdt_sem_address[spec_index]) == 0) {";
   // We have an executable or a writeable segment of a .so
   s.op->newline(1) << "if (vm_flags == 0 || vm_flags & VM_WRITE) {";
   s.op->newline(1) << "sdt_semaphore ++;";
-  s.op->newline() << "__access_process_vm (tsk, sdt_sem_address[spec_index], &sdt_semaphore, sizeof (sdt_semaphore), 1);";
+  s.op->newline() << "put_user (sdt_semaphore, (unsigned short __user*) sdt_sem_address[spec_index]);";
   s.op->newline(-1) << "}";
   s.op->newline(-1) << "}";	// sdt_sem_address
   // XXX: error handling in __access_process_vm!
@@ -5139,13 +5139,13 @@ uprobe_derived_probe_group::emit_module_exit (systemtap_session& s)
   s.op->newline() << "#endif /* 2.6.31 */";
 
   s.op->newline() << "if (tsk) {"; // just in case the thing exited while we weren't watching
-  s.op->newline(1) << "if (__access_process_vm (tsk, sdt_sem_address[sup->spec_index], &sdt_semaphore, sizeof (sdt_semaphore), 0)) {";
+  s.op->newline(1) << "if (get_user (sdt_semaphore, (unsigned short __user*) sdt_sem_address[sup->spec_index]) == 0) {";
   s.op->newline(1) << "sdt_semaphore --;";
   s.op->newline() << "#ifdef DEBUG_UPROBES";
   s.op->newline() << "_stp_dbug (__FUNCTION__,__LINE__, \"-semaphore %#x @ %#lx\\n\", sdt_semaphore, sdt_sem_address[sup->spec_index]);";
   s.op->newline() << "#endif";
-  s.op->newline() << "(void) __access_process_vm (tsk, sdt_sem_address[sup->spec_index], &sdt_semaphore, sizeof (sdt_semaphore), 1);";
-  s.op->newline(-1) << "}";	// access_process_vm
+  s.op->newline() << "put_user (sdt_semaphore, (unsigned short __user*) sdt_sem_address[sup->spec_index]);";
+  s.op->newline(-1) << "}";
   // XXX: error handling in __access_process_vm!
   // XXX: need to analyze possibility of race condition
   s.op->newline(-1) << "}";
diff --git a/translate.cxx b/translate.cxx
index 81b8bef51..88e69a666 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -5238,7 +5238,6 @@ translate_pass (systemtap_session& s)
       s.op->newline() << "#include <linux/version.h>";
       // s.op->newline() << "#include <linux/compile.h>";
       s.op->newline() << "#include \"loc2c-runtime.h\" ";
-      s.op->newline() << "#include \"access_process_vm.h\" ";
 
       s.up->emit_common_header (); // context etc.