FM / tapset

/usr/share/systemtap/tapset

Name	Size	Mode	Actions
arm/	-	0755	rm
arm64/	-	0755	rm
bpf/	-	0755	rm
dyninst/	-	0755	rm
i386/	-	0755	rm
ia64/	-	0755	rm
linux/	-	0755	rm
mips/	-	0755	rm
powerpc/	-	0755	rm
riscv/	-	0755	rm
s390/	-	0755	rm
x86_64/	-	0755	rm
ansi.stp	4178	0644	edit dl rm
argv.stp	2721	0644	edit dl rm
choose_defined.stpm	208	0644	edit dl rm
container_of.stpm	235	0644	edit dl rm
context.stp	6103	0644	edit dl rm
errno.stp	9118	0644	edit dl rm
floatingpoint.stp	6936	0644	edit dl rm
indent-default.stp	59	0644	edit dl rm
indent.stp	4590	0644	edit dl rm
init.stp	269	0644	edit dl rm
input.stp	263	0644	edit dl rm
java.stp	1346	0644	edit dl rm
libperl5.26.3-64.stp	1339	0644	edit dl rm
libpython2.7-64.stp	522	0644	edit dl rm
livepatch.stp	3006	0644	edit dl rm
logging.stp	4132	0644	edit dl rm
macros.stpm	562	0644	edit dl rm
null.stp	17	0644	edit dl rm
offsetof.stpm	183	0644	edit dl rm
oneshot.stp	38	0644	edit dl rm
pn.stp	1588	0644	edit dl rm
print_stats.stpm	1719	0644	edit dl rm
private30.stpm	80	0644	edit dl rm
prometheus.stp	129	0644	edit dl rm
prometheus.stpm	8380	0644	edit dl rm
python.stp	474	0644	edit dl rm
python2.stp	29435	0644	edit dl rm
python3.stp	36655	0644	edit dl rm
queue_stats.stp	9487	0644	edit dl rm
random.stp	432	0644	edit dl rm
README	371	0644	edit dl rm
regex.stp	4107	0644	edit dl rm
registers.stp	11081	0644	edit dl rm
sizeof.stpm	212	0644	edit dl rm
speculative.stp	1746	0644	edit dl rm
sreg_arch.stpm	263	0644	edit dl rm
stap_staticmarkers.stp	9670	0644	edit dl rm
stopwatch.stp	3063	0644	edit dl rm
string.stp	7514	0644	edit dl rm
switchfile.stp	612	0644	edit dl rm
system.stp	593	0644	edit dl rm
this.stp	160	0644	edit dl rm
timers.stp	924	0644	edit dl rm
tls.stp	8099	0644	edit dl rm
tokenize.stp	2124	0644	edit dl rm
try_assign.stpm	768	0644	edit dl rm
type_defined.stpm	374	0644	edit dl rm
tzinfo.stp	930	0644	edit dl rm
uconversions-guru.stp	6078	0644	edit dl rm
uconversions.stp	36640	0644	edit dl rm

Edit: /usr/share/systemtap/tapset/tls.stp (8099B)

# Implicit Thread Local Storage tapset
# Copyright (C) 2020, 2021 Red Hat, Inc.
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
# Reference: "ELF Handling For Thread-Local Storage" by Ulrich Drepper

/*
 * TCB Pointer points to the thread control block.  dtv points to the DTV
 * array.  DTV[1]-DTV[N]  point to tls entries for module I from the link
 * map.  DTV[1] is the main executable.  The dtv val points to the tls
 * entry where the tls variable value is located.  The tls variable value
 * is also located a fixed offset from the tcbhead so if relocations are
 * simple enough a compiler can generate a direct load.  Complicated
 * relocations may result in a compiler calling a runtime routine
 * __tls_get_addr which uses the DTV. 
 * 
 * 			        TCB Pointer
 * 			        |
 * 			        V
 * TLS				struct tcbhead
 * +---------------------+	+----------------+ 
 * |OFFSET|OFFSET|OFFSET |      | void *tcb	 |
 * |  2   |  1   |  0    |      | dtv_t *dtv	 | --+
 * +---------------------+	+----------------+   |
 * 		   ^-------------------+	     |
 *          v----------------------------------------+
 *      +----------------------------+ | 
 *  DTV |length|gen|dtv[1]|dtv[2]|...| |
 *      +----------------------------+ |
 * 	    dtv[n] |		       |
 *      +---------------------+        |
 * 	|unsigned long counter|	       |
 * 	|struct dtv_pointer { |	       |
 * 	|  void *val	      |->------+
 * 	|  void *to_free}     |
 * 	+---------------------|
 */

global tls_debug = 0
private global tls_link_map_name
private global tls_module = 0

%{
# if defined(__DYNINST__)
# if defined(__i386) || defined(__x86_64)
# include <asm/prctl.h>
# include <sys/prctl.h>
# endif
# endif
%}

// Get the thread context pointer that points to the tls thread control block
@__private30 function get_thread_context_pointer (tls_thread_reg_val:long) %{
# ifdef __i386
{
  unsigned long gs;
# if defined(__KERNEL__)
  rdmsrl(MSR_FS_BASE, gs);
# elif defined(__DYNINST__)
  int arch_prctl(int code, unsigned long *addr);
  arch_prctl(ARCH_GET_FS, &gs);
# endif
  STAP_RETVALUE = gs;
}
# elif defined __x86_64
{
  unsigned long fs;
#if defined(__KERNEL__)
  rdmsrl(MSR_FS_BASE, fs);
# elif defined(__DYNINST__)
  int arch_prctl(int code, unsigned long *addr);
  arch_prctl(ARCH_GET_FS, &fs);
# endif
  STAP_RETVALUE = fs;
}
# elif defined __s390x__
{
  unsigned long tlsval;
  asm volatile ("ear %0,%%a0" : "=r" (tlsval));
  asm volatile ("sllg %0,%0,32" : "=r" (tlsval));
  asm volatile ("ear %0,%%a1" : "=r" (tlsval));
  STAP_RETVALUE = tlsval;
}
# elif defined __aarch64__
{
  unsigned long tlsval;
  asm("mrs %0,tpidr_el0" : "=r" (tlsval));
  STAP_RETVALUE = tlsval;
}
# elif defined __powerpc64__
{
  unsigned long tcb;
  asm("subi %0,%1,28688," : "=r" (tcb) : "r" (STAP_ARG_tls_thread_reg_val)); // -0x7010
  STAP_RETVALUE = tcb;
}
# endif
%}

// Get inode of followed link
// TODO Does not follow symbolic links, e.g. to follow /lib64/libc.so.6
//      The idea was to do 'inode = get_inode_from_path (l_name); name = inode_path(inode);'

@__private30 function get_inode_from_path:long (tls_module_name) %{
  struct inode *tls_inode;
  struct path tls_path;
  int code;
  code = kern_path(/* string */ STAP_ARG_tls_module_name, LOOKUP_FOLLOW, &tls_path);
  if (code == 0)
    STAP_RETVALUE = (int64_t)tls_path.dentry->d_inode;
  else
    STAP_RETVALUE = 0;
%}

// Return basename of a path

@__private30 function basename (l_name:string)
{
   for (lni = 0; lni < strlen (l_name); lni++) {
      if (stringat(l_name, lni) == 0x2f)  // '/'
	 slash = lni;
   } 
   if (slash > 0) {
      slash += 1;
      return substr (l_name, slash, strlen(l_name)-slash);
   }
   else
      return l_name;
}

// Setup the link_map module/l_name mapping

@__private30 function setup_link_map ()
{
  delete tls_link_map_name
%( arch == "x86_64" %?
  l_map_count = @var("_rtld_global","/usr/lib64/ld-linux-x86-64.so.2")->_dl_nns
  // TODO Do namespaces need to be supported? assume [0]
  l_map = @var("_rtld_global","/usr/lib64/ld-linux-x86-64.so.2")->_dl_ns[0]->_ns_loaded;
  if (tls_debug > 1)
    println ("l_map=", @var("_rtld_global","/usr/lib64/ld-linux-x86-64.so.2")->_dl_ns[0]->_ns_loaded$);
%)
%( arch == "powerpc" %?
  l_map_count = @var("_rtld_global","/usr/lib64/ld64.so.2")->_dl_nns
  l_map = @var("_rtld_global","/usr/lib64/ld64.so.2")->_dl_ns[0]->_ns_loaded;
  if (tls_debug > 1) 
    println ("l_map=", @var("_rtld_global","/usr/lib64/ld64.so.2")->_dl_ns[0]->_ns_loaded$);
%)
%( arch == "s390" %?
  l_map_count = @var("_rtld_global","/usr/lib/ld64.so.1")->_dl_nns
  l_map = @var("_rtld_global","/usr/lib/ld64.so.1")->_dl_ns[0]->_ns_loaded;
  if (tls_debug > 1) 
    println ("l_map=", @var("_rtld_global","/usr/lib/ld64.so.1")->_dl_ns[0]->_ns_loaded$);
%)
     
  while (l_map)
    {
     l_name = user_string(l_map->l_name);
     if (l_name == "") {
	 l_map = l_map->l_next
	 continue
     }
     l_addr = user_uint64(l_map->l_addr);
     l_tls_modid = l_map->l_tls_modid
     name_base = basename (l_name);
     if (l_tls_modid != 0) {
	tls_link_map_name[l_tls_modid] = name_base;
	if (tls_debug)
	   printf("link_map: %s l_addr=%#lx modid=%d\n", tls_link_map_name[l_tls_modid], l_addr, l_tls_modid);
       }
     l_map = l_map->l_next
    }
}

// Compare module names.  
// sonames, real sonames, and linker sonames should compare equal

@__private30 function regex_module_compare (stap_mod:string, map_mod:string)
{
   // Not an soname
   if (stap_mod !~ "^lib.*$") 
      return stap_mod == map_mod;

// Most common case libMATCH-1.soMATCH-2
   // MATCH-1 is the soname minus lib prefix and .so* suffix
   if (stap_mod !~ "lib([-\._\+a-zA-Z0-9]+)\.so([\.0-9]*)")
      return 0;
   stap_lib = matched(1);

if (map_mod !~ "lib([-\._\+a-zA-Z0-9]+)\.so([\.0-9]*)")
      return 0;
   map_lib = matched(1);
   if (stap_lib == map_lib)
     return 1;
   
   // The above will miss e.g. libc.so.6/libc-2.31.so
   // MATCH-1 is the soname minus lib prefix and -version.so suffix
   if (stap_mod !~ "lib([_\+a-zA-Z0-9]+)([-\.0-9]*)\.so([\.0-9]*)")
     return 0;
   stap_lib = matched(1);
   if (map_mod !~ "lib([_\+a-zA-Z0-9]+)([-\.0-9]*)\.so([\.0-9]*)")
     return 0;
   map_lib = matched(1);
   if (stap_lib == map_lib)
     return 1;
   else
     return 0;
}

// Find the module by matching the probe name to the link_map name

@__private30 function set_tls_module_by_name (tls_module:string)
{
  matched_proc = basename(tls_module);

if (tls_debug)
    printf("Looking for %s in link_map\n", matched_proc);
  foreach (lm in tls_link_map_name) {
    if (lm==0) continue;
    if (regex_module_compare (matched_proc, tls_link_map_name[lm])) {
       if (tls_debug)
	 printf("Name Match: %s \n", tls_link_map_name[lm]);
       return lm;
    }
  }
  return 1;
}

/**
 * sfunction __push_tls_address - Handle implicit tls variable relocation
 * 
 * Description: Called for DW_OP_GNU_push_tls_address relocation from loc2stap.css::location_context::translate
 */

function __push_tls_address (tls_var_offset:long, tls_module:string) 
{
%( arch == "powerpc" %?
   // It seems the value of r13 cannot be dependably relied on in get_thread_context_pointer
   r13 = register("r13")
   %:
   r13 = 0
%)
  tcbhead = get_thread_context_pointer (r13);
  if (tls_debug > 1)
    printf ("tls_module=%s tcbhead=%#lx/%d\n", tls_module, tcbhead, tcbhead);
  setup_link_map ();
  module = set_tls_module_by_name (tls_module);
  if (module >= 0) 
    {
      // dtv[-1] is module count
      // dtv[0] is generation count
      // dtv[1] is module[0] info, the main executable
      // dtv[2..n] is module info for dependent shared objects
      dtv$pointer$val = @cast(tcbhead, "tcbhead", "<linux/stp_tls.h>")->dtv[module]->pointer->val;
      if (tls_debug > 1)
	printf ("dtv$pointer$val=%#lx, tls_var_offset=%#lx, module=%d\n", dtv$pointer$val, tls_var_offset, module);
      return dtv$pointer$val + tls_var_offset;
    }
  else
    return 0;
}

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