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Revision eb35bdd7bca29a13c8ecd44e6fd747a84ce675db authored by Will Deacon on 11 September 2014, 13:38:16 UTC, committed by Will Deacon on 11 September 2014, 17:34:58 UTC 
arm64: flush TLS registers during exec
 
Nathan reports that we leak TLS information from the parent context
during an exec, as we don't clear the TLS registers when flushing the
thread state.

This patch updates the flushing code so that we:

  (1) Unconditionally zero the tpidr_el0 register (since this is fully
      context switched for native tasks and zeroed for compat tasks)

  (2) Zero the tp_value state in thread_info before clearing the
      tpidrr0_el0 register for compat tasks (since this is only writable
      by the set_tls compat syscall and therefore not fully switched).

A missing compiler barrier is also added to the compat set_tls syscall.

Cc: <stable@vger.kernel.org>
Acked-by: Nathan Lynch <Nathan_Lynch@mentor.com>
Reported-by: Nathan Lynch <Nathan_Lynch@mentor.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
1 parent 3d8afe3
Raw File
bloat-o-meter 
#!/usr/bin/python
#
# Copyright 2004 Matt Mackall <mpm@selenic.com>
#
# inspired by perl Bloat-O-Meter (c) 1997 by Andi Kleen
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

import sys, os, re

if len(sys.argv) != 3:
    sys.stderr.write("usage: %s file1 file2\n" % sys.argv[0])
    sys.exit(-1)

def getsizes(file):
    sym = {}
    for l in os.popen("nm --size-sort " + file).readlines():
        size, type, name = l[:-1].split()
        if type in "tTdDbBrR":
            # strip generated symbols
            if name.startswith("__mod_"): continue
            if name == "linux_banner": continue
            # statics and some other optimizations adds random .NUMBER
            name = re.sub(r'\.[0-9]+', '', name)
            sym[name] = sym.get(name, 0) + int(size, 16)
    return sym

old = getsizes(sys.argv[1])
new = getsizes(sys.argv[2])
grow, shrink, add, remove, up, down = 0, 0, 0, 0, 0, 0
delta, common = [], {}

for a in old:
    if a in new:
        common[a] = 1

for name in old:
    if name not in common:
        remove += 1
        down += old[name]
        delta.append((-old[name], name))

for name in new:
    if name not in common:
        add += 1
        up += new[name]
        delta.append((new[name], name))

for name in common:
        d = new.get(name, 0) - old.get(name, 0)
        if d>0: grow, up = grow+1, up+d
        if d<0: shrink, down = shrink+1, down-d
        delta.append((d, name))

delta.sort()
delta.reverse()

print "add/remove: %s/%s grow/shrink: %s/%s up/down: %s/%s (%s)" % \
      (add, remove, grow, shrink, up, -down, up-down)
print "%-40s %7s %7s %+7s" % ("function", "old", "new", "delta")
for d, n in delta:
    if d: print "%-40s %7s %7s %+7d" % (n, old.get(n,"-"), new.get(n,"-"), d)
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