CONFIG_SYMBOL_PREFIX: cleanup.

We have CONFIG_SYMBOL_PREFIX, which three archs define to the string
"_".  But Al Viro broke this in "consolidate cond_syscall and
SYSCALL_ALIAS declarations" (in linux-next), and he's not the first to
do so.

Using CONFIG_SYMBOL_PREFIX is awkward, since we usually just want to
prefix it so something.  So various places define helpers which are
defined to nothing if CONFIG_SYMBOL_PREFIX isn't set:

1) include/asm-generic/unistd.h defines __SYMBOL_PREFIX.
2) include/asm-generic/vmlinux.lds.h defines VMLINUX_SYMBOL(sym)
3) include/linux/export.h defines MODULE_SYMBOL_PREFIX.
4) include/linux/kernel.h defines SYMBOL_PREFIX (which differs from #7)
5) kernel/modsign_certificate.S defines ASM_SYMBOL(sym)
6) scripts/modpost.c defines MODULE_SYMBOL_PREFIX
7) scripts/Makefile.lib defines SYMBOL_PREFIX on the commandline if
   CONFIG_SYMBOL_PREFIX is set, so that we have a non-string version
   for pasting.

(arch/h8300/include/asm/linkage.h defines SYMBOL_NAME(), too).

Let's solve this properly:
1) No more generic prefix, just CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX.
2) Make linux/export.h usable from asm.
3) Define VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR().
4) Make everyone use them.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Tested-by: James Hogan <james.hogan@imgtec.com> (metag)
module: fix symbol versioning with symbol prefixes

Fix symbol versioning on architectures with symbol prefixes. Although
the build was free from warnings the actual modules still wouldn't load
as the ____versions table contained unprefixed symbol names, which were
being compared against the prefixed symbol names when checking the
symbol versions.

This is fixed by modifying modpost to add the symbol prefix to the
____versions table it outputs (Modules.symvers still contains unprefixed
symbol names). The check_modstruct_version() function is also fixed as
it checks the version of the unprefixed "module_layout" symbol which
would no longer work.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jonathan Kliegman <kliegs@chromium.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (use VMLINUX_SYMBOL_STR)
genksyms: pass symbol-prefix instead of arch

Pass symbol-prefix to genksyms instead of arch, so that the decision
what symbol prefix to use is kept in one place.

Basically genksyms used to take a -a $ARCH argument and it used that to
determine whether to add an underscore symbol prefix. It's now changed
to take a -s $SYMBOL_PREFIX argument so that the caller decides whether
a symbol prefix is required. The build system then uses
CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX to determine whether to pass the
argument.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
modpost: minor cleanup.

We want a strends() function next, so make one and use it appropriately,
making new_module() arg const while we're at it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
modpost: add -T option to read module names from file/stdin.

Because there are too many modules in the world.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
modpost: handle huge numbers of modules.

strace shows:
72102 execve("/bin/sh", ["/bin/sh", "-c", "echo '  scripts/mod/modpost -m -a
-o /cc/wfg/sound-compiletest/Module.symvers      -s'; scripts/
mod/modpost -m -a -o /cc/wfg/sound-compiletest/Module.symvers      -s vmlinux
arch/x86/crypto/ablk_helper.o arch/x86/crypto/aes-i586.o arch
/x86/crypto/aesni-intel.o arch/x86/crypto/crc32-pclmul.o
...
drivers/ata/sata_promise.o "...], [/* 119 vars */] <unfinished ...>
71827 wait4(-1,  <unfinished ...>
72102 <... execve resumed> )            = -1 E2BIG (Argument list too long)

So we re-run the shell command which produces the list and feed it into modpost -T -.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
MODSIGN: do not send garbage to stderr when enabling modules signature

When compiling kernel with -jN (N > 1), all warning/error messages
printed while openssl is generating key pair may get mixed dots and
other symbols openssl sends to stderr. This patch makes sure openssl
logs go to default stdout.

Example of the garbage on stderr:

crypto/anubis.c:581: warning: ‘inter’ is used uninitialized in this function
Generating a 4096 bit RSA private key
.........
drivers/gpu/drm/i915/i915_gem_gtt.c: In function ‘gen6_ggtt_insert_entries’:
drivers/gpu/drm/i915/i915_gem_gtt.c:440: warning: ‘addr’ may be used uninitialized in this function
.net/mac80211/tx.c: In function ‘ieee80211_subif_start_xmit’:
net/mac80211/tx.c:1780: warning: ‘chanctx_conf’ may be used uninitialized in this function
..drivers/isdn/hardware/mISDN/hfcpci.c: In function ‘hfcpci_softirq’:
.....drivers/isdn/hardware/mISDN/hfcpci.c:2298: warning: ignoring return value of ‘driver_for_each_device’, declared with attribute warn_unused_result

Signed-off-by: David Cohen <david.a.cohen@intel.com>
Reviewed-by: mark gross <mark.gross@intel.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
kernel: kallsyms: memory override issue, need check destination buffer length

  We don't export any symbols > 128 characters, but if we did then
  kallsyms_expand_symbol() would overflow the buffer handed to it.
  So we need check destination buffer length when copying.

  the related test:
    if we define an EXPORT function which name more than 128.
    will panic when call kallsyms_lookup_name by init_kprobes on booting.
    after check the length (provide this patch), it is ok.

  Implementaion:
    add additional destination buffer length parameter (maxlen)
    if uncompressed string is too long (>= maxlen), it will be truncated.
    not check the parameters whether valid, since it is a static function.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
module: don't unlink the module until we've removed all exposure.

Otherwise we get a race between unload and reload of the same module:
the new module doesn't see the old one in the list, but then fails because
it can't register over the still-extant entries in sysfs:

 [  103.981925] ------------[ cut here ]------------
 [  103.986902] WARNING: at fs/sysfs/dir.c:536 sysfs_add_one+0xab/0xd0()
 [  103.993606] Hardware name: CrownBay Platform
 [  103.998075] sysfs: cannot create duplicate filename '/module/pch_gbe'
 [  104.004784] Modules linked in: pch_gbe(+) [last unloaded: pch_gbe]
 [  104.011362] Pid: 3021, comm: modprobe Tainted: G        W    3.9.0-rc5+ #5
 [  104.018662] Call Trace:
 [  104.021286]  [<c103599d>] warn_slowpath_common+0x6d/0xa0
 [  104.026933]  [<c1168c8b>] ? sysfs_add_one+0xab/0xd0
 [  104.031986]  [<c1168c8b>] ? sysfs_add_one+0xab/0xd0
 [  104.037000]  [<c1035a4e>] warn_slowpath_fmt+0x2e/0x30
 [  104.042188]  [<c1168c8b>] sysfs_add_one+0xab/0xd0
 [  104.046982]  [<c1168dbe>] create_dir+0x5e/0xa0
 [  104.051633]  [<c1168e78>] sysfs_create_dir+0x78/0xd0
 [  104.056774]  [<c1262bc3>] kobject_add_internal+0x83/0x1f0
 [  104.062351]  [<c126daf6>] ? kvasprintf+0x46/0x60
 [  104.067231]  [<c1262ebd>] kobject_add_varg+0x2d/0x50
 [  104.072450]  [<c1262f07>] kobject_init_and_add+0x27/0x30
 [  104.078075]  [<c1089240>] mod_sysfs_setup+0x80/0x540
 [  104.083207]  [<c1260851>] ? module_bug_finalize+0x51/0xc0
 [  104.088720]  [<c108ab29>] load_module+0x1429/0x18b0

We can teardown sysfs first, then to be sure, put the state in
MODULE_STATE_UNFORMED so it's ignored while we deconstruct it.

Reported-by: Veaceslav Falico <vfalico@redhat.com>
Tested-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
X.509: Support parse long form of length octets in Authority Key Identifier

Per X.509 spec in 4.2.1.1 section, the structure of Authority Key
Identifier Extension is:

   AuthorityKeyIdentifier ::= SEQUENCE {
      keyIdentifier             [0] KeyIdentifier           OPTIONAL,
      authorityCertIssuer       [1] GeneralNames            OPTIONAL,
      authorityCertSerialNumber [2] CertificateSerialNumber OPTIONAL  }

   KeyIdentifier ::= OCTET STRING

When a certificate also provides
authorityCertIssuer and authorityCertSerialNumber then the length of
AuthorityKeyIdentifier SEQUENCE is likely to long form format.
e.g.
   The example certificate demos/tunala/A-server.pem in openssl source:

X509v3 Authority Key Identifier:
    keyid:49:FB:45:72:12:C4:CC:E1:45:A1:D3:08:9E:95:C4:2C:6D:55:3F:17
    DirName:/C=NZ/L=Wellington/O=Really Irresponsible Authorisation Authority (RIAA)/OU=Cert-stamping/CN=Jackov al-Trades/emailAddress=none@fake.domain
    serial:00

Current parsing rule of OID_authorityKeyIdentifier only take care the
short form format, it causes load certificate to modsign_keyring fail:

[   12.061147] X.509: Extension: 47
[   12.075121] MODSIGN: Problem loading in-kernel X.509 certificate (-74)

So, this patch add the parsing rule for support long form format against
Authority Key Identifier.

v3:
Changed the size check in "Short Form length" case, we allow v[3] smaller
then (vlen - 4) because authorityCertIssuer and authorityCertSerialNumber
are also possible attach in AuthorityKeyIdentifier sequence.

v2:
 - Removed comma from author's name.
 - Moved 'Short Form length' comment inside the if-body.
 - Changed the type of sub to size_t.
 - Use ASN1_INDEFINITE_LENGTH rather than writing 0x80 and 127.
 - Moved the key_len's value assignment before alter v.
 - Fixed the typo of octets.
 - Add 2 to v before entering the loop for calculate the length.
 - Removed the comment of check vlen.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Chun-Yi Lee <jlee@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
modpost: fix unwanted VMLINUX_SYMBOL_STR expansion

Commit a4b6a77b77ba4f526392612c2365797fab956014 ("module: fix symbol
versioning with symbol prefixes") broke the MODVERSIONS loading of any
module using memcmp (e.g. ipv6) on x86_32, as it's defined to
__builtin_memcmp which is expanded by VMLINUX_SYMBOL_STR. Use
__VMLINUX_SYMBOL_STR instead which doesn't expand the argument.

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: <stable@vger.kernel.org> # 3.9
ipc: move rcu_read_unlock() out of sem_unlock() and into callers

The IPC locking is a mess, and sem_unlock() unlocks not only the
semaphore spinlock, it also drops the rcu read lock.  Unlike sem_lock(),
which just gets the spin-lock, and expects the caller to get the rcu
read lock.

This all makes things very hard to follow, and it's very confusing when
you take the rcu read lock in one function, and then release it in
another.  And it has caused actual bugs: the sem_obtain_lock() function
ended up dropping the RCU read lock twice in one error path, because it
first did the sem_unlock(), and then did a rcu_read_unlock() to match
the rcu_read_lock() it had done.

This is just a totally mindless "remove rcu_read_unlock() from
sem_unlock() and add it immediately after each caller" (except for the
aforementioned bug where we did too many rcu_read_unlock(), and in
find_alloc_undo() where we just got the rcu_read_lock() to correct for
the fact that sem_unlock would immediately drop it again).

We can (and should) clean things up further, but this fixes the bug with
the minimal amount of subtlety.

Reviewed-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc: sem_putref() does not need the semaphore lock any more

ipc_rcu_putref() uses atomics for the refcount, and the games to lock
and unlock the semaphore just to try to keep the reference counting
working are no longer useful.

Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc: move the rcu_read_lock() from sem_lock_and_putref() into callers

This is another ipc semaphore locking cleanup, trying to make the
locking more straightforward.  We move the rcu read locking into the
callers of sem_lock_and_putref(), which in general means that we now
mostly do the rcu_read_lock() and rcu_read_unlock() in the same
function.

Mostly.  We still have the ipc_addid/newary/freeary mess, and things
like ipcctl_pre_down_nolock().

Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc: fix double sem unlock in semctl error path

Fix another ipc locking buglet introduced by the scalability patches:
when semctl_down() was changed to delay the semaphore locking, one error
path for security_sem_semctl() went through the semaphore unlock logic
even though the semaphore had never been locked.

Introduced by commit 16df3674efe3 ("ipc,sem: do not hold ipc lock more
than necessary")

Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc: move sem_obtain_lock() rcu locking into the only caller

sem_obtain_lock() was another of those functions that returned with the
RCU lock held for reading in the success case.  Move the RCU locking to
the caller (semtimedop()), making it more obvious.  We already did RCU
locking elsewhere in that function.

Side note: why does semtimedop() re-do the semphore lookup after the
sleep, rather than just getting a reference to the semaphore it already
looked up originally?

Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc: simplify semtimedop/semctl_main() common error path handling

With various straight RCU lock/unlock movements, one common exit path
pattern had become

	rcu_read_unlock();
	goto out_wakeup;

and in fact there were no cases where we wanted to exit to out_wakeup
_without_ releasing the RCU read lock.

So replace that pattern with "goto out_rcu_wakeup", and remove the old
out_wakeup.

Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc: simplify rcu_read_lock() in semctl_nolock()

This trivially combines two rcu_read_lock() calls in both sides of a
if-statement into one single one in front of the if-statement.

Split out as an independent cleanup from the previous commit.

Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arm: single_open() leaks

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
cris: single_open() leaks

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>