Since commit 8a0a9bd4, this comment in mmap_rnd() does not
hold true as the value returned by get_random_int() will in fact be

different every single call. Remove the comment and simplify the code
back to its original desired form.

This reverts commit a5adc91a which is no longer necessary and
also fixes the sparc code that copied this same adjustment.
Signed-off-by: NDan McGee <dpmcgee@gmail.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Make sure compiler won't do weird things with limits. E.g. fetching
them twice may return 2 different values after writable limits are
implemented.

I.e. either use rlimit helpers added in
3e10e716
or ACCESS_ONCE if not applicable.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@ozlabs.org
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This file is only useful on 64-bit, so we name it accordingly.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

On 64bit there is a possibility our stack and mmap randomisation will put
the two close enough such that we can't expand our stack to match the ulimit
specified.

To avoid this, start the upper mmap address at 1GB + 128MB below the top of our
address space, so in the worst case we end up with the same ~128MB hole as in
32bit. This works because we randomise the stack over a 1GB range.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

get_random_int() returns the same value within a 1 jiffy interval. This means
that the mmap and stack regions will almost always end up the same distance
apart, making a relative offset based attack possible.

To fix this, shift the randomness we use for the mmap region by 1 bit.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Randomise mmap start address - 8MB on 32bit and 1GB on 64bit tasks.
Until ppc32 uses the mmap.c functionality, this is ppc64 specific.

Before:

# ./test & cat /proc/${!}/maps|tail -2|head -1
f75fe000-f7fff000 rw-p f75fe000 00:00 0
f75fe000-f7fff000 rw-p f75fe000 00:00 0
f75fe000-f7fff000 rw-p f75fe000 00:00 0
f75fe000-f7fff000 rw-p f75fe000 00:00 0
f75fe000-f7fff000 rw-p f75fe000 00:00 0

After:
# ./test & cat /proc/${!}/maps|tail -2|head -1
f718b000-f7b8c000 rw-p f718b000 00:00 0
f7551000-f7f52000 rw-p f7551000 00:00 0
f6ee7000-f78e8000 rw-p f6ee7000 00:00 0
f74d4000-f7ed5000 rw-p f74d4000 00:00 0
f6e9d000-f789e000 rw-p f6e9d000 00:00 0

Similar for 64bit, but with 1GB of scatter:
# ./test & cat /proc/${!}/maps|tail -2|head -1
fffb97b5000-fffb97b6000 rw-p fffb97b5000 00:00 0
fffce9a3000-fffce9a4000 rw-p fffce9a3000 00:00 0
fffeaaf2000-fffeaaf3000 rw-p fffeaaf2000 00:00 0
fffd88ac000-fffd88ad000 rw-p fffd88ac000 00:00 0
fffbc62e000-fffbc62f000 rw-p fffbc62e000 00:00 0
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Rearrange mmap.c to better match the x86 version.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We currently place mmaps just below the stack on 32bit, but leave them
in the middle of the address space on 64bit:

00100000-00120000 r-xp 00100000 00:00 0                    [vdso]
10000000-10010000 r-xp 00000000 08:06 179534               /tmp/sleep
10010000-10020000 rw-p 00000000 08:06 179534               /tmp/sleep
10020000-10130000 rw-p 10020000 00:00 0                    [heap]
40000000000-40000030000 r-xp 00000000 08:06 440743         /lib64/ld-2.9.so
40000030000-40000040000 rw-p 00020000 08:06 440743         /lib64/ld-2.9.so
40000050000-400001f0000 r-xp 00000000 08:06 440671         /lib64/libc-2.9.so
400001f0000-40000200000 r--p 00190000 08:06 440671         /lib64/libc-2.9.so
40000200000-40000220000 rw-p 001a0000 08:06 440671         /lib64/libc-2.9.so
40000220000-40008230000 rw-p 40000220000 00:00 0
fffffbc0000-fffffd10000 rw-p fffffeb0000 00:00 0           [stack]

Right now it isn't an issue, but at some stage we will run into mmap or
hugetlb allocation issues. Using the same layout as 32bit gives us a
some breathing room. This matches what x86-64 is doing too.

00100000-00103000 r-xp 00100000 00:00 0                    [vdso]
10000000-10001000 r-xp 00000000 08:06 554894               /tmp/test
10010000-10011000 r--p 00000000 08:06 554894               /tmp/test
10011000-10012000 rw-p 00001000 08:06 554894               /tmp/test
10012000-10113000 rw-p 10012000 00:00 0                    [heap]
fffefdf7000-ffff7df8000 rw-p fffefdf7000 00:00 0
ffff7df8000-ffff7f97000 r-xp 00000000 08:06 130591         /lib64/libc-2.9.so
ffff7f97000-ffff7fa6000 ---p 0019f000 08:06 130591         /lib64/libc-2.9.so
ffff7fa6000-ffff7faa000 r--p 0019e000 08:06 130591         /lib64/libc-2.9.so
ffff7faa000-ffff7fc0000 rw-p 001a2000 08:06 130591         /lib64/libc-2.9.so
ffff7fc0000-ffff7fc4000 rw-p ffff7fc0000 00:00 0
ffff7fc4000-ffff7fec000 r-xp 00000000 08:06 130663         /lib64/ld-2.9.so
ffff7fee000-ffff7ff0000 rw-p ffff7fee000 00:00 0
ffff7ffa000-ffff7ffb000 rw-p ffff7ffa000 00:00 0
ffff7ffb000-ffff7ffc000 r--p 00027000 08:06 130663         /lib64/ld-2.9.so
ffff7ffc000-ffff7fff000 rw-p 00028000 08:06 130663         /lib64/ld-2.9.so
ffff7fff000-ffff8000000 rw-p ffff7fff000 00:00 0
fffffc59000-fffffc6e000 rw-p ffffffeb000 00:00 0           [stack]
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.

This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
   getting them indirectly

Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
   they don't need sched.h
b) sched.h stops being dependency for significant number of files:
   on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
   after patch it's only 3744 (-8.3%).

Cross-compile tested on

	all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
	alpha alpha-up
	arm
	i386 i386-up i386-defconfig i386-allnoconfig
	ia64 ia64-up
	m68k
	mips
	parisc parisc-up
	powerpc powerpc-up
	s390 s390-up
	sparc sparc-up
	sparc64 sparc64-up
	um-x86_64
	x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig

as well as my two usual configs.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch removes all self references and fixes references to files
in the now defunct arch/ppc64 tree.  I think this accomplises
everything wanted, though there might be a few references I missed.
Signed-off-by: NJon Mason <jdmason@us.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This moves the remaining files in arch/ppc64/mm to arch/powerpc/mm,
and arranges that we use them when compiling with ARCH=ppc64.
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!