linux-stable.git/arch/powerpc/kernel/process.c, branch v4.5

mm: ASLR: use get_random_long()

2016-02-27T18:28:52+00:00

Replace calls to get_random_int() followed by a cast to (unsigned long)
with calls to get_random_long().  Also address shifting bug which, in
case of x86 removed entropy mask for mmap_rnd_bits values > 31 bits.

Signed-off-by: Daniel Cashman 
Acked-by: Kees Cook 
Cc: "Theodore Ts'o" 
Cc: Arnd Bergmann 
Cc: Greg Kroah-Hartman 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: David S. Miller 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: H. Peter Anvin 
Cc: Al Viro 
Cc: Nick Kralevich 
Cc: Jeff Vander Stoep 
Cc: Mark Salyzyn 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'powerpc-4.4-3' into next

2015-12-14T09:40:32+00:00

Merge the two TM fixes we merged in 4.4. We are about to merge selftests
for these, and without the fixes the selftests will oops.

powerpc fixes for 4.4 #2

 - tm: Block signal return from setting invalid MSR state from Michael Neuling
 - tm: Check for already reclaimed tasks from Michael Neuling

powerpc: Print MSR TM bits in oops messages

2015-12-14T09:40:26+00:00

Print MSR TM bits in oops messages.  This appends them to the end
like this:

    MSR: 8000000502823031 

You get the TM[] only if at least one TM MSR bit is set.  Inside the
TM[], E means Enabled (bit 32), S means Suspended (bit 33), and T
means Transactional (bit 34)

If no bits are set, you get no TM[] output.

Include rework of printbits() to handle this case.

Signed-off-by: Michael Neuling 
Signed-off-by: Michael Ellerman

powerpc: Fix DSCR inheritance over fork()

2015-12-10T10:11:13+00:00

Two DSCR tests have a hack in them:

	/*
	 * XXX: Force a context switch out so that DSCR
	 * current value is copied into the thread struct
	 * which is required for the child to inherit the
	 * changed value.
	 */
	sleep(1);

We should not be working around this in the testcase, it is a kernel bug.
Fix it by copying the current DSCR to the child, instead of what we
had in the thread struct at last context switch.

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Call restore_sprs() before _switch()

2015-12-10T10:10:55+00:00

commit 152d523e6307 ("powerpc: Create context switch helpers save_sprs()
and restore_sprs()") moved the restore of SPRs after the call to _switch().

There is an issue with this approach - new tasks do not return through
_switch(), they are set up by copy_thread() to directly return through
ret_from_fork() or ret_from_kernel_thread(). This means restore_sprs() is
not getting called for new tasks.

Fix this by moving restore_sprs() before _switch().

Fixes: 152d523e6307 ("powerpc: Create context switch helpers save_sprs() and restore_sprs()")
Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Call check_if_tm_restore_required() in enable_kernel_*()

2015-12-10T09:10:53+00:00

Commit a0e72cf12b1a ("powerpc: Create msr_check_and_{set,clear}()")
removed a call to check_if_tm_restore_required() in the
enable_kernel_*() functions. Add them back in.

Fixes: a0e72cf12b1a ("powerpc: Create msr_check_and_{set,clear}()")
Reported-by: Rashmica Gupta 
Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: clean up asm/switch_to.h

2015-12-02T08:34:41+00:00

Remove a bunch of unnecessary fallback functions and group
things in a more logical way.

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: Rearrange __switch_to()

2015-12-02T08:34:41+00:00

Most of __switch_to() is housekeeping, TLB batching, timekeeping etc.
Move these away from the more complex and critical context switching
code.

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: create flush_all_to_thread()

2015-12-02T08:34:40+00:00

Create a single function that flushes everything (FP, VMX, VSX, SPE).
Doing this all at once means we only do one MSR write.

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc: create giveup_all()

2015-12-02T08:34:26+00:00

Create a single function that gives everything up (FP, VMX, VSX, SPE).
Doing this all at once means we only do one MSR write.

A context switch microbenchmark using yield():

http://ozlabs.org/~anton/junkcode/context_switch2.c

./context_switch2 --test=yield --fp --altivec --vector 0 0

shows an improvement of 3% on POWER8.

Signed-off-by: Anton Blanchard 
[mpe: giveup_all() needs to be EXPORT_SYMBOL'ed]
Signed-off-by: Michael Ellerman