linux-toradex.git/arch, branch v3.2.33

arch/tile: avoid generating .eh_frame information in modules

2012-10-30T23:26:55+00:00

commit 627072b06c362bbe7dc256f618aaa63351f0cfe6 upstream.

The tile tool chain uses the .eh_frame information for backtracing.
The vmlinux build drops any .eh_frame sections at link time, but when
present in kernel modules, it causes a module load failure due to the
presence of unsupported pc-relative relocations.  When compiling to
use compiler feedback support, the compiler by default omits .eh_frame
information, so we don't see this problem.  But when not using feedback,
we need to explicitly suppress the .eh_frame.

Signed-off-by: Chris Metcalf 
Signed-off-by: Ben Hutchings

ARM: 7559/1: smp: switch away from the idmap before updating init_mm.mm_count

2012-10-30T23:26:54+00:00

commit 5f40b909728ad784eb43aa309d3c4e9bdf050781 upstream.

When booting a secondary CPU, the primary CPU hands two sets of page
tables via the secondary_data struct:

	(1) swapper_pg_dir: a normal, cacheable, shared (if SMP) mapping
	    of the kernel image (i.e. the tables used by init_mm).

	(2) idmap_pgd: an uncached mapping of the .idmap.text ELF
	    section.

The idmap is generally used when enabling and disabling the MMU, which
includes early CPU boot. In this case, the secondary CPU switches to
swapper as soon as it enters C code:

	struct mm_struct *mm = &init_mm;
	unsigned int cpu = smp_processor_id();

	/*
	 * All kernel threads share the same mm context; grab a
	 * reference and switch to it.
	 */
	atomic_inc(&mm->mm_count);
	current->active_mm = mm;
	cpumask_set_cpu(cpu, mm_cpumask(mm));
	cpu_switch_mm(mm->pgd, mm);

This causes a problem on ARMv7, where the identity mapping is treated as
strongly-ordered leading to architecturally UNPREDICTABLE behaviour of
exclusive accesses, such as those used by atomic_inc.

This patch re-orders the secondary_start_kernel function so that we
switch to swapper before performing any exclusive accesses.

Cc: David McKay 
Reported-by: Gilles Chanteperdrix 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King 
Signed-off-by: Ben Hutchings

xen/x86: don't corrupt %eip when returning from a signal handler

2012-10-30T23:26:52+00:00

commit a349e23d1cf746f8bdc603dcc61fae9ee4a695f6 upstream.

In 32 bit guests, if a userspace process has %eax == -ERESTARTSYS
(-512) or -ERESTARTNOINTR (-513) when it is interrupted by an event
/and/ the process has a pending signal then %eip (and %eax) are
corrupted when returning to the main process after handling the
signal.  The application may then crash with SIGSEGV or a SIGILL or it
may have subtly incorrect behaviour (depending on what instruction it
returned to).

The occurs because handle_signal() is incorrectly thinking that there
is a system call that needs to restarted so it adjusts %eip and %eax
to re-execute the system call instruction (even though user space had
not done a system call).

If %eax == -514 (-ERESTARTNOHAND (-514) or -ERESTART_RESTARTBLOCK
(-516) then handle_signal() only corrupted %eax (by setting it to
-EINTR).  This may cause the application to crash or have incorrect
behaviour.

handle_signal() assumes that regs->orig_ax >= 0 means a system call so
any kernel entry point that is not for a system call must push a
negative value for orig_ax.  For example, for physical interrupts on
bare metal the inverse of the vector is pushed and page_fault() sets
regs->orig_ax to -1, overwriting the hardware provided error code.

xen_hypervisor_callback() was incorrectly pushing 0 for orig_ax
instead of -1.

Classic Xen kernels pushed %eax which works as %eax cannot be both
non-negative and -RESTARTSYS (etc.), but using -1 is consistent with
other non-system call entry points and avoids some of the tests in
handle_signal().

There were similar bugs in xen_failsafe_callback() of both 32 and
64-bit guests. If the fault was corrected and the normal return path
was used then 0 was incorrectly pushed as the value for orig_ax.

Signed-off-by: David Vrabel 
Acked-by: Jan Beulich 
Acked-by: Ian Campbell 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Ben Hutchings

s390: fix linker script for 31 bit builds

2012-10-30T23:26:52+00:00

commit c985cb37f1b39c2c8035af741a2a0b79f1fbaca7 upstream.

Because of a change in the s390 arch backend of binutils (commit 23ecd77
"Pick the default arch depending on the target size" in binutils repo)
31 bit builds will fail since the linker would now try to create 64 bit
binary output.
Fix this by setting OUTPUT_ARCH to s390:31-bit instead of s390.
Thanks to Andreas Krebbel for figuring out the issue.

Fixes this build error:

  LD      init/built-in.o
s390x-4.7.2-ld: s390:31-bit architecture of input file
 `arch/s390/kernel/head.o' is incompatible with s390:64-bit output

Cc: Andreas Krebbel 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

oprofile, x86: Fix wrapping bug in op_x86_get_ctrl()

2012-10-30T23:26:45+00:00

commit 44009105081b51417f311f4c3be0061870b6b8ed upstream.

The "event" variable is a u16 so the shift will always wrap to zero
making the line a no-op.

Signed-off-by: Dan Carpenter 
Signed-off-by: Robert Richter 
Signed-off-by: Ben Hutchings

xen/bootup: allow {read|write}_cr8 pvops call.

2012-10-30T23:26:45+00:00

commit 1a7bbda5b1ab0e02622761305a32dc38735b90b2 upstream.

We actually do not do anything about it. Just return a default
value of zero and if the kernel tries to write anything but 0
we BUG_ON.

This fixes the case when an user tries to suspend the machine
and it blows up in save_processor_state b/c 'read_cr8' is set
to NULL and we get:

kernel BUG at /home/konrad/ssd/linux/arch/x86/include/asm/paravirt.h:100!
invalid opcode: 0000 [#1] SMP
Pid: 2687, comm: init.late Tainted: G           O 3.6.0upstream-00002-gac264ac-dirty #4 Bochs Bochs
RIP: e030:[]  [] save_processor_state+0x212/0x270

.. snip..
Call Trace:
 [] do_suspend_lowlevel+0xf/0xac
 [] ? x86_acpi_suspend_lowlevel+0x10c/0x150
 [] acpi_suspend_enter+0x57/0xd5

Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Ben Hutchings

xen/bootup: allow read_tscp call for Xen PV guests.

2012-10-30T23:26:44+00:00

commit cd0608e71e9757f4dae35bcfb4e88f4d1a03a8ab upstream.

The hypervisor will trap it. However without this patch,
we would crash as the .read_tscp is set to NULL. This patch
fixes it and sets it to the native_read_tscp call.

Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Ben Hutchings

mips,kgdb: fix recursive page fault with CONFIG_KPROBES

2012-10-30T23:26:44+00:00

commit f0a996eeeda214f4293e234df33b29bec003b536 upstream.

This fault was detected using the kgdb test suite on boot and it
crashes recursively due to the fact that CONFIG_KPROBES on mips adds
an extra die notifier in the page fault handler.  The crash signature
looks like this:

kgdbts:RUN bad memory access test
KGDB: re-enter exception: ALL breakpoints killed
Call Trace:
[<807b7548>] dump_stack+0x20/0x54
[<807b7548>] dump_stack+0x20/0x54

The fix for now is to have kgdb return immediately if the fault type
is DIE_PAGE_FAULT and allow the kprobe code to decide what is supposed
to happen.

Cc: Masami Hiramatsu 
Cc: David S. Miller 
Signed-off-by: Jason Wessel 
Signed-off-by: Ben Hutchings

ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels

2012-10-30T23:26:38+00:00

commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 upstream.

Michael Olbrich reported that his test program fails when built with
-O2 -mcpu=cortex-a8 -mfpu=neon, and a kernel which supports v6 and v7
CPUs:

volatile int x = 2;
volatile int64_t y = 2;

int main() {
	volatile int a = 0;
	volatile int64_t b = 0;
	while (1) {
		a = (a + x) % (1 << 30);
		b = (b + y) % (1 << 30);
		assert(a == b);
	}
}

and two instances are run.  When built for just v7 CPUs, this program
works fine.  It uses the "vadd.i64 d19, d18, d16" VFP instruction.

It appears that we do not save the high-16 double VFP registers across
context switches when the kernel is built for v6 CPUs.  Fix that.

Tested-By: Michael Olbrich 
Signed-off-by: Russell King 
Signed-off-by: Ben Hutchings

sparc64: Be less verbose during vmemmap population.

2012-10-30T23:26:32+00:00

[ Upstream commit 2856cc2e4d0852c3ddaae9dcb19cb9396512eb08 ]

On a 2-node machine with 256GB of ram we get 512 lines of
console output, which is just too much.

This mimicks Yinghai Lu's x86 commit c2b91e2eec9678dbda274e906cc32ea8f711da3b
(x86_64/mm: check and print vmemmap allocation continuous) except that
we aren't ever going to get contiguous block pointers in between calls
so just print when the virtual address or node changes.

This decreases the output by an order of 16.

Also demote this to KERN_DEBUG.

Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings