linux-toradex.git/arch/arm/kernel, branch v3.4.2

ARM: 7409/1: Do not call flush_cache_user_range with mmap_sem held

2012-06-01T07:18:28+00:00

commit 435a7ef52db7d86e67a009b36cac1457f8972391 upstream.

We can't be holding the mmap_sem while calling flush_cache_user_range
because the flush can fault. If we fault on a user address, the
page fault handler will try to take mmap_sem again. Since both places
acquire the read lock, most of the time it succeeds. However, if another
thread tries to acquire the write lock on the mmap_sem (e.g. mmap) in
between the call to flush_cache_user_range and the fault, the down_read
in do_page_fault will deadlock.

[will: removed drop of vma parameter as already queued by rmk (7365/1)]

Acked-by: Catalin Marinas 
Signed-off-by: Dima Zavin 
Signed-off-by: John Stultz 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: 7365/1: drop unused parameter from flush_cache_user_range

2012-06-01T07:18:28+00:00

commit 4542b6a0fa6b48d9ae6b41c1efeb618b7a221b2a upstream.

vma isn't used and flush_cache_user_range isn't a standard macro that
is used on several archs with the same prototype. In fact only unicore32
has a macro with the same name (with an identical implementation and no
in-tree users).

This is a part of a patch proposed by Dima Zavin (with Message-id:
1272439931-12795-1-git-send-email-dima@android.com) that didn't get
accepted.

Cc: Dima Zavin 
Acked-by: Catalin Marinas 
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Russell King 
Cc: Will Deacon 
Signed-off-by: Greg Kroah-Hartman

ARM: 7414/1: SMP: prevent use of the console when using idmap_pgd

2012-05-06T10:10:41+00:00

Commit 4e8ee7de227e3ab9a72040b448ad728c5428a042 (ARM: SMP: use
idmap_pgd for mapping MMU enable during secondary booting)
switched secondary boot to use idmap_pgd, which is initialized
during early_initcall, instead of a page table initialized during
__cpu_up.  This causes idmap_pgd to contain the static mappings
but be missing all dynamic mappings.

If a console is registered that creates a dynamic mapping, the
printk in secondary_start_kernel will trigger a data abort on
the missing mapping before the exception handlers have been
initialized, leading to a hang.  Initial boot is not affected
because no consoles have been registered, and resume is usually
not affected because the offending console is suspended.
Onlining a cpu with hotplug triggers the problem.

A workaround is to the printk in secondary_start_kernel until
after the page tables have been switched back to init_mm.

Cc: 
Signed-off-by: Colin Cross 
Signed-off-by: Russell King

ARM: 7412/1: audit: use only AUDIT_ARCH_ARM regardless of endianness

2012-05-05T12:54:01+00:00

The machine endianness has no direct correspondence to the syscall ABI,
so use only AUDIT_ARCH_ARM when identifying the ABI to the audit tools
in userspace.

Cc: stable@vger.kernel.org
Signed-off-by: Will Deacon 
Signed-off-by: Russell King

ARM: 7411/1: audit: fix treatment of saved ip register during syscall tracing

2012-05-05T12:54:01+00:00

The ARM audit code incorrectly uses the saved application ip register
value to infer syscall entry or exit. Additionally, the saved value will
be clobbered if the current task is not being traced, which can lead to
libc corruption if ip is live (apparently glibc uses it for the TLS
pointer).

This patch fixes the syscall tracing code so that the why parameter is
used to infer the syscall direction and the saved ip is only updated if
we know that we will be signalling a ptrace trap.

Reported-and-Tested-by: Jon Masters 

Cc: stable@vger.kernel.org
Cc: Eric Paris 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King

ARM: 7410/1: Add extra clobber registers for assembly in kernel_execve

2012-05-05T12:54:01+00:00

The inline assembly in kernel_execve() uses r8 and r9.  Since this
code sequence does not return, it usually doesn't matter if the
register clobber list is accurate.  However, I saw a case where a
particular version of gcc used r8 as an intermediate for the value
eventually passed to r9.  Because r8 is used in the inline
assembly, and not mentioned in the clobber list, r9 was set
to an incorrect value.

This resulted in a kernel panic on execution of the first user-space
program in the system.  r9 is used in ret_to_user as the thread_info
pointer, and if it's wrong, bad things happen.

Cc: 
Signed-off-by: Tim Bird 
Signed-off-by: Russell King

ARM: 7406/1: hotplug: copy the affinity mask when forcefully migrating IRQs

2012-04-28T10:01:31+00:00

When a CPU is hotplugged off, we migrate any IRQs currently affine to it
away and onto another online CPU by calling the irq_set_affinity
function of the relevant interrupt controller chip. This function
returns either IRQ_SET_MASK_OK or IRQ_SET_MASK_OK_NOCOPY, to indicate
whether irq_data.affinity was updated.

If we are forcefully migrating an interrupt (because the affinity mask
no longer identifies any online CPUs) then we should update the IRQ
affinity mask to reflect the new CPU set. Failure to do so can
potentially leave /proc/irq/n/smp_affinity identifying only offline
CPUs, which may confuse userspace IRQ balancing daemons.

This patch updates migrate_one_irq to copy the affinity mask when
the interrupt chip returns IRQ_SET_MASK_OK after forcefully changing the
affinity of an interrupt.

Cc: stable@vger.kernel.org
Reported-by: Leif Lindholm 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King

ARM: 7405/1: kexec: call platform_cpu_kill on the killer rather than the victim

2012-04-28T10:01:31+00:00

When performing a kexec on an SMP system, the secondary cores are stopped
by calling machine_shutdown(), which in turn issues IPIs to offline the
other CPUs. Unfortunately, this isn't enough to reboot the cores into
a new kernel (since they are just executing a cpu_relax loop somewhere
in memory) so we make use of platform_cpu_kill, part of the CPU hotplug
implementation, to place the cores somewhere safe. This function expects
to be called on the killing CPU for each core that it takes out.

This patch moves the platform_cpu_kill callback out of the IPI handler
and into smp_send_stop, therefore ensuring that it executes on the
killing CPU rather than on the victim, matching what the hotplug code
requires.

Cc: stable@vger.kernel.org
Reported-by: Russell King 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King

ARM: 7399/1: vfp: move user vfp state save/restore code out of signal.c

2012-04-23T14:44:41+00:00

The user VFP state must be preserved (subject to ucontext modifications)
across invocation of a signal handler and this is currently handled by
vfp_{preserve,restore}_context in signal.c

Since this code requires intimate low-level knowledge of the VFP state,
this patch moves it into vfpmodule.c.

Signed-off-by: Will Deacon 
Signed-off-by: Russell King

Revert "ARM: 7359/2: smp_twd: Only wait for reprogramming on active cpus"

2012-04-19T18:35:10+00:00

This reverts commit 9f85550347f51c79a917b2aec04c90691c11e20a.

Peter Zijlstra says:
| Argh, how did that ever make it upstream, please drop.
|
| Russell, please make that go away upstream.
|
| Like I said, this is both completely the wrong way to solve, and you're
| so not paying attention, see:
|
|   5fbd036b552f633abb394a319f7c62a5c86a9cd7
|   2baab4e90495ebc9826c93f79d74d6e60a828d24
|   e3831edd59edf57ca11fc289f08961b20baf5146
|
| What's even worse:
|
| git describe --contains 9f85550347f51c79a917b2aec04c90691c11e20a --match "v*"
| v3.4-rc3~1^2~3
|
| that nonsense got merged long after those other commits.

Linus Walleij says:
| My bad, was because the initial patch was submitted march 9th before
| these fixes were merged:
| http://marc.info/?l=linux-arm-kernel&m=133159655513844&w=2
|
| It was pending for a while in Russell's patch tracker and I
| rebased it to -rc2 without paying enough attention to recent
| related scheduler fixes ... lesson learned.

Signed-off-by: Russell King