linux-toradex.git/arch, branch v3.0.52

x86: Remove the ancient and deprecated disable_hlt() and enable_hlt() facility

2012-11-05T08:44:26+00:00

commit f6365201d8a21fb347260f89d6e9b3e718d63c70 upstream.

The X86_32-only disable_hlt/enable_hlt mechanism was used by the
32-bit floppy driver. Its effect was to replace the use of the
HLT instruction inside default_idle() with cpu_relax() - essentially
it turned off the use of HLT.

This workaround was commented in the code as:

 "disable hlt during certain critical i/o operations"

 "This halt magic was a workaround for ancient floppy DMA
  wreckage. It should be safe to remove."

H. Peter Anvin additionally adds:

 "To the best of my knowledge, no-hlt only existed because of
  flaky power distributions on 386/486 systems which were sold to
  run DOS.  Since DOS did no power management of any kind,
  including HLT, the power draw was fairly uniform; when exposed
  to the much hhigher noise levels you got when Linux used HLT
  caused some of these systems to fail.

  They were by far in the minority even back then."

Alan Cox further says:

 "Also for the Cyrix 5510 which tended to go castors up if a HLT
  occurred during a DMA cycle and on a few other boxes HLT during
  DMA tended to go astray.

  Do we care ? I doubt it. The 5510 was pretty obscure, the 5520
  fixed it, the 5530 is probably the oldest still in any kind of
  use."

So, let's finally drop this.

Signed-off-by: Len Brown 
Signed-off-by: Josh Boyer 
Signed-off-by: Andrew Morton 
Acked-by: "H. Peter Anvin" 
Acked-by: Alan Cox 
Cc: Stephen Hemminger 
Link: http://lkml.kernel.org/n/tip-3rhk9bzf0x9rljkv488tloib@git.kernel.org
[ If anyone cares then alternative instruction patching could be
  used to replace HLT with a one-byte NOP instruction. Much simpler. ]
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86, mm: Undo incorrect revert in arch/x86/mm/init.c

2012-10-31T16:51:37+00:00

commit f82f64dd9f485e13f29f369772d4a0e868e5633a upstream.

Commit

    844ab6f9 x86, mm: Find_early_table_space based on ranges that are actually being mapped

added back some lines back wrongly that has been removed in commit

    7b16bbf97 Revert "x86/mm: Fix the size calculation of mapping tables"

remove them again.

Signed-off-by: Yinghai Lu 
Link: http://lkml.kernel.org/r/CAE9FiQW_vuaYQbmagVnxT2DGsYc=9tNeAbdBq53sYkitPOwxSQ@mail.gmail.com
Acked-by: Jacob Shin 
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

x86, mm: Find_early_table_space based on ranges that are actually being mapped

2012-10-31T16:51:37+00:00

commit 844ab6f993b1d32eb40512503d35ff6ad0c57030 upstream.

Current logic finds enough space for direct mapping page tables from 0
to end. Instead, we only need to find enough space to cover mr[0].start
to mr[nr_range].end -- the range that is actually being mapped by
init_memory_mapping()

This is needed after 1bbbbe779aabe1f0768c2bf8f8c0a5583679b54a, to address
the panic reported here:

  https://lkml.org/lkml/2012/10/20/160
  https://lkml.org/lkml/2012/10/21/157

Signed-off-by: Jacob Shin 
Link: http://lkml.kernel.org/r/20121024195311.GB11779@jshin-Toonie
Tested-by: Tom Rini 
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

ARM: at91/i2c: change id to let i2c-gpio work

2012-10-31T16:51:37+00:00

commit 7840487cd6298f9f931103b558290d8d98d41c49 upstream.

The i2c core driver will turn the platform device ID to busnum
When using platfrom device ID as -1, it means dynamically assigned
the busnum. When writing code, we need to make sure the busnum,
and call i2c_register_board_info(int busnum, ...) to register device
if using -1, we do not know the value of busnum

In order to solve this issue, set the platform device ID as a fix number
Here using 0 to match the busnum used in i2c_regsiter_board_info()

Signed-off-by: Bo Shen 
Acked-by: Jean Delvare 
Signed-off-by: Nicolas Ferre 
Acked-by: Jean-Christophe PLAGNIOL-VILLARD 
Acked-by: Ludovic Desroches 
Signed-off-by: Greg Kroah-Hartman

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

2012-10-31T16:51:34+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.

Reported-by: Gilles Chanteperdrix 
Cc: David McKay 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

sparc64: Be less verbose during vmemmap population.

2012-10-28T17:02:13+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: Greg Kroah-Hartman

sparc64: do not clobber personality flags in sys_sparc64_personality()

2012-10-28T17:02:13+00:00

[ Upstream commit a27032eee8cb6e16516f13c8a9752e9d5d4cc430 ]

There are multiple errors in how sys_sparc64_personality() handles
personality flags stored in top three bytes.

- directly comparing current->personality against PER_LINUX32 doesn't work
  in cases when any of the personality flags stored in the top three bytes
  are used.
- directly forcefully setting personality to PER_LINUX32 or PER_LINUX
  discards any flags stored in the top three bytes

Fix the first one by properly using personality() macro to compare only
PER_MASK bytes.
Fix the second one by setting only the bits that should be set, instead of
overwriting the whole value.

Signed-off-by: Jiri Kosina 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sparc64: Fix bit twiddling in sparc_pmu_enable_event().

2012-10-28T17:02:13+00:00

[ Upstream commit e793d8c6740f8fe704fa216e95685f4d92c4c4b9 ]

There was a serious disconnect in the logic happening in
sparc_pmu_disable_event() vs. sparc_pmu_enable_event().

Event disable is implemented by programming a NOP event into the PCR.

However, event enable was not reversing this operation.  Instead, it
was setting the User/Priv/Hypervisor trace enable bits.

That's not sparc_pmu_enable_event()'s job, that's what
sparc_pmu_enable() and sparc_pmu_disable() do .

The intent of sparc_pmu_enable_event() is clear, since it first clear
out the event type encoding field.  So fix this by OR'ing in the event
encoding rather than the trace enable bits.

Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sparc64: Like x86 we should check current->mm during perf backtrace generation.

2012-10-28T17:02:13+00:00

[ Upstream commit 08280e6c4c2e8049ac61d9e8e3536ec1df629c0d ]

If the MM is not active, only report the top-level PC.  Do not try to
access the address space.

Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sparc64: fix ptrace interaction with force_successful_syscall_return()

2012-10-28T17:02:13+00:00

[ Upstream commit 55c2770e413e96871147b9406a9c41fe9bc5209c ]

we want syscall_trace_leave() called on exit from any syscall;
skipping its call in case we'd done force_successful_syscall_return()
is broken...

Signed-off-by: Al Viro 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman