linux.git/arch/powerpc/kernel/setup_64.c, branch v3.18.64

Revert "powerpc/numa: Fix percpu allocations to be NUMA aware"

2017-08-11T16:30:08+00:00

This reverts commit 138bb14846a5856747694ae9ef565c9eb4533a1e which is
commit ba4a648f12f4cd0a8003dd229b6ca8a53348ee4b upstream.

Michal Hocko writes:

JFYI. We have encountered a regression after applying this patch on a
large ppc machine. While the patch is the right thing to do it doesn't
work well with the current vmalloc area size on ppc and large machines
where NUMA nodes are very far from each other. Just for the reference
the boot fails on such a machine with bunch of warning preceeding it.
See http://lkml.kernel.org/r/20170724134240.GL25221@dhcp22.suse.cz

It seems the right thing to do is to enlarge the vmalloc space on ppc
but this is not the case in the upstream kernel yet AFAIK. It is also
questionable whether that is a stable material but I will decision on
you here.

We have reverted this patch from our 4.4 based kernel.

Newer kernels do not have enlarged vmalloc space yet AFAIK so they won't
work properly eiter. This bug is quite rare though because you need a
specific HW configuration to trigger the issue - namely NUMA nodes have
to be far away from each other in the physical memory space.

Cc: Michal Hocko 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Signed-off-by: Greg Kroah-Hartman

powerpc/numa: Fix percpu allocations to be NUMA aware

2017-06-14T10:54:19+00:00

commit ba4a648f12f4cd0a8003dd229b6ca8a53348ee4b upstream.

In commit 8c272261194d ("powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID"), we
switched to the generic implementation of cpu_to_node(), which uses a percpu
variable to hold the NUMA node for each CPU.

Unfortunately we neglected to notice that we use cpu_to_node() in the allocation
of our percpu areas, leading to a chicken and egg problem. In practice what
happens is when we are setting up the percpu areas, cpu_to_node() reports that
all CPUs are on node 0, so we allocate all percpu areas on node 0.

This is visible in the dmesg output, as all pcpu allocs being in group 0:

  pcpu-alloc: [0] 00 01 02 03 [0] 04 05 06 07
  pcpu-alloc: [0] 08 09 10 11 [0] 12 13 14 15
  pcpu-alloc: [0] 16 17 18 19 [0] 20 21 22 23
  pcpu-alloc: [0] 24 25 26 27 [0] 28 29 30 31
  pcpu-alloc: [0] 32 33 34 35 [0] 36 37 38 39
  pcpu-alloc: [0] 40 41 42 43 [0] 44 45 46 47

To fix it we need an early_cpu_to_node() which can run prior to percpu being
setup. We already have the numa_cpu_lookup_table we can use, so just plumb it
in. With the patch dmesg output shows two groups, 0 and 1:

  pcpu-alloc: [0] 00 01 02 03 [0] 04 05 06 07
  pcpu-alloc: [0] 08 09 10 11 [0] 12 13 14 15
  pcpu-alloc: [0] 16 17 18 19 [0] 20 21 22 23
  pcpu-alloc: [1] 24 25 26 27 [1] 28 29 30 31
  pcpu-alloc: [1] 32 33 34 35 [1] 36 37 38 39
  pcpu-alloc: [1] 40 41 42 43 [1] 44 45 46 47

We can also check the data_offset in the paca of various CPUs, with the fix we
see:

  CPU 0:  data_offset = 0x0ffe8b0000
  CPU 24: data_offset = 0x1ffe5b0000

And we can see from dmesg that CPU 24 has an allocation on node 1:

  node   0: [mem 0x0000000000000000-0x0000000fffffffff]
  node   1: [mem 0x0000001000000000-0x0000001fffffffff]

Fixes: 8c272261194d ("powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID")
Signed-off-by: Michael Ellerman 
Reviewed-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc: Disable HFSCR[TM] if TM is not supported

2017-04-22T05:15:01+00:00

commit 7ed23e1bae8bf7e37fd555066550a00b95a3a98b upstream.

On Power8 & Power9 the early CPU inititialisation in __init_HFSCR()
turns on HFSCR[TM] (Hypervisor Facility Status and Control Register
[Transactional Memory]), but that doesn't take into account that TM
might be disabled by CPU features, or disabled by the kernel being built
with CONFIG_PPC_TRANSACTIONAL_MEM=n.

So later in boot, when we have setup the CPU features, clear HSCR[TM] if
the TM CPU feature has been disabled. We use CPU_FTR_TM_COMP to account
for the CONFIG_PPC_TRANSACTIONAL_MEM=n case.

Without this a KVM guest might try use TM, even if told not to, and
cause an oops in the host kernel. Typically the oops is seen in
__kvmppc_vcore_entry() and may or may not be fatal to the host, but is
always bad news.

In practice all shipping CPU revisions do support TM, and all host
kernels we are aware of build with TM support enabled, so no one should
actually be able to hit this in the wild.

Fixes: 2a3563b023e5 ("powerpc: Setup in HFSCR for POWER8")
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Benjamin Herrenschmidt 
Tested-by: Sam Bobroff 
[mpe: Rewrite change log with input from Sam, add Fixes/stable]
Signed-off-by: Michael Ellerman 
[sb: Backported to linux-4.4.y: adjusted context]
Signed-off-by: Sam Bobroff 
Signed-off-by: Greg Kroah-Hartman

powerpc: Add printk levels to setup_system output

2014-10-16T06:37:27+00:00

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

powerpc: Remove powerpc specific cmd_line

2014-10-02T07:33:55+00:00

There is no need for yet another copy of the command line, just
use boot_command_line like everyone else.

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

powerpc/ppc64: Print CPU/MMU/FW features at boot

2014-09-25T13:14:55+00:00

"Helps debug funky firmware issues".

After:
  Starting Linux PPC64 #108 SMP Wed Aug 6 19:04:51 EST 2014
  -----------------------------------------------------
  ppc64_pft_size    = 0x1a
  phys_mem_size     = 0x200000000
  cpu_features      = 0x17fc7a6c18500249
    possible        = 0x1fffffff18700649
    always          = 0x0000000000000040
  cpu_user_features = 0xdc0065c2 0xee000000
  mmu_features      = 0x5a000001
  firmware_features = 0x00000001405a440b
  htab_hash_mask    = 0x7ffff
  -----------------------------------------------------

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Michael Ellerman

powerpc/ppc64: Clean up the boot-time settings display

2014-09-25T13:14:55+00:00

At boot we display a bunch of low level settings which can be useful to
know, and can help to spot bugs when things are fundamentally
misconfigured.

At the moment they are very widely spaced, so that we can accommodate
the line:

  ppc64_caches.dcache_line_size = 0xYY

But we only print that line when the cache line size is not 128, ie.
almost never, so it just makes the display look odd usually.

The ppc64_caches prefix is redundant so remove it, which means we can
align things a bit closer for the common case. While we're there
replace the last use of camelCase (physicalMemorySize), and use
phys_mem_size.

Before:
  Starting Linux PPC64 #104 SMP Wed Aug 6 18:41:34 EST 2014
  -----------------------------------------------------
  ppc64_pft_size                = 0x1a
  physicalMemorySize            = 0x200000000
  ppc64_caches.dcache_line_size = 0xf0
  ppc64_caches.icache_line_size = 0xf0
  htab_address                  = 0xdeadbeef
  htab_hash_mask                = 0x7ffff
  physical_start                = 0xf000bar
  -----------------------------------------------------

After:
  Starting Linux PPC64 #103 SMP Wed Aug 6 18:38:04 EST 2014
  -----------------------------------------------------
  ppc64_pft_size    = 0x1a
  phys_mem_size     = 0x200000000
  dcache_line_size  = 0xf0
  icache_line_size  = 0xf0
  htab_address      = 0xdeadbeef
  htab_hash_mask    = 0x7ffff
  physical_start    = 0xf000bar
  -----------------------------------------------------

This patch is final, no bike shedding ;)

Signed-off-by: Michael Ellerman

arch/powerpc: replace obsolete strict_strto* calls

2014-08-08T22:57:28+00:00

Replace strict_strto calls with more appropriate kstrto calls

Signed-off-by: Daniel Walter 
Cc: Benjamin Herrenschmidt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge remote-tracking branch 'scott/next' into next

2014-08-05T04:13:41+00:00

Scott writes:

Highlights include e6500 hardware threading support, an e6500 TLB erratum
workaround, corenet error reporting, support for a new board, and some
minor fixes.

powerpc/e6500: Add support for hardware threads

2014-07-30T00:26:20+00:00

The general idea is that each core will release all of its
threads into the secondary thread startup code, which will
eventually wait in the secondary core holding area, for the
appropriate bit in the PACA to be set. The kick_cpu function
pointer will set that bit in the PACA, and thus "release"
the core/thread to boot. We also need to do a few things that
U-Boot normally does for CPUs (like enable branch prediction).

Signed-off-by: Andy Fleming 
[scottwood@freescale.com: various changes, including only enabling
 threads if Linux wants to kick them]
Signed-off-by: Scott Wood