linux-stable.git/arch/powerpc/kernel/setup_64.c, branch linux-2.6.36.y

powerpc: Correct smt_enabled=X boot option for > 2 threads per core

2010-08-24T05:26:30+00:00

The 'smt_enabled=X' boot option does not handle values of X > 2.
For Power 7 processors with smt modes of 0,1,2,3, and 4 this does
not work.  This patch allows the smt_enabled option to be set to
any value limited to a max equal to the number of threads per
core.

Signed-off-by: Nathan Fontenot 
Signed-off-by: Benjamin Herrenschmidt

Merge commit 'gcl/next' into next

2010-08-04T00:26:03+00:00

powerpc/kexec: Switch to a static PACA on the way out

2010-07-31T04:56:30+00:00

With dynamic PACAs, the kexecing CPU's PACA won't lie within the kernel
static data and there is a chance that something may stomp it when preparing
to kexec.  This patch switches this final CPU to a static PACA just before
we pull the switch.

Signed-off-by: Matt Evans 
Signed-off-by: Benjamin Herrenschmidt

lmb: rename to memblock

2010-07-14T07:14:00+00:00

via following scripts

      FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')

      sed -i \
        -e 's/lmb/memblock/g' \
        -e 's/LMB/MEMBLOCK/g' \
        $FILES

      for N in $(find . -name lmb.[ch]); do
        M=$(echo $N | sed 's/lmb/memblock/g')
        mv $N $M
      done

and remove some wrong change like lmbench and dlmb etc.

also move memblock.c from lib/ to mm/

Suggested-by: Ingo Molnar 
Acked-by: "H. Peter Anvin" 
Acked-by: Benjamin Herrenschmidt 
Acked-by: Linus Torvalds 
Signed-off-by: Yinghai Lu 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Optimise per cpu accesses on 64bit

2010-07-09T01:28:30+00:00

Now we dynamically allocate the paca array, it takes an extra load
whenever we want to access another cpu's paca. One place we do that a lot
is per cpu variables. A simple example:

DEFINE_PER_CPU(unsigned long, vara);
unsigned long test4(int cpu)
{
	return per_cpu(vara, cpu);
}

This takes 4 loads, 5 if you include the actual load of the per cpu variable:

    ld r11,-32760(r30)  # load address of paca pointer
    ld r9,-32768(r30)   # load link address of percpu variable
    sldi r3,r29,9       # get offset into paca (each entry is 512 bytes)
    ld r0,0(r11)        # load paca pointer
    add r3,r0,r3        # paca + offset
    ld r11,64(r3)       # load paca[cpu].data_offset

    ldx r3,r9,r11       # load per cpu variable

If we remove the ppc64 specific per_cpu_offset(), we get the generic one
which indexes into a statically allocated array. This removes one load and
one add:

    ld r11,-32760(r30)  # load address of __per_cpu_offset
    ld r9,-32768(r30)   # load link address of percpu variable
    sldi r3,r29,3       # get offset into __per_cpu_offset (each entry 8 bytes)
    ldx r11,r11,r3      # load __per_cpu_offset[cpu]

    ldx r3,r9,r11       # load per cpu variable

Having all the offsets in one array also helps when iterating over a per cpu
variable across a number of cpus, such as in the scheduler. Before we would
need to load one paca cacheline when calculating each per cpu offset. Now we
have 16 (128 / sizeof(long)) per cpu offsets in each cacheline.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Unconditionally enabled irq stacks

2010-06-15T05:02:37+00:00

Irq stacks provide an essential protection from stack overflows through
external interrupts, at the cost of two additionals stacks per CPU.

Enable them unconditionally to simplify the kernel build and prevent
people from accidentally disabling them.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Use more accurate limit for first segment memory allocations

2010-05-21T07:31:10+00:00

Author: Milton Miller 

On large machines we are running out of room below 256MB. In some cases we
only need to ensure the allocation is in the first segment, which may be
256MB or 1TB.

Add slb0_limit and use it to specify the upper limit for the irqstack and
emergency stacks.

On a large ppc64 box, this fixes a panic at boot when the crashkernel=
option is specified (previously we would run out of memory below 256MB).

Signed-off-by: Milton Miller 
Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Use common cpu_die (fixes SMP+SUSPEND build)

2010-05-21T07:31:08+00:00

Configuring a powerpc 32 bit kernel for both SMP and SUSPEND turns on
CPU_HOTPLUG to enable disable_nonboot_cpus to be called by the common
suspend code.  Previously the definition of cpu_die for ppc32 was in
the powermac platform code, causing it to be undefined if that platform
as not selected.

arch/powerpc/kernel/built-in.o: In function 'cpu_idle':
arch/powerpc/kernel/idle.c:98: undefined reference to 'cpu_die'

Move the code from setup_64 to smp.c and rename the power mac
versions to their specific names.

Note that this does not setup the cpu_die pointers in either
smp_ops (request a given cpu die) or ppc_md (make this cpu die),
for other platforms but there are generic versions in smp.c.

Reported-by: Matt Sealey 
Reported-by: Kumar Gala 
Signed-off-by: Milton Miller 
Signed-off-by: Anton Vorontsov 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix swiotlb to respect the boot option

2010-03-19T05:38:16+00:00

powerpc initializes swiotlb before parsing the kernel boot options so
swiotlb options (e.g. specifying the swiotlb buffer size) are ignored.

Any time before freeing bootmem works for swiotlb so this patch moves
powerpc's swiotlb initialization after parsing the kernel boot
options, mem_init (as x86 does).

Signed-off-by: FUJITA Tomonori 
Tested-by: Becky Bruce 
Tested-by: Albert Herranz 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Dynamically allocate pacas

2010-03-09T00:52:52+00:00

On 64-bit kernels we currently have a 512 byte struct paca_struct for
each cpu (usually just called "the paca"). Currently they are statically
allocated, which means a kernel built for a large number of cpus will
waste a lot of space if it's booted on a machine with few cpus.

We can avoid that by only allocating the number of pacas we need at
boot. However this is complicated by the fact that we need to access
the paca before we know how many cpus there are in the system.

The solution is to dynamically allocate enough space for NR_CPUS pacas,
but then later in boot when we know how many cpus we have, we free any
unused pacas.

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