Age | Commit message (Collapse) | Author |
|
Impact: cleanup
tj: * changed cpu to unsigned as was done on mmu_context_64.h as cpu
id is officially unsigned int
* added missing ';' to 32bit version of deactivate_mm()
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: cleanup
%fs is currently set to __KERNEL_DS at boot, and conditionally
switched to __KERNEL_PERCPU for secondary cpus. Instead, initialize
GDT_ENTRY_PERCPU to the same attributes as GDT_ENTRY_KERNEL_DS and
set %fs to __KERNEL_PERCPU unconditionally.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: slightly better code generation for percpu_to_op()
The processor will sign-extend 32-bit immediate values in 64-bit
operations. Use the 'e' constraint ("32-bit signed integer constant,
or a symbolic reference known to fit that range") for 64-bit constants.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: cleanup && more compact percpu area layout with future changes
Move 64-bit GDT to page-aligned section and clean up comment
formatting.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: cleanup
In switch_to(), instead of taking offset to irq_stack_union.stack,
make it a proper percpu access using __percpu_arg() and per_cpu_var().
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: cleanup
Remove byte locks implementation, which was introduced by Jeremy in
8efcbab6 ("paravirt: introduce a "lock-byte" spinlock implementation"),
but turned out to be dead code that is not used by any in-kernel
virtualization guest (Xen uses its own variant of spinlocks implementation
and KVM is not planning to move to byte locks).
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
Impact: cleanup, restructure code to improve assembly
gcc isn't _all_ that smart about spilling registers to stack or reusing
stack slots, even with branch annotations. do_page_fault contained a lot
of functionality, so split unlikely paths into their own functions, and
mark them as noinline just to be sure. I consider this actually to be
somewhat of a cleanup too: the main function now contains about half
the number of lines so the normal path is easier to read, while the error
cases are also nicely split away.
Also, ensure the order of arguments to functions is always the same: regs,
addr, error_code. This can reduce code size a tiny bit, and just looks neater
too.
And add a couple of branch annotations.
Before:
do_page_fault:
subq $360, %rsp #,
After:
do_page_fault:
subq $56, %rsp #,
bloat-o-meter:
add/remove: 8/0 grow/shrink: 0/1 up/down: 2222/-1680 (542)
function old new delta
__bad_area_nosemaphore - 506 +506
no_context - 474 +474
vmalloc_fault - 424 +424
spurious_fault - 358 +358
mm_fault_error - 272 +272
bad_area_access_error - 89 +89
bad_area - 89 +89
bad_area_nosemaphore - 10 +10
do_page_fault 2464 784 -1680
Yes, the total size increases by 542 bytes, due to the extra function calls.
But these will very rarely be called (except for vmalloc_fault) in a normal
workload. Importantly, do_page_fault is less than 1/3rd it's original size,
and touches far less stack.
Existing gotos and branch hints did move a lot of the infrequently used text
out of the fastpath, but that's even further improved after this patch.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
|
|
Impact: fix bootup crash
The cpumask is now passed in as a reference to mm->cpu_vm_mask, not on
the stack - hence it is not constant anymore during the TLB flush.
That way it could race and some static sanity checks would trigger:
[ 238.154287] ------------[ cut here ]------------
[ 238.156039] kernel BUG at arch/x86/kernel/tlb_32.c:130!
[ 238.156039] invalid opcode: 0000 [#1] SMP
[ 238.156039] last sysfs file: /sys/class/net/eth2/address
[ 238.156039] Modules linked in:
[ 238.156039]
[ 238.156039] Pid: 6493, comm: ifup-eth Not tainted (2.6.29-rc2-tip #1) P4DC6
[ 238.156039] EIP: 0060:[<c0118f87>] EFLAGS: 00010202 CPU: 2
[ 238.156039] EIP is at native_flush_tlb_others+0x35/0x158
[ 238.156039] EAX: c0ef972c EBX: f6143301 ECX: 00000000 EDX: 00000000
[ 238.156039] ESI: f61433a8 EDI: f6143200 EBP: f34f3e00 ESP: f34f3df0
[ 238.156039] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[ 238.156039] Process ifup-eth (pid: 6493, ti=f34f2000 task=f399ab00 task.ti=f34f2000)
[ 238.156039] Stack:
[ 238.156039] ffffffff f61433a8 ffffffff f6143200 f34f3e18 c0118e9c 00000000 f6143200
[ 238.156039] f61433a8 f5bec738 f34f3e28 c0119435 c2b5b830 f6143200 f34f3e34 c01c2dc3
[ 238.156039] bffd9000 f34f3e60 c01c3051 00000000 ffffffff f34f3e4c 00000000 00000071
[ 238.156039] Call Trace:
[ 238.156039] [<c0118e9c>] ? flush_tlb_others+0x52/0x5b
[ 238.156039] [<c0119435>] ? flush_tlb_mm+0x7f/0x8b
[ 238.156039] [<c01c2dc3>] ? tlb_finish_mmu+0x2d/0x55
[ 238.156039] [<c01c3051>] ? exit_mmap+0x124/0x170
[ 238.156039] [<c013e965>] ? mmput+0x40/0xf5
[ 238.156039] [<c01e4788>] ? flush_old_exec+0x640/0x94b
[ 238.156039] [<c01ddb4e>] ? fsnotify_access+0x37/0x39
[ 238.156039] [<c01e3435>] ? kernel_read+0x39/0x4b
[ 238.156039] [<c021bc8a>] ? load_elf_binary+0x4a1/0x11bb
[ 238.156039] [<c01c0af9>] ? might_fault+0x51/0x9c
[ 238.156039] [<c010a2cc>] ? paravirt_read_tsc+0x20/0x4f
[ 238.156039] [<c010a406>] ? native_sched_clock+0x5d/0x60
[ 238.156039] [<c01e2fda>] ? search_binary_handler+0xab/0x2c4
[ 238.156039] [<c021b7e9>] ? load_elf_binary+0x0/0x11bb
[ 238.156039] [<c04ae9a5>] ? _raw_read_unlock+0x21/0x46
[ 238.156039] [<c021b7e9>] ? load_elf_binary+0x0/0x11bb
[ 238.156039] [<c01e2fe1>] ? search_binary_handler+0xb2/0x2c4
[ 238.156039] [<c01e4076>] ? do_execve+0x21c/0x2ee
[ 238.156039] [<c01029b7>] ? sys_execve+0x51/0x8c
[ 238.156039] [<c0103eaf>] ? sysenter_do_call+0x12/0x43
Fix it by not assuming that the cpumask is constant.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/percpu
|
|
Impact: cleanup
Signed-off-by: Brian Gerst <brgerst@gmail.com>
|
|
Impact: x86_64 percpu area layout change, irq_stack now at the beginning
Now that the PDA is empty except for the stack canary, it can be removed.
The irqstack is moved to the start of the per-cpu section. If the stack
protector is enabled, the canary overlaps the bottom 48 bytes of the irqstack.
tj: * updated subject
* dropped asm relocation of irq_stack_ptr
* updated comments a bit
* rebased on top of stack canary changes
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: cleanup
Use cpu_number to determine if the adjustment is necessary.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: cleanup
Copy the code to cpu_init() to satisfy the requirement that the cpu
be reinitialized. Remove all other calls, since the segments are
already initialized in head_64.S.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: no unnecessary stack canary swapping during context switch
There's no point in moving stack_canary around during context switch
if it's not enabled. Conditionalize it.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: cleanup
Make the following cleanups.
* remove duplicate comment from boot_init_stack_canary() which fits
better in the other place - cpu_idle().
* move stack_canary offset check from __switch_to() to
boot_init_stack_canary().
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Impact: fix crash with memory hotplug enabled
kernel_physical_mapping_init() is called during memory hotplug
so it does not belong in the init section.
If the kernel is built with CONFIG_DEBUG_SECTION_MISMATCH=y on
the make command line, arch/x86/mm/init_64.c is compiled with
the -fno-inline-functions-called-once gcc option defeating
inlining of kernel_physical_mapping_init() within init_memory_mapping().
When kernel_physical_mapping_init() is not inlined it is placed
in the .init.text section according to the __init in it's current
declaration. A later call to kernel_physical_mapping_init() during
a memory hotplug operation encounters an int3 trap because the
.init.text section memory has been freed.
This patch eliminates the crash caused by the int3 trap by moving the
non-inlined kernel_physical_mapping_init() from .init.text to .meminit.text.
Signed-off-by: Gary Hade <garyhade@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
-tip testing found this crash:
> [ 35.258515] calling acpi_cpufreq_init+0x0/0x127 @ 1
> [ 35.264127] BUG: unable to handle kernel NULL pointer dereference at (null)
> [ 35.267554] IP: [<ffffffff80478092>] __bitmap_intersects+0x48/0x73
> [ 35.267554] PGD 0
> [ 35.267554] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c is still broken: there's no
allocation of the variable mask, so we pass in an uninitialized cmd.mask
field to drv_read(), which then passes it to the scheduler which then
crashes ...
Switch it over to the much simpler constant-cpumask-pointers approach.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
Impact: use new work_on_cpu function to reduce stack usage
Replace the saving of current->cpus_allowed and set_cpus_allowed_ptr() with
a work_on_cpu function for drv_read() and drv_write().
Basically converts do_drv_{read,write} into "work_on_cpu" functions that
are now called by drv_read and drv_write.
Note: This patch basically reverts 50c668d6 which reverted 7503bfba, now
that the work_on_cpu() function is more stable.
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Dieter Ries <clip2@gmx.de>
Tested-by: Maciej Rutecki <maciej.rutecki@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: <cpufreq@vger.kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
Impact: build fix
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
Since commit 75c46fa, "x64, x2apic/intr-remap: MSI and MSI-X
support for interrupt remapping infrastructure", x86 has had an
implementation of arch_setup_msi_irqs().
That implementation does not call arch_setup_msi_irq(), instead it calls
setup_irq(). No other x86 code calls arch_setup_msi_irq().
That leaves only arch_setup_msi_irqs() in drivers/pci/msi.c, but that
routine is overridden by the x86 version of arch_setup_msi_irqs().
So arch_setup_msi_irq() is dead code, remove it.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
|
|
The function setup_cpu_local_masks() has been marked __init, in
order to remove the following section mismatch messages:
WARNING: vmlinux.o(.text+0x3c2c7): Section mismatch in reference from the function setup_cpu_local_masks() to the function .init.text:alloc_bootmem_cpumask_var()
The function setup_cpu_local_masks() references
the function __init alloc_bootmem_cpumask_var().
This is often because setup_cpu_local_masks lacks a __init
annotation or the annotation of alloc_bootmem_cpumask_var is wrong.
WARNING: vmlinux.o(.text+0x3c2d3): Section mismatch in reference from the function setup_cpu_local_masks() to the function .init.text:alloc_bootmem_cpumask_var()
The function setup_cpu_local_masks() references
the function __init alloc_bootmem_cpumask_var().
This is often because setup_cpu_local_masks lacks a __init
annotation or the annotation of alloc_bootmem_cpumask_var is wrong.
WARNING: vmlinux.o(.text+0x3c2df): Section mismatch in reference from the function setup_cpu_local_masks() to the function .init.text:alloc_bootmem_cpumask_var()
The function setup_cpu_local_masks() references
the function __init alloc_bootmem_cpumask_var().
This is often because setup_cpu_local_masks lacks a __init
annotation or the annotation of alloc_bootmem_cpumask_var is wrong.
WARNING: vmlinux.o(.text+0x3c2eb): Section mismatch in reference from the function setup_cpu_local_masks() to the function .init.text:alloc_bootmem_cpumask_var()
The function setup_cpu_local_masks() references
the function __init alloc_bootmem_cpumask_var().
This is often because setup_cpu_local_masks lacks a __init
annotation or the annotation of alloc_bootmem_cpumask_var is wrong.
Signed-off-by: Leonardo Potenza <lpotenza@inwind.it>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
Impact: add debug warning
Fire off one message if two apic's discovered with different
apic versions. (this code is only called during CPU init)
The goal of this is to pave the way of the removal of the apic_version[]
array. We dont expect any apic version incompatibilities in the x86
landscape of systems [if so we dont handle them very well and probably
never will handle deep apic version assymetries well], but it's prudent
to have a debug check for one kernel cycle nevertheless.
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
Impact: cleanup
Move/remove leftover RDC321 files. Now that it's not a subarch anymore,
arch/x86/mach-rdc321x and arch/x86/include/asm/mach-rdc321x/ are not
needed.
One include file was still in use: rdc321x_defs.h, move that to the
generic x86 asm header directory.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
Conflicts:
arch/x86/include/asm/pda.h
arch/x86/include/asm/system.h
Also, moved include/asm-x86/stackprotector.h to arch/x86/include/asm.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
Accessing memory through %gs should not use rip-relative addressing.
Adding a P prefix for the argument tells gcc to not add (%rip) to
the memory references.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
tj: s/isidle/is_idle/
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
tj: * s/nodenumber/node_number/
* removed now unused pda variable from pda_init()
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
tj: s/irqcount/irq_count/
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
tj: * in asm-offsets_64.c, pda.h inclusion shouldn't be removed as pda
is still referenced in the file
* s/oldrsp/old_rsp/
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Also clean up PER_CPU_VAR usage in xen-asm_64.S
tj: * remove now unused stack_thread_info()
* s/kernelstack/kernel_stack/
* added FIXME comment in xen-asm_64.S
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
tj: moved cpu_number definition out of CONFIG_HAVE_SETUP_PER_CPU_AREA
for voyager.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Move the exception stacks to per-cpu, removing specific allocation code.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Move the irqstackptr variable from the PDA to per-cpu. Make the
stacks themselves per-cpu, removing some specific allocation code.
Add a seperate flag (is_boot_cpu) to simplify the per-cpu boot
adjustments.
tj: * sprinkle some underbars around.
* irq_stack_ptr is not used till traps_init(), no reason to
initialize it early. On SMP, just leaving it NULL till proper
initialization in setup_per_cpu_areas() works. Dropped
is_boot_cpu and early irq_stack_ptr initialization.
* do DECLARE/DEFINE_PER_CPU(char[IRQ_STACK_SIZE], irq_stack)
instead of (char, irq_stack[IRQ_STACK_SIZE]).
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Fire off one message if two apic's discovered with different
apic versions.
Signed-off-by: Mike Travis <travis@sgi.com>
|
|
Impact: use new work_on_cpu function to reduce stack usage
Replace the saving of current->cpus_allowed and set_cpus_allowed_ptr() with
a work_on_cpu function for drv_read() and drv_write().
Basically converts do_drv_{read,write} into "work_on_cpu" functions that
are now called by drv_read and drv_write.
Note: This patch basically reverts 50c668d6 which reverted 7503bfba, now
that the work_on_cpu() function is more stable.
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Dieter Ries <clip2@gmx.de>
Tested-by: Maciej Rutecki <maciej.rutecki@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: <cpufreq@vger.kernel.org>
|
|
Fix two compilation warnings in drivers/acpi/sleep.c, one triggered
by unsetting CONFIG_SUSPEND and the other triggered by unsetting
CONFIG_HIBERNATION, by moving some code under the appropriate
#ifdefs .
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
|
|
|
|
Check CONFIG_FREEZER instead of CONFIG_PM because kprobe booster
depends on freeze_processes() and thaw_processes() when CONFIG_PREEMPT=y.
This fixes a linkage error which occurs when CONFIG_PREEMPT=y, CONFIG_PM=y
and CONFIG_FREEZER=n.
Reported-by: Cheng Renquan <crquan@gmail.com>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Len Brown <len.brown@intel.com>
|
|
On x86_64, if get_per_cpu_var() is used before per cpu area is setup
(if lockdep is turned on, it happens), it needs this_cpu_off to point
to __per_cpu_load. Initialize accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
EXPORT_PER_CPU_SYMBOL() got misplaced during merge leading to build
failure. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
It is an optimization and a cleanup, and adds the following new
generic percpu methods:
percpu_read()
percpu_write()
percpu_add()
percpu_sub()
percpu_and()
percpu_or()
percpu_xor()
and implements support for them on x86. (other architectures will fall
back to a default implementation)
The advantage is that for example to read a local percpu variable,
instead of this sequence:
return __get_cpu_var(var);
ffffffff8102ca2b: 48 8b 14 fd 80 09 74 mov -0x7e8bf680(,%rdi,8),%rdx
ffffffff8102ca32: 81
ffffffff8102ca33: 48 c7 c0 d8 59 00 00 mov $0x59d8,%rax
ffffffff8102ca3a: 48 8b 04 10 mov (%rax,%rdx,1),%rax
We can get a single instruction by using the optimized variants:
return percpu_read(var);
ffffffff8102ca3f: 65 48 8b 05 91 8f fd mov %gs:0x7efd8f91(%rip),%rax
I also cleaned up the x86-specific APIs and made the x86 code use
these new generic percpu primitives.
tj: * fixed generic percpu_sub() definition as Roel Kluin pointed out
* added percpu_and() for completeness's sake
* made generic percpu ops atomic against preemption
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Do the following cleanups:
* kill x86_64_init_pda() which now is equivalent to pda_init()
* use per_cpu_offset() instead of cpu_pda() when initializing
initial_gs
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
pda is now a percpu variable and there's no reason it can't use plain
x86 percpu accessors. Add x86_test_and_clear_bit_percpu() and replace
pda op implementations with wrappers around x86 percpu accessors.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
[ Based on original patch from Christoph Lameter and Mike Travis. ]
As pda is now allocated in percpu area, it can easily be made a proper
percpu variable. Make it so by defining per cpu symbol from linker
script and declaring it in C code for SMP and simply defining it for
UP. This change cleans up code and brings SMP and UP closer a bit.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
Now that pda is allocated as part of percpu, percpu doesn't need to be
accessed through pda. Unify x86_64 SMP percpu access with x86_32 SMP
one. Other than the segment register, operand size and the base of
percpu symbols, they behave identical now.
This patch replaces now unnecessary pda->data_offset with a dummy
field which is necessary to keep stack_canary at its place. This
patch also moves per_cpu_offset initialization out of init_gdt() into
setup_per_cpu_areas(). Note that this change also necessitates
explicit per_cpu_offset initializations in voyager_smp.c.
With this change, x86_OP_percpu()'s are as efficient on x86_64 as on
x86_32 and also x86_64 can use assembly PER_CPU macros.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|
|
[ Based on original patch from Christoph Lameter and Mike Travis. ]
Currently pdas and percpu areas are allocated separately. %gs points
to local pda and percpu area can be reached using pda->data_offset.
This patch folds pda into percpu area.
Due to strange gcc requirement, pda needs to be at the beginning of
the percpu area so that pda->stack_canary is at %gs:40. To achieve
this, a new percpu output section macro - PERCPU_VADDR_PREALLOC() - is
added and used to reserve pda sized chunk at the start of the percpu
area.
After this change, for boot cpu, %gs first points to pda in the
data.init area and later during setup_per_cpu_areas() gets updated to
point to the actual pda. This means that setup_per_cpu_areas() need
to reload %gs for CPU0 while clearing pda area for other cpus as cpu0
already has modified it when control reaches setup_per_cpu_areas().
This patch also removes now unnecessary get_local_pda() and its call
sites.
A lot of this patch is taken from Mike Travis' "x86_64: Fold pda into
per cpu area" patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
|