Pull timer updates from Thomas Gleixner:
"The timer departement provides:
- More y2038 work in the area of ntp and pps.
- Optimization of posix cpu timers
- New time related selftests
- Some new clocksource drivers
- The usual pile of fixes, cleanups and improvements"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
timeconst: Update path in comment
timers/x86/hpet: Type adjustments
clocksource/drivers/armada-370-xp: Implement ARM delay timer
clocksource/drivers/tango_xtal: Add new timer for Tango SoCs
clocksource/drivers/imx: Allow timer irq affinity change
clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr()
clocksource/drivers/h8300_*: Remove unneeded memset()s
clocksource/drivers/sh_cmt: Remove unneeded memset() in sh_cmt_setup()
clocksource/drivers/em_sti: Remove unneeded memset()s
clocksource/drivers/mediatek: Use GPT as sched clock source
clockevents/drivers/mtk: Fix spurious interrupt leading to crash
posix_cpu_timer: Reduce unnecessary sighand lock contention
posix_cpu_timer: Convert cputimer->running to bool
posix_cpu_timer: Check thread timers only when there are active thread timers
posix_cpu_timer: Optimize fastpath_timer_check()
timers, kselftest: Add 'adjtick' test to validate adjtimex() tick adjustments
timers: Use __fls in apply_slack()
clocksource: Remove return statement from void functions
net: sfc: avoid using timespec
ntp/pps: use y2038 safe types in pps_event_time
...
Commit 4857c91f0d changed the way how irq affinity is setup in
setup_ioapic_dest() from using the core helper function to
unconditionally calling the irq_set_affinity() callback of the
underlying irq chip.
That results in a NULL pointer dereference for the rare case where the
underlying irq chip is lapic_chip which has no irq_set_affinity()
callback. lapic_chip is occasionally used for the timer interrupt (irq
0).
The fix is simple: Check the availability of the callback instead of
calling it unconditionally.
Fixes: 4857c91f0d "x86/ioapic: Force affinity setting in setup_ioapic_dest()"
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Commit 6894258eda broke drivers that pass NULL as the device pointer
to dma_alloc. The reason is that arch_dma_alloc_attrs() now calls
dma_alloc_coherent_gfp_flags() which in turn calls
dma_alloc_coherent_mask(), where the device pointer is dereferenced
unconditionally.
Fix things by moving the ISA DMA fallback device assignment before the
call to dma_alloc_coherent_gfp_flags().
Fixes: 6894258eda ("dma-mapping: consolidate dma_{alloc,free}_{attrs,coherent}")
Reported-and-tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/1445807503-8920-1-git-send-email-ville.syrjala@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The per CPU thermal vector init code checks if the thermal
vector is already installed and complains and bails out if it
is.
This happens after kexec, as kernel shut down does not clear the
thermal vector APIC register.
This causes two problems:
1. So we always do not fully initialize thermal reports after
kexec. The CPU is still likely initialized, as the previous
kernel should have done it. But we don't set up the software
pointer to the thermal vector, so reporting may end up with a
unknown thermal interrupt message.
2. Also it complains for every logical CPU, even though the
value is actually derived from BP only.
The problem is that we end up with one message per CPU, so on
larger systems it becomes very noisy and messes up the otherwise
nicely formatted CPU bootup numbers in the kernel log.
Just remove the check. I checked the code and there's no valid
code paths where the thermal init code for a CPU could be called
multiple times.
Why the kernel does not clean up this value on shutdown:
The thermal monitoring is controlled per logical CPU thread.
Normal shutdown code is just running on one CPU. To disable it
we would need a broadcast NMI to all CPUs on shut down. That's
overkill for this. So we just ignore it after kexec.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1445246268-26285-9-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
People reported that when allocating crashkernel memory using
the ",high" and ",low" syntax, there were cases where the
reservation of the high portion succeeds but the reservation of
the low portion fails.
Then kexec can load the kdump kernel successfully, but booting
the kdump kernel fails as there's no low memory.
The low memory allocation for the kdump kernel can fail on large
systems for a couple of reasons. For example, the manually
specified crashkernel low memory can be too large and thus no
adequate memblock region would be found.
Therefore, we try to reserve low memory for the crash kernel
*after* the high memory portion has been allocated. If that
fails, we free crashkernel high memory too and return. The user
can then take measures accordingly.
Tested-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Baoquan He <bhe@redhat.com>
[ Massage text. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Young <dyoung@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: WANG Chao <chaowang@redhat.com>
Cc: jerry_hoemann@hp.com
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/1445246268-26285-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
A sporadic hang with consequent crash is observed when booting Hyper-V Gen1
guests:
Call Trace:
<IRQ>
[<ffffffff810ab68d>] ? trace_hardirqs_off+0xd/0x10
[<ffffffff8107b616>] queue_work_on+0x46/0x90
[<ffffffff81365696>] ? add_interrupt_randomness+0x176/0x1d0
...
<EOI>
[<ffffffff81471ddb>] ? _raw_spin_unlock_irqrestore+0x3b/0x60
[<ffffffff810c295e>] __irq_put_desc_unlock+0x1e/0x40
[<ffffffff810c5c35>] irq_modify_status+0xb5/0xd0
[<ffffffff8104adbb>] mp_register_handler+0x4b/0x70
[<ffffffff8104c55a>] mp_irqdomain_alloc+0x1ea/0x2a0
[<ffffffff810c7f10>] irq_domain_alloc_irqs_recursive+0x40/0xa0
[<ffffffff810c860c>] __irq_domain_alloc_irqs+0x13c/0x2b0
[<ffffffff8104b070>] alloc_isa_irq_from_domain.isra.1+0xc0/0xe0
[<ffffffff8104bfa5>] mp_map_pin_to_irq+0x165/0x2d0
[<ffffffff8104c157>] pin_2_irq+0x47/0x80
[<ffffffff81744253>] setup_IO_APIC+0xfe/0x802
...
[<ffffffff814631c0>] ? rest_init+0x140/0x140
The issue is easily reproducible with a simple instrumentation: if
mdelay(10) is put between mp_setup_entry() and mp_register_handler() calls
in mp_irqdomain_alloc() Hyper-V guest always fails to boot when re-routing
IRQ0. The issue seems to be caused by the fact that we don't disable
interrupts while doing IOPIC programming for legacy IRQs and IRQ0 actually
happens.
Protect the setup sequence against concurrent interrupts.
[ tglx: Make the protection unconditional and not only for legacy
interrupts ]
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1444930943-19336-1-git-send-email-vkuznets@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
On 32-bit systems, the initial_page_table is reused by
efi_call_phys_prolog as an identity map to call
SetVirtualAddressMap. efi_call_phys_prolog takes care of
converting the current CPU's GDT to a physical address too.
For PAE kernels the identity mapping is achieved by aliasing the
first PDPE for the kernel memory mapping into the first PDPE
of initial_page_table. This makes the EFI stub's trick "just work".
However, for non-PAE kernels there is no guarantee that the identity
mapping in the initial_page_table extends as far as the GDT; in this
case, accesses to the GDT will cause a page fault (which quickly becomes
a triple fault). Fix this by copying the kernel mappings from
swapper_pg_dir to initial_page_table twice, both at PAGE_OFFSET and at
identity mapping.
For some reason, this is only reproducible with QEMU's dynamic translation
mode, and not for example with KVM. However, even under KVM one can clearly
see that the page table is bogus:
$ qemu-system-i386 -pflash OVMF.fd -M q35 vmlinuz0 -s -S -daemonize
$ gdb
(gdb) target remote localhost:1234
(gdb) hb *0x02858f6f
Hardware assisted breakpoint 1 at 0x2858f6f
(gdb) c
Continuing.
Breakpoint 1, 0x02858f6f in ?? ()
(gdb) monitor info registers
...
GDT= 0724e000 000000ff
IDT= fffbb000 000007ff
CR0=0005003b CR2=ff896000 CR3=032b7000 CR4=00000690
...
The page directory is sane:
(gdb) x/4wx 0x32b7000
0x32b7000: 0x03398063 0x03399063 0x0339a063 0x0339b063
(gdb) x/4wx 0x3398000
0x3398000: 0x00000163 0x00001163 0x00002163 0x00003163
(gdb) x/4wx 0x3399000
0x3399000: 0x00400003 0x00401003 0x00402003 0x00403003
but our particular page directory entry is empty:
(gdb) x/1wx 0x32b7000 + (0x724e000 >> 22) * 4
0x32b7070: 0x00000000
[ It appears that you can skate past this issue if you don't receive
any interrupts while the bogus GDT pointer is loaded, or if you avoid
reloading the segment registers in general.
Andy Lutomirski provides some additional insight:
"AFAICT it's entirely permissible for the GDTR and/or LDT
descriptor to point to unmapped memory. Any attempt to use them
(segment loads, interrupts, IRET, etc) will try to access that memory
as if the access came from CPL 0 and, if the access fails, will
generate a valid page fault with CR2 pointing into the GDT or
LDT."
Up until commit 23a0d4e8fa ("efi: Disable interrupts around EFI
calls, not in the epilog/prolog calls") interrupts were disabled
around the prolog and epilog calls, and the functional GDT was
re-installed before interrupts were re-enabled.
Which explains why no one has hit this issue until now. ]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: Laszlo Ersek <lersek@redhat.com>
Cc: <stable@vger.kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
[ Updated changelog. ]
ACPI specifies the following rules when listing APIC IDs:
(1) Boot processor is listed first
(2) For multi-threaded processors, BIOS should list the first logical
processor of each of the individual multi-threaded processors in MADT
before listing any of the second logical processors.
(3) APIC IDs < 0xFF should be listed in APIC subtable, APIC IDs >= 0xFF
should be listed in X2APIC subtable
Because of above, when there's more than 0xFF logical CPUs, BIOS
interleaves APIC/X2APIC subtables.
Assuming, there's 72 cores, 72 hyper-threads each, 288 CPUs total,
listing is like this:
APIC (0,4,8, .., 252)
X2APIC (258,260,264, .. 284)
APIC (1,5,9,...,253)
X2APIC (259,261,265,...,285)
APIC (2,6,10,...,254)
X2APIC (260,262,266,..,286)
APIC (3,7,11,...,251)
X2APIC (255,261,262,266,..,287)
Now, before this patch, due to how ACPI MADT subtables were parsed (BSP
then X2APIC then APIC), kernel enumerated CPUs in reverted order (i.e.
high APIC IDs were getting low logical IDs, and low APIC IDs were
getting high logical IDs).
This is wrong for the following reasons:
() it's hard to predict how cores and threads are enumerated
() when it's hard to predict, s/w threads cannot be properly affinitized
causing significant performance impact due to e.g. inproper cache
sharing
() enumeration is inconsistent with how threads are enumerated on
other Intel Xeon processors
So, order in which MADT APIC/X2APIC handlers are passed is
reverse and both handlers are passed to be called during same MADT
table to walk to achieve correct CPU enumeration.
In scenario when someone boots kernel with options 'maxcpus=72 nox2apic',
in result less cores may be booted, since some of the CPUs the kernel
will try to use will have APIC ID >= 0xFF. In such case, one
should not pass 'nox2apic'.
Disclimer: code parsing MADT APIC/X2APIC has not been touched since 2009,
when X2APIC support was initially added. I do not know why MADT parsing
code was added in the reversed order in the first place.
I guess it didn't matter at that time since nobody cared about cores
with APIC IDs >= 0xFF, right?
This patch is based on work of "Yinghai Lu <yinghai@kernel.org>"
previously published at https://lkml.org/lkml/2013/1/21/563
Here's the explanation why parsing interface needs to be changed
and why simpler approach will not work https://lkml.org/lkml/2015/9/7/285
Signed-off-by: Lukasz Anaczkowski <lukasz.anaczkowski@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de> (commit message)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull v4.4 EFI updates from Matt Fleming:
- Make the EFI System Resource Table (ESRT) driver explicitly
non-modular by ripping out the module_* code since Kconfig doesn't
allow it to be built as a module anyway. (Paul Gortmaker)
- Make the x86 efi=debug kernel parameter, which enables EFI debug
code and output, generic and usable by arm64. (Leif Lindholm)
- Add support to the x86 EFI boot stub for 64-bit Graphics Output
Protocol frame buffer addresses. (Matt Fleming)
- Detect when the UEFI v2.5 EFI_PROPERTIES_TABLE feature is enabled
in the firmware and set an efi.flags bit so the kernel knows when
it can apply more strict runtime mapping attributes - Ard Biesheuvel
- Auto-load the efi-pstore module on EFI systems, just like we
currently do for the efivars module. (Ben Hutchings)
- Add "efi_fake_mem" kernel parameter which allows the system's EFI
memory map to be updated with additional attributes for specific
memory ranges. This is useful for testing the kernel code that handles
the EFI_MEMORY_MORE_RELIABLE memmap bit even if your firmware
doesn't include support. (Taku Izumi)
Note: there is a semantic conflict between the following two commits:
8a53554e12 ("x86/efi: Fix multiple GOP device support")
ae2ee627dc ("efifb: Add support for 64-bit frame buffer addresses")
I fixed up the interaction in the merge commit, changing the type of
current_fb_base from u32 to u64.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are following warnings on unpatched code:
arch/x86/kernel/early_printk.c:198:32: warning: incorrect type in initializer (different address spaces)
arch/x86/kernel/early_printk.c:198:32: expected void [noderef] <asn:2>*vaddr
arch/x86/kernel/early_printk.c:198:32: got unsigned int [usertype] *<noident>
arch/x86/kernel/early_printk.c:205:32: warning: incorrect type in initializer (different address spaces)
arch/x86/kernel/early_printk.c:205:32: expected void [noderef] <asn:2>*vaddr
arch/x86/kernel/early_printk.c:205:32: got unsigned int [usertype] *<noident>
Annotate it proper.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: http://lkml.kernel.org/r/1444646837-42615-1-git-send-email-andriy.shevchenko@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pave the way for checking the current patch level of the
microcode in a core. We want to be able to do stuff depending on
the patch level - in this case decide whether to update or not.
But that will be added in a later patch.
Drop unused local var uci assignment, while at it.
Integrate a fix for 32-bit and CONFIG_PARAVIRT from Takashi Iwai:
Use native_rdmsr() in check_current_patch_level() because with
CONFIG_PARAVIRT enabled and on 32-bit, where we run before
paging has been enabled, we cannot deref pv_info yet. Or we
could, but we'd need to access its physical address. This way of
fixing it is simpler. See:
https://bugzilla.suse.com/show_bug.cgi?id=943179 for the background.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Takashi Iwai <tiwai@suse.com>:
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1444641762-9437-6-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch introduces new boot option named "efi_fake_mem".
By specifying this parameter, you can add arbitrary attribute
to specific memory range.
This is useful for debugging of Address Range Mirroring feature.
For example, if "efi_fake_mem=2G@4G:0x10000,2G@0x10a0000000:0x10000"
is specified, the original (firmware provided) EFI memmap will be
updated so that the specified memory regions have
EFI_MEMORY_MORE_RELIABLE attribute (0x10000):
<original>
efi: mem36: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x00000020a0000000) (129536MB)
<updated>
efi: mem36: [Conventional Memory| |MR| | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x0000000180000000) (2048MB)
efi: mem37: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000180000000-0x00000010a0000000) (61952MB)
efi: mem38: [Conventional Memory| |MR| | | | |WB|WT|WC|UC] range=[0x00000010a0000000-0x0000001120000000) (2048MB)
efi: mem39: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000001120000000-0x00000020a0000000) (63488MB)
And you will find that the following message is output:
efi: Memory: 4096M/131455M mirrored memory
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
In multi-segment system, uncore devices may belong to buses whose segment
number is other than 0:
....
0000:ff:10.5 System peripheral: Intel Corporation Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 03)
...
0001:7f:10.5 System peripheral: Intel Corporation Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 03)
...
0001:bf:10.5 System peripheral: Intel Corporation Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 03)
...
0001:ff:10.5 System peripheral: Intel Corporation Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 03
...
In that case, relation of bus number and physical id may be broken
because "uncore_pcibus_to_physid" doesn't take account of PCI segment.
For example, bus 0000:ff and 0001:ff uses the same entry of
"uncore_pcibus_to_physid" array.
This patch fixes this problem by introducing the segment-aware pci2phy_map instead.
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: hpa@zytor.com
Link: http://lkml.kernel.org/r/1443096621-4119-1-git-send-email-izumi.taku@jp.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch adds new PMUs to support cstate related free running
(read-only) counters. These counters may be used simultaneously by other
tools, such as turbostat. However, it still make sense to implement them
in perf. Because we can conveniently collect them together with other
events, and allow to use them from tools without special MSR access
code.
These counters include CORE_C*_RESIDENCY and PKG_C*_RESIDENCY.
According to counters' scope and category, two PMUs are registered with
the perf_event core subsystem.
- 'cstate_core': The counter is available for each physical core. The
counters include CORE_C*_RESIDENCY.
- 'cstate_pkg': The counter is available for each physical package. The
counters include PKG_C*_RESIDENCY.
The events are exposed in sysfs for use by perf stat and other tools.
The files are:
/sys/devices/cstate_core/events/c*-residency
/sys/devices/cstate_pkg/events/c*-residency
These events only support system-wide mode counting.
The /sys/devices/cstate_*/cpumask file can be used by tools to figure
out which CPUs to monitor by default.
The PMU type (attr->type) is dynamically allocated and is available from
/sys/devices/core_misc/type and /sys/device/cstate_*/type.
Sampling is not supported.
Here is an example.
- To caculate the fraction of time when the core is running in C6 state
CORE_C6_time% = CORE_C6_RESIDENCY / TSC
# perf stat -x, -e"cstate_core/c6-residency/,msr/tsc/" -C0 -- taskset -c 0 sleep 5
11838820015,,cstate_core/c6-residency/,5175919658,100.00
11877130740,,msr/tsc/,5175922010,100.00
For sleep, 99.7% of time we ran in C6 state.
# perf stat -x, -e"cstate_core/c6-residency/,msr/tsc/" -C0 -- taskset -c 0 busyloop
1253316,,cstate_core/c6-residency/,4360969154,100.00
10012635248,,msr/tsc/,4360972366,100.00
For busyloop, 0.01% of time we ran in C6 state.
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1443443404-8581-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 fixes from Ingo Molnar:
"Fixes all around the map: W+X kernel mapping fix, WCHAN fixes, two
build failure fixes for corner case configs, x32 header fix and a
speling fix"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/headers/uapi: Fix __BITS_PER_LONG value for x32 builds
x86/mm: Set NX on gap between __ex_table and rodata
x86/kexec: Fix kexec crash in syscall kexec_file_load()
x86/process: Unify 32bit and 64bit implementations of get_wchan()
x86/process: Add proper bound checks in 64bit get_wchan()
x86, efi, kasan: Fix build failure on !KASAN && KMEMCHECK=y kernels
x86/hyperv: Fix the build in the !CONFIG_KEXEC_CORE case
x86/cpufeatures: Correct spelling of the HWP_NOTIFY flag
The original bug is a page fault crash that sometimes happens
on big machines when preparing ELF headers:
BUG: unable to handle kernel paging request at ffffc90613fc9000
IP: [<ffffffff8103d645>] prepare_elf64_ram_headers_callback+0x165/0x260
The bug is caused by us under-counting the number of memory ranges
and subsequently not allocating enough ELF header space for them.
The bug is typically masked on smaller systems, because the ELF header
allocation is rounded up to the next page.
This patch modifies the code in fill_up_crash_elf_data() by using
walk_system_ram_res() instead of walk_system_ram_range() to correctly
count the max number of crash memory ranges. That's because the
walk_system_ram_range() filters out small memory regions that
reside in the same page, but walk_system_ram_res() does not.
Here's how I found the bug:
After tracing prepare_elf64_headers() and prepare_elf64_ram_headers_callback(),
the code uses walk_system_ram_res() to fill-in crash memory regions information
to the program header, so it counts those small memory regions that
reside in a page area.
But, when the kernel was using walk_system_ram_range() in
fill_up_crash_elf_data() to count the number of crash memory regions,
it filters out small regions.
I printed those small memory regions, for example:
kexec: Get nr_ram ranges. vaddr=0xffff880077592258 paddr=0x77592258, sz=0xdc0
Based on the code in walk_system_ram_range(), this memory region
will be filtered out:
pfn = (0x77592258 + 0x1000 - 1) >> 12 = 0x77593
end_pfn = (0x77592258 + 0xfc0 -1 + 1) >> 12 = 0x77593
end_pfn - pfn = 0x77593 - 0x77593 = 0 <=== if (end_pfn > pfn) is FALSE
So, the max_nr_ranges that's counted by the kernel doesn't include
small memory regions - causing us to under-allocate the required space.
That causes the page fault crash that happens in a later code path
when preparing ELF headers.
This bug is not easy to reproduce on small machines that have few
CPUs, because the allocated page aligned ELF buffer has more free
space to cover those small memory regions' PT_LOAD headers.
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: kexec@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1443531537-29436-1-git-send-email-jlee@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Newer KVM won't be exposing PVCLOCK_COUNTS_FROM_ZERO anymore.
The purpose of that flags was to start counting system time from 0 when
the KVM clock has been initialized.
We can achieve the same by selecting one read as the initial point.
A simple subtraction will work unless the KVM clock count overflows
earlier (has smaller width) than scheduler's cycle count. We should be
safe till x86_128.
Because PVCLOCK_COUNTS_FROM_ZERO was enabled only on new hypervisors,
setting sched clock as stable based on PVCLOCK_TSC_STABLE_BIT might
regress on older ones.
I presume we don't need to change kvm_clock_read instead of introducing
kvm_sched_clock_read. A problem could arise in case sched_clock is
expected to return the same value as get_cycles, but we should have
merged those clocks in that case.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
