| Age | Commit message (Collapse) | Author | Files | Lines |
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In the case where KASAN directly allocates memory to back vmalloc space,
don't map the early shadow page over it.
We prepopulate pgds/p4ds for the range that would otherwise be empty.
This is required to get it synced to hardware on boot, allowing the
lower levels of the page tables to be filled dynamically.
Link: http://lkml.kernel.org/r/20191031093909.9228-5-dja@axtens.net
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Supporting VMAP_STACK with KASAN_VMALLOC is straightforward:
- clear the shadow region of vmapped stacks when swapping them in
- tweak Kconfig to allow VMAP_STACK to be turned on with KASAN
Link: http://lkml.kernel.org/r/20191031093909.9228-4-dja@axtens.net
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There's a bug in the new PAT code, the conversion of memtype_check_conflict()
is buggy:
8d04a5f97a5f: ("x86/mm/pat: Convert the PAT tree to a generic interval tree")
dprintk("Overlap at 0x%Lx-0x%Lx\n", match->start, match->end);
found_type = match->type;
- node = rb_next(&match->rb);
- while (node) {
- match = rb_entry(node, struct memtype, rb);
-
- if (match->start >= end) /* Checked all possible matches */
- goto success;
-
- if (is_node_overlap(match, start, end) &&
- match->type != found_type) {
+ match = memtype_interval_iter_next(match, start, end);
+ while (match) {
+ if (match->type != found_type)
goto failure;
- }
- node = rb_next(&match->rb);
+ match = memtype_interval_iter_next(match, start, end);
}
Note how the '>= end' condition to end the interval check, got converted
into:
+ match = memtype_interval_iter_next(match, start, end);
This is subtly off by one, because the interval trees interfaces require
closed interval parameters:
include/linux/interval_tree_generic.h
/* \
* Iterate over intervals intersecting [start;last] \
* \
* Note that a node's interval intersects [start;last] iff: \
* Cond1: ITSTART(node) <= last \
* and \
* Cond2: start <= ITLAST(node) \
*/ \
...
if (ITSTART(node) <= last) { /* Cond1 */ \
if (start <= ITLAST(node)) /* Cond2 */ \
return node; /* node is leftmost match */ \
[start;last] is a closed interval (note that '<= last' check) - while the
PAT 'end' parameter is 1 byte beyond the end of the range, because
ioremap() and the other mapping APIs usually use the [start,end)
half-open interval, derived from 'size'.
This is what ioremap() does for example:
/*
* Mappings have to be page-aligned
*/
offset = phys_addr & ~PAGE_MASK;
phys_addr &= PHYSICAL_PAGE_MASK;
size = PAGE_ALIGN(last_addr+1) - phys_addr;
retval = reserve_memtype(phys_addr, (u64)phys_addr + size,
pcm, &new_pcm);
phys_addr+size will be on a page boundary, after the last byte of the
mapped interval.
So the correct parameter to use in the interval tree searches is not
'end' but 'end-1'.
This could have relevance if conflicting PAT ranges are exactly adjacent,
for example a future WC region is followed immediately by an already
mapped UC- region - in this case memtype_check_conflict() would
incorrectly deny the WC memtype region and downgrade the memtype to UC-.
BTW., rather annoyingly this downgrading is done silently in
memtype_check_insert():
int memtype_check_insert(struct memtype *new,
enum page_cache_mode *ret_type)
{
int err = 0;
err = memtype_check_conflict(new->start, new->end, new->type, ret_type);
if (err)
return err;
if (ret_type)
new->type = *ret_type;
memtype_interval_insert(new, &memtype_rbroot);
return 0;
}
So on such a conflict we'd just silently get UC- in *ret_type, and write
it into the new region, never the wiser ...
So assuming that the patch below fixes the primary bug the diagnostics
side of ioremap() cache attribute downgrades would be another thing to
fix.
Anyway, I checked all the interval-tree iterations, and most of them are
off by one - but I think the one related to memtype_check_conflict() is
the one causing this particular performance regression.
The only correct interval-tree searches were these two:
arch/x86/mm/pat_interval.c: match = memtype_interval_iter_first(&memtype_rbroot, 0, ULONG_MAX);
arch/x86/mm/pat_interval.c: match = memtype_interval_iter_next(match, 0, ULONG_MAX);
The ULONG_MAX was hiding the off-by-one in plain sight. :-)
Note that the bug was probably benign in the sense of implementing a too
strict cache attribute conflict policy and downgrading cache attributes,
so AFAICS the worst outcome of this bug would be a performance regression,
not any instabilities.
Reported-by: kernel test robot <rong.a.chen@intel.com>
Reported-by: Kenneth R. Crudup <kenny@panix.com>
Reported-by: Mariusz Ceier <mceier+kernel@gmail.com>
Tested-by: Mariusz Ceier <mceier@gmail.com>
Tested-by: Kenneth R. Crudup <kenny@panix.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191201144947.GA4167@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Patch series "elide extraneous generated code for folded p4d/pud/pmd", v3.
This series came out of seemingly benign excursion into
understanding/removing __ARCH_USE_5LEVEL_HACK from ARC port showing some
extraneous code being generated despite folded p4d/pud/pmd
| bloat-o-meter2 vmlinux-[AB]*
| add/remove: 0/0 grow/shrink: 3/0 up/down: 130/0 (130)
| function old new delta
| free_pgd_range 548 660 +112
| p4d_clear_bad 2 20 +18
The patches here address that
| bloat-o-meter2 vmlinux-[BF]*
| add/remove: 0/2 grow/shrink: 0/1 up/down: 0/-386 (-386)
| function old new delta
| pud_clear_bad 20 - -20
| p4d_clear_bad 20 - -20
| free_pgd_range 660 314 -346
The code savings are not a whole lot, but still worthwhile IMHO.
This patch (of 5):
With paging code made 5-level compliant, this is no longer needed. ARC
has software page walker with 2 lookup levels (pgd -> pte)
This was expected to be non functional change but ended with slight
code bloat due to needless inclusions of p*d_free_tlb() macros which
will be addressed in further patches.
| bloat-o-meter2 vmlinux-[AB]*
| add/remove: 0/0 grow/shrink: 2/0 up/down: 128/0 (128)
| function old new delta
| free_pgd_range 546 656 +110
| p4d_clear_bad 2 20 +18
| Total: Before=4137148, After=4137276, chg 0.000000%
Link: http://lkml.kernel.org/r/20191016162400.14796-2-vgupta@synopsys.com
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Remove compat vdso code, since there is hardly any compat user space
left. Still existing compat user space will have to use system calls
instead.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull seccomp updates from Kees Cook:
"Mostly this is implementing the new flag SECCOMP_USER_NOTIF_FLAG_CONTINUE,
but there are cleanups as well.
- implement SECCOMP_USER_NOTIF_FLAG_CONTINUE (Christian Brauner)
- fixes to selftests (Christian Brauner)
- remove secure_computing() argument (Christian Brauner)"
* tag 'seccomp-v5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
seccomp: rework define for SECCOMP_USER_NOTIF_FLAG_CONTINUE
seccomp: fix SECCOMP_USER_NOTIF_FLAG_CONTINUE test
seccomp: simplify secure_computing()
seccomp: test SECCOMP_USER_NOTIF_FLAG_CONTINUE
seccomp: add SECCOMP_USER_NOTIF_FLAG_CONTINUE
seccomp: avoid overflow in implicit constant conversion
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git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull Hyper-V updates from Sasha Levin:
- support for new VMBus protocols (Andrea Parri)
- hibernation support (Dexuan Cui)
- latency testing framework (Branden Bonaby)
- decoupling Hyper-V page size from guest page size (Himadri Pandya)
* tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (22 commits)
Drivers: hv: vmbus: Fix crash handler reset of Hyper-V synic
drivers/hv: Replace binary semaphore with mutex
drivers: iommu: hyperv: Make HYPERV_IOMMU only available on x86
HID: hyperv: Add the support of hibernation
hv_balloon: Add the support of hibernation
x86/hyperv: Implement hv_is_hibernation_supported()
Drivers: hv: balloon: Remove dependencies on guest page size
Drivers: hv: vmbus: Remove dependencies on guest page size
x86: hv: Add function to allocate zeroed page for Hyper-V
Drivers: hv: util: Specify ring buffer size using Hyper-V page size
Drivers: hv: Specify receive buffer size using Hyper-V page size
tools: hv: add vmbus testing tool
drivers: hv: vmbus: Introduce latency testing
video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver
video: hyperv: hyperv_fb: Obtain screen resolution from Hyper-V host
hv_netvsc: Add the support of hibernation
hv_sock: Add the support of hibernation
video: hyperv_fb: Add the support of hibernation
scsi: storvsc: Add the support of hibernation
Drivers: hv: vmbus: Add module parameter to cap the VMBus version
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RAS fix from Borislav Petkov:
"One urgent fix for the thermal throttling machinery: the recent change
reworking the thermal notifications forgot to mask out read-only and
reserved bits in the thermal status MSRs, leading to exceptions while
writing those MSRs.
The fix takes care of masking out those bits first"
* 'ras-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce/therm_throt: Mask out read-only and reserved MSR bits
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git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc updates from Helge Deller:
"Just trivial small updates: An assembler register optimization in the
inlined networking checksum functions, a compiler warning fix and
don't unneccesary print a runtime warning on machines which wouldn't
be affected anyway"
* 'parisc-5.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: Avoid spurious inequivalent alias kernel error messages
kexec: Fix pointer-to-int-cast warnings
parisc: Do not hardcode registers in checksum functions
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Highlights:
- Infrastructure for secure boot on some bare metal Power9 machines.
The firmware support is still in development, so the code here
won't actually activate secure boot on any existing systems.
- A change to xmon (our crash handler / pseudo-debugger) to restrict
it to read-only mode when the kernel is lockdown'ed, otherwise it's
trivial to drop into xmon and modify kernel data, such as the
lockdown state.
- Support for KASLR on 32-bit BookE machines (Freescale / NXP).
- Fixes for our flush_icache_range() and __kernel_sync_dicache()
(VDSO) to work with memory ranges >4GB.
- Some reworks of the pseries CMM (Cooperative Memory Management)
driver to make it behave more like other balloon drivers and enable
some cleanups of generic mm code.
- A series of fixes to our hardware breakpoint support to properly
handle unaligned watchpoint addresses.
Plus a bunch of other smaller improvements, fixes and cleanups.
Thanks to: Alastair D'Silva, Andrew Donnellan, Aneesh Kumar K.V,
Anthony Steinhauser, Cédric Le Goater, Chris Packham, Chris Smart,
Christophe Leroy, Christopher M. Riedl, Christoph Hellwig, Claudio
Carvalho, Daniel Axtens, David Hildenbrand, Deb McLemore, Diana
Craciun, Eric Richter, Geert Uytterhoeven, Greg Kroah-Hartman, Greg
Kurz, Gustavo L. F. Walbon, Hari Bathini, Harish, Jason Yan, Krzysztof
Kozlowski, Leonardo Bras, Mathieu Malaterre, Mauro S. M. Rodrigues,
Michal Suchanek, Mimi Zohar, Nathan Chancellor, Nathan Lynch, Nayna
Jain, Nick Desaulniers, Oliver O'Halloran, Qian Cai, Rasmus Villemoes,
Ravi Bangoria, Sam Bobroff, Santosh Sivaraj, Scott Wood, Thomas Huth,
Tyrel Datwyler, Vaibhav Jain, Valentin Longchamp, YueHaibing"
* tag 'powerpc-5.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (144 commits)
powerpc/fixmap: fix crash with HIGHMEM
x86/efi: remove unused variables
powerpc: Define arch_is_kernel_initmem_freed() for lockdep
powerpc/prom_init: Use -ffreestanding to avoid a reference to bcmp
powerpc: Avoid clang warnings around setjmp and longjmp
powerpc: Don't add -mabi= flags when building with Clang
powerpc: Fix Kconfig indentation
powerpc/fixmap: don't clear fixmap area in paging_init()
selftests/powerpc: spectre_v2 test must be built 64-bit
powerpc/powernv: Disable native PCIe port management
powerpc/kexec: Move kexec files into a dedicated subdir.
powerpc/32: Split kexec low level code out of misc_32.S
powerpc/sysdev: drop simple gpio
powerpc/83xx: map IMMR with a BAT.
powerpc/32s: automatically allocate BAT in setbat()
powerpc/ioremap: warn on early use of ioremap()
powerpc: Add support for GENERIC_EARLY_IOREMAP
powerpc/fixmap: Use __fix_to_virt() instead of fix_to_virt()
powerpc/8xx: use the fixmapped IMMR in cpm_reset()
powerpc/8xx: add __init to cpm1 init functions
...
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Pull ARM updates from Russell King:
- improve ARM implementation of pfn_valid()
- various sparse fixes
- spelling fixes
- add further ARMv8 debug architecture versions
- clang fix for decompressor
- update to generic vDSO
- remove Brahma-B53 from spectre hardening
- initialise broadcast hrtimer device
- use correct nm executable in decompressor
- remove old mcount et.al.
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (26 commits)
ARM: 8940/1: ftrace: remove mcount(),ftrace_caller_old() and ftrace_call_old()
ARM: 8939/1: kbuild: use correct nm executable
ARM: 8938/1: kernel: initialize broadcast hrtimer based clock event device
ARM: 8937/1: spectre-v2: remove Brahma-B53 from hardening
ARM: 8933/1: replace Sun/Solaris style flag on section directive
ARM: 8932/1: Add clock_gettime64 entry point
ARM: 8931/1: Add clock_getres entry point
ARM: 8930/1: Add support for generic vDSO
ARM: 8929/1: use APSR_nzcv instead of r15 as mrc operand
ARM: 8927/1: ARM/hw_breakpoint: add more ARMv8 debug architecture versions support
ARM: 8918/2: only build return_address() if needed
ARM: 8928/1: ARM_ERRATA_775420: Spelling s/date/data/
ARM: 8925/1: tcm: include <asm/tcm.h> for missing declarations
ARM: 8924/1: tcm: make dtcm_end and itcm_end static
ARM: 8923/1: mm: include <asm/vga.h> for vga_base
ARM: 8922/1: parse_dt_topology() rate is pointer to __be32
ARM: 8920/1: share get_signal_page from signal.c to process.c
ARM: 8919/1: make unexported functions static
ARM: 8917/1: mm: include <asm/set_memory.h>
ARM: 8916/1: mm: make set_section_perms() static
...
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git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux
Pull nds32 updates from Greentime Hu:
- code clean up
- add a nds32 maintainer
* tag 'nds32-for-linus-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux:
MAINTAINERS: add nds32 maintainer
nds32: Move static keyword to the front of declaration
nds32: Fix typo in Kconfig.cpu
nds32: remove unneeded clean-files for DTB
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... for better readability.
No functional changes.
[ Minor edit. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The livepatch consistency model requires reliable stack tracing
architecture support in order to work properly. In order to achieve
this, two main issues have to be solved. First, reliable and consistent
call chain backtracing has to be ensured. Second, the unwinder needs to
be able to detect stack corruptions and return errors.
The "zSeries ELF Application Binary Interface Supplement" says:
"The stack pointer points to the first word of the lowest allocated
stack frame. If the "back chain" is implemented this word will point to
the previously allocated stack frame (towards higher addresses), except
for the first stack frame, which shall have a back chain of zero (NULL).
The stack shall grow downwards, in other words towards lower addresses."
"back chain" is optional. GCC option -mbackchain enables it. Quoting
Martin Schwidefsky [1]:
"The compiler is called with the -mbackchain option, all normal C
function will store the backchain in the function prologue. All
functions written in assembler code should do the same, if you find one
that does not we should fix that. The end result is that a task that
*voluntarily* called schedule() should have a proper backchain at all
times.
Dependent on the use case this may or may not be enough. Asynchronous
interrupts may stop the CPU at the beginning of a function, if kernel
preemption is enabled we can end up with a broken backchain. The
production kernels for IBM Z are all compiled *without* kernel
preemption. So yes, we might get away without the objtool support.
On a side-note, we do have a line item to implement the ORC unwinder for
the kernel, that includes the objtool support. Once we have that we can
drop the -mbackchain option for the kernel build. That gives us a nice
little performance benefit. I hope that the change from backchain to the
ORC unwinder will not be too hard to implement in the livepatch tools."
Since -mbackchain is enabled by default when the kernel is compiled, the
call chain backtracing should be currently ensured and objtool should
not be necessary for livepatch purposes.
Regarding the second issue, stack corruptions and non-reliable states
have to be recognized by the unwinder. Mainly it means to detect
preemption or page faults, the end of the task stack must be reached,
return addresses must be valid text addresses and hacks like function
graph tracing and kretprobes must be properly detected.
Unwinding a running task's stack is not a problem, because there is a
livepatch requirement that every checked task is blocked, except for the
current task. Due to that, the implementation can be much simpler
compared to the existing non-reliable infrastructure. We can consider a
task's kernel/thread stack only and skip the other stacks.
[1] 20180912121106.31ffa97c@mschwideX1 [not archived on lore.kernel.org]
Link: https://lkml.kernel.org/r/20191106095601.29986-5-mbenes@suse.cz
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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ABI requires SP to be aligned 8 bytes, report unwinding error otherwise.
Link: https://lkml.kernel.org/r/20191106095601.29986-5-mbenes@suse.cz
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Currently unwinder unconditionally returns %r14 from the first frame
pointed by %r15 from pt_regs. A task could be interrupted when a function
already allocated this frame (if it needs it) for its callees or to
store local variables. In that case this frame would contain random
values from stack or values stored there by a callee. As we are only
interested in %r14 to get potential return address, skip bogus return
addresses which doesn't belong to kernel text.
This helps to avoid duplicating filtering logic in unwider users, most
of which use unwind_get_return_address() and would choke on bogus 0
address returned by it otherwise.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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A comment in arch/s390/include/asm/unwind.h says:
> If 'first_frame' is not zero unwind_start skips unwind frames until it
> reaches the specified stack pointer.
> The end of the unwinding is indicated with unwind_done, this can be true
> right after unwind_start, e.g. with first_frame!=0 that can not be found.
> unwind_next_frame skips to the next frame.
> Once the unwind is completed unwind_error() can be used to check if there
> has been a situation where the unwinder could not correctly understand
> the tasks call chain.
With this change backchain unwinder now comply with behaviour
described. As well as matches orc unwinder implementation. Now unwinder
starts from reliable state, i.e. __unwind_start own stack frame is
taken or stack frame generated by __switch_to (ksp) - both known to be
valid. In case of pt_regs %r15 is better match for pt_regs psw, than
sometimes random "sp" caller passed.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Add unwinding from program check handler tests. Unwinder should be able
to unwind through pt_regs stored by program check handler on task stack.
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Add unwinding from irq context tests. Unwinder should be able to unwind
through irq stack to task stack up to task pt_regs.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Add stack name, sp and reliable information into test unwinding
results. Also consider ip outside of kernel text as failure if the
state is reported reliable.
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Add CALL_ON_STACK helper testing. Tests make sure that we can unwind from
switched stack to original one up to task pt_regs (nodat -> task stack).
UWM_SWITCH_STACK could not be used together with UWM_THREAD because
get_stack_info explicitly restricts unwinding to task stack if
task != current.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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CALL_ON_STACK defines and initializes register variables. Inline
assembly which follows might trigger compiler to generate memory access
for "stack" argument (e.g. in case of S390_lowcore.nodat_stack). This
memory access produces a function call under kasan with outline
instrumentation which clobbers registers.
Switch "stack" argument in CALL_ON_STACK helper to use memory reference
constraint and perform load instead.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Currently unwinder test passes if unwinding results contain unwindme_func2
and unwindme_func1 functions.
Now that unwinder reports success upon reaching task pt_regs, check
that unwinding ended successfully in every test.
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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unwind_for_each_frame can take at least 8 different sets of parameters.
Add a test to make sure they all are handled in a sane way.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Co-developed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Always inline get_stack_pointer() to avoid potential problems
due to compiler inlining decisions, i.e. getting stack pointer of
get_stack_pointer() itself which is later reused.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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The config option CONFIG_PCI_NR_FUNCTIONS sets a limit on the number of
PCI functions we can support. Previously on reaching this limit there
was no indication why newly attached devices are not recognized by Linux
which could be quite confusing. Thus this patch adds a pr_err() for this
case.
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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When UID checking was turned off during runtime in the underlying
hypervisor, a PCI device may be attached with the same UID. This is
already detected but happens silently. Add an error message so it can
more easily be understood why a device was not added.
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Each SBDT is located at a 4KB page and contains 512 entries.
Each entry of a SDBT points to a SDB, a 4KB page containing
sampled data. The last entry is a link to another SDBT page.
When an event is created the function sequence executed is:
__hw_perf_event_init()
+--> allocate_buffers()
+--> realloc_sampling_buffers()
+---> alloc_sample_data_block()
Both functions realloc_sampling_buffers() and
alloc_sample_data_block() allocate pages and the allocation
can fail. This is handled correctly and all allocated
pages are freed and error -ENOMEM is returned to the
top calling function. Finally the event is not created.
Once the event has been created, the amount of initially
allocated SDBT and SDB can be too low. This is detected
during measurement interrupt handling, where the amount
of lost samples is calculated. If the number of lost samples
is too high considering sampling frequency and already allocated
SBDs, the number of SDBs is enlarged during the next execution
of cpumsf_pmu_enable().
If more SBDs need to be allocated, functions
realloc_sampling_buffers()
+---> alloc-sample_data_block()
are called to allocate more pages. Page allocation may fail
and the returned error is ignored. A SDBT and SDB setup
already exists.
However the modified SDBTs and SDBs might end up in a situation
where the first entry of an SDBT does not point to an SDB,
but another SDBT, basicly an SBDT without payload.
This can not be handled by the interrupt handler, where an SDBT
must have at least one entry pointing to an SBD.
Add a check to avoid SDBTs with out payload (SDBs) when enlarging
the buffer setup.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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The macro TEAR_REG() saves the last used SDBT address
in the perf_hw_event structure. This is also done
by function hw_reset_registers() which is a one-liner
and simply uses macro TEAR_REG(). Remove function
hw_reset_registers(), which is only used one time and use
macro TEAR_REG() instead. This macro is used throughout
the code anyway.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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In interrupt handling the function extend_sampling_buffer()
is called after checking for a possibly extension.
This check is not necessary as the called function itself
performs this check again.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Replace hard coded function names in debug statements
by the "%s ...", __func__ construct suggested by checkpatch.pl
script. Use consistent debug print format of the form variable
blank value. Also add leading 0x for all hex values.
Print allocated page addresses consistantly as hex numbers
with leading 0x.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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The KASLR offset is added to vmcoreinfo in arch_crash_save_vmcoreinfo(),
so that it can be found by crash when processing kernel dumps.
However, arch_crash_save_vmcoreinfo() is called during a subsys_initcall,
so if the kernel crashes before that, we have no vmcoreinfo and no KASLR
offset.
Fix this by storing the KASLR offset in the lowcore, where the vmcore_info
pointer will be stored, and where it can be found by crash. In order to
make it distinguishable from a real vmcore_info pointer, mark it as uneven
(KASLR offset itself is aligned to THREAD_SIZE).
When arch_crash_save_vmcoreinfo() stores the real vmcore_info pointer in
the lowcore, it overwrites the KASLR offset. At that point, the KASLR
offset is not yet added to vmcoreinfo, so we also need to move the
mem_assign_absolute() behind the vmcoreinfo_append_str().
Fixes: b2d24b97b2a9 ("s390/kernel: add support for kernel address space layout randomization (KASLR)")
Cc: <stable@vger.kernel.org> # v5.2+
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Consider reaching task pt_regs graceful unwinder termination. Task
pt_regs itself never contains a valid state to which a task might return
within the kernel context (user task pt_regs is a special case). Since
we already avoid printing user task pt_regs and in most cases we don't
even bother filling task pt_regs psw and r15 with something reasonable
simply skip task pt_regs altogether. With this change unwind_error() now
accurately represent whether unwinder reached task pt_regs successfully
or failed along the way.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Add missing allocation of pt_regs at the bottom of the stack. This
makes it consistent with other stack setup cases and also what stack
unwinder expects.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Currently unwinder yields 2 entries when pt_regs are met:
sp="address of pt_regs itself" ip=pt_regs->psw
sp=pt_regs->gprs[15] ip="r14 from stack frame pointed by pt_regs->gprs[15]"
And neither of those 2 states (combination of sp and ip) ever happened.
reuse_sp has been introduced by commit a1d863ac3e10 ("s390/unwind: fix
mixing regs and sp"). reuse_sp=true makes unwinder keen to produce the
following result, when pt_regs are given (as an arg to unwind_start):
sp=pt_regs->gprs[15] ip=pt_regs->psw
sp=pt_regs->gprs[15] ip="r14 from stack frame pointed by pt_regs->gprs[15]"
The first state is an actual state in which a task was when pt_regs were
collected. The second state is marked unreliable and is for debugging
purposes to cover the case when a task has been interrupted in between
stack frame allocation and writing back_chain - in this case r14 might
show an actual caller.
Make unwinder behaviour enabled via reuse_sp=true default and drop the
special case handling.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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If unwinder is looking at pt_regs which is not on stack then something
went wrong and an error has to be reported rather than successful
unwinding termination.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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CALL_ON_STACK is intended to be used for temporary stack switching with
potential return to the caller.
When CALL_ON_STACK is misused to switch from nodat stack to task stack
back_chain information would later lead stack unwinder from task stack into
(per cpu) nodat stack which is reused for other purposes. This would
yield confusing unwinding result or errors.
To avoid that introduce CALL_ON_STACK_NORETURN to be used instead. It
makes sure that back_chain is zeroed and unwinder finishes gracefully
ending up at task pt_regs.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Currently CALL_ON_STACK saves r15 as back_chain in the first stack frame of
the stack we about to switch to. But if a function which uses CALL_ON_STACK
calls other function it allocates a stack frame for a callee. In this
case r15 is pointing to a callee stack frame and not a stack frame of
function itself. This results in dummy unwinding entry with random
sp and ip values.
Introduce and utilize current_frame_address macro to get an address of
actual function stack frame.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Avoid mixture of task == NULL and task == current meaning the same
thing and simply always initialize task with current in unwind_start.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Make sure preemption is disabled when temporary switching to nodat
stack with CALL_ON_STACK helper, because nodat stack is per cpu.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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disabled_wait uses _THIS_IP_ and assumes that compiler would inline it.
Make sure this assumption is always correct by utilizing __always_inline.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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getcpu reads the required values for cpu and node with two
instructions. This might lead to an inconsistent result if user space
gets preempted and migrated to a different CPU between the two
instructions.
Fix this by using just a single instruction to read both values at
once.
This is currently rather a theoretical bug, since there is no real
NUMA support available (except for NUMA emulation).
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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When a secondary CPU is brought up it must initialize its control
registers. CPU A which triggers that a secondary CPU B is brought up
stores its control register contents into the lowcore of new CPU B,
which then loads these values on startup.
This is problematic in various ways: the control register which
contains the home space ASCE will correctly contain the kernel ASCE;
however control registers for primary and secondary ASCEs are
initialized with whatever values were present in CPU A.
Typically:
- the primary ASCE will contain the user process ASCE of the process
that triggered onlining of CPU B.
- the secondary ASCE will contain the percpu VDSO ASCE of CPU A.
Due to lazy ASCE handling we may also end up with other combinations.
When then CPU B switches to a different process (!= idle) it will
fixup the primary ASCE. However the problem is that the (wrong) ASCE
from CPU A was loaded into control register 1: as soon as an ASCE is
attached (aka loaded) a CPU is free to generate TLB entries using that
address space.
Even though it is very unlikey that CPU B will actually generate such
entries, this could result in TLB entries of the address space of the
process that ran on CPU A. These entries shouldn't exist at all and
could cause problems later on.
Furthermore the secondary ASCE of CPU B will not be updated correctly.
This means that processes may see wrong results or even crash if they
access VDSO data on CPU B. The correct VDSO ASCE will eventually be
loaded on return to user space as soon as the kernel executed a call
to strnlen_user or an atomic futex operation on CPU B.
Fix both issues by intializing the to be loaded control register
contents with the correct ASCEs and also enforce (re-)loading of the
ASCEs upon first context switch and return to user space.
Fixes: 0aaba41b58bc ("s390: remove all code using the access register mode")
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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On s390 bpf_get_stack_raw_tp() returns 0 entries for both kernel and
user stacks. While there is no practical unwinding solution for userspace
on s390 at this moment, there certainly is a kernel unwinder. However,
it is not properly integrated with BPF.
In order to start unwinding, bpf_get_stack_raw_tp() obtains the current
kernel register values using perf_fetch_caller_regs(), which is not
implemented for s390. The actual unwinding then happens by passing those
registers to perf_callchain_kernel().
Implement perf_arch_fetch_caller_regs() for s390, where
__builtin_frame_address(0) points to back_chain.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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system_call assembly code always pushes pointer to struct pt_regs as the
last additional parameter for all system calls. The only user of this
feature is xtensa_rt_sigreturn.
Avoid this special case. Define xtensa_rt_sigreturn as accepting no
argiments. Use current_pt_regs to get pointer to struct pt_regs in
xtensa_rt_sigreturn. Don't pass additional parameter from system_call
code.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
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Don't overwrite return value if system call was cancelled at entry by
ptrace. Return status code from do_syscall_trace_enter so that
pt_regs::syscall doesn't need to be changed to skip syscall.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
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system_call saves and restores syscall number across system call to make
clone and execv entry and exit tracing match. This complicates things
when syscall code may be changed by ptrace.
Preserve syscall code in copy_thread and start_thread directly instead of
doing tricks in system_call.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD
KVM: Add support for secure guests under the Protected Execution
Framework (PEF) Ultravisor on POWER.
This enables secure memory to be represented as device memory,
which provides a way for the host to keep track of which pages of a
secure guest have been moved into secure memory managed by the
ultravisor and are no longer accessible by the host, and manage
movement of pages between secure and normal memory.
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Commit f2bb86937d86 ("powerpc/fixmap: don't clear fixmap area in
paging_init()") removed the clearing of fixmap area in order to
avoid clearing fixmapped areas set earlier.
However unlike all other users of fixmap which use __set_fixmap(),
HIGHMEM functions directly use __set_pte_at(). This means
the page table must pre-exist, otherwise the following crash
can be encoutered due to the lack of entry in the PGD.
Oops: Kernel access of bad area, sig: 11 [#1]
BE PAGE_SIZE=4K MMU=Hash PowerMac
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.0+ #2528
NIP: c0144ce8 LR: c0144ccc CTR: 00000080
REGS: ef0b5aa0 TRAP: 0300 Not tainted (5.4.0+)
MSR: 00009032 <EE,ME,IR,DR,RI> CR: 44282842 XER: 00000000
DAR: fffdf000 DSISR: 42000000
GPR00: c0144ccc ef0b5b58 ef0b0000 fffdf000 fffdf000 00000000 c0000f7c 00000000
GPR08: c0833000 fffdf000 00000000 ef1c53c9 24042842 00000000 00000000 00000000
GPR16: 00000000 00000000 ef7e7358 effe8160 00000000 c08a9660 c0851644 00000004
GPR24: c08c70a8 00002dc2 00000000 00000001 00000201 effe8160 effe8160 00000000
NIP [c0144ce8] prep_new_page+0x138/0x178
LR [c0144ccc] prep_new_page+0x11c/0x178
Call Trace:
[ef0b5b58] [c0144ccc] prep_new_page+0x11c/0x178 (unreliable)
[ef0b5b88] [c0147218] get_page_from_freelist+0x1fc/0xd88
[ef0b5c38] [c0148328] __alloc_pages_nodemask+0xd4/0xbb4
[ef0b5cf8] [c0142ba8] __vmalloc_node_range+0x1b4/0x2e0
[ef0b5d38] [c0142dd0] vzalloc+0x48/0x58
[ef0b5d58] [c0301c8c] check_partition+0x58/0x244
[ef0b5d78] [c02ffe80] blk_add_partitions+0x44/0x2cc
[ef0b5db8] [c01a32d8] bdev_disk_changed+0x68/0xfc
[ef0b5de8] [c01a4494] __blkdev_get+0x290/0x460
[ef0b5e28] [c02fdd40] __device_add_disk+0x480/0x4d8
[ef0b5e68] [c0810688] brd_init+0xc0/0x188
[ef0b5e88] [c0005194] do_one_initcall+0x40/0x19c
[ef0b5ee8] [c07dd4dc] kernel_init_freeable+0x164/0x230
[ef0b5f28] [c0005408] kernel_init+0x18/0x10c
[ef0b5f38] [c0014274] ret_from_kernel_thread+0x14/0x1c
Partially revert that commit to still clear the fixmap area dedicated
to HIGHMEM.
Fixes: f2bb86937d86 ("powerpc/fixmap: don't clear fixmap area in paging_init()")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d42fa9747df5afa41e67b08e374c98d3b40529c9.1574927918.git.christophe.leroy@c-s.fr
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After recent cpuidle updates the "disabled" field in struct
cpuidle_state is only used by two drivers (intel_idle and shmobile
cpuidle) for marking unusable idle states, but that may as well be
achieved with the help of a state flag, so define an "unusable" idle
state flag, CPUIDLE_FLAG_UNUSABLE, make the drivers in question use
it instead of the "disabled" field and make the core set
CPUIDLE_STATE_DISABLED_BY_DRIVER for the idle states with that flag
set.
After the above changes, the "disabled" field in struct cpuidle_state
is not used any more, so drop it.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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