This reverts commit 7d06fed77b.
This introduced vmem_mutex locking from vmem_map_4k_page()
function called from smp_reinit_ipl_cpu() with interrupts
disabled. While it is a pre-SMP early initcall no other CPUs
running in parallel nor other code taking vmem_mutex on this
boot stage - it still needs to be fixed.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Temporary unsetting of the prefix page in memcpy_absolute() routine
poses a risk of executing code path with unexpectedly disabled prefix
page. This rework avoids the prefix page uninstalling and disabling
of normal and machine check interrupts when accessing the absolute
zero memory.
Although memcpy_absolute() routine can access the whole memory, it is
only used to update the absolute zero lowcore. This rework therefore
introduces a new mechanism for the absolute zero lowcore access and
scraps memcpy_absolute() routine for good.
Instead, an area is reserved in the virtual memory that is used for
the absolute lowcore access only. That area holds an array of 8KB
virtual mappings - one per CPU. Whenever a CPU is brought online, the
corresponding item is mapped to the real address of the previously
installed prefix page.
The absolute zero lowcore access works like this: a CPU calls the
new primitive get_abs_lowcore() to obtain its 8KB mapping as a
pointer to the struct lowcore. Virtual address references to that
pointer get translated to the real addresses of the prefix page,
which in turn gets swapped with the absolute zero memory addresses
due to prefixing. Once the pointer is not needed it must be released
with put_abs_lowcore() primitive:
struct lowcore *abs_lc;
unsigned long flags;
abs_lc = get_abs_lowcore(&flags);
abs_lc->... = ...;
put_abs_lowcore(abs_lc, flags);
To ensure the described mechanism works large segment- and region-
table entries must be avoided for the 8KB mappings. Failure to do
so results in usage of Region-Frame Absolute Address (RFAA) or
Segment-Frame Absolute Address (SFAA) large page fields. In that
case absolute addresses would be used to address the prefix page
instead of the real ones and the prefixing would get bypassed.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Make the absolute lowcore assignments immediately follow
the boot CPU lowcore same member assignments. This way
readability improves when reading from up to down, with
no out of order mcck stack allocation in-between.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
As result of commit 915fea04f9 ("s390/smp: enable DAT before
CPU restart callback is called") the low-address protection bit
gets mistakenly unset in control register 0 save area of the
absolute zero memory. That area is used when manual PSW restart
happened to hit an offline CPU. In this case the low-address
protection for that CPU will be dropped.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Fixes: 915fea04f9 ("s390/smp: enable DAT before CPU restart callback is called")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
When RDRAND was introduced, there was much discussion on whether it
should be trusted and how the kernel should handle that. Initially, two
mechanisms cropped up, CONFIG_ARCH_RANDOM, a compile time switch, and
"nordrand", a boot-time switch.
Later the thinking evolved. With a properly designed RNG, using RDRAND
values alone won't harm anything, even if the outputs are malicious.
Rather, the issue is whether those values are being *trusted* to be good
or not. And so a new set of options were introduced as the real
ones that people use -- CONFIG_RANDOM_TRUST_CPU and "random.trust_cpu".
With these options, RDRAND is used, but it's not always credited. So in
the worst case, it does nothing, and in the best case, maybe it helps.
Along the way, CONFIG_ARCH_RANDOM's meaning got sort of pulled into the
center and became something certain platforms force-select.
The old options don't really help with much, and it's a bit odd to have
special handling for these instructions when the kernel can deal fine
with the existence or untrusted existence or broken existence or
non-existence of that CPU capability.
Simplify the situation by removing CONFIG_ARCH_RANDOM and using the
ordinary asm-generic fallback pattern instead, keeping the two options
that are actually used. For now it leaves "nordrand" for now, as the
removal of that will take a different route.
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
s390x appears to present two RNG interfaces:
- a "TRNG" that gathers entropy using some hardware function; and
- a "DRBG" that takes in a seed and expands it.
Previously, the TRNG was wired up to arch_get_random_{long,int}(), but
it was observed that this was being called really frequently, resulting
in high overhead. So it was changed to be wired up to arch_get_random_
seed_{long,int}(), which was a reasonable decision. Later on, the DRBG
was then wired up to arch_get_random_{long,int}(), with a complicated
buffer filling thread, to control overhead and rate.
Fortunately, none of the performance issues matter much now. The RNG
always attempts to use arch_get_random_seed_{long,int}() first, which
means a complicated implementation of arch_get_random_{long,int}() isn't
really valuable or useful to have around. And it's only used when
reseeding, which means it won't hit the high throughput complications
that were faced before.
So this commit returns to an earlier design of just calling the TRNG in
arch_get_random_seed_{long,int}(), and returning false in arch_get_
random_{long,int}().
Part of what makes the simplification possible is that the RNG now seeds
itself using the TRNG at bootup. But this only works if the TRNG is
detected early in boot, before random_init() is called. So this commit
also causes that check to happen in setup_arch().
Cc: stable@vger.kernel.org
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Ingo Franzki <ifranzki@linux.ibm.com>
Cc: Juergen Christ <jchrist@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20220610222023.378448-1-Jason@zx2c4.com
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
SPX instruction called from set_prefix() expects physical
address of the lowcore to be installed, but instead the
virtual address is passed.
Note: this does not fix a bug currently, since virtual and
physical addresses are identical.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Macro mem_assign_absolute() is able to access the whole memory, but
is only used and makes sense when updating the absolute lowcore.
Instead, introduce get_abs_lowcore() and put_abs_lowcore() macros
that limit access to absolute lowcore addresses only.
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Machine generations up to z9 (released in May 2006) have been officially
out of service for several years now (z9 end of service - January 31, 2019).
No distributions build kernels supporting those old machine generations
anymore, except Debian, which seems to pick the oldest supported
generation. The team supporting Debian on s390 has been notified about
the change.
Raising minimum supported machine generation to z10 helps to reduce
maintenance cost and effectively remove code, which is not getting
enough testing coverage due to lack of older hardware and distributions
support. Besides that this unblocks some optimization opportunities and
allows to use wider instruction set in asm files for future features
implementation. Due to this change spectre mitigation and usercopy
implementations could be drastically simplified and many newer instructions
could be converted from ".insn" encoding to instruction names.
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
We need to preserve the values at OLDMEM_BASE and OLDMEM_SIZE which are
used by zgetdump in case when kdump crashes. In that case zgetdump will
attempt to read OLDMEM_BASE and OLDMEM_SIZE in order to find out where
the memory range [0 - OLDMEM_SIZE] belonging to the production kernel is.
Fixes: f1a5469474 ("s390/setup: don't reserve memory that occupied decompressor's head")
Cc: stable@vger.kernel.org # 5.15+
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Updating of the pointer to machine check extended save area
on the IPL CPU needs the lowcore protection to be disabled.
Disable interrupts while the protection is off to avoid
unnoticed writes to the lowcore.
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
- Avoid using ULONG_MAX in memblock_remove, it has no functional change
but makes memblock_dbg output a range which makes sense.
- Actually finish memblock memory setup before doing amode31/cr/uv
setup.
- Move memblock_dump_all() debug output after memblock memory setup is
complete. This gives us final "memory" regions if they were trimmed
due to addressing limits and still "physmem" regions as original info
which came from mem_detect.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
There is a difference in how architectures treat "mem=" option. For some
that is an amount of online memory, for s390 and x86 this is the limiting
max address. Some memblock api like memblock_enforce_memory_limit()
take limit argument and explicitly treat it as the size of online memory,
and use __find_max_addr to convert it to an actual max address. Current
s390 usage:
memblock_enforce_memory_limit(memblock_end_of_DRAM());
yields different results depending on presence of memory holes (offline
memory blocks in between online memory). If there are no memory holes
limit == max_addr in memblock_enforce_memory_limit() and it does trim
online memory and reserved memory regions. With memory holes present it
actually does nothing.
Since we already use memblock_remove() explicitly to trim online memory
regions to potential limit (think mem=, kdump, addressing limits, etc.)
drop the usage of memblock_enforce_memory_limit() altogether. Trimming
reserved regions should not be required, since we now use
memblock_set_current_limit() to limit allocations and any explicit memory
reservations above the limit is an actual problem we should not hide.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Such reserved memory region, if not cleaned up later causes problems when
memblock_free_all() is called to release free pages to the buddy allocator
and those reserved regions are carried over to reserve_bootmem_region()
which marks the pages as PageReserved.
Instead use memblock_set_current_limit() to make sure memblock allocations
do not go over identity mapping (which could happen when "mem=" option
is used or during kdump).
Cc: stable@vger.kernel.org
Fixes: 73045a08cf ("s390: unify identity mapping limits handling")
Reported-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
- Add support for ftrace with direct call and ftrace direct call samples.
- Add support for kernel command lines longer than current 896 bytes and
make its length configurable.
- Add support for BEAR enhancement facility to improve last breaking
event instruction tracking.
- Add kprobes sanity checks and testcases to prevent kprobe in the mid
of an instruction.
- Allow concurrent access to /dev/hwc for the CPUMF users.
- Various ftrace / jump label improvements.
- Convert unwinder tests to KUnit.
- Add s390_iommu_aperture kernel parameter to tweak the limits on
concurrently usable DMA mappings.
- Add ap.useirq AP module option which can be used to disable interrupt
use.
- Add add_disk() error handling support to block device drivers.
- Drop arch specific and use generic implementation of strlcpy and strrchr.
- Several __pa/__va usages fixes.
- Various cio, crypto, pci, kernel doc and other small fixes and
improvements all over the code.
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Merge tag 's390-5.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Vasily Gorbik:
- Add support for ftrace with direct call and ftrace direct call
samples.
- Add support for kernel command lines longer than current 896 bytes
and make its length configurable.
- Add support for BEAR enhancement facility to improve last breaking
event instruction tracking.
- Add kprobes sanity checks and testcases to prevent kprobe in the mid
of an instruction.
- Allow concurrent access to /dev/hwc for the CPUMF users.
- Various ftrace / jump label improvements.
- Convert unwinder tests to KUnit.
- Add s390_iommu_aperture kernel parameter to tweak the limits on
concurrently usable DMA mappings.
- Add ap.useirq AP module option which can be used to disable interrupt
use.
- Add add_disk() error handling support to block device drivers.
- Drop arch specific and use generic implementation of strlcpy and
strrchr.
- Several __pa/__va usages fixes.
- Various cio, crypto, pci, kernel doc and other small fixes and
improvements all over the code.
[ Merge fixup as per https://lore.kernel.org/all/YXAqZ%2FEszRisunQw@osiris/ ]
* tag 's390-5.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (63 commits)
s390: make command line configurable
s390: support command lines longer than 896 bytes
s390/kexec_file: move kernel image size check
s390/pci: add s390_iommu_aperture kernel parameter
s390/spinlock: remove incorrect kernel doc indicator
s390/string: use generic strlcpy
s390/string: use generic strrchr
s390/ap: function rework based on compiler warning
s390/cio: make ccw_device_dma_* more robust
s390/vfio-ap: s390/crypto: fix all kernel-doc warnings
s390/hmcdrv: fix kernel doc comments
s390/ap: new module option ap.useirq
s390/cpumf: Allow multiple processes to access /dev/hwc
s390/bitops: return true/false (not 1/0) from bool functions
s390: add support for BEAR enhancement facility
s390: introduce nospec_uses_trampoline()
s390: rename last_break to pgm_last_break
s390/ptrace: add last_break member to pt_regs
s390/sclp: sort out physical vs virtual pointers usage
s390/setup: convert start and end initrd pointers to virtual
...
We want to specify flags when hotplugging memory. Let's prepare to pass
flags to memblock_add_node() by adjusting all existing users.
Note that when hotplugging memory the system is already up and running
and we might have concurrent memblock users: for example, while we're
hotplugging memory, kexec_file code might search for suitable memory
regions to place kexec images. It's important to add the memory
directly to memblock via a single call with the right flags, instead of
adding the memory first and apply flags later: otherwise, concurrent
memblock users might temporarily stumble over memblocks with wrong
flags, which will be important in a follow-up patch that introduces a
new flag to properly handle add_memory_driver_managed().
Link: https://lkml.kernel.org/r/20211004093605.5830-4-david@redhat.com
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Shahab Vahedi <shahab@synopsys.com> [arch/arc]
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jianyong Wu <Jianyong.Wu@arm.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since memblock_free() operates on a physical range, make its name
reflect it and rename it to memblock_phys_free(), so it will be a
logical counterpart to memblock_phys_alloc().
The callers are updated with the below semantic patch:
@@
expression addr;
expression size;
@@
- memblock_free(addr, size);
+ memblock_phys_free(addr, size);
Link: https://lkml.kernel.org/r/20210930185031.18648-6-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Juergen Gross <jgross@suse.com>
Cc: Shahab Vahedi <Shahab.Vahedi@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The Breaking-Event-Address-Register (BEAR) stores the address of the
last breaking event instruction. Breaking events are usually instructions
that change the program flow - for example branches, and instructions
that modify the address in the PSW like lpswe. This is useful for debugging
wild branches, because one could easily figure out where the wild branch
was originating from.
What is problematic is that lpswe is considered a breaking event, and
therefore overwrites BEAR on kernel exit. The BEAR enhancement facility
adds new instructions that allow to save/restore BEAR and also an lpswey
instruction that doesn't cause a breaking event. So we can save BEAR on
kernel entry and restore it on exit to user space.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Variables initrd_start and initrd_end are expected to hold
virtual memory pointers, not physical.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
memblock_reserve() function accepts physcal address of a memory
block to be reserved, but provided with virtual memory pointers.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The memory for amode31 section is allocated from the decompressed
kernel. Instead, allocate that memory from the decompressor. This
is a prerequisite to allow initialization of the virtual memory
before the decompressed kernel takes over.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
- Fix topology update on cpu hotplug, so notifiers see expected masks. This bug
was uncovered with SCHED_CORE support.
- Fix stack unwinding so that the correct number of entries are omitted like
expected by common code. This fixes KCSAN selftests.
- Add kmemleak annotation to stack_alloc to avoid false positive kmemleak
warnings.
- Avoid layering violation in common I/O code and don't unregister subchannel
from child-drivers.
- Remove xpram device driver for which no real use case exists since the kernel
is 64 bit only. Also all hypervisors got required support removed in the
meantime, which means the xpram device driver is dead code.
- Fix -ENODEV handling of clp_get_state in our PCI code.
- Enable KFENCE in debug defconfig.
- Cleanup hugetlbfs s390 specific Kconfig dependency.
- Quite a lot of trivial fixes to get rid of "W=1" warnings, and and other
simple cleanups.
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Merge tag 's390-5.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull more s390 updates from Heiko Carstens:
"Except for the xpram device driver removal it is all about fixes and
cleanups.
- Fix topology update on cpu hotplug, so notifiers see expected
masks. This bug was uncovered with SCHED_CORE support.
- Fix stack unwinding so that the correct number of entries are
omitted like expected by common code. This fixes KCSAN selftests.
- Add kmemleak annotation to stack_alloc to avoid false positive
kmemleak warnings.
- Avoid layering violation in common I/O code and don't unregister
subchannel from child-drivers.
- Remove xpram device driver for which no real use case exists since
the kernel is 64 bit only. Also all hypervisors got required
support removed in the meantime, which means the xpram device
driver is dead code.
- Fix -ENODEV handling of clp_get_state in our PCI code.
- Enable KFENCE in debug defconfig.
- Cleanup hugetlbfs s390 specific Kconfig dependency.
- Quite a lot of trivial fixes to get rid of "W=1" warnings, and and
other simple cleanups"
* tag 's390-5.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
hugetlbfs: s390 is always 64bit
s390/ftrace: remove incorrect __va usage
s390/zcrypt: remove incorrect kernel doc indicators
scsi: zfcp: fix kernel doc comments
s390/sclp: add __nonstring annotation
s390/hmcdrv_ftp: fix kernel doc comment
s390: remove xpram device driver
s390/pci: read clp_list_pci_req only once
s390/pci: fix clp_get_state() handling of -ENODEV
s390/cio: fix kernel doc comment
s390/ctrlchar: fix kernel doc comment
s390/con3270: use proper type for tasklet function
s390/cpum_cf: move array from header to C file
s390/mm: fix kernel doc comments
s390/topology: fix topology information when calling cpu hotplug notifiers
s390/unwind: use current_frame_address() to unwind current task
s390/configs: enable CONFIG_KFENCE in debug_defconfig
s390/entry: make oklabel within CHKSTG macro local
s390: add kmemleak annotation in stack_alloc()
s390/cio: dont unregister subchannel from child-drivers
Merge misc updates from Andrew Morton:
"173 patches.
Subsystems affected by this series: ia64, ocfs2, block, and mm (debug,
pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap,
bootmem, sparsemem, vmalloc, kasan, pagealloc, memory-failure,
hugetlb, userfaultfd, vmscan, compaction, mempolicy, memblock,
oom-kill, migration, ksm, percpu, vmstat, and madvise)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (173 commits)
mm/madvise: add MADV_WILLNEED to process_madvise()
mm/vmstat: remove unneeded return value
mm/vmstat: simplify the array size calculation
mm/vmstat: correct some wrong comments
mm/percpu,c: remove obsolete comments of pcpu_chunk_populated()
selftests: vm: add COW time test for KSM pages
selftests: vm: add KSM merging time test
mm: KSM: fix data type
selftests: vm: add KSM merging across nodes test
selftests: vm: add KSM zero page merging test
selftests: vm: add KSM unmerge test
selftests: vm: add KSM merge test
mm/migrate: correct kernel-doc notation
mm: wire up syscall process_mrelease
mm: introduce process_mrelease system call
memblock: make memblock_find_in_range method private
mm/mempolicy.c: use in_task() in mempolicy_slab_node()
mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies
mm/mempolicy: advertise new MPOL_PREFERRED_MANY
mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY
...
There are a lot of uses of memblock_find_in_range() along with
memblock_reserve() from the times memblock allocation APIs did not exist.
memblock_find_in_range() is the very core of memblock allocations, so any
future changes to its internal behaviour would mandate updates of all the
users outside memblock.
Replace the calls to memblock_find_in_range() with an equivalent calls to
memblock_phys_alloc() and memblock_phys_alloc_range() and make
memblock_find_in_range() private method of memblock.
This simplifies the callers, ensures that (unlikely) errors in
memblock_reserve() are handled and improves maintainability of
memblock_find_in_range().
Link: https://lkml.kernel.org/r/20210816122622.30279-1-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Acked-by: Kirill A. Shutemov <kirill.shtuemov@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [ACPI]
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Nick Kossifidis <mick@ics.forth.gr> [riscv]
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kmemleak with enabled auto scanning reports that our stack allocation is
lost. This is because we're saving the pointer + STACK_INIT_OFFSET to
lowcore. When kmemleak now scans the objects, it thinks that this one is
lost because it can't find a corresponding pointer.
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
The restart interrupt is triggered whenever a secondary CPU is
brought online, a remote function call dispatched from another
CPU or a manual PSW restart is initiated and causes the system
to kdump. The handling routine is always called with DAT turned
off. It then initializes the stack frame and invokes a callback.
The existing callbacks handle DAT as follows:
* __do_restart() and __machine_kexec() turn in on upon entry;
* __ipl_run(), __reipl_run() and __dump_run() do not turn it
right away, but all of them call diag308() - which turns DAT
on, but only if kasan is enabled;
In addition to the described complexity all callbacks (and the
functions they call) should avoid kasan instrumentation while
DAT is off.
This update enables DAT in the assembler restart handler and
relieves any callbacks (which are mostly C functions) from
dealing with DAT altogether.
There are four types of CPU restart that initialize control
registers in different ways:
1. Start of secondary CPU on boot - control registers are
inherited from the IPL CPU;
2. Restart of online CPU - control registers of the CPU being
restarted are kept;
3. Hotplug of offline CPU - control registers are inherited
from the starting CPU;
4. Start of offline CPU triggered by manual PSW restart -
the control registers are read from the absolute lowcore
and contain the boot time IPL CPU values updated with all
follow-up calls of smp_ctl_set_bit() and smp_ctl_clear_bit()
routines;
In first three cases contents of the control registers is the
most recent. In the latter case control registers are good
enough to facilitate successful completion of kdump operation.
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
The memory block occupied by the SCLP early buffer that is allocated
by the decompressor and then handed over to the decompressed kernel,
must be reserved to prevent it from being reused for other purposes.
This is necessary because the SCLP early buffer is still in use
during kernel initialization.
Fixes: f1d3c53237 ("s390/boot: move sclp early buffer from fixed address in asm to C")
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reported-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The dma section name is confusing, since the code which resides within
that section has nothing to do with direct memory access. Instead the
limitation is that the code has to run in 31 bit addressing mode, and
therefore has to reside below 2GB. So the name was chosen since
ZONE_DMA is the same region.
To reduce confusion rename the section to amode31, which hopefully
describes better what this is about.
Note: this will also change vmcoreinfo strings
- SDMA=... gets renamed to SAMODE31=...
- EDMA=... gets renamed to EAMODE31=...
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Move setup_hwcaps() to processor.c for two reasons:
- make setup.c a bit smaller
- have allmost all of the hwcap code in one file
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Remove s390 part of all HWCAP defines, just to make them shorter and
easier to handle. The namespace is anyway per architecture.
This is similar to what arm64 has.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
In order to support the use of enhanced PCI instructions in both kernel-
and userspace we need both hardware support and proper setup in the
kernel. The latter can be toggled off with the pci=nomio command line
option.
Thus availability of this feature in userspace depends on all of kernel
configuration (CONFIG_PCI), hardware support and the current kernel
command line and can thus not rely solely on a facility bit. Instead
let's introduce a new ELF hardware capability bit HWCAP_S390_PCI_MIO to
tell userspace whether these PCI instructions can be used.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Add hardware capability bits and feature tags to /proc/cpuinfo
for NNPA and Vector-Packed-Decimal-Enhancement Facility 2.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
There is no useful information within [STARTUP_NORMAL_OFFSET, HEAD_END] now.
But the memory region [0, STARTUP_NORMAL_OFFSET] is used by:
* lowcore
* kdump for swapping memory
* stand-alone zipl dumpers for code, data, stack and heap
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This change simplifies the task of making the decompressor relocatable.
The decompressor's image contains special DMA sections between _sdma and
_edma. This DMA segment is loaded at boot as part of the decompressor and
then simply handed over to the decompressed kernel. The decompressor itself
never uses it in any way. The primary reason for this is the need to keep
the aforementioned DMA segment below 2GB which is required by architecture,
and because the decompressor is always loaded at a fixed low physical
address, it is guaranteed that the DMA region will not cross the 2GB
memory limit. If the DMA region had been placed in the decompressed kernel,
then KASLR would make this guarantee impossible to fulfill or it would
be restricted to the first 2GB of memory address space.
This commit moves all DMA sections between _sdma and _edma from
the decompressor's image to the decompressed kernel's image. The complete
DMA region is placed in the init section of the decompressed kernel and
immediately relocated below 2GB at start-up before it is needed by other
parts of the decompressed kernel. The relocation of the DMA region happens
even if the decompressed kernel is already located below 2GB in order
to keep the first implementation simple. The relocation should not have
any noticeable impact on boot time because the DMA segment is only a couple
of pages.
After relocating the DMA sections, the kernel has to fix all references
which point into it. In order to automate this, place all variables
pointing into the DMA sections in a special .dma.refs section. All such
variables must be defined using the new __dma_ref macro. Only variables
containing addresses within the DMA sections must be placed in the new
.dma.refs section.
Furthermore, move the initialization of control registers from
the decompressor to the decompressed kernel because some control registers
reference tables that must be placed in the DMA data section to
guarantee that their addresses are below 2G. Because the decompressed
kernel relocates the DMA sections at startup, the content of control
registers CR2, CR5 and CR15 must be updated with new addresses after
the relocation. The decompressed kernel initializes all control registers
early at boot and then updates the content of CR2, CR5 and CR15
as soon as the DMA relocation has occurred. This practically reverts
the commit a80313ff91 ("s390/kernel: introduce .dma sections").
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
The new boot data struct shall replace global variables OLDMEM_BASE and
OLDMEM_SIZE. It is initialized in the decompressor and passed
to the decompressed kernel. In comparison to the old solution, this one
doesn't access data at fixed physical addresses which will become important
when the decompressor becomes relocatable.
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
The new boot data struct shall replace global variables INITRD_START and
INITRD_SIZE. It is initialized in the decompressor and passed
to the decompressed kernel. In comparison to the old solution, this one
doesn't access data at fixed physical addresses which will become important
when the decompressor becomes relocatable.
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
- Fix preempt_count initialization.
- Rework call_on_stack() macro to add proper type handling and avoid
possible register corruption.
- More error prone "register asm" removal and fixes.
- Fix syscall restarting when multiple signals are coming in. This adds
minimalistic trampolines to vdso so we can return from signal without
using the stack which requires pgm check handler hacks when NX is
enabled.
- Remove HAVE_IRQ_EXIT_ON_IRQ_STACK since this is no longer true after
switch to generic entry.
- Fix protected virtualization secure storage access exception handling.
- Make machine check C handler always enter with DAT enabled and move
register validation to C code.
- Fix tinyconfig boot problem by avoiding MONITOR CALL without CONFIG_BUG.
- Increase asm symbols alignment to 16 to make it consistent with
compilers.
- Enable concurrent access to the CPU Measurement Counter Facility.
- Add support for dynamic AP bus size limit and rework ap_dqap to deal
with messages greater than recv buffer.
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Merge tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull more s390 updates from Vasily Gorbik:
- Fix preempt_count initialization.
- Rework call_on_stack() macro to add proper type handling and avoid
possible register corruption.
- More error prone "register asm" removal and fixes.
- Fix syscall restarting when multiple signals are coming in. This adds
minimalistic trampolines to vdso so we can return from signal without
using the stack which requires pgm check handler hacks when NX is
enabled.
- Remove HAVE_IRQ_EXIT_ON_IRQ_STACK since this is no longer true after
switch to generic entry.
- Fix protected virtualization secure storage access exception
handling.
- Make machine check C handler always enter with DAT enabled and move
register validation to C code.
- Fix tinyconfig boot problem by avoiding MONITOR CALL without
CONFIG_BUG.
- Increase asm symbols alignment to 16 to make it consistent with
compilers.
- Enable concurrent access to the CPU Measurement Counter Facility.
- Add support for dynamic AP bus size limit and rework ap_dqap to deal
with messages greater than recv buffer.
* tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (41 commits)
s390: preempt: Fix preempt_count initialization
s390/linkage: increase asm symbols alignment to 16
s390: rename CALL_ON_STACK_NORETURN() to call_on_stack_noreturn()
s390: add type checking to CALL_ON_STACK_NORETURN() macro
s390: remove old CALL_ON_STACK() macro
s390/softirq: use call_on_stack() macro
s390/lib: use call_on_stack() macro
s390/smp: use call_on_stack() macro
s390/kexec: use call_on_stack() macro
s390/irq: use call_on_stack() macro
s390/mm: use call_on_stack() macro
s390: introduce proper type handling call_on_stack() macro
s390/irq: simplify on_async_stack()
s390/irq: inline do_softirq_own_stack()
s390/irq: simplify do_softirq_own_stack()
s390/ap: get rid of register asm in ap_dqap()
s390: rename PIF_SYSCALL_RESTART to PIF_EXECVE_PGSTE_RESTART
s390: move restart of execve() syscall
s390/signal: remove sigreturn on stack
s390/signal: switch to using vdso for sigreturn and syscall restart
...
S390's init_idle_preempt_count(p, cpu) doesn't actually let us initialize the
preempt_count of the requested CPU's idle task: it unconditionally writes
to the current CPU's. This clearly conflicts with idle_threads_init(),
which intends to initialize *all* the idle tasks, including their
preempt_count (or their CPU's, if the arch uses a per-CPU preempt_count).
Unfortunately, it seems the way s390 does things doesn't let us initialize
every possible CPU's preempt_count early on, as the pages where this
resides are only allocated when a CPU is brought up and are freed when it
is brought down.
Let the arch-specific code set a CPU's preempt_count when its lowcore is
allocated, and turn init_idle_preempt_count() into an empty stub.
Fixes: f1a0a376ca ("sched/core: Initialize the idle task with preemption disabled")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20210707163338.1623014-1-valentin.schneider@arm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Lower case matches the call_on_stack() macro and is easier to read.
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Since OLDMEM_BASE/OLDMEM_SIZE is already taken into consideration and is
reflected in ident_map_size. reserve/remove_oldmem() is no longer needed
and could be removed.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Currently there are two separate places where kernel memory layout has
to be known and adjusted:
1. early kasan setup.
2. paging setup later.
Those 2 places had to be kept in sync and adjusted to reflect peculiar
technical details of one another. With additional factors which influence
kernel memory layout like ultravisor secure storage limit, complexity
of keeping two things in sync grew up even more.
Besides that if we look forward towards creating identity mapping and
enabling DAT before jumping into uncompressed kernel - that would also
require full knowledge of and control over kernel memory layout.
So, de-duplicate and move kernel memory layout setup logic into
the decompressor.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The lowcore for IPL CPU is special. It is allocated early
in the boot process using memblock and never freed since.
The reason is pcpu_alloc_lowcore() and pcpu_free_lowcore()
routines use page allocator which is not available when
the IPL CPU is getting initialized.
Similar problem is already addressed for stacks - once the
virtual memory is available the early boot stacks get re-
allocated. Doing the same for lowcore will allow freeing
the IPL CPU lowcore and make no difference between the
boot and secondary CPUs.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Console name reported in /proc/consoles:
ttyS1 -W- (EC p ) 4:65
does not match the char device name:
crw--w---- 1 root root 4, 65 May 17 12:18 /dev/ttysclp0
so debian-installer inside a QEMU s390x instance gets confused and fails
to start with the following error:
steal-ctty: No such file or directory
Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>
Link: https://lore.kernel.org/r/20210427194010.9330-1-vvidic@valentin-vidic.from.hr
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
With gcc-11, there are a lot of warnings because the facility functions
are accessing lowcore through a null pointer. Fix this by moving the
facility arrays away from lowcore.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
The PoP documents:
134: The vector packed decimal facility is installed in the
z/Architecture architectural mode. When bit 134 is
one, bit 129 is also one.
135: The vector enhancements facility 1 is installed in
the z/Architecture architectural mode. When bit 135
is one, bit 129 is also one.
Looks like we confuse the vector enhancements facility 1 ("EXT") with the
Vector packed decimal facility ("BCD"). Let's fix the facility checks.
Detected while working on QEMU/tcg z14 support and only unlocking
the vector enhancements facility 1, but not the vector packed decimal
facility.
Fixes: 2583b848ca ("s390: report new vector facilities")
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20210503121244.25232-1-david@redhat.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Use memblock_free_late() to free the old machine check stack to the
buddy allocator instead of leaking it.
Fixes: b61b159512 ("s390: add stack for machine check handler")
Cc: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
The previous code used the normal kernel stack for machine checks.
This is problematic when a machine check interrupts a system call
or interrupt handler right at the beginning where registers are set up.
Assume system_call is interrupted at the first instruction and a machine
check is triggered. The machine check handler is called, checks the PSW
to see whether it is coming from user space, notices that it is already
in kernel mode but %r15 still contains the user space stack. This would
lead to a kernel crash.
There are basically two ways of fixing that: Either using the 'critical
cleanup' approach which compares the address in the PSW to see whether
it is already at a point where the stack has been set up, or use an extra
stack for the machine check handler.
For simplicity, we will go with the second approach and allocate an extra
stack. This adds some memory overhead for large systems, but usually large
system have plenty of memory so this isn't really a concern. But it keeps
the mchk stack setup simple and less error prone.
Fixes: 0b0ed657fe ("s390: remove critical section cleanup from entry.S")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Cc: <stable@kernel.org> # v5.8+
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
