ordinary user mode tasks.
In commit 40966e316f ("kthread: Ensure struct kthread is present for
all kthreads") caused init and the user mode helper threads that call
kernel_execve to have struct kthread allocated for them. This struct
kthread going away during execve in turned made a use after free of
struct kthread possible.
The commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
init and umh") is enough to fix the use after free and is simple enough
to be backportable.
The rest of the changes pass struct kernel_clone_args to clean things
up and cause the code to make sense.
In making init and the user mode helpers tasks purely user mode tasks
I ran into two complications. The function task_tick_numa was
detecting tasks without an mm by testing for the presence of
PF_KTHREAD. The initramfs code in populate_initrd_image was using
flush_delayed_fput to ensuere the closing of all it's file descriptors
was complete, and flush_delayed_fput does not work in a userspace thread.
I have looked and looked and more complications and in my code review
I have not found any, and neither has anyone else with the code sitting
in linux-next.
Link: https://lkml.kernel.org/r/87mtfu4up3.fsf@email.froward.int.ebiederm.org
Eric W. Biederman (8):
kthread: Don't allocate kthread_struct for init and umh
fork: Pass struct kernel_clone_args into copy_thread
fork: Explicity test for idle tasks in copy_thread
fork: Generalize PF_IO_WORKER handling
init: Deal with the init process being a user mode process
fork: Explicitly set PF_KTHREAD
fork: Stop allowing kthreads to call execve
sched: Update task_tick_numa to ignore tasks without an mm
arch/alpha/kernel/process.c | 13 ++++++------
arch/arc/kernel/process.c | 13 ++++++------
arch/arm/kernel/process.c | 12 ++++++-----
arch/arm64/kernel/process.c | 12 ++++++-----
arch/csky/kernel/process.c | 15 ++++++-------
arch/h8300/kernel/process.c | 10 ++++-----
arch/hexagon/kernel/process.c | 12 ++++++-----
arch/ia64/kernel/process.c | 15 +++++++------
arch/m68k/kernel/process.c | 12 ++++++-----
arch/microblaze/kernel/process.c | 12 ++++++-----
arch/mips/kernel/process.c | 13 ++++++------
arch/nios2/kernel/process.c | 12 ++++++-----
arch/openrisc/kernel/process.c | 12 ++++++-----
arch/parisc/kernel/process.c | 18 +++++++++-------
arch/powerpc/kernel/process.c | 15 +++++++------
arch/riscv/kernel/process.c | 12 ++++++-----
arch/s390/kernel/process.c | 12 ++++++-----
arch/sh/kernel/process_32.c | 12 ++++++-----
arch/sparc/kernel/process_32.c | 12 ++++++-----
arch/sparc/kernel/process_64.c | 12 ++++++-----
arch/um/kernel/process.c | 15 +++++++------
arch/x86/include/asm/fpu/sched.h | 2 +-
arch/x86/include/asm/switch_to.h | 8 +++----
arch/x86/kernel/fpu/core.c | 4 ++--
arch/x86/kernel/process.c | 18 +++++++++-------
arch/xtensa/kernel/process.c | 17 ++++++++-------
fs/exec.c | 8 ++++---
include/linux/sched/task.h | 8 +++++--
init/initramfs.c | 2 ++
init/main.c | 2 +-
kernel/fork.c | 46 +++++++++++++++++++++++++++++++++-------
kernel/sched/fair.c | 2 +-
kernel/umh.c | 6 +++---
33 files changed, 234 insertions(+), 160 deletions(-)
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull kthread updates from Eric Biederman:
"This updates init and user mode helper tasks to be ordinary user mode
tasks.
Commit 40966e316f ("kthread: Ensure struct kthread is present for
all kthreads") caused init and the user mode helper threads that call
kernel_execve to have struct kthread allocated for them. This struct
kthread going away during execve in turned made a use after free of
struct kthread possible.
Here, commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
init and umh") is enough to fix the use after free and is simple
enough to be backportable.
The rest of the changes pass struct kernel_clone_args to clean things
up and cause the code to make sense.
In making init and the user mode helpers tasks purely user mode tasks
I ran into two complications. The function task_tick_numa was
detecting tasks without an mm by testing for the presence of
PF_KTHREAD. The initramfs code in populate_initrd_image was using
flush_delayed_fput to ensuere the closing of all it's file descriptors
was complete, and flush_delayed_fput does not work in a userspace
thread.
I have looked and looked and more complications and in my code review
I have not found any, and neither has anyone else with the code
sitting in linux-next"
* tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
sched: Update task_tick_numa to ignore tasks without an mm
fork: Stop allowing kthreads to call execve
fork: Explicitly set PF_KTHREAD
init: Deal with the init process being a user mode process
fork: Generalize PF_IO_WORKER handling
fork: Explicity test for idle tasks in copy_thread
fork: Pass struct kernel_clone_args into copy_thread
kthread: Don't allocate kthread_struct for init and umh
- Add Tegra234 cpufreq support (Sumit Gupta).
- Clean up and enhance the Mediatek cpufreq driver (Wan Jiabing,
Rex-BC Chen, and Jia-Wei Chang).
- Fix up the CPPC cpufreq driver after recent changes (Zheng Bin,
Pierre Gondois).
- Minor update to dt-binding for Qcom's opp-v2-kryo-cpu (Yassine
Oudjana).
- Use list iterator only inside the list_for_each_entry loop (Xiaomeng
Tong, and Jakob Koschel).
- New APIs related to finding OPP based on interconnect bandwidth
(Krzysztof Kozlowski).
- Fix the missing of_node_put() in _bandwidth_supported() (Dan
Carpenter).
- Cleanups (Krzysztof Kozlowski, and Viresh Kumar).
- Add Out of Band mode description to the intel-speed-select utility
documentation (Srinivas Pandruvada).
- Add power sequences support to the system reboot and power off
code and make related platform-specific changes for multiple
platforms (Dmitry Osipenko, Geert Uytterhoeven).
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Merge tag 'pm-5.19-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more power management updates from Rafael Wysocki:
"These update the ARM cpufreq drivers and fix up the CPPC cpufreq
driver after recent changes, update the OPP code and PM documentation
and add power sequences support to the system reboot and power off
code.
Specifics:
- Add Tegra234 cpufreq support (Sumit Gupta)
- Clean up and enhance the Mediatek cpufreq driver (Wan Jiabing,
Rex-BC Chen, and Jia-Wei Chang)
- Fix up the CPPC cpufreq driver after recent changes (Zheng Bin,
Pierre Gondois)
- Minor update to dt-binding for Qcom's opp-v2-kryo-cpu (Yassine
Oudjana)
- Use list iterator only inside the list_for_each_entry loop
(Xiaomeng Tong, and Jakob Koschel)
- New APIs related to finding OPP based on interconnect bandwidth
(Krzysztof Kozlowski)
- Fix the missing of_node_put() in _bandwidth_supported() (Dan
Carpenter)
- Cleanups (Krzysztof Kozlowski, and Viresh Kumar)
- Add Out of Band mode description to the intel-speed-select utility
documentation (Srinivas Pandruvada)
- Add power sequences support to the system reboot and power off code
and make related platform-specific changes for multiple platforms
(Dmitry Osipenko, Geert Uytterhoeven)"
* tag 'pm-5.19-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (60 commits)
cpufreq: CPPC: Fix unused-function warning
cpufreq: CPPC: Fix build error without CONFIG_ACPI_CPPC_CPUFREQ_FIE
Documentation: admin-guide: PM: Add Out of Band mode
kernel/reboot: Change registration order of legacy power-off handler
m68k: virt: Switch to new sys-off handler API
kernel/reboot: Add devm_register_restart_handler()
kernel/reboot: Add devm_register_power_off_handler()
soc/tegra: pmc: Use sys-off handler API to power off Nexus 7 properly
reboot: Remove pm_power_off_prepare()
regulator: pfuze100: Use devm_register_sys_off_handler()
ACPI: power: Switch to sys-off handler API
memory: emif: Use kernel_can_power_off()
mips: Use do_kernel_power_off()
ia64: Use do_kernel_power_off()
x86: Use do_kernel_power_off()
sh: Use do_kernel_power_off()
m68k: Switch to new sys-off handler API
powerpc: Use do_kernel_power_off()
xen/x86: Use do_kernel_power_off()
parisc: Use do_kernel_power_off()
...
- Convert to the generic mmap support (ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT).
- Add support for outline-only KASAN with 64-bit Radix MMU (P9 or later).
- Increase SIGSTKSZ and MINSIGSTKSZ and add support for AT_MINSIGSTKSZ.
- Enable the DAWR (Data Address Watchpoint) on POWER9 DD2.3 or later.
- Drop support for system call instruction emulation.
- Many other small features and fixes.
Thanks to: Alexey Kardashevskiy, Alistair Popple, Andy Shevchenko, Bagas Sanjaya, Bjorn
Helgaas, Bo Liu, Chen Huang, Christophe Leroy, Colin Ian King, Daniel Axtens, Dwaipayan
Ray, Fabiano Rosas, Finn Thain, Frank Rowand, Fuqian Huang, Guilherme G. Piccoli, Hangyu
Hua, Haowen Bai, Haren Myneni, Hari Bathini, He Ying, Jason Wang, Jiapeng Chong, Jing
Yangyang, Joel Stanley, Julia Lawall, Kajol Jain, Kevin Hao, Krzysztof Kozlowski, Laurent
Dufour, Lv Ruyi, Madhavan Srinivasan, Magali Lemes, Miaoqian Lin, Minghao Chi, Nathan
Chancellor, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Oscar Salvador, Pali Rohár,
Paul Mackerras, Peng Wu, Qing Wang, Randy Dunlap, Reza Arbab, Russell Currey, Sohaib
Mohamed, Vaibhav Jain, Vasant Hegde, Wang Qing, Wang Wensheng, Xiang wangx, Xiaomeng Tong,
Xu Wang, Yang Guang, Yang Li, Ye Bin, YueHaibing, Yu Kuai, Zheng Bin, Zou Wei, Zucheng
Zheng.
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Merge tag 'powerpc-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Convert to the generic mmap support (ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
- Add support for outline-only KASAN with 64-bit Radix MMU (P9 or later)
- Increase SIGSTKSZ and MINSIGSTKSZ and add support for AT_MINSIGSTKSZ
- Enable the DAWR (Data Address Watchpoint) on POWER9 DD2.3 or later
- Drop support for system call instruction emulation
- Many other small features and fixes
Thanks to Alexey Kardashevskiy, Alistair Popple, Andy Shevchenko, Bagas
Sanjaya, Bjorn Helgaas, Bo Liu, Chen Huang, Christophe Leroy, Colin Ian
King, Daniel Axtens, Dwaipayan Ray, Fabiano Rosas, Finn Thain, Frank
Rowand, Fuqian Huang, Guilherme G. Piccoli, Hangyu Hua, Haowen Bai,
Haren Myneni, Hari Bathini, He Ying, Jason Wang, Jiapeng Chong, Jing
Yangyang, Joel Stanley, Julia Lawall, Kajol Jain, Kevin Hao, Krzysztof
Kozlowski, Laurent Dufour, Lv Ruyi, Madhavan Srinivasan, Magali Lemes,
Miaoqian Lin, Minghao Chi, Nathan Chancellor, Naveen N. Rao, Nicholas
Piggin, Oliver O'Halloran, Oscar Salvador, Pali Rohár, Paul Mackerras,
Peng Wu, Qing Wang, Randy Dunlap, Reza Arbab, Russell Currey, Sohaib
Mohamed, Vaibhav Jain, Vasant Hegde, Wang Qing, Wang Wensheng, Xiang
wangx, Xiaomeng Tong, Xu Wang, Yang Guang, Yang Li, Ye Bin, YueHaibing,
Yu Kuai, Zheng Bin, Zou Wei, and Zucheng Zheng.
* tag 'powerpc-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (200 commits)
powerpc/64: Include cache.h directly in paca.h
powerpc/64s: Only set HAVE_ARCH_UNMAPPED_AREA when CONFIG_PPC_64S_HASH_MMU is set
powerpc/xics: Include missing header
powerpc/powernv/pci: Drop VF MPS fixup
powerpc/fsl_book3e: Don't set rodata RO too early
powerpc/microwatt: Add mmu bits to device tree
powerpc/powernv/flash: Check OPAL flash calls exist before using
powerpc/powermac: constify device_node in of_irq_parse_oldworld()
powerpc/powermac: add missing g5_phy_disable_cpu1() declaration
selftests/powerpc/pmu: fix spelling mistake "mis-match" -> "mismatch"
powerpc: Enable the DAWR on POWER9 DD2.3 and above
powerpc/64s: Add CPU_FTRS_POWER10 to ALWAYS mask
powerpc/64s: Add CPU_FTRS_POWER9_DD2_2 to CPU_FTRS_ALWAYS mask
powerpc: Fix all occurences of "the the"
selftests/powerpc/pmu/ebb: remove fixed_instruction.S
powerpc/platforms/83xx: Use of_device_get_match_data()
powerpc/eeh: Drop redundant spinlock initialization
powerpc/iommu: Add missing of_node_put in iommu_init_early_dart
powerpc/pseries/vas: Call misc_deregister if sysfs init fails
powerpc/papr_scm: Fix leaking nvdimm_events_map elements
...
subsystems. Most notably some maintenance work in ocfs2 and initramfs.
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Merge tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc updates from Andrew Morton:
"The non-MM patch queue for this merge window.
Not a lot of material this cycle. Many singleton patches against
various subsystems. Most notably some maintenance work in ocfs2
and initramfs"
* tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (65 commits)
kcov: update pos before writing pc in trace function
ocfs2: dlmfs: fix error handling of user_dlm_destroy_lock
ocfs2: dlmfs: don't clear USER_LOCK_ATTACHED when destroying lock
fs/ntfs: remove redundant variable idx
fat: remove time truncations in vfat_create/vfat_mkdir
fat: report creation time in statx
fat: ignore ctime updates, and keep ctime identical to mtime in memory
fat: split fat_truncate_time() into separate functions
MAINTAINERS: add Muchun as a memcg reviewer
proc/sysctl: make protected_* world readable
ia64: mca: drop redundant spinlock initialization
tty: fix deadlock caused by calling printk() under tty_port->lock
relay: remove redundant assignment to pointer buf
fs/ntfs3: validate BOOT sectors_per_clusters
lib/string_helpers: fix not adding strarray to device's resource list
kernel/crash_core.c: remove redundant check of ck_cmdline
ELF, uapi: fixup ELF_ST_TYPE definition
ipc/mqueue: use get_tree_nodev() in mqueue_get_tree()
ipc: update semtimedop() to use hrtimer
ipc/sem: remove redundant assignments
...
- don't over-decrypt memory (Robin Murphy)
- takes min align mask into account for the swiotlb max mapping size
(Tianyu Lan)
- use GFP_ATOMIC in dma-debug (Mikulas Patocka)
- fix DMA_ATTR_NO_KERNEL_MAPPING on xen/arm (me)
- don't fail on highmem CMA pages in dma_direct_alloc_pages (me)
- cleanup swiotlb initialization and share more code with swiotlb-xen
(me, Stefano Stabellini)
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Merge tag 'dma-mapping-5.19-2022-05-25' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping updates from Christoph Hellwig:
- don't over-decrypt memory (Robin Murphy)
- takes min align mask into account for the swiotlb max mapping size
(Tianyu Lan)
- use GFP_ATOMIC in dma-debug (Mikulas Patocka)
- fix DMA_ATTR_NO_KERNEL_MAPPING on xen/arm (me)
- don't fail on highmem CMA pages in dma_direct_alloc_pages (me)
- cleanup swiotlb initialization and share more code with swiotlb-xen
(me, Stefano Stabellini)
* tag 'dma-mapping-5.19-2022-05-25' of git://git.infradead.org/users/hch/dma-mapping: (23 commits)
dma-direct: don't over-decrypt memory
swiotlb: max mapping size takes min align mask into account
swiotlb: use the right nslabs-derived sizes in swiotlb_init_late
swiotlb: use the right nslabs value in swiotlb_init_remap
swiotlb: don't panic when the swiotlb buffer can't be allocated
dma-debug: change allocation mode from GFP_NOWAIT to GFP_ATIOMIC
dma-direct: don't fail on highmem CMA pages in dma_direct_alloc_pages
swiotlb-xen: fix DMA_ATTR_NO_KERNEL_MAPPING on arm
x86: remove cruft from <asm/dma-mapping.h>
swiotlb: remove swiotlb_init_with_tbl and swiotlb_init_late_with_tbl
swiotlb: merge swiotlb-xen initialization into swiotlb
swiotlb: provide swiotlb_init variants that remap the buffer
swiotlb: pass a gfp_mask argument to swiotlb_init_late
swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction
swiotlb: make the swiotlb_init interface more useful
x86: centralize setting SWIOTLB_FORCE when guest memory encryption is enabled
x86: remove the IOMMU table infrastructure
MIPS/octeon: use swiotlb_init instead of open coding it
arm/xen: don't check for xen_initial_domain() in xen_create_contiguous_region
swiotlb: rename swiotlb_late_init_with_default_size
...
All three versions of klp_arch_set_pc() do exactly the same: they
call ftrace_instruction_pointer_set().
Call ftrace_instruction_pointer_set() directly and remove
klp_arch_set_pc().
As klp_arch_set_pc() was the only thing remaining in asm/livepatch.h
on x86 and s390, remove asm/livepatch.h
livepatch.h remains on powerpc but its content is exclusively used
by powerpc specific code.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Petr Mladek <pmladek@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Petr Mladek <pmladek@suse.com>
needed anymore
- Other misc improvements
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Merge tag 'x86_core_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core x86 updates from Borislav Petkov:
- Remove all the code around GS switching on 32-bit now that it is not
needed anymore
- Other misc improvements
* tag 'x86_core_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
bug: Use normal relative pointers in 'struct bug_entry'
x86/nmi: Make register_nmi_handler() more robust
x86/asm: Merge load_gs_index()
x86/32: Remove lazy GS macros
ELF: Remove elf_core_copy_kernel_regs()
x86/32: Simplify ELF_CORE_COPY_REGS
The hardware bug in POWER9 preventing use of the DAWR was fixed in
DD2.3. Set the CPU_FTR_DAWR feature bit on these newer systems to start
using it again, and update the documentation accordingly.
The CPU features for DD2.3 are currently determined by "DD2.2 or later"
logic. In adding DD2.3 as a discrete case for the first time here, I'm
carrying the quirks of DD2.2 forward to keep all behavior outside of
this DAWR change the same. This leaves the assessment and potential
removal of those quirks on DD2.3 for later.
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220503170152.23412-1-arbab@linux.ibm.com
Implement a limited form of KASAN for Book3S 64-bit machines running under
the Radix MMU, supporting only outline mode.
- Enable the compiler instrumentation to check addresses and maintain the
shadow region. (This is the guts of KASAN which we can easily reuse.)
- Require kasan-vmalloc support to handle modules and anything else in
vmalloc space.
- KASAN needs to be able to validate all pointer accesses, but we can't
instrument all kernel addresses - only linear map and vmalloc. On boot,
set up a single page of read-only shadow that marks all iomap and
vmemmap accesses as valid.
- Document KASAN in powerpc docs.
Background
----------
KASAN support on Book3S is a bit tricky to get right:
- It would be good to support inline instrumentation so as to be able to
catch stack issues that cannot be caught with outline mode.
- Inline instrumentation requires a fixed offset.
- Book3S runs code with translations off ("real mode") during boot,
including a lot of generic device-tree parsing code which is used to
determine MMU features.
[ppc64 mm note: The kernel installs a linear mapping at effective
address c000...-c008.... This is a one-to-one mapping with physical
memory from 0000... onward. Because of how memory accesses work on
powerpc 64-bit Book3S, a kernel pointer in the linear map accesses the
same memory both with translations on (accessing as an 'effective
address'), and with translations off (accessing as a 'real
address'). This works in both guests and the hypervisor. For more
details, see s5.7 of Book III of version 3 of the ISA, in particular
the Storage Control Overview, s5.7.3, and s5.7.5 - noting that this
KASAN implementation currently only supports Radix.]
- Some code - most notably a lot of KVM code - also runs with translations
off after boot.
- Therefore any offset has to point to memory that is valid with
translations on or off.
One approach is just to give up on inline instrumentation. This way
boot-time checks can be delayed until after the MMU is set is up, and we
can just not instrument any code that runs with translations off after
booting. Take this approach for now and require outline instrumentation.
Previous attempts allowed inline instrumentation. However, they came with
some unfortunate restrictions: only physically contiguous memory could be
used and it had to be specified at compile time. Maybe we can do better in
the future.
[paulus@ozlabs.org - Rebased onto 5.17. Note that a kernel with
CONFIG_KASAN=y will crash during boot on a machine using HPT
translation because not all the entry points to the generic
KASAN code are protected with a call to kasan_arch_is_ready().]
Originally-by: Balbir Singh <bsingharora@gmail.com> # ppc64 out-of-line radix version
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
[mpe: Update copyright year and comment formatting]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/YoTE69OQwiG7z+Gu@cleo
Disable address sanitization for raw and non-maskable interrupt
handlers, because they can run in real mode, where we cannot access
the shadow memory. (Note that kasan_arch_is_ready() doesn't test for
real mode, since it is a static branch for speed, and in any case not
all the entry points to the generic KASAN code are protected by
kasan_arch_is_ready guards.)
The changes to interrupt_nmi_enter/exit_prepare() look larger than
they actually are. The changes are equivalent to adding
!IS_ENABLED(CONFIG_KASAN) to the conditions for calling nmi_enter() or
nmi_exit() in real mode. That is, the code is equivalent to using the
following condition for calling nmi_enter/exit:
if (((!IS_ENABLED(CONFIG_PPC_BOOK3S_64) ||
!firmware_has_feature(FW_FEATURE_LPAR) ||
radix_enabled()) &&
!IS_ENABLED(CONFIG_KASAN) ||
(mfmsr() & MSR_DR))
That unwieldy condition has been split into several statements with
comments, for easier reading.
The nmi_ipi_lock functions that call atomic functions (i.e.,
nmi_ipi_lock_start(), nmi_ipi_lock() and nmi_ipi_unlock()), besides
being marked noinstr, now call arch_atomic_* functions instead of
atomic_* functions because with KASAN enabled, the atomic_* functions
are wrappers which explicitly do address sanitization on their
arguments. Since we are trying to avoid address sanitization, we have
to use the lower-level arch_atomic_* versions.
In hv_nmi_check_nonrecoverable(), the regs_set_unrecoverable() call
has been open-coded so as to avoid having to either trust the inlining
or mark regs_set_unrecoverable() as noinstr.
[paulus@ozlabs.org: combined a few work-in-progress commits of
Daniel's and wrote the commit message.]
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/YoTFGaKM8Pd46PIK@cleo
module_trampoline_target() is quite a hot path used when
activating/deactivating function tracer.
Avoid the heavy copy_from_kernel_nofault() by doing four calls
to copy_inst_from_kernel_nofault().
Use __copy_inst_from_kernel_nofault() for the 3 last calls. First call
is done to copy_from_kernel_nofault() to check address is within
kernel space. No risk to wrap out the top of kernel space because the
last page is never mapped so if address is in last page the first copy
will fails and the other ones will never be performed.
And also make it notrace just like all functions that call it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c55559103e014b7863161559d340e8e9484eaaa6.1652074503.git.christophe.leroy@csgroup.eu
Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new sys-off API.
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since commit 0c0c52306f ("powerpc: Only support DYNAMIC_FTRACE not
static"), CONFIG_DYNAMIC_FTRACE is always selected when
CONFIG_FUNCTION_TRACER is selected.
To avoid confusion and have the reader wonder what's happen when
CONFIG_FUNCTION_TRACER is selected and CONFIG_DYNAMIC_FTRACE is not,
use CONFIG_FUNCTION_TRACER in ifdefs instead of CONFIG_DYNAMIC_FTRACE.
As CONFIG_FUNCTION_GRAPH_TRACER depends on CONFIG_FUNCTION_TRACER,
ftrace.o doesn't need to appear for both symbols in Makefile.
Then as ftrace.o is built only when CONFIG_FUNCTION_TRACER is selected
ifdef CONFIG_FUNCTION_TRACER is not needed in ftrace.c, and since it
implies CONFIG_DYNAMIC_FTRACE, CONFIG_DYNAMIC_FTRACE is not needed
in ftrace.c
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/628d357503eb90b4a034f99b7df516caaff4d279.1652074503.git.christophe.leroy@csgroup.eu
Inlining ftrace_modify_code(), it increases a bit the
size of ftrace code but brings 5% improvment on ftrace
activation.
Usually in C files we let gcc decide what to do but here
it really help to 'help' gcc to decide to inline, thought
we don't want to force it with an __always_inline that
would be too much for CONFIG_CC_OPTIMIZE_FOR_SIZE.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1597a06d57cfc80e6853838c4066e799bf6c7977.1652074503.git.christophe.leroy@csgroup.eu
Since commit d5937db114 ("powerpc/code-patching: Fix patch_branch()
return on out-of-range failure") patch_branch() fails with -ERANGE
when trying to branch out of range.
No need to perform the test twice. Remove redundant create_branch()
calls.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/aa45fbad0b4b7493080835d8276c0cb4ce146503.1652074503.git.christophe.leroy@csgroup.eu
When we have CONFIG_DYNAMIC_FTRACE_WITH_ARGS,
prepare_ftrace_return() is called by ftrace_graph_func()
otherwise prepare_ftrace_return() is called from assembly.
Refactor prepare_ftrace_return() into a static
__prepare_ftrace_return() that will be called by both
prepare_ftrace_return() and ftrace_graph_func().
It will allow GCC to fold __prepare_ftrace_return() inside
ftrace_graph_func().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0d42deafe353980c66cf19d3132638c05ba9f4a9.1652074503.git.christophe.leroy@csgroup.eu
rtas_call must not be called with the MMU disabled because in case
of rtas error, log_error is called which requires MMU enabled. Add
a test and warning for this.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220308135047.478297-14-npiggin@gmail.com
PAPR specifies that RTAS may be called with MSR[RI] enabled if the
calling context is recoverable, and RTAS will manage RI as necessary.
Call the rtas entry point with RI enabled, and add a check to ensure
the caller has RI enabled.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220308135047.478297-10-npiggin@gmail.com
On 64-bit, PACA is saved in a SPRG so it does not need to be saved on
stack. We also don't need to mask off the top bits for real mode
addresses because the architecture does this for us.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220308135047.478297-8-npiggin@gmail.com
Disable MSR[EE] in C code rather than asm.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220308135047.478297-5-npiggin@gmail.com
Implement the AT_MINSIGSTKSZ AUXV entry, allowing userspace to
dynamically size stack allocations in a manner forward-compatible with
new processor state saved in the signal frame
For now these statically find the maximum signal frame size rather than
doing any runtime testing of features to minimise the size.
glibc 2.34 will take advantage of this, as will applications that use
use _SC_MINSIGSTKSZ and _SC_SIGSTKSZ.
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
References: 94b07c1f8c ("arm64: signal: Report signal frame size to userspace via auxv")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220307182734.289289-2-npiggin@gmail.com
The PowerPC vDSO uses $(CC) to link, which differs from the rest of the
kernel, which uses $(LD) directly. As a result, the default linker of
the compiler is used, which may differ from the linker requested by the
builder. For example:
$ make ARCH=powerpc LLVM=1 mrproper defconfig arch/powerpc/kernel/vdso/
...
$ llvm-readelf -p .comment arch/powerpc/kernel/vdso/vdso{32,64}.so.dbg
File: arch/powerpc/kernel/vdso/vdso32.so.dbg
String dump of section '.comment':
[ 0] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: arch/powerpc/kernel/vdso/vdso64.so.dbg
String dump of section '.comment':
[ 0] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
LLVM=1 sets LD=ld.lld but ld.lld is not used to link the vDSO; GNU ld is
because "ld" is the default linker for clang on most Linux platforms.
This is a problem for Clang's Link Time Optimization as implemented in
the kernel because use of GNU ld with LTO requires the LLVMgold plugin,
which is not technically supported for ld.bfd per
https://llvm.org/docs/GoldPlugin.html. Furthermore, if LLVMgold.so is
missing from a user's system, the build will fail, even though LTO as it
is implemented in the kernel requires ld.lld to avoid this dependency in
the first place.
Ultimately, the PowerPC vDSO should be converted to compiling and
linking with $(CC) and $(LD) respectively but there were issues last
time this was tried, potentially due to older but supported tool
versions. To avoid regressing GCC + binutils, use the compiler option
'-fuse-ld', which tells the compiler which linker to use when it is
invoked as both the compiler and linker. Use '-fuse-ld=lld' when
LD=ld.lld has been specified (CONFIG_LD_IS_LLD) so that the vDSO is
linked with the same linker as the rest of the kernel.
$ llvm-readelf -p .comment arch/powerpc/kernel/vdso/vdso{32,64}.so.dbg
File: arch/powerpc/kernel/vdso/vdso32.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: arch/powerpc/kernel/vdso/vdso64.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
LD can be a full path to ld.lld, which will not be handled properly by
'-fuse-ld=lld' if the full path to ld.lld is outside of the compiler's
search path. '-fuse-ld' can take a path to the linker but it is
deprecated in clang 12.0.0; '--ld-path' is preferred for this scenario.
Use '--ld-path' if it is supported, as it will handle a full path or
just 'ld.lld' properly. See the LLVM commit below for the full details
of '--ld-path'.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://github.com/ClangBuiltLinux/linux/issues/774
Link: 1bc5c84710
Link: https://lore.kernel.org/r/20220511185001.3269404-3-nathan@kernel.org
When linking vdso{32,64}.so.dbg with ld.lld, there is a warning about
not finding _start for the starting address:
ld.lld: warning: cannot find entry symbol _start; not setting start address
ld.lld: warning: cannot find entry symbol _start; not setting start address
Looking at GCC + GNU ld, the entry point address is 0x0:
$ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
File: vdso32.so.dbg
Entry point address: 0x0
File: vdso64.so.dbg
Entry point address: 0x0
This matches what ld.lld emits:
$ powerpc64le-linux-gnu-readelf -p .comment vdso{32,64}.so.dbg
File: vdso32.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: vdso64.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
$ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
File: vdso32.so.dbg
Entry point address: 0x0
File: vdso64.so.dbg
Entry point address: 0x0
Remove ENTRY to remove the warning, as it is unnecessary for the vDSO to
function correctly.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220511185001.3269404-2-nathan@kernel.org
When the mmu_feature_keys[] was introduced in the commit c12e6f24d4
("powerpc: Add option to use jump label for mmu_has_feature()"),
it is unlikely that it would be used either directly or indirectly in
the out of tree modules. So we exported it as GPL only.
But with the evolution of the codes, especially the PPC_KUAP support, it
may be indirectly referenced by some primitive macro or inline functions
such as get_user() or __copy_from_user_inatomic(), this will make it
impossible to build many non GPL modules (such as ZFS) on ppc
architecture. Fix this by exposing the mmu_feature_keys[] to the non-GPL
modules too.
Fixes: 7613f5a66b ("powerpc/64s/kuap: Use mmu_has_feature()")
Reported-by: Nathaniel Filardo <nwfilardo@gmail.com>
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220329085709.4132729-1-haokexin@gmail.com
The panic notifiers infrastructure is a bit limited in the scope of
the callbacks - basically every kind of functionality is dropped
in a list that runs in the same point during the kernel panic path.
This is not really on par with the complexities and particularities
of architecture / hypervisors' needs, and a refactor is ongoing.
As part of this refactor, it was observed that powerpc has 2 notifiers,
with mixed goals: one is just a KASLR offset dumper, whereas the other
aims to hard-disable IRQs (necessary on panic path), warn firmware of
the panic event (fadump) and run low-level platform-specific machinery
that might stop kernel execution and never come back.
Clearly, the 2nd notifier has opposed goals: disable IRQs / fadump
should run earlier while low-level platform actions should
run late since it might not even return. Hence, this patch decouples
the notifiers splitting them in three:
- First one is responsible for hard-disable IRQs and fadump,
should run early;
- The kernel KASLR offset dumper is really an informative notifier,
harmless and may run at any moment in the panic path;
- The last notifier should run last, since it aims to perform
low-level actions for specific platforms, and might never return.
It is also only registered for 2 platforms, pseries and ps3.
The patch better documents the notifiers and clears the code too,
also removing a useless header.
Currently no functionality change should be observed, but after
the planned panic refactor we should expect more panic reliability
with this patch.
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Reviewed-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220427224924.592546-9-gpiccoli@igalia.com
LoPAPR defines guest visible IOMMU with hypercalls to use it -
H_PUT_TCE/etc. Implemented first on POWER7 where hypercalls would trap
in the KVM in the real mode (with MMU off). The problem with the real mode
is some memory is not available and some API usage crashed the host but
enabling MMU was an expensive operation.
The problems with the real mode handlers are:
1. Occasionally these cannot complete the request so the code is
copied+modified to work in the virtual mode, very little is shared;
2. The real mode handlers have to be linked into vmlinux to work;
3. An exception in real mode immediately reboots the machine.
If the small DMA window is used, the real mode handlers bring better
performance. However since POWER8, there has always been a bigger DMA
window which VMs use to map the entire VM memory to avoid calling
H_PUT_TCE. Such 1:1 mapping happens once and uses H_PUT_TCE_INDIRECT
(a bulk version of H_PUT_TCE) which virtual mode handler is even closer
to its real mode version.
On POWER9 hypercalls trap straight to the virtual mode so the real mode
handlers never execute on POWER9 and later CPUs.
So with the current use of the DMA windows and MMU improvements in
POWER9 and later, there is no point in duplicating the code.
The 32bit passed through devices may slow down but we do not have many
of these in practice. For example, with this applied, a 1Gbit ethernet
adapter still demostrates above 800Mbit/s of actual throughput.
This removes the real mode handlers from KVM and related code from
the powernv platform.
This updates the list of implemented hcalls in KVM-HV as the realmode
handlers are removed.
This changes ABI - kvmppc_h_get_tce() moves to the KVM module and
kvmppc_find_table() is static now.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220506053755.3820702-1-aik@ozlabs.ru
RTAS runs in real mode (MSR[DR] and MSR[IR] unset) and in 32-bit big
endian mode (MSR[SF,LE] unset).
The change in MSR is done in enter_rtas() in a relatively complex way,
since the MSR value could be hardcoded.
Furthermore, a panic has been reported when hitting the watchdog interrupt
while running in RTAS, this leads to the following stack trace:
watchdog: CPU 24 Hard LOCKUP
watchdog: CPU 24 TB:997512652051031, last heartbeat TB:997504470175378 (15980ms ago)
...
Supported: No, Unreleased kernel
CPU: 24 PID: 87504 Comm: drmgr Kdump: loaded Tainted: G E X 5.14.21-150400.71.1.bz196362_2-default #1 SLE15-SP4 (unreleased) 0d821077ef4faa8dfaf370efb5fdca1fa35f4e2c
NIP: 000000001fb41050 LR: 000000001fb4104c CTR: 0000000000000000
REGS: c00000000fc33d60 TRAP: 0100 Tainted: G E X (5.14.21-150400.71.1.bz196362_2-default)
MSR: 8000000002981000 <SF,VEC,VSX,ME> CR: 48800002 XER: 20040020
CFAR: 000000000000011c IRQMASK: 1
GPR00: 0000000000000003 ffffffffffffffff 0000000000000001 00000000000050dc
GPR04: 000000001ffb6100 0000000000000020 0000000000000001 000000001fb09010
GPR08: 0000000020000000 0000000000000000 0000000000000000 0000000000000000
GPR12: 80040000072a40a8 c00000000ff8b680 0000000000000007 0000000000000034
GPR16: 000000001fbf6e94 000000001fbf6d84 000000001fbd1db0 000000001fb3f008
GPR20: 000000001fb41018 ffffffffffffffff 000000000000017f fffffffffffff68f
GPR24: 000000001fb18fe8 000000001fb3e000 000000001fb1adc0 000000001fb1cf40
GPR28: 000000001fb26000 000000001fb460f0 000000001fb17f18 000000001fb17000
NIP [000000001fb41050] 0x1fb41050
LR [000000001fb4104c] 0x1fb4104c
Call Trace:
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
Oops: Unrecoverable System Reset, sig: 6 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
...
Supported: No, Unreleased kernel
CPU: 24 PID: 87504 Comm: drmgr Kdump: loaded Tainted: G E X 5.14.21-150400.71.1.bz196362_2-default #1 SLE15-SP4 (unreleased) 0d821077ef4faa8dfaf370efb5fdca1fa35f4e2c
NIP: 000000001fb41050 LR: 000000001fb4104c CTR: 0000000000000000
REGS: c00000000fc33d60 TRAP: 0100 Tainted: G E X (5.14.21-150400.71.1.bz196362_2-default)
MSR: 8000000002981000 <SF,VEC,VSX,ME> CR: 48800002 XER: 20040020
CFAR: 000000000000011c IRQMASK: 1
GPR00: 0000000000000003 ffffffffffffffff 0000000000000001 00000000000050dc
GPR04: 000000001ffb6100 0000000000000020 0000000000000001 000000001fb09010
GPR08: 0000000020000000 0000000000000000 0000000000000000 0000000000000000
GPR12: 80040000072a40a8 c00000000ff8b680 0000000000000007 0000000000000034
GPR16: 000000001fbf6e94 000000001fbf6d84 000000001fbd1db0 000000001fb3f008
GPR20: 000000001fb41018 ffffffffffffffff 000000000000017f fffffffffffff68f
GPR24: 000000001fb18fe8 000000001fb3e000 000000001fb1adc0 000000001fb1cf40
GPR28: 000000001fb26000 000000001fb460f0 000000001fb17f18 000000001fb17000
NIP [000000001fb41050] 0x1fb41050
LR [000000001fb4104c] 0x1fb4104c
Call Trace:
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
---[ end trace 3ddec07f638c34a2 ]---
This happens because MSR[RI] is unset when entering RTAS but there is no
valid reason to not set it here.
RTAS is expected to be called with MSR[RI] as specified in PAPR+ section
"7.2.1 Machine State":
R1–7.2.1–9. If called with MSR[RI] equal to 1, then RTAS must protect
its own critical regions from recursion by setting the MSR[RI] bit to
0 when in the critical regions.
Fixing this by reviewing the way MSR is compute before calling RTAS. Now a
hardcoded value meaning real mode, 32 bits big endian mode and Recoverable
Interrupt is loaded. In the case MSR[S] is set, it will remain set while
entering RTAS as only urfid can unset it (thanks Fabiano).
In addition a check is added in do_enter_rtas() to detect calls made with
MSR[RI] unset, as we are forcing it on later.
This patch has been tested on the following machines:
Power KVM Guest
P8 S822L (host Ubuntu kernel 5.11.0-49-generic)
PowerVM LPAR
P8 9119-MME (FW860.A1)
p9 9008-22L (FW950.00)
P10 9080-HEX (FW1010.00)
Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220504101244.12107-1-ldufour@linux.ibm.com
