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When detecting a spurious EL1 translation fault, we have the CPU retry
the translation using an AT S1E1R instruction, and inspect PAR_EL1 to
determine if the fault was spurious.
When PAR_EL1.F == 0, the AT instruction successfully translated the
address without a fault, which implies the original fault was spurious.
However, in this case we return false and treat the original fault as if
it was not spurious.
Invert the return value so that we treat such a case as spurious.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Fixes: 42f91093b043 ("arm64: mm: Ignore spurious translation faults taken from the kernel")
Tested-by: James Morse <james.morse@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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The 'F' field of the PAR_EL1 register lives in bit 0, not bit 1.
Fix the broken definition in 'sysreg.h'.
Fixes: e8620cff9994 ("arm64: sysreg: Add some field definitions for PAR_EL1")
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Preempting from IRQ-return means that the task has its PSTATE saved
on the stack, which will get restored when the task is resumed and does
the actual IRQ return.
However, enabling some CPU features requires modifying the PSTATE. This
means that, if a task was scheduled out during an IRQ-return before all
CPU features are enabled, the task might restore a PSTATE that does not
include the feature enablement changes once scheduled back in.
* Task 1:
PAN == 0 ---| |---------------
| |<- return from IRQ, PSTATE.PAN = 0
| <- IRQ |
+--------+ <- preempt() +--
^
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reschedule Task 1, PSTATE.PAN == 1
* Init:
--------------------+------------------------
^
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enable_cpu_features
set PSTATE.PAN on all CPUs
Worse than this, since PSTATE is untouched when task switching is done,
a task missing the new bits in PSTATE might affect another task, if both
do direct calls to schedule() (outside of IRQ/exception contexts).
Fix this by preventing preemption on IRQ-return until features are
enabled on all CPUs.
This way the only PSTATE values that are saved on the stack are from
synchronous exceptions. These are expected to be fatal this early, the
exception is BRK for WARN_ON(), but as this uses do_debug_exception()
which keeps IRQs masked, it shouldn't call schedule().
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
[james: Replaced a really cool hack, with an even simpler static key in C.
expanded commit message with Julien's cover-letter ascii art]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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There is a bug in create_safe_exec_page(), when page table is allocated
it is not checked that table is allocated successfully:
But it is dereferenced in: pgd_none(READ_ONCE(*pgdp)). Check that
allocation was successful.
Fixes: 82869ac57b5d ("arm64: kernel: Add support for hibernate/suspend-to-disk")
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Will Deacon <will@kernel.org>
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If CONFIG_ARM64_SVE=n then we fail to report ID_AA64ZFR0_EL1 as 0 when
read by userspace, despite being required by the architecture. Although
this is theoretically a change in ABI, userspace will first check for
the presence of SVE via the HWCAP or the ID_AA64PFR0_EL1.SVE field
before probing the ID_AA64ZFR0_EL1 register. Given that these are
reported correctly for this configuration, we can safely tighten up the
current behaviour.
Ensure ID_AA64ZFR0_EL1 is treated as RAZ when CONFIG_ARM64_SVE=n.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Fixes: 06a916feca2b ("arm64: Expose SVE2 features for userspace")
Signed-off-by: Will Deacon <will@kernel.org>
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We export the entire kernel address space (i.e. the whole of the TTBR1
address range) via /proc/kcore. The kc_vaddr_to_offset() and
kc_offset_to_vaddr() macros are intended to convert between a kernel
virtual address and its offset relative to the start of the TTBR1
address space.
Prior to commit:
14c127c957c1c607 ("arm64: mm: Flip kernel VA space")
... the offset was calculated relative to VA_START, which at the time
was the start of the TTBR1 address space. At this time, PAGE_OFFSET
pointed to the high half of the TTBR1 address space where arm64's
linear map lived.
That commit swapped the position of VA_START and PAGE_OFFSET, but
failed to update kc_vaddr_to_offset() or kc_offset_to_vaddr(), so
since then the two macros behave incorrectly.
Note that VA_START was subsequently renamed to PAGE_END in commit:
77ad4ce69321abbe ("arm64: memory: rename VA_START to PAGE_END")
As the generic implementations of the two macros calculate the offset
relative to PAGE_OFFSET (which is now the start of the TTBR1 address
space), we can delete the arm64 implementation and use those.
Fixes: 14c127c957c1c607 ("arm64: mm: Flip kernel VA space")
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>
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There are no return value checking when using kzalloc() and kcalloc() for
memory allocation. so add it.
Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Signed-off-by: Will Deacon <will@kernel.org>
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CONFIG_COMPAT_VDSO is defined by passing '-DCONFIG_COMPAT_VDSO' to the
compiler when the generic compat vDSO code is in use. It's much cleaner
and simpler to expose this as a proper Kconfig option (like x86 does),
so do that and remove the bodge.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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For consistency with CROSS_COMPILE_COMPAT, mechanically rename COMPATCC
to CC_COMPAT so that specifying aspects of the compat vDSO toolchain in
the environment isn't needlessly confusing.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Directly passing the '--target' option to clang by appending to
COMPATCC does not work if COMPATCC has been specified explicitly as
an argument to Make unless the 'override' directive is used, which is
ugly and different to what is done in the top-level Makefile.
Move the '--target' option for clang out of COMPATCC and into
VDSO_CAFLAGS, where it will be picked up when compiling and assembling
the 32-bit vDSO under clang.
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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KBUILD_CPPFLAGS is defined differently depending on whether the main
compiler is clang or not. This means that it is not possible to build
the compat vDSO with GCC if the rest of the kernel is built with clang.
Define VDSO_CPPFLAGS directly to break this dependency and allow a clang
kernel to build a compat vDSO with GCC:
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- \
CROSS_COMPILE_COMPAT=arm-linux-gnueabihf- CC=clang \
COMPATCC=arm-linux-gnueabihf-gcc
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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There's no need to export COMPATCC, so just define it locally in the
vdso32/Makefile, which is the only place where it is used.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Rather than force the use of GCC for the compat cross-compiler, instead
extract the target from CROSS_COMPILE_COMPAT and pass it to clang if the
main compiler is clang.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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The jump labels are not used in vdso32 since it is not possible to run
runtime patching on them.
Remove the configuration option from the Makefile.
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Older versions of binutils (prior to 2.24) do not support the "ISHLD"
option for memory barrier instructions, which leads to a build failure
when assembling the vdso32 library.
Add a compilation time mechanism that detects if binutils supports those
instructions and configure the kernel accordingly.
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Moving over to the generic C implementation of the vDSO inadvertently
left some stale files behind which are no longer used. Remove them.
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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The .config file and the generated include/config/auto.conf can
end up out of sync after a set of commands since
CONFIG_CROSS_COMPILE_COMPAT_VDSO is not updated correctly.
The sequence can be reproduced as follows:
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig
[...]
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig
[set CONFIG_CROSS_COMPILE_COMPAT_VDSO="arm-linux-gnueabihf-"]
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-
Which results in:
arch/arm64/Makefile:62: CROSS_COMPILE_COMPAT not defined or empty,
the compat vDSO will not be built
even though the compat vDSO has been built:
$ file arch/arm64/kernel/vdso32/vdso.so
arch/arm64/kernel/vdso32/vdso.so: ELF 32-bit LSB pie executable, ARM,
EABI5 version 1 (SYSV), dynamically linked,
BuildID[sha1]=c67f6c786f2d2d6f86c71f708595594aa25247f6, stripped
A similar case that involves changing the configuration parameter
multiple times can be reconducted to the same family of problems.
Remove the use of CONFIG_CROSS_COMPILE_COMPAT_VDSO altogether and
instead rely on the cross-compiler prefix coming from the environment
via CROSS_COMPILE_COMPAT, much like we do for the rest of the kernel.
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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When detecting a spurious EL1 translation fault, we attempt to compare
ESR_EL1.DFSC with PAR_EL1.FST. We erroneously use FIELD_PREP() to
extract PAR_EL1.FST, when we should be using FIELD_GET().
In the wise words of Robin Murphy:
| FIELD_GET() is a UBFX, FIELD_PREP() is a BFI
Using FIELD_PREP() means that that dfsc & ESR_ELx_FSC_TYPE is always
zero, and hence not equal to ESR_ELx_FSC_FAULT. Thus we detect any
unhandled translation fault as spurious.
... so let's use FIELD_GET() to ensure we don't decide all translation
faults are spurious. ESR_EL1.DFSC occupies bits [5:0], and requires no
shifting.
Fixes: 42f91093b043332a ("arm64: mm: Ignore spurious translation faults taken from the kernel")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Robin Murphy <robin.murphy@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
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CPUs affected by Neoverse-N1 #1542419 may execute a stale instruction if
it was recently modified. The affected sequence requires freshly written
instructions to be executable before a branch to them is updated.
There are very few places in the kernel that modify executable text,
all but one come with sufficient synchronisation:
* The module loader's flush_module_icache() calls flush_icache_range(),
which does a kick_all_cpus_sync()
* bpf_int_jit_compile() calls flush_icache_range().
* Kprobes calls aarch64_insn_patch_text(), which does its work in
stop_machine().
* static keys and ftrace both patch between nops and branches to
existing kernel code (not generated code).
The affected sequence is the interaction between ftrace and modules.
The module PLT is cleaned using __flush_icache_range() as the trampoline
shouldn't be executable until we update the branch to it.
Drop the double-underscore so that this path runs kick_all_cpus_sync()
too.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Commit bd82d4bd2188 ("arm64: Fix incorrect irqflag restore for priority
masking") added a macro to the entry.S call paths that leave the
PSTATE.I bit set. This tells the pPNMI masking logic that interrupts
are masked by the CPU, not by the PMR. This value is read back by
local_daif_save().
Commit bd82d4bd2188 added this call to el0_svc, as el0_svc_handler
is called with interrupts masked. el0_svc_compat was missed, but should
be covered in the same way as both of these paths end up in
el0_svc_common(), which expects to unmask interrupts.
Fixes: bd82d4bd2188 ("arm64: Fix incorrect irqflag restore for priority masking")
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Signed-off-by: Will Deacon <will@kernel.org>
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If we take an unhandled fault in the kernel, we call show_pte() to dump
the {PGDP,PGD,PUD,PMD,PTE} values for the corresponding page table walk,
where the PGDP value is virt_to_phys(mm->pgd).
The boot-time and runtime kernel page tables, init_pg_dir and
swapper_pg_dir respectively, are kernel symbols. Thus, it is not valid
to call virt_to_phys() on either of these, though we'll do so if we take
a fault on a TTBR1 address.
When CONFIG_DEBUG_VIRTUAL is not selected, virt_to_phys() will silently
fix this up. However, when CONFIG_DEBUG_VIRTUAL is selected, this
results in splats as below. Depending on when these occur, they can
happen to suppress information needed to debug the original unhandled
fault, such as the backtrace:
| Unable to handle kernel paging request at virtual address ffff7fffec73cf0f
| Mem abort info:
| ESR = 0x96000004
| EC = 0x25: DABT (current EL), IL = 32 bits
| SET = 0, FnV = 0
| EA = 0, S1PTW = 0
| Data abort info:
| ISV = 0, ISS = 0x00000004
| CM = 0, WnR = 0
| ------------[ cut here ]------------
| virt_to_phys used for non-linear address: 00000000102c9dbe (swapper_pg_dir+0x0/0x1000)
| WARNING: CPU: 1 PID: 7558 at arch/arm64/mm/physaddr.c:15 __virt_to_phys+0xe0/0x170 arch/arm64/mm/physaddr.c:12
| Kernel panic - not syncing: panic_on_warn set ...
| SMP: stopping secondary CPUs
| Dumping ftrace buffer:
| (ftrace buffer empty)
| Kernel Offset: disabled
| CPU features: 0x0002,23000438
| Memory Limit: none
| Rebooting in 1 seconds..
We can avoid this by ensuring that we call __pa_symbol() for
init_mm.pgd, as this will always be a kernel symbol. As the dumped
{PGD,PUD,PMD,PTE} values are the raw values from the relevant entries we
don't need to handle these specially.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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The HWCAP framework will detect a new capability based on the sanitized
version of the ID registers.
Sanitization is based on a whitelist, so any field not described will end
up to be zeroed.
At the moment, ID_AA64ISAR1_EL1.FRINTTS is not described in
ftr_id_aa64isar1. This means the field will be zeroed and therefore the
userspace will not be able to see the HWCAP even if the hardware
supports the feature.
This can be fixed by describing the field in ftr_id_aa64isar1.
Fixes: ca9503fc9e98 ("arm64: Expose FRINT capabilities to userspace")
Signed-off-by: Julien Grall <julien.grall@arm.com>
Cc: mark.brown@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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As of ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly"),
inline functions are no longer annotated with '__always_inline', which
allows the compiler to decide whether inlining is really a good idea or
not. Although this is a great idea on paper, the reality is that AArch64
GCC prior to 9.1 has been shown to get confused when creating an
out-of-line copy of a function passing explicit 'register' variables
into an inline assembly block:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91111
It's not clear whether this is specific to arm64 or not but, for now,
ensure that all of our functions using 'register' variables are marked
as '__always_inline' so that the old behaviour is effectively preserved.
Hopefully other architectures are luckier with their compilers.
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
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The system which has SVE feature crashed because of
the memory pointed by task->thread.sve_state was destroyed
by someone.
That is because sve_state is freed while the forking the
child process. The child process has the pointer of sve_state
which is same as the parent's because the child's task_struct
is copied from the parent's one. If the copy_process()
fails as an error on somewhere, for example, copy_creds(),
then the sve_state is freed even if the parent is alive.
The flow is as follows.
copy_process
p = dup_task_struct
=> arch_dup_task_struct
*dst = *src; // copy the entire region.
:
retval = copy_creds
if (retval < 0)
goto bad_fork_free;
:
bad_fork_free:
...
delayed_free_task(p);
=> free_task
=> arch_release_task_struct
=> fpsimd_release_task
=> __sve_free
=> kfree(task->thread.sve_state);
// free the parent's sve_state
Move child's sve_state = NULL and clearing TIF_SVE flag
to arch_dup_task_struct() so that the child doesn't free the
parent's one.
There is no need to wait until copy_process() to clear TIF_SVE for
dst, because the thread flags for dst are initialized already by
copying the src task_struct.
This change simplifies the code, so get rid of comments that are no
longer needed.
As a note, arm64 used to have thread_info on the stack. So it
would not be possible to clear TIF_SVE until the stack is initialized.
From commit c02433dd6de3 ("arm64: split thread_info from task stack"),
the thread_info is part of the task, so it should be valid to modify
the flag from arch_dup_task_struct().
Cc: stable@vger.kernel.org # 4.15.x-
Fixes: bc0ee4760364 ("arm64/sve: Core task context handling")
Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Reported-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Suggested-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Tested-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Commit 73f381660959 ("arm64: Advertise mitigation of Spectre-v2, or lack
thereof") renamed the caller of the install_bp_hardening_cb() function
but forgot to update a comment, which can be confusing when trying to
follow the code flow.
Fixes: 73f381660959 ("arm64: Advertise mitigation of Spectre-v2, or lack thereof")
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Pull csky updates from Guo Ren:
"This round of csky subsystem just some fixups:
- Fix mb() synchronization problem
- Fix dma_alloc_coherent with PAGE_SO attribute
- Fix cache_op failed when cross memory ZONEs
- Optimize arch_sync_dma_for_cpu/device with dma_inv_range
- Fix ioremap function losing
- Fix arch_get_unmapped_area() implementation
- Fix defer cache flush for 610
- Support kernel non-aligned access
- Fix 610 vipt cache flush mechanism
- Fix add zero_fp fixup perf backtrace panic
- Move static keyword to the front of declaration
- Fix csky_pmu.max_period assignment
- Use generic free_initrd_mem()
- entry: Remove unneeded need_resched() loop"
* tag 'csky-for-linus-5.4-rc1' of git://github.com/c-sky/csky-linux:
csky: Move static keyword to the front of declaration
csky: entry: Remove unneeded need_resched() loop
csky: Fixup csky_pmu.max_period assignment
csky: Fixup add zero_fp fixup perf backtrace panic
csky: Use generic free_initrd_mem()
csky: Fixup 610 vipt cache flush mechanism
csky: Support kernel non-aligned access
csky: Fixup defer cache flush for 610
csky: Fixup arch_get_unmapped_area() implementation
csky: Fixup ioremap function losing
csky: Optimize arch_sync_dma_for_cpu/device with dma_inv_range
csky/dma: Fixup cache_op failed when cross memory ZONEs
csky: Fixup dma_alloc_coherent with PAGE_SO attribute
csky: Fixup mb() synchronization problem
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git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc
Pull ARM SoC fixes from Olof Johansson:
"A few fixes that have trickled in through the merge window:
- Video fixes for OMAP due to panel-dpi driver removal
- Clock fixes for OMAP that broke no-idle quirks + nfsroot on DRA7
- Fixing arch version on ASpeed ast2500
- Two fixes for reset handling on ARM SCMI"
* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
ARM: aspeed: ast2500 is ARMv6K
reset: reset-scmi: add missing handle initialisation
firmware: arm_scmi: reset: fix reset_state assignment in scmi_domain_reset
bus: ti-sysc: Remove unpaired sysc_clkdm_deny_idle()
ARM: dts: logicpd-som-lv: Fix i2c2 and i2c3 Pin mux
ARM: dts: am3517-evm: Fix missing video
ARM: dts: logicpd-torpedo-baseboard: Fix missing video
ARM: omap2plus_defconfig: Fix missing video
bus: ti-sysc: Fix handling of invalid clocks
bus: ti-sysc: Fix clock handling for no-idle quirks
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Move the static keyword to the front of declaration of
csky_pmu_of_device_ids, and resolve the following compiler
warning that can be seen when building with warnings
enabled (W=1):
arch/csky/kernel/perf_event.c:1340:1: warning:
‘static’ is not at beginning of declaration [-Wold-style-declaration]
Signed-off-by: Krzysztof Wilczynski <kw@linux.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
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Since the enabling and disabling of IRQs within preempt_schedule_irq()
is contained in a need_resched() loop, we don't need the outer arch
code loop.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
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The csky_pmu.max_period has type u64, and BIT() can only return
32 bits unsigned long on C-SKY. The initialization for max_period
will be incorrect when count_width is bigger than 32.
Use BIT_ULL()
Signed-off-by: Mao Han <han_mao@c-sky.com>
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
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We need set fp zero to let backtrace know the end. The patch fixup perf
callchain panic problem, because backtrace didn't know what is the end
of fp.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reported-by: Mao Han <han_mao@c-sky.com>
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The csky implementation of free_initrd_mem() is an open-coded version of
free_reserved_area() without poisoning.
Remove it and make csky use the generic version of free_initrd_mem().
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into arm/fixes
Fixes for omap variants
Few fixes for ti-sysc interconnect target module driver for no-idle
quirks that caused nfsroot to fail on some dra7 boards.
And let's fixes to get LCD working again for logicpd board that got
broken a while back with removal of panel-dpi driver. We need to now
use generic CONFIG_DRM_PANEL_SIMPLE instead.
* tag 'fixes-5.4-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
bus: ti-sysc: Remove unpaired sysc_clkdm_deny_idle()
ARM: dts: logicpd-som-lv: Fix i2c2 and i2c3 Pin mux
ARM: dts: am3517-evm: Fix missing video
ARM: dts: logicpd-torpedo-baseboard: Fix missing video
ARM: omap2plus_defconfig: Fix missing video
bus: ti-sysc: Fix handling of invalid clocks
bus: ti-sysc: Fix clock handling for no-idle quirks
Link: https://lore.kernel.org/r/pull-1568819401-72461@atomide.com
Signed-off-by: Olof Johansson <olof@lixom.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
More libnvdimm updates from Dan Williams:
- Complete the reworks to interoperate with powerpc dynamic huge page
sizes
- Fix a crash due to missed accounting for the powerpc 'struct
page'-memmap mapping granularity
- Fix badblock initialization for volatile (DRAM emulated) pmem ranges
- Stop triggering request_key() notifications to userspace when
NVDIMM-security is disabled / not present
- Miscellaneous small fixups
* tag 'libnvdimm-fixes-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
libnvdimm/region: Enable MAP_SYNC for volatile regions
libnvdimm: prevent nvdimm from requesting key when security is disabled
libnvdimm/region: Initialize bad block for volatile namespaces
libnvdimm/nfit_test: Fix acpi_handle redefinition
libnvdimm/altmap: Track namespace boundaries in altmap
libnvdimm: Fix endian conversion issues
libnvdimm/dax: Pick the right alignment default when creating dax devices
powerpc/book3s64: Export has_transparent_hugepage() related functions.
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"An assortment of fixes that were either missed by me, or didn't arrive
quite in time for the first v5.4 pull.
- Most notable is a fix for an issue with tlbie (broadcast TLB
invalidation) on Power9, when using the Radix MMU. The tlbie can
race with an mtpid (move to PID register, essentially MMU context
switch) on another thread of the core, which can cause stores to
continue to go to a page after it's unmapped.
- A fix in our KVM code to add a missing barrier, the lack of which
has been observed to cause missed IPIs and subsequently stuck CPUs
in the host.
- A change to the way we initialise PCR (Processor Compatibility
Register) to make it forward compatible with future CPUs.
- On some older PowerVM systems our H_BLOCK_REMOVE support could
oops, fix it to detect such systems and fallback to the old
invalidation method.
- A fix for an oops seen on some machines when using KASAN on 32-bit.
- A handful of other minor fixes, and two new selftests.
Thanks to: Alistair Popple, Aneesh Kumar K.V, Christophe Leroy,
Gustavo Romero, Joel Stanley, Jordan Niethe, Laurent Dufour, Michael
Roth, Oliver O'Halloran"
* tag 'powerpc-5.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/eeh: Fix eeh eeh_debugfs_break_device() with SRIOV devices
powerpc/nvdimm: use H_SCM_QUERY hcall on H_OVERLAP error
powerpc/nvdimm: Use HCALL error as the return value
selftests/powerpc: Add test case for tlbie vs mtpidr ordering issue
powerpc/mm: Fixup tlbie vs mtpidr/mtlpidr ordering issue on POWER9
powerpc/book3s64/radix: Rename CPU_FTR_P9_TLBIE_BUG feature flag
powerpc/book3s64/mm: Don't do tlbie fixup for some hardware revisions
powerpc/pseries: Call H_BLOCK_REMOVE when supported
powerpc/pseries: Read TLB Block Invalidate Characteristics
KVM: PPC: Book3S HV: use smp_mb() when setting/clearing host_ipi flag
powerpc/mm: Fix an Oops in kasan_mmu_init()
powerpc/mm: Add a helper to select PAGE_KERNEL_RO or PAGE_READONLY
powerpc/64s: Set reserved PCR bits
powerpc: Fix definition of PCR bits to work with old binutils
powerpc/book3s64/radix: Remove WARN_ON in destroy_context()
powerpc/tm: Add tm-poison test
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Ingo Molnar:
"A kexec fix for the case when GCC_PLUGIN_STACKLEAK=y is enabled"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/purgatory: Disable the stackleak GCC plugin for the purgatory
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull kernel lockdown mode from James Morris:
"This is the latest iteration of the kernel lockdown patchset, from
Matthew Garrett, David Howells and others.
From the original description:
This patchset introduces an optional kernel lockdown feature,
intended to strengthen the boundary between UID 0 and the kernel.
When enabled, various pieces of kernel functionality are restricted.
Applications that rely on low-level access to either hardware or the
kernel may cease working as a result - therefore this should not be
enabled without appropriate evaluation beforehand.
The majority of mainstream distributions have been carrying variants
of this patchset for many years now, so there's value in providing a
doesn't meet every distribution requirement, but gets us much closer
to not requiring external patches.
There are two major changes since this was last proposed for mainline:
- Separating lockdown from EFI secure boot. Background discussion is
covered here: https://lwn.net/Articles/751061/
- Implementation as an LSM, with a default stackable lockdown LSM
module. This allows the lockdown feature to be policy-driven,
rather than encoding an implicit policy within the mechanism.
The new locked_down LSM hook is provided to allow LSMs to make a
policy decision around whether kernel functionality that would allow
tampering with or examining the runtime state of the kernel should be
permitted.
The included lockdown LSM provides an implementation with a simple
policy intended for general purpose use. This policy provides a coarse
level of granularity, controllable via the kernel command line:
lockdown={integrity|confidentiality}
Enable the kernel lockdown feature. If set to integrity, kernel features
that allow userland to modify the running kernel are disabled. If set to
confidentiality, kernel features that allow userland to extract
confidential information from the kernel are also disabled.
This may also be controlled via /sys/kernel/security/lockdown and
overriden by kernel configuration.
New or existing LSMs may implement finer-grained controls of the
lockdown features. Refer to the lockdown_reason documentation in
include/linux/security.h for details.
The lockdown feature has had signficant design feedback and review
across many subsystems. This code has been in linux-next for some
weeks, with a few fixes applied along the way.
Stephen Rothwell noted that commit 9d1f8be5cf42 ("bpf: Restrict bpf
when kernel lockdown is in confidentiality mode") is missing a
Signed-off-by from its author. Matthew responded that he is providing
this under category (c) of the DCO"
* 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (31 commits)
kexec: Fix file verification on S390
security: constify some arrays in lockdown LSM
lockdown: Print current->comm in restriction messages
efi: Restrict efivar_ssdt_load when the kernel is locked down
tracefs: Restrict tracefs when the kernel is locked down
debugfs: Restrict debugfs when the kernel is locked down
kexec: Allow kexec_file() with appropriate IMA policy when locked down
lockdown: Lock down perf when in confidentiality mode
bpf: Restrict bpf when kernel lockdown is in confidentiality mode
lockdown: Lock down tracing and perf kprobes when in confidentiality mode
lockdown: Lock down /proc/kcore
x86/mmiotrace: Lock down the testmmiotrace module
lockdown: Lock down module params that specify hardware parameters (eg. ioport)
lockdown: Lock down TIOCSSERIAL
lockdown: Prohibit PCMCIA CIS storage when the kernel is locked down
acpi: Disable ACPI table override if the kernel is locked down
acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down
ACPI: Limit access to custom_method when the kernel is locked down
x86/msr: Restrict MSR access when the kernel is locked down
x86: Lock down IO port access when the kernel is locked down
...
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git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull integrity updates from Mimi Zohar:
"The major feature in this time is IMA support for measuring and
appraising appended file signatures. In addition are a couple of bug
fixes and code cleanup to use struct_size().
In addition to the PE/COFF and IMA xattr signatures, the kexec kernel
image may be signed with an appended signature, using the same
scripts/sign-file tool that is used to sign kernel modules.
Similarly, the initramfs may contain an appended signature.
This contained a lot of refactoring of the existing appended signature
verification code, so that IMA could retain the existing framework of
calculating the file hash once, storing it in the IMA measurement list
and extending the TPM, verifying the file's integrity based on a file
hash or signature (eg. xattrs), and adding an audit record containing
the file hash, all based on policy. (The IMA support for appended
signatures patch set was posted and reviewed 11 times.)
The support for appended signature paves the way for adding other
signature verification methods, such as fs-verity, based on a single
system-wide policy. The file hash used for verifying the signature and
the signature, itself, can be included in the IMA measurement list"
* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
ima: ima_api: Use struct_size() in kzalloc()
ima: use struct_size() in kzalloc()
sefltest/ima: support appended signatures (modsig)
ima: Fix use after free in ima_read_modsig()
MODSIGN: make new include file self contained
ima: fix freeing ongoing ahash_request
ima: always return negative code for error
ima: Store the measurement again when appraising a modsig
ima: Define ima-modsig template
ima: Collect modsig
ima: Implement support for module-style appended signatures
ima: Factor xattr_verify() out of ima_appraise_measurement()
ima: Add modsig appraise_type option for module-style appended signatures
integrity: Select CONFIG_KEYS instead of depending on it
PKCS#7: Introduce pkcs7_get_digest()
PKCS#7: Refactor verify_pkcs7_signature()
MODSIGN: Export module signature definitions
ima: initialize the "template" field with the default template
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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull more RISC-V updates from Paul Walmsley:
"Some additional RISC-V updates.
This includes one significant fix:
- Prevent interrupts from being unconditionally re-enabled during
exception handling if they were disabled in the context in which
the exception occurred
Also a few other fixes:
- Fix a build error when sparse memory support is manually enabled
- Prevent CPUs beyond CONFIG_NR_CPUS from being enabled in early boot
And a few minor improvements:
- DT improvements: in the FU540 SoC DT files, improve U-Boot
compatibility by adding an "ethernet0" alias, drop an unnecessary
property from the DT files, and add support for the PWM device
- KVM preparation: add a KVM-related macro for future RISC-V KVM
support, and export some symbols required to build KVM support as
modules
- defconfig additions: build more drivers by default for QEMU
configurations"
* tag 'riscv/for-v5.4-rc1-b' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: Avoid interrupts being erroneously enabled in handle_exception()
riscv: dts: sifive: Drop "clock-frequency" property of cpu nodes
riscv: dts: sifive: Add ethernet0 to the aliases node
RISC-V: Export kernel symbols for kvm
KVM: RISC-V: Add KVM_REG_RISCV for ONE_REG interface
arch/riscv: disable excess harts before picking main boot hart
RISC-V: Enable VIRTIO drivers in RV64 and RV32 defconfig
RISC-V: Fix building error when CONFIG_SPARSEMEM_MANUAL=y
riscv: dts: Add DT support for SiFive FU540 PWM driver
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git://git.kernel.org/pub/scm/linux/kernel/git/lftan/nios2
Pull nios2 fix from Ley Foon Tan:
"Make sure the command line buffer is NUL-terminated"
* tag 'nios2-v5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/lftan/nios2:
nios2: force the string buffer NULL-terminated
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Pull more KVM updates from Paolo Bonzini:
"x86 KVM changes:
- The usual accuracy improvements for nested virtualization
- The usual round of code cleanups from Sean
- Added back optimizations that were prematurely removed in 5.2 (the
bare minimum needed to fix the regression was in 5.3-rc8, here
comes the rest)
- Support for UMWAIT/UMONITOR/TPAUSE
- Direct L2->L0 TLB flushing when L0 is Hyper-V and L1 is KVM
- Tell Windows guests if SMT is disabled on the host
- More accurate detection of vmexit cost
- Revert a pvqspinlock pessimization"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (56 commits)
KVM: nVMX: cleanup and fix host 64-bit mode checks
KVM: vmx: fix build warnings in hv_enable_direct_tlbflush() on i386
KVM: x86: Don't check kvm_rebooting in __kvm_handle_fault_on_reboot()
KVM: x86: Drop ____kvm_handle_fault_on_reboot()
KVM: VMX: Add error handling to VMREAD helper
KVM: VMX: Optimize VMX instruction error and fault handling
KVM: x86: Check kvm_rebooting in kvm_spurious_fault()
KVM: selftests: fix ucall on x86
Revert "locking/pvqspinlock: Don't wait if vCPU is preempted"
kvm: nvmx: limit atomic switch MSRs
kvm: svm: Intercept RDPRU
kvm: x86: Add "significant index" flag to a few CPUID leaves
KVM: x86/mmu: Skip invalid pages during zapping iff root_count is zero
KVM: x86/mmu: Explicitly track only a single invalid mmu generation
KVM: x86/mmu: Revert "KVM: x86/mmu: Remove is_obsolete() call"
KVM: x86/mmu: Revert "Revert "KVM: MMU: reclaim the zapped-obsolete page first""
KVM: x86/mmu: Revert "Revert "KVM: MMU: collapse TLB flushes when zap all pages""
KVM: x86/mmu: Revert "Revert "KVM: MMU: zap pages in batch""
KVM: x86/mmu: Revert "Revert "KVM: MMU: add tracepoint for kvm_mmu_invalidate_all_pages""
KVM: x86/mmu: Revert "Revert "KVM: MMU: show mmu_valid_gen in shadow page related tracepoints""
...
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s/CONFIG_IOV/CONFIG_PCI_IOV/
Whoops.
Fixes: bd6461cc7b3c ("powerpc/eeh: Add a eeh_dev_break debugfs interface")
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Fixup the #endif comment as well]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190926122502.14826-1-oohall@gmail.com
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull more s390 updates from Vasily Gorbik:
- Fix three kasan findings
- Add PERF_EVENT_IOC_PERIOD ioctl support
- Add Crypto Express7S support and extend sysfs attributes for pkey
- Minor common I/O layer documentation corrections
* tag 's390-5.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/cio: exclude subchannels with no parent from pseudo check
s390/cio: avoid calling strlen on null pointer
s390/topology: avoid firing events before kobjs are created
s390/cpumf: Remove mixed white space
s390/cpum_sf: Support ioctl PERF_EVENT_IOC_PERIOD
s390/zcrypt: CEX7S exploitation support
s390/cio: fix intparm documentation
s390/pkey: Add sysfs attributes to emit AES CIPHER key blobs
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A last-minute fixlet which I'd failed to merge at the appropriate time
had the predictable effect.
Fixes: f672e2c217e2d4b2 ("lib: untag user pointers in strn*_user")
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The naming of pgtable_page_{ctor,dtor}() seems to have confused a few
people, and until recently arm64 used these erroneously/pointlessly for
other levels of page table.
To make it incredibly clear that these only apply to the PTE level, and to
align with the naming of pgtable_pmd_page_{ctor,dtor}(), let's rename them
to pgtable_pte_page_{ctor,dtor}().
These changes were generated with the following shell script:
----
git grep -lw 'pgtable_page_.tor' | while read FILE; do
sed -i '{s/pgtable_page_ctor/pgtable_pte_page_ctor/}' $FILE;
sed -i '{s/pgtable_page_dtor/pgtable_pte_page_dtor/}' $FILE;
done
----
... with the documentation re-flowed to remain under 80 columns, and
whitespace fixed up in macros to keep backslashes aligned.
There should be no functional change as a result of this patch.
Link: http://lkml.kernel.org/r/20190722141133.3116-1-mark.rutland@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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hexagon never reserves or initializes initrd and the only mention of it is
the empty free_initrd_mem() function.
As we have a generic implementation of free_initrd_mem(), there is no need
to define an empty stub for the hexagon implementation and it can be
dropped.
Link: http://lkml.kernel.org/r/1565858133-25852-1-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When a process expects no accesses to a certain memory range for a long
time, it could hint kernel that the pages can be reclaimed instantly but
data should be preserved for future use. This could reduce workingset
eviction so it ends up increasing performance.
This patch introduces the new MADV_PAGEOUT hint to madvise(2) syscall.
MADV_PAGEOUT can be used by a process to mark a memory range as not
expected to be used for a long time so that kernel reclaims *any LRU*
pages instantly. The hint can help kernel in deciding which pages to
evict proactively.
A note: It doesn't apply SWAP_CLUSTER_MAX LRU page isolation limit
intentionally because it's automatically bounded by PMD size. If PMD
size(e.g., 256) makes some trouble, we could fix it later by limit it to
SWAP_CLUSTER_MAX[1].
- man-page material
MADV_PAGEOUT (since Linux x.x)
Do not expect access in the near future so pages in the specified
regions could be reclaimed instantly regardless of memory pressure.
Thus, access in the range after successful operation could cause
major page fault but never lose the up-to-date contents unlike
MADV_DONTNEED. Pages belonging to a shared mapping are only processed
if a write access is allowed for the calling process.
MADV_PAGEOUT cannot be applied to locked pages, Huge TLB pages, or
VM_PFNMAP pages.
[1] https://lore.kernel.org/lkml/20190710194719.GS29695@dhcp22.suse.cz/
[minchan@kernel.org: clear PG_active on MADV_PAGEOUT]
Link: http://lkml.kernel.org/r/20190802200643.GA181880@google.com
[akpm@linux-foundation.org: resolve conflicts with hmm.git]
Link: http://lkml.kernel.org/r/20190726023435.214162-5-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: kbuild test robot <lkp@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Colascione <dancol@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tim Murray <timmurray@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patch series "Introduce MADV_COLD and MADV_PAGEOUT", v7.
- Background
The Android terminology used for forking a new process and starting an app
from scratch is a cold start, while resuming an existing app is a hot
start. While we continually try to improve the performance of cold
starts, hot starts will always be significantly less power hungry as well
as faster so we are trying to make hot start more likely than cold start.
To increase hot start, Android userspace manages the order that apps
should be killed in a process called ActivityManagerService.
ActivityManagerService tracks every Android app or service that the user
could be interacting with at any time and translates that into a ranked
list for lmkd(low memory killer daemon). They are likely to be killed by
lmkd if the system has to reclaim memory. In that sense they are similar
to entries in any other cache. Those apps are kept alive for
opportunistic performance improvements but those performance improvements
will vary based on the memory requirements of individual workloads.
- Problem
Naturally, cached apps were dominant consumers of memory on the system.
However, they were not significant consumers of swap even though they are
good candidate for swap. Under investigation, swapping out only begins
once the low zone watermark is hit and kswapd wakes up, but the overall
allocation rate in the system might trip lmkd thresholds and cause a
cached process to be killed(we measured performance swapping out vs.
zapping the memory by killing a process. Unsurprisingly, zapping is 10x
times faster even though we use zram which is much faster than real
storage) so kill from lmkd will often satisfy the high zone watermark,
resulting in very few pages actually being moved to swap.
- Approach
The approach we chose was to use a new interface to allow userspace to
proactively reclaim entire processes by leveraging platform information.
This allowed us to bypass the inaccuracy of the kernel’s LRUs for pages
that are known to be cold from userspace and to avoid races with lmkd by
reclaiming apps as soon as they entered the cached state. Additionally,
it could provide many chances for platform to use much information to
optimize memory efficiency.
To achieve the goal, the patchset introduce two new options for madvise.
One is MADV_COLD which will deactivate activated pages and the other is
MADV_PAGEOUT which will reclaim private pages instantly. These new
options complement MADV_DONTNEED and MADV_FREE by adding non-destructive
ways to gain some free memory space. MADV_PAGEOUT is similar to
MADV_DONTNEED in a way that it hints the kernel that memory region is not
currently needed and should be reclaimed immediately; MADV_COLD is similar
to MADV_FREE in a way that it hints the kernel that memory region is not
currently needed and should be reclaimed when memory pressure rises.
This patch (of 5):
When a process expects no accesses to a certain memory range, it could
give a hint to kernel that the pages can be reclaimed when memory pressure
happens but data should be preserved for future use. This could reduce
workingset eviction so it ends up increasing performance.
This patch introduces the new MADV_COLD hint to madvise(2) syscall.
MADV_COLD can be used by a process to mark a memory range as not expected
to be used in the near future. The hint can help kernel in deciding which
pages to evict early during memory pressure.
It works for every LRU pages like MADV_[DONTNEED|FREE]. IOW, It moves
active file page -> inactive file LRU
active anon page -> inacdtive anon LRU
Unlike MADV_FREE, it doesn't move active anonymous pages to inactive file
LRU's head because MADV_COLD is a little bit different symantic.
MADV_FREE means it's okay to discard when the memory pressure because the
content of the page is *garbage* so freeing such pages is almost zero
overhead since we don't need to swap out and access afterward causes just
minor fault. Thus, it would make sense to put those freeable pages in
inactive file LRU to compete other used-once pages. It makes sense for
implmentaion point of view, too because it's not swapbacked memory any
longer until it would be re-dirtied. Even, it could give a bonus to make
them be reclaimed on swapless system. However, MADV_COLD doesn't mean
garbage so reclaiming them requires swap-out/in in the end so it's bigger
cost. Since we have designed VM LRU aging based on cost-model, anonymous
cold pages would be better to position inactive anon's LRU list, not file
LRU. Furthermore, it would help to avoid unnecessary scanning if system
doesn't have a swap device. Let's start simpler way without adding
complexity at this moment. However, keep in mind, too that it's a caveat
that workloads with a lot of pages cache are likely to ignore MADV_COLD on
anonymous memory because we rarely age anonymous LRU lists.
* man-page material
MADV_COLD (since Linux x.x)
Pages in the specified regions will be treated as less-recently-accessed
compared to pages in the system with similar access frequencies. In
contrast to MADV_FREE, the contents of the region are preserved regardless
of subsequent writes to pages.
MADV_COLD cannot be applied to locked pages, Huge TLB pages, or VM_PFNMAP
pages.
[akpm@linux-foundation.org: resolve conflicts with hmm.git]
Link: http://lkml.kernel.org/r/20190726023435.214162-2-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: kbuild test robot <lkp@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Daniel Colascione <dancol@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tim Murray <timmurray@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patch series "arm64: untag user pointers passed to the kernel", v19.
=== Overview
arm64 has a feature called Top Byte Ignore, which allows to embed pointer
tags into the top byte of each pointer. Userspace programs (such as
HWASan, a memory debugging tool [1]) might use this feature and pass
tagged user pointers to the kernel through syscalls or other interfaces.
Right now the kernel is already able to handle user faults with tagged
pointers, due to these patches:
1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a
tagged pointer")
2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged
pointers")
3. 276e9327 ("arm64: entry: improve data abort handling of tagged
pointers")
This patchset extends tagged pointer support to syscall arguments.
As per the proposed ABI change [3], tagged pointers are only allowed to be
passed to syscalls when they point to memory ranges obtained by anonymous
mmap() or sbrk() (see the patchset [3] for more details).
For non-memory syscalls this is done by untaging user pointers when the
kernel performs pointer checking to find out whether the pointer comes
from userspace (most notably in access_ok). The untagging is done only
when the pointer is being checked, the tag is preserved as the pointer
makes its way through the kernel and stays tagged when the kernel
dereferences the pointer when perfoming user memory accesses.
The mmap and mremap (only new_addr) syscalls do not currently accept
tagged addresses. Architectures may interpret the tag as a background
colour for the corresponding vma.
Other memory syscalls (mprotect, etc.) don't do user memory accesses but
rather deal with memory ranges, and untagged pointers are better suited to
describe memory ranges internally. Thus for memory syscalls we untag
pointers completely when they enter the kernel.
=== Other approaches
One of the alternative approaches to untagging that was considered is to
completely strip the pointer tag as the pointer enters the kernel with
some kind of a syscall wrapper, but that won't work with the countless
number of different ioctl calls. With this approach we would need a
custom wrapper for each ioctl variation, which doesn't seem practical.
An alternative approach to untagging pointers in memory syscalls prologues
is to inspead allow tagged pointers to be passed to find_vma() (and other
vma related functions) and untag them there. Unfortunately, a lot of
find_vma() callers then compare or subtract the returned vma start and end
fields against the pointer that was being searched. Thus this approach
would still require changing all find_vma() callers.
=== Testing
The following testing approaches has been taken to find potential issues
with user pointer untagging:
1. Static testing (with sparse [2] and separately with a custom static
analyzer based on Clang) to track casts of __user pointers to integer
types to find places where untagging needs to be done.
2. Static testing with grep to find parts of the kernel that call
find_vma() (and other similar functions) or directly compare against
vm_start/vm_end fields of vma.
3. Static testing with grep to find parts of the kernel that compare
user pointers with TASK_SIZE or other similar consts and macros.
4. Dynamic testing: adding BUG_ON(has_tag(addr)) to find_vma() and running
a modified syzkaller version that passes tagged pointers to the kernel.
Based on the results of the testing the requried patches have been added
to the patchset.
=== Notes
This patchset is meant to be merged together with "arm64 relaxed ABI" [3].
This patchset is a prerequisite for ARM's memory tagging hardware feature
support [4].
This patchset has been merged into the Pixel 2 & 3 kernel trees and is
now being used to enable testing of Pixel phones with HWASan.
Thanks!
[1] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html
[2] https://github.com/lucvoo/sparse-dev/commit/5f960cb10f56ec2017c128ef9d16060e0145f292
[3] https://lkml.org/lkml/2019/6/12/745
[4] https://community.arm.com/processors/b/blog/posts/arm-a-profile-architecture-2018-developments-armv85a
This patch (of 11)
This patch is a part of a series that extends kernel ABI to allow to pass
tagged user pointers (with the top byte set to something else other than
0x00) as syscall arguments.
strncpy_from_user and strnlen_user accept user addresses as arguments, and
do not go through the same path as copy_from_user and others, so here we
need to handle the case of tagged user addresses separately.
Untag user pointers passed to these functions.
Note, that this patch only temporarily untags the pointers to perform
validity checks, but then uses them as is to perform user memory accesses.
[andreyknvl@google.com: fix sparc4 build]
Link: http://lkml.kernel.org/r/CAAeHK+yx4a-P0sDrXTUxMvO2H0CJZUFPffBrg_cU7oJOZyC7ew@mail.gmail.com
Link: http://lkml.kernel.org/r/c5a78bcad3e94d6cda71fcaa60a423231ae71e4c.1563904656.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
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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Add RB_DECLARE_CALLBACKS_MAX, which generates augmented rbtree callbacks
for the case where the augmented value is a scalar whose definition
follows a max(f(node)) pattern. This actually covers all present uses of
RB_DECLARE_CALLBACKS, and saves some (source) code duplication in the
various RBCOMPUTE function definitions.
[walken@google.com: fix mm/vmalloc.c]
Link: http://lkml.kernel.org/r/CANN689FXgK13wDYNh1zKxdipeTuALG4eKvKpsdZqKFJ-rvtGiQ@mail.gmail.com
[walken@google.com: re-add check to check_augmented()]
Link: http://lkml.kernel.org/r/20190727022027.GA86863@google.com
Link: http://lkml.kernel.org/r/20190703040156.56953-3-walken@google.com
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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