Traps enable interrupts conditionally but rely on the ASM return code to
disable them again. That results in redundant interrupt disable and trace
calls.
Make the trap handlers disable interrupts before returning to avoid that,
which allows simplification of the ASM entry code in follow up changes.
Originally-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134903.622702796@linutronix.de
When PARAVIRT_XXL is in use, then load_gs_index() uses xen_load_gs_index()
and asm_load_gs_index() is unused.
It's therefore pointless to use the paravirtualized SWAPGS implementation
in asm_load_gs_index(). Switch it to a plain swapgs.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Juergen Gross <jgross@suse.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200512213809.583980272@linutronix.de
There is absolutely no point in doing this in ASM code. Move it to C.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134903.531534675@linutronix.de
Replace the notrace and NOKPROBE annotations with noinstr.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134903.439765290@linutronix.de
This is called from deep entry ASM in a situation where instrumentation
will cause more harm than providing useful information.
Switch from memmove() to memcpy() because memmove() can't be called
from noinstr code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134903.346741553@linutronix.de
Currently entry_64_compat is exempt from objtool, but with vmlinux
mode there is no hiding it.
Make the following changes to make it pass:
- change entry_SYSENTER_compat to STT_NOTYPE; it's not a function
and doesn't have function type stack setup.
- mark all STT_NOTYPE symbols with UNWIND_HINT_EMPTY; so we do
validate them and don't treat them as unreachable.
- don't abuse RSP as a temp register, this confuses objtool
mightily as it (rightfully) thinks we're doing unspeakable
things to the stack.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134341.272248024@linutronix.de
Prevent the compiler from uninlining and creating traceable/probable
functions as this is invoked _after_ context tracking switched to
CONTEXT_USER and rcu idle.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134340.902709267@linutronix.de
This is another step towards more C-code and less convoluted ASM.
Similar to the entry path, invoke the tracer before context tracking which
might turn off RCU and invoke lockdep as the last step before going back to
user space. Annotate the code sections in exit_to_user_mode() accordingly
so objtool won't complain about the tracer invocation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134340.703783926@linutronix.de
Now that the C entry points are safe, move the irq flags tracing code into
the entry helper:
- Invoke lockdep before calling into context tracking
- Use the safe trace_hardirqs_on_prepare() trace function after context
tracking established state and RCU is watching.
enter_from_user_mode() is also still invoked from the exception/interrupt
entry code which still contains the ASM irq flags tracing. So this is just
a redundant and harmless invocation of tracing / lockdep until these are
removed as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134340.611961721@linutronix.de
Mark the various syscall entries with noinstr to protect them against
instrumentation and add the noinstrumentation_begin()/end() annotations to mark the
parts of the functions which are safe to call out into instrumentable code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134340.520277507@linutronix.de
Both the callers in the low level ASM code and __context_tracking_exit()
which is invoked from enter_from_user_mode() via user_exit_irqoff() are
marked NOKPROBE. Allowing enter_from_user_mode() to be probed is
inconsistent at best.
Aside of that while function tracing per se is safe the function trace
entry/exit points can be used via BPF as well which is not safe to use
before context tracking has reached CONTEXT_KERNEL and adjusted RCU.
Mark it noinstr which moves it into the instrumentation protected text
section and includes notrace.
Note, this needs further fixups in context tracking to ensure that the
full call chain is protected. Will be addressed in follow up changes.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134340.429059405@linutronix.de
All ASM code which is not part of the entry functionality can move out into
the .text section. No reason to keep it in the non-instrumentable entry
section.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134340.320164650@linutronix.de
All ASM code which is not part of the entry functionality can move out into
the .text section. No reason to keep it in the non-instrumentable entry
section.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134340.227579223@linutronix.de
Warnings, bugs and stack protection fails from noinstr sections, e.g. low
level and early entry code, are likely to be fatal.
Mark them as "safe" to be invoked from noinstr protected code to avoid
annotating all usage sites. Getting the information out is important.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134100.376598577@linutronix.de
That code is already not traceable. Move it into the noinstr section so the
objtool section validation does not trigger.
Annotate the warning code as "safe". While it might be not under all
circumstances, getting the information out is important enough.
Should this ever trigger from the sensitive code which is shielded against
instrumentation, e.g. low level entry, then the printk is the least of the
worries.
Addresses the objtool warnings:
vmlinux.o: warning: objtool: context_tracking_recursion_enter()+0x7: call to __this_cpu_preempt_check() leaves .noinstr.text section
vmlinux.o: warning: objtool: __context_tracking_exit()+0x17: call to __this_cpu_preempt_check() leaves .noinstr.text section
vmlinux.o: warning: objtool: __context_tracking_enter()+0x2a: call to __this_cpu_preempt_check() leaves .noinstr.text section
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134340.902709267@linutronix.de
context tracking lacks a few protection mechanisms against instrumentation:
- While the core functions are marked NOKPROBE they lack protection
against function tracing which is required as the function entry/exit
points can be utilized by BPF.
- static functions invoked from the protected functions need to be marked
as well as they can be instrumented otherwise.
- using plain inline allows the compiler to emit traceable and probable
functions.
Fix this by marking the functions noinstr and converting the plain inlines
to __always_inline.
The NOKPROBE_SYMBOL() annotations are removed as the .noinstr.text section
is already excluded from being probed.
Cures the following objtool warnings:
vmlinux.o: warning: objtool: enter_from_user_mode()+0x34: call to __context_tracking_exit() leaves .noinstr.text section
vmlinux.o: warning: objtool: prepare_exit_to_usermode()+0x29: call to __context_tracking_enter() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_return_slowpath()+0x29: call to __context_tracking_enter() leaves .noinstr.text section
vmlinux.o: warning: objtool: do_syscall_64()+0x7f: call to __context_tracking_enter() leaves .noinstr.text section
vmlinux.o: warning: objtool: do_int80_syscall_32()+0x3d: call to __context_tracking_enter() leaves .noinstr.text section
vmlinux.o: warning: objtool: do_fast_syscall_32()+0x9c: call to __context_tracking_enter() leaves .noinstr.text section
and generates new ones...
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134340.811520478@linutronix.de
The sanitizers are not really applicable to the fragile low level entry
code. Entry code needs to carefully setup a normal 'runtime' environment.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134059.970057117@linutronix.de
No users left since two years due to commit 21d375b6b3 ("x86/entry/64:
Remove the SYSCALL64 fast path")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.061301403@linutronix.de
GAS cannot optimize out the test and conditional jump when context tracking
is disabled and CALL_enter_from_user_mode is an empty macro.
Wrap it in #ifdeffery. Will go away once all this is moved to C.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134058.955968069@linutronix.de
Use of memmove() in #DF is problematic considered tracing and other
instrumentation.
Remove the memmove() call and simply write out what needs doing; this
even clarifies the code, win-win! The code copies from the espfix64
stack to the normal task stack, there is no possible way for that to
overlap.
Survives selftests/x86, specifically sigreturn_64.
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134058.863038566@linutronix.de
A data breakpoint near the top of an IST stack will cause unrecoverable
recursion. A data breakpoint on the GDT, IDT, or TSS is terrifying.
Prevent either of these from happening.
Co-developed-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134058.272448010@linutronix.de
With commit dc20b2d526 ("x86/idt: Move interrupt gate initialization to
IDT code") non assigned system vectors are also marked as used in
'used_vectors' (now 'system_vectors') bitmap. This makes checks in
arch_show_interrupts() whether a particular system vector is allocated to
always pass and e.g. 'Hyper-V reenlightenment interrupts' entry always
shows up in /proc/interrupts.
Another side effect of having all unassigned system vectors marked as used
is that irq_matrix_debug_show() will wrongly count them among 'System'
vectors.
As it is now ensured that alloc_intr_gate() is not called after init, it is
possible to leave unused entries in 'system_vectors' unset to fix these
issues.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200428093824.1451532-4-vkuznets@redhat.com
There seems to be no reason to allocate interrupt gates after init. Mark
alloc_intr_gate() as __init and add WARN_ON() checks making sure it is
only used before idt_setup_apic_and_irq_gates() finalizes IDT setup and
maps all un-allocated entries to spurious entries.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200428093824.1451532-3-vkuznets@redhat.com
As a preparatory change for making alloc_intr_gate() __init split
xen_callback_vector() into callback vector setup via hypercall
(xen_setup_callback_vector()) and interrupt gate allocation
(xen_alloc_callback_vector()).
xen_setup_callback_vector() is being called twice: on init and upon
system resume from xen_hvm_post_suspend(). alloc_intr_gate() only
needs to be called once.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200428093824.1451532-2-vkuznets@redhat.com
machine_check is function address, the address operator on it is nop for
compiler.
Make it consistent with the other function addresses in the same file.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200419144049.1906-3-laijs@linux.alibaba.com
The label .Lcommon_\sym was introduced by 39e9543344.
(x86-64: Reduce amount of redundant code generated for invalidate_interruptNN)
And all the other relevant information was removed by 52aec3308d
(x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR)
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200419144049.1906-4-laijs@linux.alibaba.com
Commit cfa7ede20f ("arm64: set TEXT_OFFSET to 0x0 in preparation for
removing it entirely") results in boot failures when booting kernels that
are built without KASLR support on broken bootloaders that ignore the
TEXT_OFFSET value passed via the header, and use the default of 0x80000
instead.
To work around this, turn CONFIG_RELOCATABLE on by default, even if KASLR
itself (CONFIG_RANDOMIZE_BASE) is turned off, and require CONFIG_EXPERT
to be enabled to deviate from this. Then, emit a warning into the kernel
log if we are not booting via the EFI stub (which is permitted to deviate
from the placement restrictions) and the kernel base address is not placed
according to the rules as laid out in Documentation/arm64/booting.rst.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200611124330.252163-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Redefine GZIP, BZIP2, LZOP variables as KGZIP, KBZIP2, KLZOP resp.
GZIP, BZIP2, LZOP env variables are reserved by the tools. The original
attempt to redefine them internally doesn't work in makefiles/scripts
intercall scenarios, e.g., "make GZIP=gzip bindeb-pkg" and results in
broken builds. There can be other broken build commands because of this,
so the universal solution is to use non-reserved env variables for the
compression tools.
Fixes: 8dfb61dcba ("kbuild: add variables for compression tools")
Signed-off-by: Denis Efremov <efremov@linux.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Even after commit c624adc9cb ("samples: fix binderfs sample"), this
sample is never compiled.
'hostprogs' teaches Kbuild that this is a host program, but not enough
to order to compile it. You must add it to 'always-y' to really compile
it.
Since this sample has never been compiled in upstream, various issues
are left unnoticed.
[1] compilers without <linux/android/binderfs.h> are still widely used
<linux/android/binderfs.h> is only available since commit c13295ad21
("binderfs: rename header to binderfs.h"), i.e., Linux 5.0
If your compiler is based on UAPI headers older than Linux 5.0, you
will see the following error:
samples/binderfs/binderfs_example.c:16:10: fatal error: linux/android/binderfs.h: No such file or directory
#include <linux/android/binderfs.h>
^~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
You cannot rely on compilers having such a new header.
The common approach is to install UAPI headers of this kernel into
usr/include, and then add it to the header search path.
I added 'depends on HEADERS_INSTALL' in Kconfig, and '-I usr/include'
compiler flag in Makefile.
[2] compile the sample for target architecture
Because headers_install works for the target architecture, only the
native compiler was able to build sample code that requires
'-I usr/include'.
Commit 7f3a59db27 ("kbuild: add infrastructure to build userspace
programs") added the new syntax 'userprogs' to compile user-space
programs for the target architecture.
Use it, and then 'ifndef CROSS_COMPILE' will go away.
I added 'depends on CC_CAN_LINK' because $(CC) is not necessarily
capable of linking user-space programs.
[3] use subdir-y to descend into samples/binderfs
Since this directory does not contain any kernel-space code, it has no
point in generating built-in.a or modules.order.
Replace obj-$(CONFIG_...) with subdir-$(CONFIG_...).
[4] -Wunused-variable warning
If I compile this, I see the following warning.
samples/binderfs/binderfs_example.c: In function 'main':
samples/binderfs/binderfs_example.c:21:9: warning: unused variable 'len' [-Wunused-variable]
21 | size_t len;
| ^~~
I removed the unused 'len'.
[5] CONFIG_ANDROID_BINDERFS is not required
Since this is a user-space standalone program, it is independent of
the kernel configuration.
Remove 'depends on ANDROID_BINDERFS'.
Fixes: 9762dc1432 ("samples: add binderfs sample program")
Fixes: c624adc9cb ("samples: fix binderfs sample")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
It is not the common usage to have a comma between the name and the
email address, so remove it.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Fixes: f54736925a ("i2c: npcm7xx: Add support for slave mode for Nuvoton")
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
sysfs. In drivers, sun4i now uses 4 bits to store the clock's m divider;
ast sets up 24/32-bit color mode correctly.
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Merge tag 'drm-misc-next-fixes-2020-06-11' of git://anongit.freedesktop.org/drm/drm-misc into drm-next
In core, DRM connectors now notify userspace of hotplug events via
sysfs. In drivers, sun4i now uses 4 bits to store the clock's m divider;
ast sets up 24/32-bit color mode correctly.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20200611075007.GA15098@linux-uq9g
Currently the switch statement for format->cpp[0] value 4 assigns
color_index which is never read again and then falls through to the
default case and returns. This looks like a missing break statement
bug. Fix this by adding a break statement.
Addresses-Coverity: ("Unused value")
Fixes: 259d14a76a ("drm/ast: Split ast_set_vbios_mode_info()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20200610115804.1132338-1-colin.king@canonical.com
kdb has to get messages on consoles even when the system is stopped.
It uses kdb_printf() internally and calls console drivers on its own.
It uses a hack to reuse an existing code. It sets "kdb_trap_printk"
global variable to redirect even the normal printk() into the
kdb_printf() variant.
The variable "kdb_trap_printk" is checked in printk_default() and
it is ignored when printk is redirected to printk_safe in NMI context.
Solve this by moving the check into printk_func().
It is obvious that it is not fully safe. But it does not make things
worse. The console drivers are already called in this context by
db_printf() direct calls.
Reported-by: Sumit Garg <sumit.garg@linaro.org>
Tested-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200520102233.GC3464@linux-b0ei
Currently instrumentation of atomic primitives is done at the architecture
level, while composites or fallbacks are provided at the generic level.
The result is that there are no uninstrumented variants of the
fallbacks. Since there is now need of such variants to isolate text poke
from any form of instrumentation invert this ordering.
Doing this means moving the instrumentation into the generic code as
well as having (for now) two variants of the fallbacks.
Notes:
- the various *cond_read* primitives are not proper fallbacks
and got moved into linux/atomic.c. No arch_ variants are
generated because the base primitives smp_cond_load*()
are instrumented.
- once all architectures are moved over to arch_atomic_ one of the
fallback variants can be removed and some 2300 lines reclaimed.
- atomic_{read,set}*() are no longer double-instrumented
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20200505134058.769149955@linutronix.de
Use __always_inline for atomic fallback wrappers. When building for size
(CC_OPTIMIZE_FOR_SIZE), some compilers appear to be less inclined to
inline even relatively small static inline functions that are assumed to
be inlinable such as atomic ops. This can cause problems, for example in
UACCESS regions.
While the fallback wrappers aren't pure wrappers, they are trivial
nonetheless, and the function they wrap should determine the final
inlining policy.
For x86 tinyconfig we observe:
- vmlinux baseline: 1315988
- vmlinux with patch: 1315928 (-60 bytes)
[ tglx: Cherry-picked from KCSAN ]
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The Qualcomm ipq6018 has apcs block, add compatible for the same. Also,
the ipq6018 apcs provides a clock functionality similar to msm8916 but
the clock driver is different.
Create a child device based on the apcs compatible for the clock
controller functionality.
Signed-off-by: Sivaprakash Murugesan <sivaprak@codeaurora.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Some apcs mailbox devices supports a clock driver, the compatible
strings of devices supporting clock driver along with the clock driver
name are maintained in a separate structure within the mailbox driver.
And the clock driver is added based on device match.
With increase in number of devices supporting the clock feature move the
clock driver name inside the driver data. so that we can use a single
API to get the register offset of mailbox driver and clock driver name
together, and the clock driver will be added based on the driver data.
Signed-off-by: Sivaprakash Murugesan <sivaprak@codeaurora.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
The original vdso_data page is empty, so the permission of the vdso_data
page can be the same with the vdso text page. After introducing the vDSO
common flow, the vdso_data is not empty and the permission should be
changed to read-only.
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Even if RISC-V has supported the vDSO feature, the latency of the functions
for obtaining the system time is still expensive. It is because these
functions still trigger a corresponding system call in the process, which
slows down the response time. If we want to remove the system call to
reduce the latency, the kernel should have the ability to output the system
clock information to userspace. This patch introduces the vDSO common flow
to enable the kernel to achieve the above feature and uses "rdtime"
instruction to obtain the current time in the user space. Under this
condition, the latency cost by the ecall from U-mode to S-mode can be
eliminated. After applying this patch, the latency of gettimeofday()
measured on the HiFive unleashed board can be reduced by %61.
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Some architectures like arm64 and s390 require USER_DS to be set for
kernel threads to access user address space, which is the whole purpose of
kthread_use_mm, but other like x86 don't. That has lead to a huge mess
where some callers are fixed up once they are tested on said
architectures, while others linger around and yet other like io_uring try
to do "clever" optimizations for what usually is just a trivial asignment
to a member in the thread_struct for most architectures.
Make kthread_use_mm set USER_DS, and kthread_unuse_mm restore to the
previous value instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: http://lkml.kernel.org/r/20200404094101.672954-7-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Switch the function documentation to kerneldoc comments, and add
WARN_ON_ONCE asserts that the calling thread is a kernel thread and does
not have ->mm set (or has ->mm set in the case of unuse_mm).
Also give the functions a kthread_ prefix to better document the use case.
[hch@lst.de: fix a comment typo, cover the newly merged use_mm/unuse_mm caller in vfio]
Link: http://lkml.kernel.org/r/20200416053158.586887-3-hch@lst.de
[sfr@canb.auug.org.au: powerpc/vas: fix up for {un}use_mm() rename]
Link: http://lkml.kernel.org/r/20200422163935.5aa93ba5@canb.auug.org.au
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [usb]
Acked-by: Haren Myneni <haren@linux.ibm.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Link: http://lkml.kernel.org/r/20200404094101.672954-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
cover the newly merged use_mm/unuse_mm caller in vfio
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Link: http://lkml.kernel.org/r/20200416053158.586887-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "improve use_mm / unuse_mm", v2.
This series improves the use_mm / unuse_mm interface by better documenting
the assumptions, and my taking the set_fs manipulations spread over the
callers into the core API.
This patch (of 3):
Use the proper API instead.
Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de
These helpers are only for use with kernel threads, and I will tie them
more into the kthread infrastructure going forward. Also move the
prototypes to kthread.h - mmu_context.h was a little weird to start with
as it otherwise contains very low-level MM bits.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200416053158.586887-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200404094101.672954-5-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Modify the variable type of 'skip' member of struct stack_trace.
In theory, the 'skip' variable type should be unsigned int.
There are two reasons:
- The 'skip' only has two situation, 1)Positive value, 2)Zero
- The 'skip' of struct stack_trace has inconsistent type with struct
stack_trace_data, it makes a bit confusion in the relationship between
struct stack_trace and stack_trace_data.
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: http://lkml.kernel.org/r/20200421013511.5960-1-walter-zh.wu@mediatek.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While making other modifications it was easy to confuse the two struct
members node_zones and node_zonelists. For those already familiar with
the code, this might seem to be a silly patch, but it's quite helpful to
disambiguate the similar-sounding fields
While here, add a small comment on why nr_zones isn't simply MAX_NR_ZONES
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200520205443.2757414-1-ben.widawsky@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
