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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/arch/arm/include/asm
История
Steven Rostedt 17666f02b1 ftrace: nmi safe code modification 
Impact: fix crashes that can occur in NMI handlers, if their code is modified

Modifying code is something that needs special care. On SMP boxes,
if code that is being modified is also being executed on another CPU,
that CPU will have undefined results.

The dynamic ftrace uses kstop_machine to make the system act like a
uniprocessor system. But this does not address NMIs, that can still
run on other CPUs.

One approach to handle this is to make all code that are used by NMIs
not be traced. But NMIs can call notifiers that spread throughout the
kernel and this will be very hard to maintain, and the chance of missing
a function is very high.

The approach that this patch takes is to have the NMIs modify the code
if the modification is taking place. The way this works is that just
writing to code executing on another CPU is not harmful if what is
written is the same as what exists.

Two buffers are used: an IP buffer and a "code" buffer.

The steps that the patcher takes are:

 1) Put in the instruction pointer into the IP buffer
    and the new code into the "code" buffer.
 2) Set a flag that says we are modifying code
 3) Wait for any running NMIs to finish.
 4) Write the code
 5) clear the flag.
 6) Wait for any running NMIs to finish.

If an NMI is executed, it will also write the pending code.
Multiple writes are OK, because what is being written is the same.
Then the patcher must wait for all running NMIs to finish before
going to the next line that must be patched.

This is basically the RCU approach to code modification.

Thanks to Ingo Molnar for suggesting the idea, and to Arjan van de Ven
for his guidence on what is safe and what is not.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
 		2008-10-30 21:30:08 +01:00
..
hardware [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
mach Merge branch 'pxa-all' into devel 2008-10-09 21:33:02 +01:00
Kbuild [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
a.out-core.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
a.out.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
assembler.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
atomic.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
auxvec.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
bitops.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
bug.h [ARM] 5211/2: fix a couple warnings from BUG() usage 2008-09-01 12:06:27 +01:00
bugs.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
byteorder.h Revert "[ARM] use the new byteorder headers" 2008-09-05 17:01:50 +01:00
cache.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
cacheflush.h [ARM] cachetype: move definitions to separate header 2008-09-01 12:06:24 +01:00
cachetype.h [ARM] Introduce new bitmask based cache type macros 2008-09-25 15:35:28 +01:00
checksum.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
cpu-multi32.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
cpu-single.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
cpu.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
cputime.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
cputype.h [ARM] cputype: separate definitions, use them 2008-09-01 12:06:23 +01:00
current.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
delay.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
device.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
div64.h [ARM] 5320/1: fix assembly constraints in implementation of do_div() 2008-10-23 12:53:32 +01:00
dma-mapping.h [ARM] dma: fix some comments in dma-mapping.h 2008-09-30 11:30:53 +01:00
dma.h [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
domain.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
ecard.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
elf.h [PATCH] remove unused ibcs2/PER_SVR4 in SET_PERSONALITY 2008-10-16 15:40:05 +02:00
emergency-restart.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
errno.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
fb.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
fcntl.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
fiq.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
flat.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
floppy.h [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
fpstate.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
ftrace.h ftrace: nmi safe code modification 2008-10-30 21:30:08 +01:00
futex.h [ARM] 5218/1: arm: improved futex support 2008-09-01 12:06:26 +01:00
glue.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
gpio.h [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
hardirq.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
hw_irq.h [ARM] Fix circular include dependency with IRQ headers 2008-08-07 09:39:37 +01:00
hwcap.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
ide.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
io.h [ARM] Remove MT_DEVICE_IXP2000 and associated definitions 2008-10-01 16:41:06 +01:00
ioctl.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
ioctls.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
ipcbuf.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
irq.h [ARM] sparse: quieten arch/arm/kernel/irq.c 2008-09-06 10:56:27 +01:00
irq_regs.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
irqflags.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
kdebug.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
kexec.h kexec jump: rename KEXEC_CONTROL_CODE_SIZE to KEXEC_CONTROL_PAGE_SIZE 2008-08-15 08:35:42 -07:00
kgdb.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
kmap_types.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
kprobes.h [ARM] 5206/1: remove kprobe_trap_handler() hack 2008-09-01 12:06:26 +01:00
leds.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
limits.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
linkage.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
local.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
locks.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
mc146818rtc.h [ARM] Convert asm/io.h to linux/io.h 2008-09-06 12:10:45 +01:00
memory.h [ARM] 5295/1: make ZONE_DMA optional 2008-10-09 21:29:46 +01:00
mman.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
mmu.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
mmu_context.h [ARM] cachetype: move definitions to separate header 2008-09-01 12:06:24 +01:00
mmzone.h [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
module.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
msgbuf.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
mtd-xip.h [ARM] 5191/1: ARM: remove CVS keywords 2008-08-16 20:01:18 +01:00
mutex.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
nwflash.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
page-nommu.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
page.h [ARM] Improve non-executable support 2008-10-01 16:41:10 +01:00
param.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
parport.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
pci.h [ARM] Fix PCI_DMA_BUS_IS_PHYS for ARM 2008-09-13 21:35:55 +01:00
percpu.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
pgalloc.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
pgtable-hwdef.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
pgtable-nommu.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
pgtable.h Merge branch 'ptebits' into devel 2008-10-09 21:31:56 +01:00
poll.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
posix_types.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
proc-fns.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
processor.h [ARM] 5196/1: fix inline asm constraints for preload 2008-08-16 09:30:05 +01:00
procinfo.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
ptrace.h [ARM] remove pc_pointer() 2008-09-06 10:35:51 +01:00
resource.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
scatterlist.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
sections.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
segment.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
sembuf.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
serial.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
setup.h [ARM] mm: provide helpers for accessing membanks 2008-10-01 17:22:02 +01:00
shmbuf.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
shmparam.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
sigcontext.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
siginfo.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
signal.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
sizes.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
smp.h [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
socket.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
sockios.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
sparsemem.h [ARM] mm: enable sparsemem on clps7500 and RiscPC 2008-10-01 17:24:04 +01:00
spinlock.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
spinlock_types.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
stat.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
statfs.h ARM: Use <asm-generic/statfs.h> 2008-09-04 09:46:11 +01:00
string.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
suspend.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
system.h [ARM] cputype: separate definitions, use them 2008-09-01 12:06:23 +01:00
termbits.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
termios.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
therm.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
thread_info.h [ARM] remove pc_pointer() 2008-09-06 10:35:51 +01:00
thread_notify.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
timex.h [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
tlb.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
tlbflush.h [ARM] 5192/1: ARM TLB: add v7wbi_{possible,always}_flags to {possible,always}_tlb_flags 2008-08-12 19:54:08 +01:00
topology.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
traps.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
types.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
uaccess.h [ARM] 5230/1: Replace post-indexed LDRT/STRT in uaccess.h 2008-09-01 12:06:35 +01:00
ucontext.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
unaligned.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
unistd.h [ARM] 5193/1: Wire up missing syscalls 2008-08-12 19:54:07 +01:00
user.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
vfp.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
vfpmacros.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00
vga.h [ARM] Convert asm/io.h to linux/io.h 2008-09-06 12:10:45 +01:00
xor.h [ARM] move include/asm-arm to arch/arm/include/asm 2008-08-02 21:32:35 +01:00