1d05334d28
After the previous patch, vmlinux-specific KLP relocations are now
applied early during KLP module load. This means that .klp.arch
sections are no longer needed for *vmlinux-specific* KLP relocations.
One might think they're still needed for *module-specific* KLP
relocations. If a to-be-patched module is loaded *after* its
corresponding KLP module is loaded, any corresponding KLP relocations
will be delayed until the to-be-patched module is loaded. If any
special sections (.parainstructions, for example) rely on those
relocations, their initializations (apply_paravirt) need to be done
afterwards. Thus the apparent need for arch_klp_init_object_loaded()
and its corresponding .klp.arch sections -- it allows some of the
special section initializations to be done at a later time.
But... if you look closer, that dependency between the special sections
and the module-specific KLP relocations doesn't actually exist in
reality. Looking at the contents of the .altinstructions and
.parainstructions sections, there's not a realistic scenario in which a
KLP module's .altinstructions or .parainstructions section needs to
access a symbol in a to-be-patched module. It might need to access a
local symbol or even a vmlinux symbol; but not another module's symbol.
When a special section needs to reference a local or vmlinux symbol, a
normal rela can be used instead of a KLP rela.
Since the special section initializations don't actually have any real
dependency on module-specific KLP relocations, .klp.arch and
arch_klp_init_object_loaded() no longer have a reason to exist. So
remove them.
As Peter said much more succinctly:
So the reason for .klp.arch was that .klp.rela.* stuff would overwrite
paravirt instructions. If that happens you're doing it wrong. Those
RELAs are core kernel, not module, and thus should've happened in
.rela.* sections at patch-module loading time.
Reverting this removes the two apply_{paravirt,alternatives}() calls
from the late patching path, and means we don't have to worry about
them when removing module_disable_ro().
[ jpoimboe: Rewrote patch description. Tweaked klp_init_object_loaded()
error path. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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| .. | ||
| ABI | ||
| accounting | ||
| admin-guide | ||
| arm | ||
| arm64 | ||
| block | ||
| bpf | ||
| cdrom | ||
| core-api | ||
| cpu-freq | ||
| crypto | ||
| dev-tools | ||
| devicetree | ||
| doc-guide | ||
| driver-api | ||
| fault-injection | ||
| fb | ||
| features | ||
| filesystems | ||
| firmware_class | ||
| firmware-guide | ||
| fpga | ||
| gpu | ||
| hid | ||
| hwmon | ||
| i2c | ||
| ia64 | ||
| ide | ||
| iio | ||
| infiniband | ||
| input | ||
| isdn | ||
| kbuild | ||
| kernel-hacking | ||
| leds | ||
| livepatch | ||
| locking | ||
| m68k | ||
| maintainer | ||
| media | ||
| mhi | ||
| mips | ||
| misc-devices | ||
| netlabel | ||
| networking | ||
| nios2 | ||
| nvdimm | ||
| openrisc | ||
| parisc | ||
| PCI | ||
| pcmcia | ||
| power | ||
| powerpc | ||
| process | ||
| RCU | ||
| riscv | ||
| s390 | ||
| scheduler | ||
| scsi | ||
| security | ||
| sh | ||
| sound | ||
| sparc | ||
| sphinx | ||
| sphinx-static | ||
| spi | ||
| target | ||
| timers | ||
| trace | ||
| translations | ||
| usb | ||
| userspace-api | ||
| virt | ||
| vm | ||
| w1 | ||
| watchdog | ||
| x86 | ||
| xtensa | ||
| .gitignore | ||
| asm-annotations.rst | ||
| atomic_bitops.txt | ||
| atomic_t.txt | ||
| bus-virt-phys-mapping.txt | ||
| Changes | ||
| CodingStyle | ||
| conf.py | ||
| COPYING-logo | ||
| crc32.txt | ||
| debugging-via-ohci1394.txt | ||
| digsig.txt | ||
| DMA-API-HOWTO.txt | ||
| DMA-API.txt | ||
| DMA-attributes.txt | ||
| DMA-ISA-LPC.txt | ||
| docutils.conf | ||
| dontdiff | ||
| futex-requeue-pi.txt | ||
| hwspinlock.txt | ||
| index.rst | ||
| IPMI.txt | ||
| IRQ-affinity.txt | ||
| IRQ-domain.txt | ||
| IRQ.txt | ||
| irqflags-tracing.txt | ||
| Kconfig | ||
| kprobes.txt | ||
| kref.txt | ||
| logo.gif | ||
| lzo.txt | ||
| mailbox.txt | ||
| Makefile | ||
| memory-barriers.txt | ||
| nommu-mmap.txt | ||
| percpu-rw-semaphore.txt | ||
| pi-futex.txt | ||
| preempt-locking.txt | ||
| rbtree.txt | ||
| remoteproc.txt | ||
| robust-futex-ABI.txt | ||
| robust-futexes.txt | ||
| rpmsg.txt | ||
| speculation.txt | ||
| static-keys.txt | ||
| SubmittingPatches | ||
| tee.txt | ||
| this_cpu_ops.txt | ||
| unaligned-memory-access.txt | ||
| xz.txt | ||
