Add support for Arm64 including all changes in PR #1302 (@swine, @surajjs95, @t-msn, and others)

[puranjaymohan]

This is a rebase of #1302 with some more changes and some already merged patches removed.
It is supposed to work with the sframe based reliable stack unwinder posted upstream:

[PATCH 0/8] unwind, arm64: add sframe unwinder for kernel

NOTE:

• The sframe sections are skipped for now in the livepatch module because the above series doesn't support modules yet. I am trying to make that work both from the kernel side and also in Kpatch and will add a patch later.

Building and testing a livepatch on a 6.12 arm64 kernel for the following basic patch:

[ec2-user@ip-172-31-32-86 ~]$ cat CVE-1234-5678.patch
From 9c372fa658da9ac55e3acb7c3e4f3035f9241c1d Mon Sep 17 00:00:00 2001
From: Puranjay Mohan <[email protected]>
Date: Tue, 14 Jan 2025 09:40:34 +0000
Subject: [PATCH] fs: proc: cmdline: livepatch test

This patch will be turned into a livepatch.

Signed-off-by: Puranjay Mohan <[email protected]>
---
 fs/proc/cmdline.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/proc/cmdline.c b/fs/proc/cmdline.c
index a6f76121955f..90bef8411dbf 100644
--- a/fs/proc/cmdline.c
+++ b/fs/proc/cmdline.c
@@ -7,8 +7,7 @@

 static int cmdline_proc_show(struct seq_file *m, void *v)
 {
-       seq_puts(m, saved_command_line);
-       seq_putc(m, '\n');
+       seq_printf(m, "%s\n", "this has been live patched");
        return 0;
 }

--
2.47.1

[ec2-user@ip-172-31-32-86 ~]$ uname -r
6.12.11-6.47.al2023pjy.aarch64

[ec2-user@ip-172-31-32-86 ~]$ ./kpatch/kpatch-build/kpatch-build -v /usr/lib/debug/lib/modules/6.12.11-6.47.al2023pjy.aarch64/vmlinux -r kernel-6.12.11-6.47.al2023pjy.src.rpm CVE-1234-5678.patch
Using cache at /home/ec2-user/.kpatch/src
Testing patch file(s)
Reading special section data
Building original source
Building patched source
Extracting new and modified ELF sections
cmdline.o: changed function: cmdline_proc_show
Patched objects: vmlinux
Building patch module: livepatch-CVE-1234-5678.ko
SUCCESS
[ec2-user@ip-172-31-32-86 ~]$

Load and Unload test

[root@ip-172-31-32-86 ec2-user]# kpatch load livepatch-CVE-1234-5678.ko
loading patch module: livepatch-CVE-1234-5678.ko
waiting (up to 15 seconds) for patch transition to complete...
transition complete (2 seconds)
[root@ip-172-31-32-86 ec2-user]# dmesg
[69888.542598] livepatch: enabling patch 'livepatch_CVE_1234_5678'
[69888.544388] livepatch: 'livepatch_CVE_1234_5678': starting patching transition
[69890.128882] livepatch: 'livepatch_CVE_1234_5678': patching complete
[root@ip-172-31-32-86 ec2-user]#

[root@ip-172-31-32-86 ec2-user]# cat /proc/cmdline
this has been live patched

[root@ip-172-31-32-86 ec2-user]# kpatch unload livepatch-CVE-1234-5678.ko
disabling patch module: livepatch_CVE_1234_5678
waiting (up to 15 seconds) for patch transition to complete...
transition complete (1 seconds)
unloading patch module: livepatch_CVE_1234_5678
[root@ip-172-31-32-86 ec2-user]# dmesg
[69888.542598] livepatch: enabling patch 'livepatch_CVE_1234_5678'
[69888.544388] livepatch: 'livepatch_CVE_1234_5678': starting patching transition
[69890.128882] livepatch: 'livepatch_CVE_1234_5678': patching complete
[69906.212505] livepatch: 'livepatch_CVE_1234_5678': starting unpatching transition
[69907.128716] livepatch: 'livepatch_CVE_1234_5678': unpatching complete

[root@ip-172-31-32-86 ec2-user]# cat /proc/cmdline
BOOT_IMAGE=(hd0,gpt1)/boot/vmlinuz-6.12.11-6.47.al2023pjy.aarch64 root=UUID=da8e1b79-5f9e-4471-89e7-958620dff70a ro console=tty0 console=ttyS0,115200n8 nvme_core.io_timeout=4294967295 rd.emergency=poweroff rd.shell=0 selinux=1 security=selinux quiet numa_cma=1:64M

Unit tests pass with the objects at: https://github.com/mihails-strasuns/kpatch-unit-test-objs/tree/arm64

CC=gcc10 ARCHES=aarch64 make -j64 unit
make -C kpatch-build
make[1]: Entering directory '/local/home/pjy/code/Kpatch/kpatch-build'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/local/home/pjy/code/Kpatch/kpatch-build'
make -C test/unit
make[1]: Entering directory '/local/home/pjy/code/Kpatch/test/unit'
make -C objs/aarch64
make[2]: Entering directory '/local/home/pjy/code/Kpatch/test/unit/objs/aarch64'
BUILD bug-table-section
BUILD cmdline-string
BUILD data-new
BUILD data-read-mostly
BUILD fixup-section
BUILD gcc-isra
BUILD gcc-static-local-var-2
BUILD gcc-static-local-var-3
BUILD gcc-static-local-var-4
BUILD gcc-static-local-var-5
BUILD gcc-static-local-var-6
BUILD mapping
BUILD meminfo-init-FAIL
BUILD meminfo-string
BUILD new-function
BUILD parainstructions-section
BUILD smp-locks-section
BUILD special-static
BUILD syscall
BUILD tracepoints-section
TEST bug-table-section
TEST cmdline-string
TEST data-new
TEST fixup-section
TEST gcc-isra
TEST gcc-static-local-var-2
TEST gcc-static-local-var-3
TEST gcc-static-local-var-4
TEST gcc-static-local-var-5
TEST gcc-static-local-var-6
TEST meminfo-init
TEST meminfo-string
TEST new-function
TEST parainstructions-section
TEST smp-locks-section
BUILD ASSERT_RTNL-detect
TEST special-static
TEST mapping
TEST tracepoints-section
TEST syscall
TEST data-read-mostly
TEST ASSERT_RTNL-detect
make[2]: Leaving directory '/local/home/pjy/code/Kpatch/test/unit/objs/aarch64'
make[1]: Leaving directory '/local/home/pjy/code/Kpatch/test/unit'

Integration tests

[root@ip-172-31-32-86 kpatch]# KPATCH_BUILD_OPTS=-R make -j64 integration-slow
make -C kpatch-build
make -C kpatch
make -C kmod
make[1]: Entering directory '/home/ec2-user/kpatch/kpatch-build'
make[1]: Entering directory '/home/ec2-user/kpatch/kmod'
make[1]: Entering directory '/home/ec2-user/kpatch/kpatch'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/home/ec2-user/kpatch/kpatch'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/home/ec2-user/kpatch/kmod'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/home/ec2-user/kpatch/kpatch-build'
make -C test/integration slow
make[1]: Entering directory '/home/ec2-user/kpatch/test/integration'
rm -f *.ko *.log COMBINED.patch
./kpatch-test --kpatch-build-opts="-R" -d "amzn"-"2023"
build: data-new
build: gcc-static-local-var-6
build: macro-callbacks
build: module
build: new-function
build: new-globals
build: shadow-newpid
build: special-static
build: symvers-disagreement-FAIL
build: syscall
build: warn-detect-FAIL
combine: skipping amzn-2023/symvers-disagreement-FAIL.patch
combine: skipping amzn-2023/warn-detect-FAIL.patch
build: combined module
load test: data-new
load test: gcc-static-local-var-6 (no test prog)
load test: macro-callbacks (no test prog)
load test: module
load test: new-function (no test prog)
load test: new-globals (no test prog)
load test: shadow-newpid
load test: special-static (no test prog)
load test: syscall
load test: combined module
custom test: multiple
SUCCESS
make[1]: Leaving directory '/home/ec2-user/kpatch/test/integration'
[root@ip-172-31-32-86 kpatch]# echo $?
0

[ZzzMao]

If we believe the i should be either 0 or 2, would it be better if we can report an error here when the i is some other value?

[wardenjohn]

I think the function_padding_size is decideced by the nop padding at the start of the function.
The number of nop adding to the function head is decided by the N of building option
-fpatchable-function-entry.

Or maybe this function padding size can be calculated by this building option of the target kernel
build Makefile? And we can support more specific situation?