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Johan Almbladh ced185824c bpf, x86: Fix bpf mapping of atomic fetch implementation Fix the case where the dst register maps to %rax as otherwise this produces an incorrect mapping with the implementation in `981f94c3e9` ("bpf: Add bitwise atomic instructions") as %rax is clobbered given it's part of the cmpxchg as operand. The issue is similar to `b29dd96b90` ("bpf, x86: Fix BPF_FETCH atomic and/or/ xor with r0 as src") just that the case of dst register was missed. Before, dst=r0 (%rax) src=r2 (%rsi): [...] c5: mov %rax,%r10 c8: mov 0x0(%rax),%rax <---+ (broken) cc: mov %rax,%r11 \| cf: and %rsi,%r11 \| d2: lock cmpxchg %r11,0x0(%rax) <---+ d8: jne 0x00000000000000c8 \| da: mov %rax,%rsi \| dd: mov %r10,%rax \| [...] \| \| After, dst=r0 (%rax) src=r2 (%rsi): \| \| [...] \| da: mov %rax,%r10 \| dd: mov 0x0(%r10),%rax <---+ (fixed) e1: mov %rax,%r11 \| e4: and %rsi,%r11 \| e7: lock cmpxchg %r11,0x0(%r10) <---+ ed: jne 0x00000000000000dd ef: mov %rax,%rsi f2: mov %r10,%rax [...] The remaining combinations were fine as-is though: After, dst=r9 (%r15) src=r0 (%rax): [...] dc: mov %rax,%r10 df: mov 0x0(%r15),%rax e3: mov %rax,%r11 e6: and %r10,%r11 e9: lock cmpxchg %r11,0x0(%r15) ef: jne 0x00000000000000df _ f1: mov %rax,%r10 \| (unneeded, but f4: mov %r10,%rax _\| not a problem) [...] After, dst=r9 (%r15) src=r4 (%rcx): [...] de: mov %rax,%r10 e1: mov 0x0(%r15),%rax e5: mov %rax,%r11 e8: and %rcx,%r11 eb: lock cmpxchg %r11,0x0(%r15) f1: jne 0x00000000000000e1 f3: mov %rax,%rcx f6: mov %r10,%rax [...] The case of dst == src register is rejected by the verifier and therefore not supported, but x86 JIT also handles this case just fine. After, dst=r0 (%rax) src=r0 (%rax): [...] eb: mov %rax,%r10 ee: mov 0x0(%r10),%rax f2: mov %rax,%r11 f5: and %r10,%r11 f8: lock cmpxchg %r11,0x0(%r10) fe: jne 0x00000000000000ee 100: mov %rax,%r10 103: mov %r10,%rax [...] Fixes: `981f94c3e9` ("bpf: Add bitwise atomic instructions") Reported-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Co-developed-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Brendan Jackman <jackmanb@google.com> Acked-by: Alexei Starovoitov <ast@kernel.org>		2021-09-28 12:10:29 +02:00
arch	bpf, x86: Fix bpf mapping of atomic fetch implementation	2021-09-28 12:10:29 +02:00
block	block-5.15-2021-09-05	2021-09-06 10:06:26 -07:00
certs	certs: Add support for using elliptic curve keys for signing modules	2021-08-23 19:55:42 +03:00
crypto	Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2021-08-30 12:57:10 -07:00
Documentation	dt-bindings: net: sun8i-emac: Add compatible for D1	2021-09-08 11:27:34 +01:00
drivers	net: hns3: fix the timing issue of VF clearing interrupt sources	2021-09-13 14:25:37 +01:00
fs	fuse update for 5.15	2021-09-07 12:18:29 -07:00
include	bpf: Handle return value of BPF_PROG_TYPE_STRUCT_OPS prog	2021-09-14 11:09:50 -07:00
init	Enable '-Werror' by default for all kernel builds	2021-09-05 11:24:05 -07:00
ipc	memcg: enable accounting of ipc resources	2021-09-03 09:58:12 -07:00
kernel	bpf, cgroup: Assign cgroup in cgroup_sk_alloc when called from interrupt	2021-09-28 09:29:19 +02:00
lib	lib/test_scanf: split up number parsing test routines	2021-09-06 11:04:03 -07:00
LICENSES	LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes"	2021-07-15 06:31:24 -06:00
mm	Revert "mm/gup: remove try_get_page(), call try_get_compound_head() directly"	2021-09-07 11:03:45 -07:00
net	bpf, test, cgroup: Use sk_{alloc,free} for test cases	2021-09-28 09:29:28 +02:00
samples	kgdb patches for 5.15	2021-09-07 12:08:04 -07:00
scripts	don't make the syscall checking produce errors from warnings	2021-09-06 09:15:09 -07:00
security	Kbuild updates for v5.15	2021-09-03 15:33:47 -07:00
sound	Kbuild updates for v5.15	2021-09-03 15:33:47 -07:00
tools	selftests, bpf: test_lwt_ip_encap: Really disable rp_filter	2021-09-28 09:30:38 +02:00
usr	.gitignore: prefix local generated files with a slash	2021-05-02 00:43:35 +09:00
virt	KVM: Drop unused kvm_dirty_gfn_invalid()	2021-09-06 08:23:46 -04:00
.clang-format	clang-format: Update with the latest for_each macro list	2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	.gitignore: ignore only top-level modules.builtin	2021-05-02 00:43:35 +09:00
.mailmap	mailmap: update email address of Matthias Fuchs and Thomas Körper	2021-08-19 09:39:44 +02:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: move Murali Karicheri to credits	2021-04-29 15:47:30 -07:00
Kbuild	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	MAINTAINERS: Add btf headers to BPF	2021-09-28 09:28:47 +02:00
Makefile	Enable '-Werror' by default for all kernel builds	2021-09-05 11:24:05 -07:00
README	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.