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[ Upstream commit 066baf92bed934c9fb4bcee97a193f47aa63431c ]
copy_mc_to_user() has the destination marked __user on powerpc, but not on
x86; the latter results in a sparse warning in lib/iov_iter.c.
Fix this by applying the tag on x86 too.
Fixes: ec6347bb4339 ("x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230925120309.1731676-3-dhowells@redhat.com
cc: Dan Williams <dan.j.williams@intel.com>
cc: Thomas Gleixner <tglx@linutronix.de>
cc: Ingo Molnar <mingo@redhat.com>
cc: Borislav Petkov <bp@alien8.de>
cc: Dave Hansen <dave.hansen@linux.intel.com>
cc: "H. Peter Anvin" <hpa@zytor.com>
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Christian Brauner <christian@brauner.io>
cc: Matthew Wilcox <willy@infradead.org>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: David Laight <David.Laight@ACULAB.COM>
cc: x86@kernel.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 79cd2a11224eab86d6673fe8a11d2046ae9d2757 upstream.
The linker script arch/x86/kernel/vmlinux.lds.S matches the thunk
sections ".text.__x86.*" from arch/x86/lib/retpoline.S as follows:
.text {
[...]
TEXT_TEXT
[...]
__indirect_thunk_start = .;
*(.text.__x86.*)
__indirect_thunk_end = .;
[...]
}
Macro TEXT_TEXT references TEXT_MAIN which normally expands to only
".text". However, with CONFIG_LTO_CLANG, TEXT_MAIN becomes
".text .text.[0-9a-zA-Z_]*" which wrongly matches also the thunk
sections. The output layout is then different than expected. For
instance, the currently defined range [__indirect_thunk_start,
__indirect_thunk_end] becomes empty.
Prevent the problem by using ".." as the first separator, for example,
".text..__x86.indirect_thunk". This pattern is utilized by other
explicit section names which start with one of the standard prefixes,
such as ".text" or ".data", and that need to be individually selected in
the linker script.
[ nathan: Fix conflicts with SRSO and fold in fix issue brought up by
Andrew Cooper in post-review:
https://lore.kernel.org/20230803230323.1478869-1-andrew.cooper3@citrix.com ]
Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230711091952.27944-2-petr.pavlu@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ba5ca5e5e6a1d55923e88b4a83da452166f5560e upstream.
Use LEA instead of ADD when adjusting %rsp in srso_safe_ret{,_alias}()
so as to avoid clobbering flags. Drop one of the INT3 instructions to
account for the LEA consuming one more byte than the ADD.
KVM's emulator makes indirect calls into a jump table of sorts, where
the destination of each call is a small blob of code that performs fast
emulation by executing the target instruction with fixed operands.
E.g. to emulate ADC, fastop() invokes adcb_al_dl():
adcb_al_dl:
<+0>: adc %dl,%al
<+2>: jmp <__x86_return_thunk>
A major motivation for doing fast emulation is to leverage the CPU to
handle consumption and manipulation of arithmetic flags, i.e. RFLAGS is
both an input and output to the target of the call. fastop() collects
the RFLAGS result by pushing RFLAGS onto the stack and popping them back
into a variable (held in %rdi in this case):
asm("push %[flags]; popf; " CALL_NOSPEC " ; pushf; pop %[flags]\n"
<+71>: mov 0xc0(%r8),%rdx
<+78>: mov 0x100(%r8),%rcx
<+85>: push %rdi
<+86>: popf
<+87>: call *%rsi
<+89>: nop
<+90>: nop
<+91>: nop
<+92>: pushf
<+93>: pop %rdi
and then propagating the arithmetic flags into the vCPU's emulator state:
ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK);
<+64>: and $0xfffffffffffff72a,%r9
<+94>: and $0x8d5,%edi
<+109>: or %rdi,%r9
<+122>: mov %r9,0x10(%r8)
The failures can be most easily reproduced by running the "emulator"
test in KVM-Unit-Tests.
If you're feeling a bit of deja vu, see commit b63f20a778c8
("x86/retpoline: Don't clobber RFLAGS during CALL_NOSPEC on i386").
In addition, this breaks booting of clang-compiled guest on
a gcc-compiled host where the host contains the %rsp-modifying SRSO
mitigations.
[ bp: Massage commit message, extend, remove addresses. ]
Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Closes: https://lore.kernel.org/all/de474347-122d-54cd-eabf-9dcc95ab9eae@amd.com
Reported-by: Srikanth Aithal <sraithal@amd.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20230810013334.GA5354@dev-arch.thelio-3990X/
Link: https://lore.kernel.org/r/20230811155255.250835-1-seanjc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9dbd23e42ff0b10c9b02c9e649c76e5228241a8e upstream.
The goal is to eventually have a proper documentation about all this.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230814164447.GFZNpZ/64H4lENIe94@fat_crate.local
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e7c25c441e9e0fa75b4c83e0b26306b702cfe90d upstream.
Since there can only be one active return_thunk, there only needs be
one (matching) untrain_ret. It fundamentally doesn't make sense to
allow multiple untrain_ret at the same time.
Fold all the 3 different untrain methods into a single (temporary)
helper stub.
Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230814121149.042774962@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 42be649dd1f2eee6b1fb185f1a231b9494cf095f upstream.
For a more consistent namespace.
[ bp: Fixup names in the doc too. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230814121148.976236447@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d025b7bac07a6e90b6b98b487f88854ad9247c39 upstream.
Rename the original retbleed return thunk and untrain_ret to
retbleed_return_thunk() and retbleed_untrain_ret().
No functional changes.
Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230814121148.909378169@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d43490d0ab824023e11d0b57d0aeec17a6e0ca13 upstream.
Use the existing configurable return thunk. There is absolute no
justification for having created this __x86_return_thunk alternative.
To clarify, the whole thing looks like:
Zen3/4 does:
srso_alias_untrain_ret:
nop2
lfence
jmp srso_alias_return_thunk
int3
srso_alias_safe_ret: // aliasses srso_alias_untrain_ret just so
add $8, %rsp
ret
int3
srso_alias_return_thunk:
call srso_alias_safe_ret
ud2
While Zen1/2 does:
srso_untrain_ret:
movabs $foo, %rax
lfence
call srso_safe_ret (jmp srso_return_thunk ?)
int3
srso_safe_ret: // embedded in movabs instruction
add $8,%rsp
ret
int3
srso_return_thunk:
call srso_safe_ret
ud2
While retbleed does:
zen_untrain_ret:
test $0xcc, %bl
lfence
jmp zen_return_thunk
int3
zen_return_thunk: // embedded in the test instruction
ret
int3
Where Zen1/2 flush the BTB entry using the instruction decoder trick
(test,movabs) Zen3/4 use BTB aliasing. SRSO adds a return sequence
(srso_safe_ret()) which forces the function return instruction to
speculate into a trap (UD2). This RET will then mispredict and
execution will continue at the return site read from the top of the
stack.
Pick one of three options at boot (evey function can only ever return
once).
[ bp: Fixup commit message uarch details and add them in a comment in
the code too. Add a comment about the srso_select_mitigation()
dependency on retbleed_select_mitigation(). Add moar ifdeffery for
32-bit builds. Add a dummy srso_untrain_ret_alias() definition for
32-bit alternatives needing the symbol. ]
Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230814121148.842775684@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit af023ef335f13c8b579298fc432daeef609a9e60 upstream.
vmlinux.o: warning: objtool: srso_untrain_ret() falls through to next function __x86_return_skl()
vmlinux.o: warning: objtool: __x86_return_thunk() falls through to next function __x86_return_skl()
This is because these functions (can) end with CALL, which objtool
does not consider a terminating instruction. Therefore, replace the
INT3 instruction (which is a non-fatal trap) with UD2 (which is a
fatal-trap).
This indicates execution will not continue past this point.
Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230814121148.637802730@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 77f67119004296a9b2503b377d610e08b08afc2a upstream.
Commit
fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
reimplemented __x86_return_thunk with a mix of SYM_FUNC_START and
SYM_CODE_END, this is not a sane combination.
Since nothing should ever actually 'CALL' this, make it consistently
CODE.
Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230814121148.571027074@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Upstream commit: 3bbbe97ad83db8d9df06daf027b0840188de625d
Fix:
vmlinux.o: warning: objtool: .export_symbol+0x29e40: data relocation to !ENDBR: srso_untrain_ret_alias+0x0
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Upstream commit: fb3bd914b3ec28f5fb697ac55c4846ac2d542855
Add a mitigation for the speculative return address stack overflow
vulnerability found on AMD processors.
The mitigation works by ensuring all RET instructions speculate to
a controlled location, similar to how speculation is controlled in the
retpoline sequence. To accomplish this, the __x86_return_thunk forces
the CPU to mispredict every function return using a 'safe return'
sequence.
To ensure the safety of this mitigation, the kernel must ensure that the
safe return sequence is itself free from attacker interference. In Zen3
and Zen4, this is accomplished by creating a BTB alias between the
untraining function srso_untrain_ret_alias() and the safe return
function srso_safe_ret_alias() which results in evicting a potentially
poisoned BTB entry and using that safe one for all function returns.
In older Zen1 and Zen2, this is accomplished using a reinterpretation
technique similar to Retbleed one: srso_untrain_ret() and
srso_safe_ret().
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This code no longer exists in mainline, because it was removed in
commit d2c95f9d6802 ("x86: don't use REP_GOOD or ERMS for user memory
clearing") upstream.
However, rather than backport the full range of x86 memory clearing and
copying cleanups, fix the exception table annotation placement for the
final 'rep movsb' in clear_user_rep_good(): rather than pointing at the
actual instruction that did the user space access, it pointed to the
register move just before it.
That made sense from a code flow standpoint, but not from an actual
usage standpoint: it means that if user access takes an exception, the
exception handler won't actually find the instruction in the exception
tables.
As a result, rather than fixing it up and returning -EFAULT, it would
then turn it into a kernel oops report instead, something like:
BUG: unable to handle page fault for address: 0000000020081000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
...
RIP: 0010:clear_user_rep_good+0x1c/0x30 arch/x86/lib/clear_page_64.S:147
...
Call Trace:
__clear_user arch/x86/include/asm/uaccess_64.h:103 [inline]
clear_user arch/x86/include/asm/uaccess_64.h:124 [inline]
iov_iter_zero+0x709/0x1290 lib/iov_iter.c:800
iomap_dio_hole_iter fs/iomap/direct-io.c:389 [inline]
iomap_dio_iter fs/iomap/direct-io.c:440 [inline]
__iomap_dio_rw+0xe3d/0x1cd0 fs/iomap/direct-io.c:601
iomap_dio_rw+0x40/0xa0 fs/iomap/direct-io.c:689
ext4_dio_read_iter fs/ext4/file.c:94 [inline]
ext4_file_read_iter+0x4be/0x690 fs/ext4/file.c:145
call_read_iter include/linux/fs.h:2183 [inline]
do_iter_readv_writev+0x2e0/0x3b0 fs/read_write.c:733
do_iter_read+0x2f2/0x750 fs/read_write.c:796
vfs_readv+0xe5/0x150 fs/read_write.c:916
do_preadv+0x1b6/0x270 fs/read_write.c:1008
__do_sys_preadv2 fs/read_write.c:1070 [inline]
__se_sys_preadv2 fs/read_write.c:1061 [inline]
__x64_sys_preadv2+0xef/0x150 fs/read_write.c:1061
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
which then looks like a filesystem bug rather than the incorrect
exception annotation that it is.
[ The alternative to this one-liner fix is to take the upstream series
that cleans this all up:
68674f94ffc9 ("x86: don't use REP_GOOD or ERMS for small memory copies")
20f3337d350c ("x86: don't use REP_GOOD or ERMS for small memory clearing")
adfcf4231b8c ("x86: don't use REP_GOOD or ERMS for user memory copies")
* d2c95f9d6802 ("x86: don't use REP_GOOD or ERMS for user memory clearing")
3639a535587d ("x86: move stac/clac from user copy routines into callers")
577e6a7fd50d ("x86: inline the 'rep movs' in user copies for the FSRM case")
8c9b6a88b7e2 ("x86: improve on the non-rep 'clear_user' function")
427fda2c8a49 ("x86: improve on the non-rep 'copy_user' function")
* e046fe5a36a9 ("x86: set FSRS automatically on AMD CPUs that have FSRM")
e1f2750edc4a ("x86: remove 'zerorest' argument from __copy_user_nocache()")
034ff37d3407 ("x86: rewrite '__copy_user_nocache' function")
with either the whole series or at a minimum the two marked commits
being needed to fix this issue ]
Reported-by: syzbot <syzbot+401145a9a237779feb26@syzkaller.appspotmail.com>
Link: https://syzkaller.appspot.com/bug?extid=401145a9a237779feb26
Fixes: 0db7058e8e23 ("x86/clear_user: Make it faster")
Cc: Borislav Petkov <bp@alien8.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9a48d604672220545d209e9996c2a1edbb5637f6 upstream.
SYM_FUNC_START_LOCAL_NOALIGN() adds an endbr leading to this layout
(leaving only the last 2 bytes of the address):
3bff <zen_untrain_ret>:
3bff: f3 0f 1e fa endbr64
3c03: f6 test $0xcc,%bl
3c04 <__x86_return_thunk>:
3c04: c3 ret
3c05: cc int3
3c06: 0f ae e8 lfence
However, "the RET at __x86_return_thunk must be on a 64 byte boundary,
for alignment within the BTB."
Use SYM_START instead.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 55d235361fccef573990dfa5724ab453866e7816 ]
Fix a warning: "found `movsd'; assuming `movsl' was meant"
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Make sure usercopy hooks from linux/instrumented.h are invoked for
copy_from_user_nmi(). This fixes KMSAN false positives reported when
dumping opcodes for a stack trace.
Link: https://lkml.kernel.org/r/20221102110611.1085175-2-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marco Elver <elver@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any
negative reports (or any positive ones, come to that).
- Also the Maple Tree from Liam Howlett. An overlapping range-based
tree for vmas. It it apparently slightly more efficient in its own
right, but is mainly targeted at enabling work to reduce mmap_lock
contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
at [1]. This has yet to be addressed due to Liam's unfortunately
timed vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down
to the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
support file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging
activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]
* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
hugetlb: allocate vma lock for all sharable vmas
hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb: fix vma lock handling during split vma and range unmapping
mglru: mm/vmscan.c: fix imprecise comments
mm/mglru: don't sync disk for each aging cycle
mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
mm: memcontrol: use do_memsw_account() in a few more places
mm: memcontrol: deprecate swapaccounting=0 mode
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
mm/secretmem: remove reduntant return value
mm/hugetlb: add available_huge_pages() func
mm: remove unused inline functions from include/linux/mm_inline.h
selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
selftests/vm: add thp collapse shmem testing
selftests/vm: add thp collapse file and tmpfs testing
selftests/vm: modularize thp collapse memory operations
selftests/vm: dedup THP helpers
mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
mm/madvise: add file and shmem support to MADV_COLLAPSE
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Borislav Petkov:
- Print the CPU number at segfault time.
The number printed is not always accurate (preemption is enabled at
that time) but the print string contains "likely" and after a lot of
back'n'forth on this, this was the consensus that was reached. See
thread at [1].
- After a *lot* of testing and polishing, finally the clear_user()
improvements to inline REP; STOSB by default
Link: https://lore.kernel.org/r/5d62c1d0-7425-d5bb-ecb5-1dc3b4d7d245@intel.com [1]
* tag 'x86_cpu_for_v6.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Print likely CPU at segfault time
x86/clear_user: Make it faster
|
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull kcfi updates from Kees Cook:
"This replaces the prior support for Clang's standard Control Flow
Integrity (CFI) instrumentation, which has required a lot of special
conditions (e.g. LTO) and work-arounds.
The new implementation ("Kernel CFI") is specific to C, directly
designed for the Linux kernel, and takes advantage of architectural
features like x86's IBT. This series retains arm64 support and adds
x86 support.
GCC support is expected in the future[1], and additional "generic"
architectural support is expected soon[2].
Summary:
- treewide: Remove old CFI support details
- arm64: Replace Clang CFI support with Clang KCFI support
- x86: Introduce Clang KCFI support"
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107048 [1]
Link: https://github.com/samitolvanen/llvm-project/commits/kcfi_generic [2]
* tag 'kcfi-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (22 commits)
x86: Add support for CONFIG_CFI_CLANG
x86/purgatory: Disable CFI
x86: Add types to indirectly called assembly functions
x86/tools/relocs: Ignore __kcfi_typeid_ relocations
kallsyms: Drop CONFIG_CFI_CLANG workarounds
objtool: Disable CFI warnings
objtool: Preserve special st_shndx indexes in elf_update_symbol
treewide: Drop __cficanonical
treewide: Drop WARN_ON_FUNCTION_MISMATCH
treewide: Drop function_nocfi
init: Drop __nocfi from __init
arm64: Drop unneeded __nocfi attributes
arm64: Add CFI error handling
arm64: Add types to indirect called assembly functions
psci: Fix the function type for psci_initcall_t
lkdtm: Emit an indirect call for CFI tests
cfi: Add type helper macros
cfi: Switch to -fsanitize=kcfi
cfi: Drop __CFI_ADDRESSABLE
cfi: Remove CONFIG_CFI_CLANG_SHADOW
...
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This is needed to allow memory tools like KASAN and KMSAN see the memory
accesses from the checksum code. Without CONFIG_GENERIC_CSUM the tools
can't see memory accesses originating from handwritten assembly code.
For KASAN it's a question of detecting more bugs, for KMSAN using the C
implementation also helps avoid false positives originating from seemingly
uninitialized checksum values.
Link: https://lkml.kernel.org/r/20220915150417.722975-38-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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KMSAN cannot intercept memory accesses within asm() statements. That's
why we add kmsan_unpoison_memory() and kmsan_check_memory() to hint it how
to handle memory copied from/to I/O memory.
Link: https://lkml.kernel.org/r/20220915150417.722975-35-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The check_object_size() helper under CONFIG_HARDENED_USERCOPY is designed
to skip any checks where the length is known at compile time as a
reasonable heuristic to avoid "likely known-good" cases. However, it can
only do this when the copy_*_user() helpers are, themselves, inline too.
Using find_vmap_area() requires taking a spinlock. The
check_object_size() helper can call find_vmap_area() when the destination
is in vmap memory. If show_regs() is called in interrupt context, it will
attempt a call to copy_from_user_nmi(), which may call check_object_size()
and then find_vmap_area(). If something in normal context happens to be
in the middle of calling find_vmap_area() (with the spinlock held), the
interrupt handler will hang forever.
The copy_from_user_nmi() call is actually being called with a fixed-size
length, so check_object_size() should never have been called in the first
place. Given the narrow constraints, just replace the
__copy_from_user_inatomic() call with an open-coded version that calls
only into the sanitizers and not check_object_size(), followed by a call
to raw_copy_from_user().
[akpm@linux-foundation.org: no instrument_copy_from_user() in my tree...]
Link: https://lkml.kernel.org/r/20220919201648.2250764-1-keescook@chromium.org
Link: https://lore.kernel.org/all/CAOUHufaPshtKrTWOz7T7QFYUNVGFm0JBjvM700Nhf9qEL9b3EQ@mail.gmail.com
Fixes: 0aef499f3172 ("mm/usercopy: Detect vmalloc overruns")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Yu Zhao <yuzhao@google.com>
Reported-by: Florian Lehner <dev@der-flo.net>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Florian Lehner <dev@der-flo.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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With CONFIG_CFI_CLANG, assembly functions indirectly called
from C code must be annotated with type identifiers to pass CFI
checking. Define the __CFI_TYPE helper macro to match the compiler
generated function preamble, and ensure SYM_TYPED_FUNC_START also
emits ENDBR with IBT.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-21-samitolvanen@google.com
|
|
Based on a patch by Mark Hemment <markhemm@googlemail.com> and
incorporating very sane suggestions from Linus.
The point here is to have the default case with FSRM - which is supposed
to be the majority of x86 hw out there - if not now then soon - be
directly inlined into the instruction stream so that no function call
overhead is taking place.
Drop the early clobbers from the @size and @addr operands as those are
not needed anymore since we have single instruction alternatives.
The benchmarks I ran would show very small improvements and a PF
benchmark would even show weird things like slowdowns with higher core
counts.
So for a ~6m running the git test suite, the function gets called under
700K times, all from padzero():
<...>-2536 [006] ..... 261.208801: padzero: to: 0x55b0663ed214, size: 3564, cycles: 21900
<...>-2536 [006] ..... 261.208819: padzero: to: 0x7f061adca078, size: 3976, cycles: 17160
<...>-2537 [008] ..... 261.211027: padzero: to: 0x5572d019e240, size: 3520, cycles: 23850
<...>-2537 [008] ..... 261.211049: padzero: to: 0x7f1288dc9078, size: 3976, cycles: 15900
...
which is around 1%-ish of the total time and which is consistent with
the benchmark numbers.
So Mel gave me the idea to simply measure how fast the function becomes.
I.e.:
start = rdtsc_ordered();
ret = __clear_user(to, n);
end = rdtsc_ordered();
Computing the mean average of all the samples collected during the test
suite run then shows some improvement:
clear_user_original:
Amean: 9219.71 (Sum: 6340154910, samples: 687674)
fsrm:
Amean: 8030.63 (Sum: 5522277720, samples: 687652)
That's on Zen3.
The situation looks a lot more confusing on Intel:
Icelake:
clear_user_original:
Amean: 19679.4 (Sum: 13652560764, samples: 693750)
Amean: 19743.7 (Sum: 13693470604, samples: 693562)
(I ran it twice just to be sure.)
ERMS:
Amean: 20374.3 (Sum: 13910601024, samples: 682752)
Amean: 20453.7 (Sum: 14186223606, samples: 693576)
FSRM:
Amean: 20458.2 (Sum: 13918381386, sample s: 680331)
The original microbenchmark which people were complaining about:
for i in $(seq 1 10); do dd if=/dev/zero of=/dev/null bs=1M status=progress count=65536; done 2>&1 | grep copied
32207011840 bytes (32 GB, 30 GiB) copied, 1 s, 32.2 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 1.93069 s, 35.6 GB/s
37597741056 bytes (38 GB, 35 GiB) copied, 1 s, 37.6 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 1.78017 s, 38.6 GB/s
62020124672 bytes (62 GB, 58 GiB) copied, 2 s, 31.0 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 2.13716 s, 32.2 GB/s
60010004480 bytes (60 GB, 56 GiB) copied, 1 s, 60.0 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 1.14129 s, 60.2 GB/s
53212086272 bytes (53 GB, 50 GiB) copied, 1 s, 53.2 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 1.28398 s, 53.5 GB/s
55698259968 bytes (56 GB, 52 GiB) copied, 1 s, 55.7 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 1.22507 s, 56.1 GB/s
55306092544 bytes (55 GB, 52 GiB) copied, 1 s, 55.3 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 1.23647 s, 55.6 GB/s
54387539968 bytes (54 GB, 51 GiB) copied, 1 s, 54.4 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 1.25693 s, 54.7 GB/s
50566529024 bytes (51 GB, 47 GiB) copied, 1 s, 50.6 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 1.35096 s, 50.9 GB/s
58308165632 bytes (58 GB, 54 GiB) copied, 1 s, 58.3 GB/s
68719476736 bytes (69 GB, 64 GiB) copied, 1.17394 s, 58.5 GB/s
Now the same thing with smaller buffers:
for i in $(seq 1 10); do dd if=/dev/zero of=/dev/null bs=1M status=progress count=8192; done 2>&1 | grep copied
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.28485 s, 30.2 GB/s
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.276112 s, 31.1 GB/s
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.29136 s, 29.5 GB/s
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.283803 s, 30.3 GB/s
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.306503 s, 28.0 GB/s
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.349169 s, 24.6 GB/s
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.276912 s, 31.0 GB/s
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.265356 s, 32.4 GB/s
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.28464 s, 30.2 GB/s
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 0.242998 s, 35.3 GB/s
is also not conclusive because it all depends on the buffer sizes,
their alignments and when the microcode detects that cachelines can be
aggregated properly and copied in bigger sizes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/CAHk-=wh=Mu_EYhtOmPn6AxoQZyEh-4fo2Zx3G7rBv1g7vwoKiw@mail.gmail.com
|
|
Do fine-grained Kconfig for all the various retbleed parts.
NOTE: if your compiler doesn't support return thunks this will
silently 'upgrade' your mitigation to IBPB, you might not like this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
|
|
Note: needs to be in a section distinct from Retpolines such that the
Retpoline RET substitution cannot possibly use immediate jumps.
ORC unwinding for zen_untrain_ret() and __x86_return_thunk() is a
little tricky but works due to the fact that zen_untrain_ret() doesn't
have any stack ops and as such will emit a single ORC entry at the
start (+0x3f).
Meanwhile, unwinding an IP, including the __x86_return_thunk() one
(+0x40) will search for the largest ORC entry smaller or equal to the
IP, these will find the one ORC entry (+0x3f) and all works.
[ Alexandre: SVM part. ]
[ bp: Build fix, massages. ]
Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
|
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Use the return thunk in asm code. If the thunk isn't needed, it will
get patched into a RET instruction during boot by apply_returns().
Since alternatives can't handle relocations outside of the first
instruction, putting a 'jmp __x86_return_thunk' in one is not valid,
therefore carve out the memmove ERMS path into a separate label and jump
to it.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
|
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Utilize -mfunction-return=thunk-extern when available to have the
compiler replace RET instructions with direct JMPs to the symbol
__x86_return_thunk. This does not affect assembler (.S) sources, only C
sources.
-mfunction-return=thunk-extern has been available since gcc 7.3 and
clang 15.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
|
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Put the actual retpoline thunk as the original code so that it can
become more complicated. Specifically, it allows RET to be a JMP,
which can't be .altinstr_replacement since that doesn't do relocations
(except for the very first instruction).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc updates from Andrew Morton:
"The non-MM patch queue for this merge window.
Not a lot of material this cycle. Many singleton patches against
various subsystems. Most notably some maintenance work in ocfs2
and initramfs"
* tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (65 commits)
kcov: update pos before writing pc in trace function
ocfs2: dlmfs: fix error handling of user_dlm_destroy_lock
ocfs2: dlmfs: don't clear USER_LOCK_ATTACHED when destroying lock
fs/ntfs: remove redundant variable idx
fat: remove time truncations in vfat_create/vfat_mkdir
fat: report creation time in statx
fat: ignore ctime updates, and keep ctime identical to mtime in memory
fat: split fat_truncate_time() into separate functions
MAINTAINERS: add Muchun as a memcg reviewer
proc/sysctl: make protected_* world readable
ia64: mca: drop redundant spinlock initialization
tty: fix deadlock caused by calling printk() under tty_port->lock
relay: remove redundant assignment to pointer buf
fs/ntfs3: validate BOOT sectors_per_clusters
lib/string_helpers: fix not adding strarray to device's resource list
kernel/crash_core.c: remove redundant check of ck_cmdline
ELF, uapi: fixup ELF_ST_TYPE definition
ipc/mqueue: use get_tree_nodev() in mqueue_get_tree()
ipc: update semtimedop() to use hrtimer
ipc/sem: remove redundant assignments
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull misc x86 updates from Borislav Petkov:
"A variety of fixes which don't fit any other tip bucket:
- Remove unnecessary function export
- Correct asm constraint
- Fix __setup handlers retval"
* tag 'x86_misc_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Cleanup the control_va_addr_alignment() __setup handler
x86: Fix return value of __setup handlers
x86/delay: Fix the wrong asm constraint in delay_loop()
x86/amd_nb: Unexport amd_cache_northbridges()
|
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core x86 updates from Borislav Petkov:
- Remove all the code around GS switching on 32-bit now that it is not
needed anymore
- Other misc improvements
* tag 'x86_core_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
bug: Use normal relative pointers in 'struct bug_entry'
x86/nmi: Make register_nmi_handler() more robust
x86/asm: Merge load_gs_index()
x86/32: Remove lazy GS macros
ELF: Remove elf_core_copy_kernel_regs()
x86/32: Simplify ELF_CORE_COPY_REGS
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Borislav Petkov:
- Serious sanitization and cleanup of the whole APERF/MPERF and
frequency invariance code along with removing the need for
unnecessary IPIs
- Finally remove a.out support
- The usual trivial cleanups and fixes all over x86
* tag 'x86_cleanups_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
x86: Remove empty files
x86/speculation: Add missing srbds=off to the mitigations= help text
x86/prctl: Remove pointless task argument
x86/aperfperf: Make it correct on 32bit and UP kernels
x86/aperfmperf: Integrate the fallback code from show_cpuinfo()
x86/aperfmperf: Replace arch_freq_get_on_cpu()
x86/aperfmperf: Replace aperfmperf_get_khz()
x86/aperfmperf: Store aperf/mperf data for cpu frequency reads
x86/aperfmperf: Make parts of the frequency invariance code unconditional
x86/aperfmperf: Restructure arch_scale_freq_tick()
x86/aperfmperf: Put frequency invariance aperf/mperf data into a struct
x86/aperfmperf: Untangle Intel and AMD frequency invariance init
x86/aperfmperf: Separate AP/BP frequency invariance init
x86/smp: Move APERF/MPERF code where it belongs
x86/aperfmperf: Dont wake idle CPUs in arch_freq_get_on_cpu()
x86/process: Fix kernel-doc warning due to a changed function name
x86: Remove a.out support
x86/mm: Replace nodes_weight() with nodes_empty() where appropriate
x86: Replace cpumask_weight() with cpumask_empty() where appropriate
x86/pkeys: Remove __arch_set_user_pkey_access() declaration
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull Intel TDX support from Borislav Petkov:
"Intel Trust Domain Extensions (TDX) support.
This is the Intel version of a confidential computing solution called
Trust Domain Extensions (TDX). This series adds support to run the
kernel as part of a TDX guest. It provides similar guest protections
to AMD's SEV-SNP like guest memory and register state encryption,
memory integrity protection and a lot more.
Design-wise, it differs from AMD's solution considerably: it uses a
software module which runs in a special CPU mode called (Secure
Arbitration Mode) SEAM. As the name suggests, this module serves as
sort of an arbiter which the confidential guest calls for services it
needs during its lifetime.
Just like AMD's SNP set, this series reworks and streamlines certain
parts of x86 arch code so that this feature can be properly
accomodated"
* tag 'x86_tdx_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
x86/tdx: Fix RETs in TDX asm
x86/tdx: Annotate a noreturn function
x86/mm: Fix spacing within memory encryption features message
x86/kaslr: Fix build warning in KASLR code in boot stub
Documentation/x86: Document TDX kernel architecture
ACPICA: Avoid cache flush inside virtual machines
x86/tdx/ioapic: Add shared bit for IOAPIC base address
x86/mm: Make DMA memory shared for TD guest
x86/mm/cpa: Add support for TDX shared memory
x86/tdx: Make pages shared in ioremap()
x86/topology: Disable CPU online/offline control for TDX guests
x86/boot: Avoid #VE during boot for TDX platforms
x86/boot: Set CR0.NE early and keep it set during the boot
x86/acpi/x86/boot: Add multiprocessor wake-up support
x86/boot: Add a trampoline for booting APs via firmware handoff
x86/tdx: Wire up KVM hypercalls
x86/tdx: Port I/O: Add early boot support
x86/tdx: Port I/O: Add runtime hypercalls
x86/boot: Port I/O: Add decompression-time support for TDX
x86/boot: Port I/O: Allow to hook up alternative helpers
...
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Remove empty files which were supposed to get removed with the
respective commits removing the functionality in them:
$ find arch/x86/ -empty
arch/x86/lib/mmx_32.c
arch/x86/include/asm/fpu/internal.h
arch/x86/include/asm/mmx.h
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220520101723.12006-1-bp@alien8.de
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- A fix to disable PCI/MSI[-X] masking for XEN_HVM guests as that is
solely controlled by the hypervisor
- A build fix to make the function prototype (__warn()) as visible as
the definition itself
- A bunch of objtool annotation fixes which have accumulated over time
- An ORC unwinder fix to handle bad input gracefully
- Well, we thought the microcode gets loaded in time in order to
restore the microcode-emulated MSRs but we thought wrong. So there's
a fix for that to have the ordering done properly
- Add new Intel model numbers
- A spelling fix
* tag 'x86_urgent_for_v5.18_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/pci/xen: Disable PCI/MSI[-X] masking for XEN_HVM guests
bug: Have __warn() prototype defined unconditionally
x86/Kconfig: fix the spelling of 'becoming' in X86_KERNEL_IBT config
objtool: Use offstr() to print address of missing ENDBR
objtool: Print data address for "!ENDBR" data warnings
x86/xen: Add ANNOTATE_NOENDBR to startup_xen()
x86/uaccess: Add ENDBR to __put_user_nocheck*()
x86/retpoline: Add ANNOTATE_NOENDBR for retpolines
x86/static_call: Add ANNOTATE_NOENDBR to static call trampoline
objtool: Enable unreachable warnings for CLANG LTO
x86,objtool: Explicitly mark idtentry_body()s tail REACHABLE
x86,objtool: Mark cpu_startup_entry() __noreturn
x86,xen,objtool: Add UNWIND hint
lib/strn*,objtool: Enforce user_access_begin() rules
MAINTAINERS: Add x86 unwinding entry
x86/unwind/orc: Recheck address range after stack info was updated
x86/cpu: Load microcode during restore_processor_state()
x86/cpu: Add new Alderlake and Raptorlake CPU model numbers
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull objtool fixes from Borislav Petkov:
"A bunch of objtool fixes to improve unwinding, sibling call detection,
fallthrough detection and relocation handling of weak symbols when the
toolchain strips section symbols"
* tag 'objtool_urgent_for_v5.18_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool: Fix code relocs vs weak symbols
objtool: Fix type of reloc::addend
objtool: Fix function fallthrough detection for vmlinux
objtool: Fix sibling call detection in alternatives
objtool: Don't set 'jump_dest' for sibling calls
x86/uaccess: Don't jump between functions
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csum_and_copy_from_user and csum_and_copy_to_user are exported by a few
architectures, but not actually used in modular code. Drop the exports.
Link: https://lkml.kernel.org/r/20220421070440.1282704-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The first "if" condition in __memcpy_flushcache is supposed to align the
"dest" variable to 8 bytes and copy data up to this alignment. However,
this condition may misbehave if "size" is greater than 4GiB.
The statement min_t(unsigned, size, ALIGN(dest, 8) - dest); casts both
arguments to unsigned int and selects the smaller one. However, the
cast truncates high bits in "size" and it results in misbehavior.
For example:
suppose that size == 0x100000001, dest == 0x200000002
min_t(unsigned, size, ALIGN(dest, 8) - dest) == min_t(0x1, 0xe) == 0x1;
...
dest += 0x1;
so we copy just one byte "and" dest remains unaligned.
This patch fixes the bug by replacing unsigned with size_t.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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For unwinding sanity, a function shouldn't jump to the middle of another
function. Move the short string user copy code out to a separate
non-function code snippet.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/9519e4853148b765e047967708f2b61e56c93186.1649718562.git.jpoimboe@redhat.com
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The __put_user_nocheck*() inner labels are exported, so in keeping with
the "allow exported functions to be indirectly called" policy, add
ENDBR.
Fixes: ed53a0d97192 ("x86/alternative: Use .ibt_endbr_seal to seal indirect calls")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/207f02177a23031091d1a608de6049a9e5e8ff80.1650300597.git.jpoimboe@redhat.com
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The retpolines are exported, so they're referenced by ksymtab sections.
But they're never indirect-branched to, so add ANNOTATE_NOENDBR.
Fixes: ed53a0d97192 ("x86/alternative: Use .ibt_endbr_seal to seal indirect calls")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/b6ec963dfd9301b6b1d74ef7758fcb0b540d6c6c.1650300597.git.jpoimboe@redhat.com
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GS is always a user segment now.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220325153953.162643-4-brgerst@gmail.com
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lib/kaslr.c is used by both the main kernel and the boot stub. It
includes asm/io.h which is supposed to be used in the main kernel. It
leads to build warnings like this with clang 13:
warning: implicit declaration of function 'outl' is invalid in C99 [-Wimplicit-function-declaration]
Replace <asm/io.h> with <asm/shared/io.h> which is suitable for both
cases.
Fixes: 1e8f93e18379 ("x86: Consolidate port I/O helpers")
Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220410200025.3stf4jjvwfe5oxew@box.shutemov.name
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The asm constraint does not reflect the fact that the asm statement can
modify the value of the local variable loops. Which it does.
Specifying the wrong constraint may lead to undefined behavior, it may
clobber random stuff (e.g. local variable, important temporary value in
regs, etc.). This is especially dangerous when the compiler decides to
inline the function and since it doesn't know that the value gets
modified, it might decide to use it from a register directly without
reloading it.
Change the constraint to "+a" to denote that the first argument is an
input and an output argument.
[ bp: Fix typo, massage commit message. ]
Fixes: e01b70ef3eb3 ("x86: fix bug in arch/i386/lib/delay.c file, delay_loop function")
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220329104705.65256-2-ammarfaizi2@gnuweeb.org
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
"A set of x86 fixes and updates:
- Make the prctl() for enabling dynamic XSTATE components correct so
it adds the newly requested feature to the permission bitmap
instead of overwriting it. Add a selftest which validates that.
- Unroll string MMIO for encrypted SEV guests as the hypervisor
cannot emulate it.
- Handle supervisor states correctly in the FPU/XSTATE code so it
takes the feature set of the fpstate buffer into account. The
feature sets can differ between host and guest buffers. Guest
buffers do not contain supervisor states. So far this was not an
issue, but with enabling PASID it needs to be handled in the buffer
offset calculation and in the permission bitmaps.
- Avoid a gazillion of repeated CPUID invocations in by caching the
values early in the FPU/XSTATE code.
- Enable CONFIG_WERROR in x86 defconfig.
- Make the X86 defconfigs more useful by adapting them to Y2022
reality"
* tag 'x86-urgent-2022-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fpu/xstate: Consolidate size calculations
x86/fpu/xstate: Handle supervisor states in XSTATE permissions
x86/fpu/xsave: Handle compacted offsets correctly with supervisor states
x86/fpu: Cache xfeature flags from CPUID
x86/fpu/xsave: Initialize offset/size cache early
x86/fpu: Remove unused supervisor only offsets
x86/fpu: Remove redundant XCOMP_BV initialization
x86/sev: Unroll string mmio with CC_ATTR_GUEST_UNROLL_STRING_IO
x86/config: Make the x86 defconfigs a bit more usable
x86/defconfig: Enable WERROR
selftests/x86/amx: Update the ARCH_REQ_XCOMP_PERM test
x86/fpu/xstate: Fix the ARCH_REQ_XCOMP_PERM implementation
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
"Assorted bits and pieces"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
aio: drop needless assignment in aio_read()
clean overflow checks in count_mounts() a bit
seq_file: fix NULL pointer arithmetic warning
uml/x86: use x86 load_unaligned_zeropad()
asm/user.h: killed unused macros
constify struct path argument of finish_automount()/do_add_mount()
fs: Remove FIXME comment in generic_write_checks()
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The io-specific memcpy/memset functions use string mmio accesses to do
their work. Under SEV, the hypervisor can't emulate these instructions
because they read/write directly from/to encrypted memory.
KVM will inject a page fault exception into the guest when it is asked
to emulate string mmio instructions for an SEV guest:
BUG: unable to handle page fault for address: ffffc90000065068
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 8000100000067 P4D 8000100000067 PUD 80001000fb067 PMD 80001000fc067 PTE 80000000fed40173
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.0-rc7 #3
As string mmio for an SEV guest can not be supported by the
hypervisor, unroll the instructions for CC_ATTR_GUEST_UNROLL_STRING_IO
enabled kernels.
This issue appears when kernels are launched in recent libvirt-managed
SEV virtual machines, because virt-install started to add a tpm-crb
device to the guest by default and proactively because, raisins:
https://github.com/virt-manager/virt-manager/commit/eb58c09f488b0633ed1eea012cd311e48864401e
and as that commit says, the default adding of a TPM can be disabled
with "virt-install ... --tpm none".
The kernel driver for tpm-crb uses memcpy_to/from_io() functions to
access MMIO memory, resulting in a page-fault injected by KVM and
crashing the kernel at boot.
[ bp: Massage and extend commit message. ]
Fixes: d8aa7eea78a1 ('x86/mm: Add Secure Encrypted Virtualization (SEV) support')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220321093351.23976-1-joro@8bytes.org
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 CET-IBT (Control-Flow-Integrity) support from Peter Zijlstra:
"Add support for Intel CET-IBT, available since Tigerlake (11th gen),
which is a coarse grained, hardware based, forward edge
Control-Flow-Integrity mechanism where any indirect CALL/JMP must
target an ENDBR instruction or suffer #CP.
Additionally, since Alderlake (12th gen)/Sapphire-Rapids, speculation
is limited to 2 instructions (and typically fewer) on branch targets
not starting with ENDBR. CET-IBT also limits speculation of the next
sequential instruction after the indirect CALL/JMP [1].
CET-IBT is fundamentally incompatible with retpolines, but provides,
as described above, speculation limits itself"
[1] https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/branch-history-injection.html
* tag 'x86_core_for_5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
kvm/emulate: Fix SETcc emulation for ENDBR
x86/Kconfig: Only allow CONFIG_X86_KERNEL_IBT with ld.lld >= 14.0.0
x86/Kconfig: Only enable CONFIG_CC_HAS_IBT for clang >= 14.0.0
kbuild: Fixup the IBT kbuild changes
x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy
x86: Remove toolchain check for X32 ABI capability
x86/alternative: Use .ibt_endbr_seal to seal indirect calls
objtool: Find unused ENDBR instructions
objtool: Validate IBT assumptions
objtool: Add IBT/ENDBR decoding
objtool: Read the NOENDBR annotation
x86: Annotate idtentry_df()
x86,objtool: Move the ASM_REACHABLE annotation to objtool.h
x86: Annotate call_on_stack()
objtool: Rework ASM_REACHABLE
x86: Mark __invalid_creds() __noreturn
exit: Mark do_group_exit() __noreturn
x86: Mark stop_this_cpu() __noreturn
objtool: Ignore extra-symbol code
objtool: Rename --duplicate to --lto
...
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull FORTIFY_SOURCE updates from Kees Cook:
"This series consists of two halves:
- strict compile-time buffer size checking under FORTIFY_SOURCE for
the memcpy()-family of functions (for extensive details and
rationale, see the first commit)
- enabling FORTIFY_SOURCE for Clang, which has had many overlapping
bugs that we've finally worked past"
* tag 'memcpy-v5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
fortify: Add Clang support
fortify: Make sure strlen() may still be used as a constant expression
fortify: Use __diagnose_as() for better diagnostic coverage
fortify: Make pointer arguments const
Compiler Attributes: Add __diagnose_as for Clang
Compiler Attributes: Add __overloadable for Clang
Compiler Attributes: Add __pass_object_size for Clang
fortify: Replace open-coded __gnu_inline attribute
fortify: Update compile-time tests for Clang 14
fortify: Detect struct member overflows in memset() at compile-time
fortify: Detect struct member overflows in memmove() at compile-time
fortify: Detect struct member overflows in memcpy() at compile-time
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