Commit graph

203,602 commits

Author SHA1 Message Date
Greg Kroah-Hartman
dd5f2ef16e x86: fix backwards merge of GDS/SRSO bit
Stable-tree-only change.

Due to the way the GDS and SRSO patches flowed into the stable tree, it
was a 50% chance that the merge of the which value GDS and SRSO should
be.  Of course, I lost that bet, and chose the opposite of what Linus
chose in commit 64094e7e31 ("Merge tag 'gds-for-linus-2023-08-01' of
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")

Fix this up by switching the values to match what is now in Linus's tree
as that is the correct value to mirror.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:51 +02:00
Borislav Petkov (AMD)
4f25355540 x86/srso: Tie SBPB bit setting to microcode patch detection
commit 5a15d83488 upstream.

The SBPB bit in MSR_IA32_PRED_CMD is supported only after a microcode
patch has been applied so set X86_FEATURE_SBPB only then. Otherwise,
guests would attempt to set that bit and #GP on the MSR write.

While at it, make SMT detection more robust as some guests - depending
on how and what CPUID leafs their report - lead to cpu_smt_control
getting set to CPU_SMT_NOT_SUPPORTED but SRSO_NO should be set for any
guest incarnation where one simply cannot do SMT, for whatever reason.

Fixes: fb3bd914b3 ("x86/srso: Add a Speculative RAS Overflow mitigation")
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:51 +02:00
Borislav Petkov (AMD)
77cf32d0db x86/srso: Add a forgotten NOENDBR annotation
Upstream commit: 3bbbe97ad8

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>
2023-08-08 20:03:51 +02:00
Josh Poimboeuf
c7f2cd0455 x86/srso: Fix return thunks in generated code
Upstream commit: 238ec850b9

Set X86_FEATURE_RETHUNK when enabling the SRSO mitigation so that
generated code (e.g., ftrace, static call, eBPF) generates "jmp
__x86_return_thunk" instead of RET.

  [ bp: Add a comment. ]

Fixes: fb3bd914b3 ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:51 +02:00
Borislav Petkov (AMD)
c9ae63d773 x86/srso: Add IBPB on VMEXIT
Upstream commit: d893832d0e

Add the option to flush IBPB only on VMEXIT in order to protect from
malicious guests but one otherwise trusts the software that runs on the
hypervisor.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
79c8091888 x86/srso: Add IBPB
Upstream commit: 233d6f68b9

Add the option to mitigate using IBPB on a kernel entry. Pull in the
Retbleed alternative so that the IBPB call from there can be used. Also,
if Retbleed mitigation is done using IBPB, the same mitigation can and
must be used here.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
98f62883e7 x86/srso: Add SRSO_NO support
Upstream commit: 1b5277c0ea

Add support for the CPUID flag which denotes that the CPU is not
affected by SRSO.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
9139f4b6dd x86/srso: Add IBPB_BRTYPE support
Upstream commit: 79113e4060

Add support for the synthetic CPUID flag which "if this bit is 1,
it indicates that MSR 49h (PRED_CMD) bit 0 (IBPB) flushes all branch
type predictions from the CPU branch predictor."

This flag is there so that this capability in guests can be detected
easily (otherwise one would have to track microcode revisions which is
impossible for guests).

It is also needed only for Zen3 and -4. The other two (Zen1 and -2)
always flush branch type predictions by default.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
ac41e90d8d x86/srso: Add a Speculative RAS Overflow mitigation
Upstream commit: fb3bd914b3

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>
2023-08-08 20:03:50 +02:00
Kim Phillips
dec3b91f2c x86/cpu, kvm: Add support for CPUID_80000021_EAX
commit 8415a74852 upstream.

Add support for CPUID leaf 80000021, EAX. The majority of the features will be
used in the kernel and thus a separate leaf is appropriate.

Include KVM's reverse_cpuid entry because features are used by VM guests, too.

  [ bp: Massage commit message. ]

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-2-kim.phillips@amd.com
[bwh: Backported to 6.1: adjust context]
Signed-off-by: Ben Hutchings <benh@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Borislav Petkov (AMD)
dfede4cb8e x86/bugs: Increase the x86 bugs vector size to two u32s
Upstream commit: 0e52740ffd

There was never a doubt in my mind that they would not fit into a single
u32 eventually.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:50 +02:00
Peter Zijlstra
9ae15aaff3 x86/mm: Use mm_alloc() in poking_init()
commit 3f4c8211d9 upstream.

Instead of duplicating init_mm, allocate a fresh mm. The advantage is
that mm_alloc() has much simpler dependencies. Additionally it makes
more conceptual sense, init_mm has no (and must not have) user state
to duplicate.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221025201057.816175235@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:49 +02:00
Juergen Gross
d972c8c08f x86/mm: fix poking_init() for Xen PV guests
commit 26ce6ec364 upstream.

Commit 3f4c8211d9 ("x86/mm: Use mm_alloc() in poking_init()") broke
the kernel for running as Xen PV guest.

It seems as if the new address space is never activated before being
used, resulting in Xen rejecting to accept the new CR3 value (the PGD
isn't pinned).

Fix that by adding the now missing call of paravirt_arch_dup_mmap() to
poking_init(). That call was previously done by dup_mm()->dup_mmap() and
it is a NOP for all cases but for Xen PV, where it is just doing the
pinning of the PGD.

Fixes: 3f4c8211d9 ("x86/mm: Use mm_alloc() in poking_init()")
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230109150922.10578-1-jgross@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:49 +02:00
Juergen Gross
7f3982de36 x86/xen: Fix secondary processors' FPU initialization
commit fe3e0a13e5 upstream.

Moving the call of fpu__init_cpu() from cpu_init() to start_secondary()
broke Xen PV guests, as those don't call start_secondary() for APs.

Call fpu__init_cpu() in Xen's cpu_bringup(), which is the Xen PV
replacement of start_secondary().

Fixes: b81fac906a ("x86/fpu: Move FPU initialization into arch_cpu_finalize_init()")
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230703130032.22916-1-jgross@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:49 +02:00
Thomas Gleixner
baa7b7501e x86/mem_encrypt: Unbreak the AMD_MEM_ENCRYPT=n build
commit 0a9567ac5e upstream.

Moving mem_encrypt_init() broke the AMD_MEM_ENCRYPT=n because the
declaration of that function was under #ifdef CONFIG_AMD_MEM_ENCRYPT and
the obvious placement for the inline stub was the #else path.

This is a leftover of commit 20f07a044a ("x86/sev: Move common memory
encryption code to mem_encrypt.c") which made mem_encrypt_init() depend on
X86_MEM_ENCRYPT without moving the prototype. That did not fail back then
because there was no stub inline as the core init code had a weak function.

Move both the declaration and the stub out of the CONFIG_AMD_MEM_ENCRYPT
section and guard it with CONFIG_X86_MEM_ENCRYPT.

Fixes: 439e17576e ("init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Closes: https://lore.kernel.org/oe-kbuild-all/202306170247.eQtCJPE8-lkp@intel.com/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:49 +02:00
Daniel Sneddon
b6fd07c41b KVM: Add GDS_NO support to KVM
commit 81ac7e5d74 upstream

Gather Data Sampling (GDS) is a transient execution attack using
gather instructions from the AVX2 and AVX512 extensions. This attack
allows malicious code to infer data that was previously stored in
vector registers. Systems that are not vulnerable to GDS will set the
GDS_NO bit of the IA32_ARCH_CAPABILITIES MSR. This is useful for VM
guests that may think they are on vulnerable systems that are, in
fact, not affected. Guests that are running on affected hosts where
the mitigation is enabled are protected as if they were running
on an unaffected system.

On all hosts that are not affected or that are mitigated, set the
GDS_NO bit.

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Daniel Sneddon
c04579e954 x86/speculation: Add Kconfig option for GDS
commit 53cf5797f1 upstream

Gather Data Sampling (GDS) is mitigated in microcode. However, on
systems that haven't received the updated microcode, disabling AVX
can act as a mitigation. Add a Kconfig option that uses the microcode
mitigation if available and disables AVX otherwise. Setting this
option has no effect on systems not affected by GDS. This is the
equivalent of setting gather_data_sampling=force.

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Daniel Sneddon
92fc27c79b x86/speculation: Add force option to GDS mitigation
commit 553a5c03e9 upstream

The Gather Data Sampling (GDS) vulnerability allows malicious software
to infer stale data previously stored in vector registers. This may
include sensitive data such as cryptographic keys. GDS is mitigated in
microcode, and systems with up-to-date microcode are protected by
default. However, any affected system that is running with older
microcode will still be vulnerable to GDS attacks.

Since the gather instructions used by the attacker are part of the
AVX2 and AVX512 extensions, disabling these extensions prevents gather
instructions from being executed, thereby mitigating the system from
GDS. Disabling AVX2 is sufficient, but we don't have the granularity
to do this. The XCR0[2] disables AVX, with no option to just disable
AVX2.

Add a kernel parameter gather_data_sampling=force that will enable the
microcode mitigation if available, otherwise it will disable AVX on
affected systems.

This option will be ignored if cmdline mitigations=off.

This is a *big* hammer.  It is known to break buggy userspace that
uses incomplete, buggy AVX enumeration.  Unfortunately, such userspace
does exist in the wild:

	https://www.mail-archive.com/bug-coreutils@gnu.org/msg33046.html

[ dhansen: add some more ominous warnings about disabling AVX ]

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Daniel Sneddon
c66ebe070d x86/speculation: Add Gather Data Sampling mitigation
commit 8974eb5882 upstream

Gather Data Sampling (GDS) is a hardware vulnerability which allows
unprivileged speculative access to data which was previously stored in
vector registers.

Intel processors that support AVX2 and AVX512 have gather instructions
that fetch non-contiguous data elements from memory. On vulnerable
hardware, when a gather instruction is transiently executed and
encounters a fault, stale data from architectural or internal vector
registers may get transiently stored to the destination vector
register allowing an attacker to infer the stale data using typical
side channel techniques like cache timing attacks.

This mitigation is different from many earlier ones for two reasons.
First, it is enabled by default and a bit must be set to *DISABLE* it.
This is the opposite of normal mitigation polarity. This means GDS can
be mitigated simply by updating microcode and leaving the new control
bit alone.

Second, GDS has a "lock" bit. This lock bit is there because the
mitigation affects the hardware security features KeyLocker and SGX.
It needs to be enabled and *STAY* enabled for these features to be
mitigated against GDS.

The mitigation is enabled in the microcode by default. Disable it by
setting gather_data_sampling=off or by disabling all mitigations with
mitigations=off. The mitigation status can be checked by reading:

    /sys/devices/system/cpu/vulnerabilities/gather_data_sampling

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Thomas Gleixner
f25ad76d92 x86/fpu: Move FPU initialization into arch_cpu_finalize_init()
commit b81fac906a upstream

Initializing the FPU during the early boot process is a pointless
exercise. Early boot is convoluted and fragile enough.

Nothing requires that the FPU is set up early. It has to be initialized
before fork_init() because the task_struct size depends on the FPU register
buffer size.

Move the initialization to arch_cpu_finalize_init() which is the perfect
place to do so.

No functional change.

This allows to remove quite some of the custom early command line parsing,
but that's subject to the next installment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.902376621@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Thomas Gleixner
e26932942b x86/fpu: Mark init functions __init
commit 1703db2b90 upstream

No point in keeping them around.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.841685728@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Thomas Gleixner
9e8d9d3990 x86/fpu: Remove cpuinfo argument from init functions
commit 1f34bb2a24 upstream

Nothing in the call chain requires it

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.783704297@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:48 +02:00
Thomas Gleixner
c956807d84 x86/init: Initialize signal frame size late
commit 54d9a91a3d upstream

No point in doing this during really early boot. Move it to an early
initcall so that it is set up before possible user mode helpers are started
during device initialization.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.727330699@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:47 +02:00
Thomas Gleixner
b0837880fa init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init()
commit 439e17576e upstream

Invoke the X86ism mem_encrypt_init() from X86 arch_cpu_finalize_init() and
remove the weak fallback from the core code.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.670360645@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:47 +02:00
Thomas Gleixner
a3342c60dc init: Remove check_bugs() leftovers
commit 61235b24b9 upstream

Everything is converted over to arch_cpu_finalize_init(). Remove the
check_bugs() leftovers including the empty stubs in asm-generic, alpha,
parisc, powerpc and xtensa.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Link: https://lore.kernel.org/r/20230613224545.553215951@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:47 +02:00
Thomas Gleixner
8beabde0ed um/cpu: Switch to arch_cpu_finalize_init()
commit 9349b5cd09 upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Richard Weinberger <richard@nod.at>
Link: https://lore.kernel.org/r/20230613224545.493148694@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:47 +02:00
Thomas Gleixner
ce97072e10 sparc/cpu: Switch to arch_cpu_finalize_init()
commit 44ade508e3 upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://lore.kernel.org/r/20230613224545.431995857@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:47 +02:00
Thomas Gleixner
84f585542e sh/cpu: Switch to arch_cpu_finalize_init()
commit 01eb454e9b upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.371697797@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:47 +02:00
Thomas Gleixner
6a90583dbd mips/cpu: Switch to arch_cpu_finalize_init()
commit 7f066a22fe upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.312438573@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:47 +02:00
Thomas Gleixner
489ae02c89 m68k/cpu: Switch to arch_cpu_finalize_init()
commit 9ceecc2589 upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230613224545.254342916@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:46 +02:00
Thomas Gleixner
08e86d42e2 loongarch/cpu: Switch to arch_cpu_finalize_init()
commit 9841c42316 upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.195288218@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:46 +02:00
Thomas Gleixner
403e4cc67e ia64/cpu: Switch to arch_cpu_finalize_init()
commit 6c38e30056 upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.137045745@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:46 +02:00
Thomas Gleixner
e2e06240ae ARM: cpu: Switch to arch_cpu_finalize_init()
commit ee31bb0524 upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.078124882@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:46 +02:00
Thomas Gleixner
7918a3555a x86/cpu: Switch to arch_cpu_finalize_init()
commit 7c7077a726 upstream

check_bugs() is a dumping ground for finalizing the CPU bringup. Only parts of
it has to do with actual CPU bugs.

Split it apart into arch_cpu_finalize_init() and cpu_select_mitigations().

Fixup the bogus 32bit comments while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230613224545.019583869@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:46 +02:00
Thomas Gleixner
d5501f2ff8 init: Provide arch_cpu_finalize_init()
commit 7725acaa4f upstream

check_bugs() has become a dumping ground for all sorts of activities to
finalize the CPU initialization before running the rest of the init code.

Most are empty, a few do actual bug checks, some do alternative patching
and some cobble a CPU advertisement string together....

Aside of that the current implementation requires duplicated function
declaration and mostly empty header files for them.

Provide a new function arch_cpu_finalize_init(). Provide a generic
declaration if CONFIG_ARCH_HAS_CPU_FINALIZE_INIT is selected and a stub
inline otherwise.

This requires a temporary #ifdef in start_kernel() which will be removed
along with check_bugs() once the architectures are converted over.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224544.957805717@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-08 20:03:46 +02:00
Mark Brown
356e711640 arm64/sme: Set new vector length before reallocating
commit 05d881b85b upstream.

As part of fixing the allocation of the buffer for SVE state when changing
SME vector length we introduced an immediate reallocation of the SVE state,
this is also done when changing the SVE vector length for consistency.
Unfortunately this reallocation is done prior to writing the new vector
length to the task struct, meaning the allocation is done with the old
vector length and can lead to memory corruption due to an undersized buffer
being used.

Move the update of the vector length before the allocation to ensure that
the new vector length is taken into account.

For some reason this isn't triggering any problems when running tests on
the arm64 fixes branch (even after repeated tries) but is triggering
issues very often after merge into mainline.

Fixes: d4d5be94a8 ("arm64/fpsimd: Ensure SME storage is allocated after SVE VL changes")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20230726-arm64-fix-sme-fix-v1-1-7752ec58af27@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-03 10:24:16 +02:00
Chenguang Zhao
2b58bd3847 LoongArch: BPF: Enable bpf_probe_read{, str}() on LoongArch
commit de0e30bee8 upstream.

Currently nettrace does not work on LoongArch due to missing
bpf_probe_read{,str}() support, with the error message:

     ERROR: failed to load kprobe-based eBPF
     ERROR: failed to load kprobe-based bpf

According to commit 0ebeea8ca8 ("bpf: Restrict bpf_probe_read{,
str}() only to archs where they work"), we only need to select
CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE to add said support,
because LoongArch does have non-overlapping address ranges for kernel
and userspace.

Cc: stable@vger.kernel.org # 6.1
Signed-off-by: Chenguang Zhao <zhaochenguang@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-03 10:24:16 +02:00
Tiezhu Yang
8a5e0c1f71 LoongArch: BPF: Fix check condition to call lu32id in move_imm()
commit 4eece7e6de upstream.

As the code comment says, the initial aim is to reduce one instruction
in some corner cases, if bit[51:31] is all 0 or all 1, no need to call
lu32id. That is to say, it should call lu32id only if bit[51:31] is not
all 0 and not all 1. The current code always call lu32id, the result is
right but the logic is unexpected and wrong, fix it.

Cc: stable@vger.kernel.org # 6.1
Fixes: 5dc615520c ("LoongArch: Add BPF JIT support")
Reported-by: Colin King (gmail) <colin.i.king@gmail.com>
Closes: https://lore.kernel.org/all/bcf97046-e336-712a-ac68-7fd194f2953e@gmail.com/
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-03 10:24:15 +02:00
Andy Shevchenko
024ed3b9b8 Revert "um: Use swap() to make code cleaner"
commit dddfa05eb5 upstream.

This reverts commit 9b0da3f223.

The sigio.c is clearly user space code which is handled by
arch/um/scripts/Makefile.rules (see USER_OBJS rule).

The above mentioned commit simply broke this agreement,
we may not use Linux kernel internal headers in them without
thorough thinking.

Hence, revert the wrong commit.

Link: https://lkml.kernel.org/r/20230724143131.30090-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202307212304.cH79zJp1-lkp@intel.com/
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Herve Codina <herve.codina@bootlin.com>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Richard Weinberger <richard@nod.at>
Cc: Yang Guang <yang.guang5@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-03 10:24:15 +02:00
Yazen Ghannam
2663e2cb91 x86/MCE/AMD: Decrement threshold_bank refcount when removing threshold blocks
commit 3ba2e83334 upstream.

AMD systems from Family 10h to 16h share MCA bank 4 across multiple CPUs.
Therefore, the threshold_bank structure for bank 4, and its threshold_block
structures, will be initialized once at boot time. And the kobject for the
shared bank will be added to each of the CPUs that share it. Furthermore,
the threshold_blocks for the shared bank will be added again to the bank's
kobject. These additions will increase the refcount for the bank's kobject.

For example, a shared bank with two blocks and shared across two CPUs will
be set up like this:

  CPU0 init
    bank create and add; bank refcount = 1; threshold_create_bank()
      block 0 init and add; bank refcount = 2; allocate_threshold_blocks()
      block 1 init and add; bank refcount = 3; allocate_threshold_blocks()
  CPU1 init
    bank add; bank refcount = 3; threshold_create_bank()
      block 0 add; bank refcount = 4; __threshold_add_blocks()
      block 1 add; bank refcount = 5; __threshold_add_blocks()

Currently in threshold_remove_bank(), if the bank is shared then
__threshold_remove_blocks() is called. Here the shared bank's kobject and
the bank's blocks' kobjects are deleted. This is done on the first call
even while the structures are still shared. Subsequent calls from other
CPUs that share the structures will attempt to delete the kobjects.

During kobject_del(), kobject->sd is removed. If the kobject is not part of
a kset with default_groups, then subsequent kobject_del() calls seem safe
even with kobject->sd == NULL.

Originally, the AMD MCA thresholding structures did not use default_groups.
And so the above behavior was not apparent.

However, a recent change implemented default_groups for the thresholding
structures. Therefore, kobject_del() will go down the sysfs_remove_groups()
code path. In this case, the first kobject_del() may succeed and remove
kobject->sd. But subsequent kobject_del() calls will give a WARNing in
kernfs_remove_by_name_ns() since kobject->sd == NULL.

Use kobject_put() on the shared bank's kobject when "removing" blocks. This
decrements the bank's refcount while keeping kobjects enabled until the
bank is no longer shared. At that point, kobject_put() will be called on
the blocks which drives their refcount to 0 and deletes them and also
decrementing the bank's refcount. And finally kobject_put() will be called
on the bank driving its refcount to 0 and deleting it.

The same example above:

  CPU1 shutdown
    bank is shared; bank refcount = 5; threshold_remove_bank()
      block 0 put parent bank; bank refcount = 4; __threshold_remove_blocks()
      block 1 put parent bank; bank refcount = 3; __threshold_remove_blocks()
  CPU0 shutdown
    bank is no longer shared; bank refcount = 3; threshold_remove_bank()
      block 0 put block; bank refcount = 2; deallocate_threshold_blocks()
      block 1 put block; bank refcount = 1; deallocate_threshold_blocks()
    put bank; bank refcount = 0; threshold_remove_bank()

Fixes: 7f99cb5e60 ("x86/CPU/AMD: Use default_groups in kobj_type")
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/alpine.LRH.2.02.2205301145540.25840@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-03 10:24:13 +02:00
Sean Christopherson
eb1a542824 KVM: x86: Disallow KVM_SET_SREGS{2} if incoming CR0 is invalid
commit 26a0652cb4 upstream.

Reject KVM_SET_SREGS{2} with -EINVAL if the incoming CR0 is invalid,
e.g. due to setting bits 63:32, illegal combinations, or to a value that
isn't allowed in VMX (non-)root mode.  The VMX checks in particular are
"fun" as failure to disallow Real Mode for an L2 that is configured with
unrestricted guest disabled, when KVM itself has unrestricted guest
enabled, will result in KVM forcing VM86 mode to virtual Real Mode for
L2, but then fail to unwind the related metadata when synthesizing a
nested VM-Exit back to L1 (which has unrestricted guest enabled).

Opportunistically fix a benign typo in the prototype for is_valid_cr4().

Cc: stable@vger.kernel.org
Reported-by: syzbot+5feef0b9ee9c8e9e5689@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000f316b705fdf6e2b4@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230613203037.1968489-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-03 10:24:08 +02:00
Sean Christopherson
d8eb0c480f KVM: VMX: Don't fudge CR0 and CR4 for restricted L2 guest
commit c4abd73520 upstream.

Stuff CR0 and/or CR4 to be compliant with a restricted guest if and only
if KVM itself is not configured to utilize unrestricted guests, i.e. don't
stuff CR0/CR4 for a restricted L2 that is running as the guest of an
unrestricted L1.  Any attempt to VM-Enter a restricted guest with invalid
CR0/CR4 values should fail, i.e. in a nested scenario, KVM (as L0) should
never observe a restricted L2 with incompatible CR0/CR4, since nested
VM-Enter from L1 should have failed.

And if KVM does observe an active, restricted L2 with incompatible state,
e.g. due to a KVM bug, fudging CR0/CR4 instead of letting VM-Enter fail
does more harm than good, as KVM will often neglect to undo the side
effects, e.g. won't clear rmode.vm86_active on nested VM-Exit, and thus
the damage can easily spill over to L1.  On the other hand, letting
VM-Enter fail due to bad guest state is more likely to contain the damage
to L2 as KVM relies on hardware to perform most guest state consistency
checks, i.e. KVM needs to be able to reflect a failed nested VM-Enter into
L1 irrespective of (un)restricted guest behavior.

Cc: Jim Mattson <jmattson@google.com>
Cc: stable@vger.kernel.org
Fixes: bddd82d19e ("KVM: nVMX: KVM needs to unset "unrestricted guest" VM-execution control in vmcs02 if vmcs12 doesn't set it")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230613203037.1968489-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-03 10:24:08 +02:00
Kirill A. Shutemov
1ecdbf2467 x86/traps: Fix load_unaligned_zeropad() handling for shared TDX memory
[ Upstream commit 9f91164061 ]

Commit c4e34dd99f ("x86: simplify load_unaligned_zeropad()
implementation") changes how exceptions around load_unaligned_zeropad()
handled.  The kernel now uses the fault_address in fixup_exception() to
verify the address calculations for the load_unaligned_zeropad().

It works fine for #PF, but breaks on #VE since no fault address is
passed down to fixup_exception().

Propagating ve_info.gla down to fixup_exception() resolves the issue.

See commit 1e7769653b ("x86/tdx: Handle load_unaligned_zeropad()
page-cross to a shared page") for more context.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Michael Kelley <mikelley@microsoft.com>
Fixes: c4e34dd99f ("x86: simplify load_unaligned_zeropad() implementation")
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:24:01 +02:00
Oliver Upton
cde7f2fd63 arm64: errata: Mitigate Ampere1 erratum AC03_CPU_38 at stage-2
[ Upstream commit 6df696cd9b ]

AmpereOne has an erratum in its implementation of FEAT_HAFDBS that
required disabling the feature on the design. This was done by reporting
the feature as not implemented in the ID register, although the
corresponding control bits were not actually RES0. This does not align
well with the requirements of the architecture, which mandates these
bits be RES0 if HAFDBS isn't implemented.

The kernel's use of stage-1 is unaffected, as the HA and HD bits are
only set if HAFDBS is detected in the ID register. KVM, on the other
hand, relies on the RES0 behavior at stage-2 to use the same value for
VTCR_EL2 on any cpu in the system. Mitigate the non-RES0 behavior by
leaving VTCR_EL2.HA clear on affected systems.

Cc: stable@vger.kernel.org
Cc: D Scott Phillips <scott@os.amperecomputing.com>
Cc: Darren Hart <darren@os.amperecomputing.com>
Acked-by: D Scott Phillips <scott@os.amperecomputing.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20230609220104.1836988-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:23:54 +02:00
Oliver Upton
eb1de0a234 KVM: arm64: Condition HW AF updates on config option
[ Upstream commit 1dfc3e9050 ]

As it currently stands, KVM makes use of FEAT_HAFDBS unconditionally.
Use of the feature in the rest of the kernel is guarded by an associated
Kconfig option.

Align KVM with the rest of the kernel and only enable VTCR_HA when
ARM64_HW_AFDBM is enabled. This can be helpful for testing changes to
the stage-2 access fault path on Armv8.1+ implementations.

Link: https://lore.kernel.org/r/20221202185156.696189-7-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Stable-dep-of: 6df696cd9b ("arm64: errata: Mitigate Ampere1 erratum AC03_CPU_38 at stage-2")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:23:54 +02:00
Huacai Chen
ecd9da1d05 MIPS: Loongson: Fix build error when make modules_install
[ Upstream commit 531b3d1195 ]

After commit 0e96ea5c3e ("MIPS: Loongson64: Clean up use of
cc-ifversion") we get a build error when make modules_install:

cc1: error: '-mloongson-mmi' must be used with '-mhard-float'

The reason is when make modules_install, 'call cc-option' doesn't work
in $(KBUILD_CFLAGS) of 'CHECKFLAGS'. Then there is no -mno-loongson-mmi
applied and -march=loongson3a enable MMI instructions.

To be detail, the error message comes from the CHECKFLAGS invocation of
$(CC) but it has no impact on the final result of make modules_install,
it is purely a cosmetic issue. The error occurs because cc-option is
defined in scripts/Makefile.compiler, which is not included in Makefile
when running 'make modules_install', as install targets are not supposed
to require the compiler; see commit 805b2e1d42 ("kbuild: include
Makefile.compiler only when compiler is needed"). As a result, the call
to check for '-mno-loongson-mmi' just never happens.

Fix this by partially reverting to the old logic, use 'call cc-option'
to conditionally apply -march=loongson3a and -march=mips64r2.

By the way, Loongson-2E/2F is also broken in commit 13ceb48bc1
("MIPS: Loongson2ef: Remove unnecessary {as,cc}-option calls") so fix it
together.

Fixes: 13ceb48bc1 ("MIPS: Loongson2ef: Remove unnecessary {as,cc}-option calls")
Fixes: 0e96ea5c3e ("MIPS: Loongson64: Clean up use of cc-ifversion")
Cc: stable@vger.kernel.org
Cc: Feiyang Chen <chenfeiyang@loongson.cn>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:23:50 +02:00
Jiaxun Yang
3fac9a39f8 MIPS: Loongson: Move arch cflags to MIPS top level Makefile
[ Upstream commit 194a835210 ]

Arch cflags should be independent to Platform.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Stable-dep-of: 531b3d1195 ("MIPS: Loongson: Fix build error when make modules_install")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:23:50 +02:00
Claudio Imbrenda
017f686bcb KVM: s390: pv: fix index value of replaced ASCE
[ Upstream commit c2fceb59bb ]

The index field of the struct page corresponding to a guest ASCE should
be 0. When replacing the ASCE in s390_replace_asce(), the index of the
new ASCE should also be set to 0.

Having the wrong index might lead to the wrong addresses being passed
around when notifying pte invalidations, and eventually to validity
intercepts (VM crash) if the prefix gets unmapped and the notifier gets
called with the wrong address.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Fixes: faa2f72cb3 ("KVM: s390: pv: leak the topmost page table when destroy fails")
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20230705111937.33472-3-imbrenda@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:23:48 +02:00
Haren Myneni
e8df129860 powerpc/pseries/vas: Hold mmap_mutex after mmap lock during window close
[ Upstream commit b59c9dc4d9 ]

Commit 8ef7b9e176 ("powerpc/pseries/vas: Close windows with DLPAR
core removal") unmaps the window paste address and issues HCALL to
close window in the hypervisor for migration or DLPAR core removal
events. So holds mmap_mutex and then mmap lock before unmap the
paste address. But if the user space issue mmap paste address at
the same time with the migration event, coproc_mmap() is called
after holding the mmap lock which can trigger deadlock when trying
to acquire mmap_mutex in coproc_mmap().

t1: mmap() call to mmap              t2: Migration event
    window paste address

do_mmap2()                           migration_store()
 ksys_mmap_pgoff()                    pseries_migrate_partition()
  vm_mmap_pgoff()                      vas_migration_handler()
    Acquire mmap lock                   reconfig_close_windows()
    do_mmap()                             lock mmap_mutex
     mmap_region()                        Acquire mmap lock
      call_mmap()                         //Wait for mmap lock
       coproc_mmap()                        unmap vma
         lock mmap_mutex                    update window status
         //wait for mmap_mutex            Release mmap lock
          mmap vma                        unlock mmap_mutex
          update window status
         unlock mmap_mutex
    ...
    Release mmap lock

Fix this deadlock issue by holding mmap lock first before mmap_mutex
in reconfig_close_windows().

Fixes: 8ef7b9e176 ("powerpc/pseries/vas: Close windows with DLPAR core removal")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230716100506.7833-1-haren@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:23:48 +02:00
Alexander Duyck
bb6ae775ff bpf, arm64: Fix BTI type used for freplace attached functions
[ Upstream commit a3f25d614b ]

When running an freplace attached bpf program on an arm64 system w were
seeing the following issue:
  Unhandled 64-bit el1h sync exception on CPU47, ESR 0x0000000036000003 -- BTI

After a bit of work to track it down I determined that what appeared to be
happening is that the 'bti c' at the start of the program was somehow being
reached after a 'br' instruction. Further digging pointed me toward the
fact that the function was attached via freplace. This in turn led me to
build_plt which I believe is invoking the long jump which is triggering
this error.

To resolve it we can replace the 'bti c' with 'bti jc' and add a comment
explaining why this has to be modified as such.

Fixes: b2ad54e153 ("bpf, arm64: Implement bpf_arch_text_poke() for arm64")
Signed-off-by: Alexander Duyck <alexanderduyck@fb.com>
Acked-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/168926677665.316237.9953845318337455525.stgit@ahduyck-xeon-server.home.arpa
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-27 08:50:44 +02:00