linux-stable.git/arch/x86/lib, branch linux-6.8.y

x86/insn: Add VEX versions of VPDPBUSD, VPDPBUSDS, VPDPWSSD and VPDPWSSDS

2024-05-30T07:49:46+00:00

[ Upstream commit b8000264348979b60dbe479255570a40e1b3a097 ]

The x86 instruction decoder is used not only for decoding kernel
instructions. It is also used by perf uprobes (user space probes) and by
perf tools Intel Processor Trace decoding. Consequently, it needs to
support instructions executed by user space also.

Intel Architecture Instruction Set Extensions and Future Features manual
number 319433-044 of May 2021, documented VEX versions of instructions
VPDPBUSD, VPDPBUSDS, VPDPWSSD and VPDPWSSDS, but the opcode map has them
listed as EVEX only.

Remove EVEX-only (ev) annotation from instructions VPDPBUSD, VPDPBUSDS,
VPDPWSSD and VPDPWSSDS, which allows them to be decoded with either a VEX
or EVEX prefix.

Fixes: 0153d98f2dd6 ("x86/insn: Add misc instructions to x86 instruction decoder")
Signed-off-by: Adrian Hunter 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20240502105853.5338-4-adrian.hunter@intel.com
Signed-off-by: Sasha Levin

x86/insn: Fix PUSH instruction in x86 instruction decoder opcode map

2024-05-30T07:49:46+00:00

[ Upstream commit 59162e0c11d7257cde15f907d19fefe26da66692 ]

The x86 instruction decoder is used not only for decoding kernel
instructions. It is also used by perf uprobes (user space probes) and by
perf tools Intel Processor Trace decoding. Consequently, it needs to
support instructions executed by user space also.

Opcode 0x68 PUSH instruction is currently defined as 64-bit operand size
only i.e. (d64). That was based on Intel SDM Opcode Map. However that is
contradicted by the Instruction Set Reference section for PUSH in the
same manual.

Remove 64-bit operand size only annotation from opcode 0x68 PUSH
instruction.

Example:

  $ cat pushw.s
  .global  _start
  .text
  _start:
          pushw   $0x1234
          mov     $0x1,%eax   # system call number (sys_exit)
          int     $0x80
  $ as -o pushw.o pushw.s
  $ ld -s -o pushw pushw.o
  $ objdump -d pushw | tail -4
  0000000000401000 <.text>:
    401000:       66 68 34 12             pushw  $0x1234
    401004:       b8 01 00 00 00          mov    $0x1,%eax
    401009:       cd 80                   int    $0x80
  $ perf record -e intel_pt//u ./pushw
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.014 MB perf.data ]

 Before:

  $ perf script --insn-trace=disasm
  Warning:
  1 instruction trace errors
           pushw   10349 [000] 10586.869237014:            401000 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw)           pushw $0x1234
           pushw   10349 [000] 10586.869237014:            401006 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw)           addb %al, (%rax)
           pushw   10349 [000] 10586.869237014:            401008 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw)           addb %cl, %ch
           pushw   10349 [000] 10586.869237014:            40100a [unknown] (/home/ahunter/git/misc/rtit-tests/pushw)           addb $0x2e, (%rax)
   instruction trace error type 1 time 10586.869237224 cpu 0 pid 10349 tid 10349 ip 0x40100d code 6: Trace doesn't match instruction

 After:

  $ perf script --insn-trace=disasm
             pushw   10349 [000] 10586.869237014:            401000 [unknown] (./pushw)           pushw $0x1234
             pushw   10349 [000] 10586.869237014:            401004 [unknown] (./pushw)           movl $1, %eax

Fixes: eb13296cfaf6 ("x86: Instruction decoder API")
Signed-off-by: Adrian Hunter 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20240502105853.5338-3-adrian.hunter@intel.com
Signed-off-by: Sasha Levin

x86/boot: Move mem_encrypt= parsing to the decompressor

2024-04-10T14:38:23+00:00

commit cd0d9d92c8bb46e77de62efd7df13069ddd61e7d upstream.

The early SME/SEV code parses the command line very early, in order to
decide whether or not memory encryption should be enabled, which needs
to occur even before the initial page tables are created.

This is problematic for a number of reasons:
- this early code runs from the 1:1 mapping provided by the decompressor
  or firmware, which uses a different translation than the one assumed by
  the linker, and so the code needs to be built in a special way;
- parsing external input while the entire kernel image is still mapped
  writable is a bad idea in general, and really does not belong in
  security minded code;
- the current code ignores the built-in command line entirely (although
  this appears to be the case for the entire decompressor)

Given that the decompressor/EFI stub is an intrinsic part of the x86
bootable kernel image, move the command line parsing there and out of
the core kernel. This removes the need to build lib/cmdline.o in a
special way, or to use RIP-relative LEA instructions in inline asm
blocks.

This involves a new xloadflag in the setup header to indicate
that mem_encrypt=on appeared on the kernel command line.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Borislav Petkov (AMD) 
Tested-by: Tom Lendacky 
Link: https://lore.kernel.org/r/20240227151907.387873-17-ardb+git@google.com
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Greg Kroah-Hartman

x86/retpoline: Add NOENDBR annotation to the SRSO dummy return thunk

2024-04-10T14:38:15+00:00

commit b377c66ae3509ccea596512d6afb4777711c4870 upstream.

srso_alias_untrain_ret() is special code, even if it is a dummy
which is called in the !SRSO case, so annotate it like its real
counterpart, to address the following objtool splat:

  vmlinux.o: warning: objtool: .export_symbol+0x2b290: data relocation to !ENDBR: srso_alias_untrain_ret+0x0

Fixes: 4535e1a4174c ("x86/bugs: Fix the SRSO mitigation on Zen3/4")
Signed-off-by: Borislav Petkov (AMD) 
Signed-off-by: Ingo Molnar 
Cc: Linus Torvalds 
Link: https://lore.kernel.org/r/20240405144637.17908-1-bp@kernel.org
Signed-off-by: Greg Kroah-Hartman

x86/retpoline: Do the necessary fixup to the Zen3/4 srso return thunk for !SRSO

2024-04-10T14:38:04+00:00

commit 0e110732473e14d6520e49d75d2c88ef7d46fe67 upstream.

The srso_alias_untrain_ret() dummy thunk in the !CONFIG_MITIGATION_SRSO
case is there only for the altenative in CALL_UNTRAIN_RET to have
a symbol to resolve.

However, testing with kernels which don't have CONFIG_MITIGATION_SRSO
enabled, leads to the warning in patch_return() to fire:

  missing return thunk: srso_alias_untrain_ret+0x0/0x10-0x0: eb 0e 66 66 2e
  WARNING: CPU: 0 PID: 0 at arch/x86/kernel/alternative.c:826 apply_returns (arch/x86/kernel/alternative.c:826

Put in a plain "ret" there so that gcc doesn't put a return thunk in
in its place which special and gets checked.

In addition:

  ERROR: modpost: "srso_alias_untrain_ret" [arch/x86/kvm/kvm-amd.ko] undefined!
  make[2]: *** [scripts/Makefile.modpost:145: Module.symvers] Chyba 1
  make[1]: *** [/usr/src/linux-6.8.3/Makefile:1873: modpost] Chyba 2
  make: *** [Makefile:240: __sub-make] Chyba 2

since !SRSO builds would use the dummy return thunk as reported by
petr.pisar@atlas.cz, https://bugzilla.kernel.org/show_bug.cgi?id=218679.

Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-lkp/202404020901.da75a60f-oliver.sang@intel.com
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/all/202404020901.da75a60f-oliver.sang@intel.com/
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

x86/bugs: Fix the SRSO mitigation on Zen3/4

2024-04-03T13:32:49+00:00

commit 4535e1a4174c4111d92c5a9a21e542d232e0fcaa upstream.

The original version of the mitigation would patch in the calls to the
untraining routines directly.  That is, the alternative() in UNTRAIN_RET
will patch in the CALL to srso_alias_untrain_ret() directly.

However, even if commit e7c25c441e9e ("x86/cpu: Cleanup the untrain
mess") meant well in trying to clean up the situation, due to micro-
architectural reasons, the untraining routine srso_alias_untrain_ret()
must be the target of a CALL instruction and not of a JMP instruction as
it is done now.

Reshuffle the alternative macros to accomplish that.

Fixes: e7c25c441e9e ("x86/cpu: Cleanup the untrain mess")
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Ingo Molnar 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

x86/lib: Revert to _ASM_EXTABLE_UA() for {get,put}_user() fixups

2024-01-29T10:40:41+00:00

During memory error injection test on kernels >= v6.4, the kernel panics
like below. However, this issue couldn't be reproduced on kernels <= v6.3.

  mce: [Hardware Error]: CPU 296: Machine Check Exception: f Bank 1: bd80000000100134
  mce: [Hardware Error]: RIP 10: {__get_user_nocheck_4+0x6/0x20}
  mce: [Hardware Error]: TSC 411a93533ed ADDR 346a8730040 MISC 86
  mce: [Hardware Error]: PROCESSOR 0:a06d0 TIME 1706000767 SOCKET 1 APIC 211 microcode 80001490
  mce: [Hardware Error]: Run the above through 'mcelog --ascii'
  mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel
  Kernel panic - not syncing: Fatal local machine check

The MCA code can recover from an in-kernel #MC if the fixup type is
EX_TYPE_UACCESS, explicitly indicating that the kernel is attempting to
access userspace memory. However, if the fixup type is EX_TYPE_DEFAULT
the only thing that is raised for an in-kernel #MC is a panic.

ex_handler_uaccess() would warn if users gave a non-canonical addresses
(with bit 63 clear) to {get, put}_user(), which was unexpected.

Therefore, commit

  b19b74bc99b1 ("x86/mm: Rework address range check in get_user() and put_user()")

replaced _ASM_EXTABLE_UA() with _ASM_EXTABLE() for {get, put}_user()
fixups. However, the new fixup type EX_TYPE_DEFAULT results in a panic.

Commit

  6014bc27561f ("x86-64: make access_ok() independent of LAM")

added the check gp_fault_address_ok() right before the WARN_ONCE() in
ex_handler_uaccess() to not warn about non-canonical user addresses due
to LAM.

With that in place, revert back to _ASM_EXTABLE_UA() for {get,put}_user()
exception fixups in order to be able to handle in-kernel MCEs correctly
again.

  [ bp: Massage commit message. ]

Fixes: b19b74bc99b1 ("x86/mm: Rework address range check in get_user() and put_user()")
Signed-off-by: Qiuxu Zhuo 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Kirill A. Shutemov 
Cc: 
Link: https://lore.kernel.org/r/20240129063842.61584-1-qiuxu.zhuo@intel.com

Merge tag 'header_cleanup-2024-01-10' of https://evilpiepirate.org/git/bcachefs

2024-01-11T00:43:55+00:00

Pull header cleanups from Kent Overstreet:
 "The goal is to get sched.h down to a type only header, so the main
  thing happening in this patchset is splitting out various _types.h
  headers and dependency fixups, as well as moving some things out of
  sched.h to better locations.

  This is prep work for the memory allocation profiling patchset which
  adds new sched.h interdepencencies"

* tag 'header_cleanup-2024-01-10' of https://evilpiepirate.org/git/bcachefs: (51 commits)
  Kill sched.h dependency on rcupdate.h
  kill unnecessary thread_info.h include
  Kill unnecessary kernel.h include
  preempt.h: Kill dependency on list.h
  rseq: Split out rseq.h from sched.h
  LoongArch: signal.c: add header file to fix build error
  restart_block: Trim includes
  lockdep: move held_lock to lockdep_types.h
  sem: Split out sem_types.h
  uidgid: Split out uidgid_types.h
  seccomp: Split out seccomp_types.h
  refcount: Split out refcount_types.h
  uapi/linux/resource.h: fix include
  x86/signal: kill dependency on time.h
  syscall_user_dispatch.h: split out *_types.h
  mm_types_task.h: Trim dependencies
  Split out irqflags_types.h
  ipc: Kill bogus dependency on spinlock.h
  shm: Slim down dependencies
  workqueue: Split out workqueue_types.h
  ...

Merge tag 'x86-cleanups-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-01-09T01:23:32+00:00

Pull x86 cleanups from Ingo Molnar:

 - Change global variables to local

 - Add missing kernel-doc function parameter descriptions

 - Remove unused parameter from a macro

 - Remove obsolete Kconfig entry

 - Fix comments

 - Fix typos, mostly scripted, manually reviewed

and a micro-optimization got misplaced as a cleanup:

 - Micro-optimize the asm code in secondary_startup_64_no_verify()

* tag 'x86-cleanups-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arch/x86: Fix typos
  x86/head_64: Use TESTB instead of TESTL in secondary_startup_64_no_verify()
  x86/docs: Remove reference to syscall trampoline in PTI
  x86/Kconfig: Remove obsolete config X86_32_SMP
  x86/io: Remove the unused 'bw' parameter from the BUILDIO() macro
  x86/mtrr: Document missing function parameters in kernel-doc
  x86/setup: Make relocated_ramdisk a local variable of relocate_initrd()

Merge tag 'x86_misc_for_v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-01-08T21:27:43+00:00

Pull misc x86 updates from Borislav Petkov:

 - Add an informational message which gets issued when IA32 emulation
   has been disabled on the cmdline

 - Clarify in detail how /proc/cpuinfo is used on x86

 - Fix a theoretical overflow in num_digits()

* tag 'x86_misc_for_v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ia32: State that IA32 emulation is disabled
  Documentation/x86: Document what /proc/cpuinfo is for
  x86/lib: Fix overflow when counting digits