kernel.git/arch/x86/kernel, branch linux-6.0.y

x86/bugs: Flush IBP in ib_prctl_set()

2023-01-12T11:00:45Z

commit a664ec9158eeddd75121d39c9a0758016097fa96 upstream. We missed the window between the TIF flag update and the next reschedule. Signed-off-by: Rodrigo Branco Reviewed-by: Borislav Petkov (AMD) Signed-off-by: Ingo Molnar Cc: Signed-off-by: Greg Kroah-Hartman

x86/kexec: Fix double-free of elf header buffer

2023-01-12T11:00:45Z

commit d00dd2f2645dca04cf399d8fc692f3f69b6dd996 upstream. After b3e34a47f989 ("x86/kexec: fix memory leak of elf header buffer"), freeing image->elf_headers in the error path of crash_load_segments() is not needed because kimage_file_post_load_cleanup() will take care of that later. And not clearing it could result in a double-free. Drop the superfluous vfree() call at the error path of crash_load_segments(). Fixes: b3e34a47f989 ("x86/kexec: fix memory leak of elf header buffer") Signed-off-by: Takashi Iwai Signed-off-by: Borislav Petkov (AMD) Acked-by: Baoquan He Acked-by: Vlastimil Babka Cc: Link: https://lore.kernel.org/r/20221122115122.13937-1-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman

x86/kprobes: Fix optprobe optimization check with CONFIG_RETHUNK

2023-01-07T10:15:51Z

commit 63dc6325ff41ee9e570bde705ac34a39c5dbeb44 upstream. Since the CONFIG_RETHUNK and CONFIG_SLS will use INT3 for stopping speculative execution after function return, kprobe jump optimization always fails on the functions with such INT3 inside the function body. (It already checks the INT3 padding between functions, but not inside the function) To avoid this issue, as same as kprobes, check whether the INT3 comes from kgdb or not, and if so, stop decoding and make it fail. The other INT3 will come from CONFIG_RETHUNK/CONFIG_SLS and those can be treated as a one-byte instruction. Fixes: e463a09af2f0 ("x86: Add straight-line-speculation mitigation") Suggested-by: Peter Zijlstra Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/167146051929.1374301.7419382929328081706.stgit@devnote3 Signed-off-by: Greg Kroah-Hartman

x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK

2023-01-07T10:15:51Z

commit 1993bf97992df2d560287f3c4120eda57426843d upstream. Since the CONFIG_RETHUNK and CONFIG_SLS will use INT3 for stopping speculative execution after RET instruction, kprobes always failes to check the probed instruction boundary by decoding the function body if the probed address is after such sequence. (Note that some conditional code blocks will be placed after function return, if compiler decides it is not on the hot path.) This is because kprobes expects kgdb puts the INT3 as a software breakpoint and it will replace the original instruction. But these INT3 are not such purpose, it doesn't need to recover the original instruction. To avoid this issue, kprobes checks whether the INT3 is owned by kgdb or not, and if so, stop decoding and make it fail. The other INT3 will come from CONFIG_RETHUNK/CONFIG_SLS and those can be treated as a one-byte instruction. Fixes: e463a09af2f0 ("x86: Add straight-line-speculation mitigation") Suggested-by: Peter Zijlstra Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/167146051026.1374301.392728975473572291.stgit@devnote3 Signed-off-by: Greg Kroah-Hartman

ftrace/x86: Add back ftrace_expected for ftrace bug reports

2023-01-07T10:15:51Z

commit fd3dc56253acbe9c641a66d312d8393cd55eb04c upstream. After someone reported a bug report with a failed modification due to the expected value not matching what was found, it came to my attention that the ftrace_expected is no longer set when that happens. This makes for debugging the issue a bit more difficult. Set ftrace_expected to the expected code before calling ftrace_bug, so that it shows what was expected and why it failed. Link: https://lore.kernel.org/all/CA+wXwBQ-VhK+hpBtYtyZP-NiX4g8fqRRWithFOHQW-0coQ3vLg@mail.gmail.com/ Link: https://lore.kernel.org/linux-trace-kernel/20221209105247.01d4e51d@gandalf.local.home Cc: Masami Hiramatsu Cc: Andrew Morton Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: "x86@kernel.org" Cc: Borislav Petkov Cc: Ingo Molnar Cc: stable@vger.kernel.org Fixes: 768ae4406a5c ("x86/ftrace: Use text_poke()") Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman

x86/microcode/intel: Do not retry microcode reloading on the APs

2023-01-07T10:15:51Z

commit be1b670f61443aa5d0d01782e9b8ea0ee825d018 upstream. The retries in load_ucode_intel_ap() were in place to support systems with mixed steppings. Mixed steppings are no longer supported and there is only one microcode image at a time. Any retries will simply reattempt to apply the same image over and over without making progress. [ bp: Zap the circumstantial reasoning from the commit message. ] Fixes: 06b8534cb728 ("x86/microcode: Rework microcode loading") Signed-off-by: Ashok Raj Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20221129210832.107850-3-ashok.raj@intel.com Signed-off-by: Greg Kroah-Hartman

x86/MCE/AMD: Clear DFR errors found in THR handler

2023-01-07T10:15:46Z

commit bc1b705b0eee4c645ad8b3bbff3c8a66e9688362 upstream. AMD's MCA Thresholding feature counts errors of all severity levels, not just correctable errors. If a deferred error causes the threshold limit to be reached (it was the error that caused the overflow), then both a deferred error interrupt and a thresholding interrupt will be triggered. The order of the interrupts is not guaranteed. If the threshold interrupt handler is executed first, then it will clear MCA_STATUS for the error. It will not check or clear MCA_DESTAT which also holds a copy of the deferred error. When the deferred error interrupt handler runs it will not find an error in MCA_STATUS, but it will find the error in MCA_DESTAT. This will cause two errors to be logged. Check for deferred errors when handling a threshold interrupt. If a bank contains a deferred error, then clear the bank's MCA_DESTAT register. Define a new helper function to do the deferred error check and clearing of MCA_DESTAT. [ bp: Simplify, convert comment to passive voice. ] Fixes: 37d43acfd79f ("x86/mce/AMD: Redo error logging from APIC LVT interrupt handlers") Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220621155943.33623-1-yazen.ghannam@amd.com Signed-off-by: Greg Kroah-Hartman

x86/fpu/xstate: Fix XSTATE_WARN_ON() to emit relevant diagnostics

2023-01-07T10:15:45Z

commit 48280042f2c6e3ac2cfb1d8b752ab4a7e0baea24 upstream. "XSAVE consistency problem" has been reported under Xen, but that's the extent of my divination skills. Modify XSTATE_WARN_ON() to force the caller to provide relevant diagnostic information, and modify each caller suitably. For check_xstate_against_struct(), this removes a double WARN() where one will do perfectly fine. CC stable as this has been wonky debugging for 7 years and it is good to have there too. Signed-off-by: Andrew Cooper Signed-off-by: Borislav Petkov Cc: Link: https://lore.kernel.org/r/20220810221909.12768-1-andrew.cooper3@citrix.com Signed-off-by: Greg Kroah-Hartman

x86/apic: Handle no CONFIG_X86_X2APIC on systems with x2APIC enabled by BIOS

2022-12-31T12:26:41Z

[ Upstream commit e3998434da4f5b1f57f8d6a8a9f8502ee3723bae ] A kernel that was compiled without CONFIG_X86_X2APIC was unable to boot on platforms that have x2APIC already enabled in the BIOS before starting the kernel. The kernel was supposed to panic with an approprite error message in validate_x2apic() due to the missing X2APIC support. However, validate_x2apic() was run too late in the boot cycle, and the kernel tried to initialize the APIC nonetheless. This resulted in an earlier panic in setup_local_APIC() because the APIC was not registered. In my experiments, a panic message in setup_local_APIC() was not visible in the graphical console, which resulted in a hang with no indication what has gone wrong. Instead of calling panic(), disable the APIC, which results in a somewhat working system with the PIC only (and no SMP). This way the user is able to diagnose the problem more easily. Disabling X2APIC mode is not an option because it's impossible on systems with locked x2APIC. The proper place to disable the APIC in this case is in check_x2apic(), which is called early from setup_arch(). Doing this in __apic_intr_mode_select() is too late. Make check_x2apic() unconditionally available and remove the empty stub. Reported-by: Paul Menzel Reported-by: Robert Elliott (Servers) Signed-off-by: Mateusz Jończyk Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/lkml/d573ba1c-0dc4-3016-712a-cc23a8a33d42@molgen.mpg.de Link: https://lore.kernel.org/lkml/20220911084711.13694-3-mat.jonczyk@o2.pl Link: https://lore.kernel.org/all/20221129215008.7247-1-mat.jonczyk@o2.pl Signed-off-by: Sasha Levin

x86/boot: Skip realmode init code when running as Xen PV guest

2022-12-31T12:26:03Z

[ Upstream commit f1e525009493cbd569e7c8dd7d58157855f8658d ] When running as a Xen PV guest there is no need for setting up the realmode trampoline, as realmode isn't supported in this environment. Trying to setup the trampoline has been proven to be problematic in some cases, especially when trying to debug early boot problems with Xen requiring to keep the EFI boot-services memory mapped (some firmware variants seem to claim basically all memory below 1Mb for boot services). Introduce new x86_platform_ops operations for that purpose, which can be set to a NOP by the Xen PV specific kernel boot code. [ bp: s/call_init_real_mode/do_init_real_mode/ ] Fixes: 084ee1c641a0 ("x86, realmode: Relocator for realmode code") Suggested-by: H. Peter Anvin Signed-off-by: Juergen Gross Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20221123114523.3467-1-jgross@suse.com Signed-off-by: Sasha Levin