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2025-03-22x86/Kconfig: Enable X86_X2APIC by default and improve help textMateusz Jończyk
As many current platforms (most modern Intel CPUs and QEMU) have x2APIC present, enable CONFIG_X86_X2APIC by default as it gives performance and functionality benefits. Additionally, if the BIOS has already switched APIC to x2APIC mode, but CONFIG_X86_X2APIC is disabled, the kernel will panic in arch/x86/kernel/apic/apic.c . Also improve the help text, which was confusing and really did not describe what the feature is about. Help text references and discussion: Both Intel [1] and AMD [3] spell the name as "x2APIC", not "x2apic". "It allows faster access to the local APIC" [2], chapter 2.1, page 15: "More efficient MSR interface to access APIC registers." "x2APIC was introduced in Intel CPUs around 2008": I was unable to find specific information which Intel CPUs support x2APIC. Wikipedia claims it was "introduced with the Nehalem microarchitecture in November 2008", but I was not able to confirm this independently. At least some Nehalem CPUs do not support x2APIC [1]. The documentation [2] is dated June 2008. Linux kernel also introduced x2APIC support in 2008, so the year seems to be right. "and in AMD EPYC CPUs in 2019": [3], page 15: "AMD introduced an x2APIC in our EPYC 7002 Series processors for the first time." "It is also frequently emulated in virtual machines, even when the host CPU does not support it." [1] "If this configuration option is disabled, the kernel will not boot on some platforms that have x2APIC enabled." According to some BIOS documentation [4], the x2APIC may be "disabled", "enabled", or "force enabled" on this system. I think that "enabled" means "made available to the operating system, but not already turned on" and "force enabled" means "already switched to x2APIC mode when the OS boots". Only in the latter mode a kernel without CONFIG_X86_X2APIC will panic in validate_x2apic() in arch/x86/kernel/apic/apic.c . QEMU 4.2.1 and my Intel HP laptop (bought in 2019) use the "enabled" mode and the kernel does not panic. [1] "Re: [Qemu-devel] [Question] why x2apic's set by default without host sup" https://lists.gnu.org/archive/html/qemu-devel/2013-07/msg03527.html [2] Intel® 64 Architecture x2APIC Specification, ( https://www.naic.edu/~phil/software/intel/318148.pdf ) [3] Workload Tuning Guide for AMD EPYC ™ 7002 Series Processor Based Servers Application Note, https://developer.amd.com/wp-content/resources/56745_0.80.pdf [4] UEFI System Utilities and Shell Command Mobile Help for HPE ProLiant Gen10, ProLiant Gen10 Plus Servers and HPE Synergy: Enabling or disabling Processor x2APIC Support https://techlibrary.hpe.com/docs/iss/proliant-gen10-uefi/s_enable_disable_x2APIC_support.html Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250321-x86_x2apic-v3-1-b0cbaa6fa338@ixit.cz
2025-03-21zstd: Increase DYNAMIC_BMI2 GCC version cutoff from 4.8 to 11.0 to work ↵Ingo Molnar
around compiler segfault Due to pending percpu improvements in -next, GCC9 and GCC10 are crashing during the build with: lib/zstd/compress/huf_compress.c:1033:1: internal compiler error: Segmentation fault 1033 | { | ^ Please submit a full bug report, with preprocessed source if appropriate. See <file:///usr/share/doc/gcc-9/README.Bugs> for instructions. The DYNAMIC_BMI2 feature is a known-challenging feature of the ZSTD library, with an existing GCC quirk turning it off for GCC versions below 4.8. Increase the DYNAMIC_BMI2 version cutoff to GCC 11.0 - GCC 10.5 is the last version known to crash. Reported-by: Michael Kelley <mhklinux@outlook.com> Debugged-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: https://lore.kernel.org/r/SN6PR02MB415723FBCD79365E8D72CA5FD4D82@SN6PR02MB4157.namprd02.prod.outlook.com Cc: Linus Torvalds <torvalds@linux-foundation.org>
2025-03-21x86/asm: Make asm export of __ref_stack_chk_guard unconditionalArd Biesheuvel
Clang does not tolerate the use of non-TLS symbols for the per-CPU stack protector very well, and to work around this limitation, the symbol passed via the -mstack-protector-guard-symbol= option is never defined in C code, but only in the linker script, and it is exported from an assembly file. This is necessary because Clang will fail to generate the correct %GS based references in a compilation unit that includes a non-TLS definition of the guard symbol being used to store the stack cookie. This problem is only triggered by symbol definitions, not by declarations, but nonetheless, the declaration in <asm/asm-prototypes.h> is conditional on __GENKSYMS__ being #define'd, so that only genksyms will observe it, but for ordinary compilation, it will be invisible. This is causing problems with the genksyms alternative gendwarfksyms, which does not #define __GENKSYMS__, does not observe the symbol declaration, and therefore lacks the information it needs to version it. Adding the #define creates problems in other places, so that is not a straight-forward solution. So take the easy way out, and drop the conditional on __GENKSYMS__, as this is not really needed to begin with. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20250320213238.4451-2-ardb@kernel.org
2025-03-19x86/mm: Only do broadcast flush from reclaim if pages were unmappedRik van Riel
Track whether pages were unmapped from any MM (even ones with a currently empty mm_cpumask) by the reclaim code, to figure out whether or not broadcast TLB flush should be done when reclaim finishes. The reason any MM must be tracked, and not only ones contributing to the tlbbatch cpumask, is that broadcast ASIDs are expected to be kept up to date even on CPUs where the MM is not currently active. This change allows reclaim to avoid doing TLB flushes when only clean page cache pages and/or slab memory were reclaimed, which is fairly common. ( This is a simpler alternative to the code that was in my INVLPGB series before, and it seems to capture most of the benefit due to how common it is to reclaim only page cache. ) Signed-off-by: Rik van Riel <riel@surriel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250319132520.6b10ad90@fangorn
2025-03-19perf/x86/intel, x86/cpu: Replace Pentium 4 model checks with VFM onesSohil Mehta
Introduce a name for an old Pentium 4 model and replace the x86_model checks with VFM ones. This gets rid of one of the last remaining Intel-specific x86_model checks. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20250318223828.2945651-3-sohil.mehta@intel.com
2025-03-19perf/x86/intel, x86/cpu: Simplify Intel PMU initializationSohil Mehta
Architectural Perfmon was introduced on the Family 6 "Core" processors starting with Yonah. Processors before Yonah need their own customized PMU initialization. p6_pmu_init() is expected to provide that initialization for early Family 6 processors. But, currently, it could get called for any Family 6 processor if the architectural perfmon feature is disabled on that processor. To simplify, restrict the P6 PMU initialization to early Family 6 processors that do not have architectural perfmon support and truly need the special handling. As a result, the "unsupported" console print becomes practically unreachable because all the released P6 processors are covered by the switch cases. Move the console print to a common location where it can cover all modern processors (including Family >15) that may not have architectural perfmon support enumerated. Also, use this opportunity to get rid of the unnecessary switch cases in P6 initialization. Only the Pentium Pro processor needs a quirk, and the rest of the processors do not need any special handling. The gaps in the case numbers are only due to no processor with those model numbers being released. Use decimal numbers to represent Intel Family numbers. Also, convert one of the last few Intel x86_model comparisons to a VFM-based one. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20250318223828.2945651-2-sohil.mehta@intel.com
2025-03-19x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headersThomas Huth
While the GCC and Clang compilers already define __ASSEMBLER__ automatically when compiling assembly code, __ASSEMBLY__ is a macro that only gets defined by the Makefiles in the kernel. This can be very confusing when switching between userspace and kernelspace coding, or when dealing with UAPI headers that rather should use __ASSEMBLER__ instead. So let's standardize on the __ASSEMBLER__ macro that is provided by the compilers now. This is mostly a mechanical patch (done with a simple "sed -i" statement), with some manual tweaks in <asm/frame.h>, <asm/hw_irq.h> and <asm/setup.h> that mentioned this macro in comments with some missing underscores. Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Juergen Gross <jgross@suse.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250314071013.1575167-38-thuth@redhat.com
2025-03-19x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI headersThomas Huth
__ASSEMBLY__ is only defined by the Makefile of the kernel, so this is not really useful for UAPI headers (unless the userspace Makefile defines it, too). Let's switch to __ASSEMBLER__ which gets set automatically by the compiler when compiling assembly code. Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Kees Cook <keescook@chromium.org> Cc: Brian Gerst <brgerst@gmail.com> Link: https://lore.kernel.org/r/20250310104256.123527-1-thuth@redhat.com
2025-03-19x86/locking/atomic: Improve performance by using asm_inline() for atomic ↵Uros Bizjak
locking instructions According to: https://gcc.gnu.org/onlinedocs/gcc/Size-of-an-asm.html the usage of asm pseudo directives in the asm template can confuse the compiler to wrongly estimate the size of the generated code. The LOCK_PREFIX macro expands to several asm pseudo directives, so its usage in atomic locking insns causes instruction length estimates to fail significantly (the specially instrumented compiler reports the estimated length of these asm templates to be 6 instructions long). This incorrect estimate further causes unoptimal inlining decisions, un-optimal instruction scheduling and un-optimal code block alignments for functions that use these locking primitives. Use asm_inline instead: https://gcc.gnu.org/pipermail/gcc-patches/2018-December/512349.html which is a feature that makes GCC pretend some inline assembler code is tiny (while it would think it is huge), instead of just asm. For code size estimation, the size of the asm is then taken as the minimum size of one instruction, ignoring how many instructions compiler thinks it is. bloat-o-meter reports the following code size increase (x86_64 defconfig, gcc-14.2.1): add/remove: 82/283 grow/shrink: 870/372 up/down: 76272/-43618 (32654) Total: Before=22770320, After=22802974, chg +0.14% with top grows (>500 bytes): Function old new delta ---------------------------------------------------------------- copy_process 6465 10191 +3726 balance_dirty_pages_ratelimited_flags 237 2949 +2712 icl_plane_update_noarm 5800 7969 +2169 samsung_input_mapping 3375 5170 +1795 ext4_do_update_inode.isra - 1526 +1526 __schedule 2416 3472 +1056 __i915_vma_resource_unhold - 946 +946 sched_mm_cid_after_execve 175 1097 +922 __do_sys_membarrier - 862 +862 filemap_fault 2666 3462 +796 nl80211_send_wiphy 11185 11874 +689 samsung_input_mapping.cold 900 1500 +600 virtio_gpu_queue_fenced_ctrl_buffer 839 1410 +571 ilk_update_pipe_csc 1201 1735 +534 enable_step - 525 +525 icl_color_commit_noarm 1334 1847 +513 tg3_read_bc_ver - 501 +501 and top shrinks (>500 bytes): Function old new delta ---------------------------------------------------------------- nl80211_send_iftype_data 580 - -580 samsung_gamepad_input_mapping.isra.cold 604 - -604 virtio_gpu_queue_ctrl_sgs 724 - -724 tg3_get_invariants 9218 8376 -842 __i915_vma_resource_unhold.part 899 - -899 ext4_mark_iloc_dirty 1735 106 -1629 samsung_gamepad_input_mapping.isra 2046 - -2046 icl_program_input_csc 2203 - -2203 copy_mm 2242 - -2242 balance_dirty_pages 2657 - -2657 These code size changes can be grouped into 4 groups: a) some functions now include once-called functions in full or in part. These are: Function old new delta ---------------------------------------------------------------- copy_process 6465 10191 +3726 balance_dirty_pages_ratelimited_flags 237 2949 +2712 icl_plane_update_noarm 5800 7969 +2169 samsung_input_mapping 3375 5170 +1795 ext4_do_update_inode.isra - 1526 +1526 that now include: Function old new delta ---------------------------------------------------------------- copy_mm 2242 - -2242 balance_dirty_pages 2657 - -2657 icl_program_input_csc 2203 - -2203 samsung_gamepad_input_mapping.isra 2046 - -2046 ext4_mark_iloc_dirty 1735 106 -1629 b) ISRA [interprocedural scalar replacement of aggregates, interprocedural pass that removes unused function return values (turning functions returning a value which is never used into void functions) and removes unused function parameters. It can also replace an aggregate parameter by a set of other parameters representing part of the original, turning those passed by reference into new ones which pass the value directly.] Top grows and shrinks of this group are listed below: Function old new delta ---------------------------------------------------------------- ext4_do_update_inode.isra - 1526 +1526 nfs4_begin_drain_session.isra - 249 +249 nfs4_end_drain_session.isra - 168 +168 __guc_action_register_multi_lrc_v70.isra 335 500 +165 __i915_gem_free_objects.isra - 144 +144 ... membarrier_register_private_expedited.isra 108 - -108 syncobj_eventfd_entry_func.isra 445 314 -131 __ext4_sb_bread_gfp.isra 140 - -140 class_preempt_notrace_destructor.isra 145 - -145 p9_fid_put.isra 151 - -151 __mm_cid_try_get.isra 238 - -238 membarrier_global_expedited.isra 294 - -294 mm_cid_get.isra 295 - -295 samsung_gamepad_input_mapping.isra.cold 604 - -604 samsung_gamepad_input_mapping.isra 2046 - -2046 c) different split points of hot/cold split that just move code around: Top grows and shrinks of this group are listed below: Function old new delta ---------------------------------------------------------------- samsung_input_mapping.cold 900 1500 +600 __i915_request_reset.cold 311 389 +78 nfs_update_inode.cold 77 153 +76 __do_sys_swapon.cold 404 455 +51 copy_process.cold - 45 +45 tg3_get_invariants.cold 73 115 +42 ... hibernate.cold 671 643 -28 copy_mm.cold 31 - -31 software_resume.cold 249 207 -42 io_poll_wake.cold 106 54 -52 samsung_gamepad_input_mapping.isra.cold 604 - -604 c) full inline of small functions with locking insn (~150 cases). These bring in most of the code size increase because the removed function code is now inlined in multiple places. E.g.: 0000000000a50e10 <release_devnum>: a50e10: 48 63 07 movslq (%rdi),%rax a50e13: 85 c0 test %eax,%eax a50e15: 7e 10 jle a50e27 <release_devnum+0x17> a50e17: 48 8b 4f 50 mov 0x50(%rdi),%rcx a50e1b: f0 48 0f b3 41 50 lock btr %rax,0x50(%rcx) a50e21: c7 07 ff ff ff ff movl $0xffffffff,(%rdi) a50e27: e9 00 00 00 00 jmp a50e2c <release_devnum+0x1c> a50e28: R_X86_64_PLT32 __x86_return_thunk-0x4 a50e2c: 0f 1f 40 00 nopl 0x0(%rax) is now fully inlined into the caller function. This is desirable due to the per function overhead of CPU bug mitigations like retpolines. FTR a) with -Os (where generated code size really matters) x86_64 defconfig object file decreases by 24.388 kbytes, representing 0.1% code size decrease: text data bss dec hex filename 23883860 4617284 814212 29315356 1bf511c vmlinux-old.o 23859472 4615404 814212 29289088 1beea80 vmlinux-new.o FTR b) clang recognizes "asm inline", but there was no difference in code sizes: text data bss dec hex filename 27577163 4503078 807732 32887973 1f5d4a5 vmlinux-clang-patched.o 27577181 4503078 807732 32887991 1f5d4b7 vmlinux-clang-unpatched.o The performance impact of the patch was assessed by recompiling fedora-41 6.13.5 kernel and running lmbench with old and new kernel. The most noticeable improvements were: Process fork+exit: 270.0952 microseconds Process fork+execve: 2620.3333 microseconds Process fork+/bin/sh -c: 6781.0000 microseconds File /usr/tmp/XXX write bandwidth: 1780350 KB/sec Pagefaults on /usr/tmp/XXX: 0.3875 microseconds to: Process fork+exit: 298.6842 microseconds Process fork+execve: 1662.7500 microseconds Process fork+/bin/sh -c: 2127.6667 microseconds File /usr/tmp/XXX write bandwidth: 1950077 KB/sec Pagefaults on /usr/tmp/XXX: 0.1958 microseconds and from: Socket bandwidth using localhost 0.000001 2.52 MB/sec 0.000064 163.02 MB/sec 0.000128 321.70 MB/sec 0.000256 630.06 MB/sec 0.000512 1207.07 MB/sec 0.001024 2004.06 MB/sec 0.001437 2475.43 MB/sec 10.000000 5817.34 MB/sec Avg xfer: 3.2KB, 41.8KB in 1.2230 millisecs, 34.15 MB/sec AF_UNIX sock stream bandwidth: 9850.01 MB/sec Pipe bandwidth: 4631.28 MB/sec to: Socket bandwidth using localhost 0.000001 3.13 MB/sec 0.000064 187.08 MB/sec 0.000128 324.12 MB/sec 0.000256 618.51 MB/sec 0.000512 1137.13 MB/sec 0.001024 1962.95 MB/sec 0.001437 2458.27 MB/sec 10.000000 6168.08 MB/sec Avg xfer: 3.2KB, 41.8KB in 1.0060 millisecs, 41.52 MB/sec AF_UNIX sock stream bandwidth: 9921.68 MB/sec Pipe bandwidth: 4649.96 MB/sec [ mingo: Prettified the changelog a bit. ] Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20250309170955.48919-1-ubizjak@gmail.com
2025-03-19x86/asm: Use asm_inline() instead of asm() in clwb()Uros Bizjak
Use asm_inline() to instruct the compiler that the size of asm() is the minimum size of one instruction, ignoring how many instructions the compiler thinks it is. ALTERNATIVE macro that expands to several pseudo directives causes instruction length estimate to count more than 20 instructions. bloat-o-meter reports slight increase of the code size for x86_64 defconfig object file, compiled with gcc-14.2: add/remove: 0/2 grow/shrink: 3/0 up/down: 190/-59 (131) Function old new delta __copy_user_flushcache 166 247 +81 __memcpy_flushcache 369 437 +68 arch_wb_cache_pmem 6 47 +41 __pfx_clean_cache_range 16 - -16 clean_cache_range 43 - -43 Total: Before=22807167, After=22807298, chg +0.00% The compiler now inlines and removes the clean_cache_range() function. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250313102715.333142-2-ubizjak@gmail.com
2025-03-19x86/asm: Use CLFLUSHOPT and CLWB mnemonics in <asm/special_insns.h>Uros Bizjak
Current minimum required version of binutils is 2.25, which supports CLFLUSHOPT and CLWB instruction mnemonics. Replace the byte-wise specification of CLFLUSHOPT and CLWB with these proper mnemonics. No functional change intended. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250313102715.333142-1-ubizjak@gmail.com
2025-03-19x86/hweight: Use asm_inline() instead of asm()Uros Bizjak
Use asm_inline() to instruct the compiler that the size of asm() is the minimum size of one instruction, ignoring how many instructions the compiler thinks it is. ALTERNATIVE macro that expands to several pseudo directives causes instruction length estimate to count more than 20 instructions. bloat-o-meter reports slight reduction of the code size for x86_64 defconfig object file, compiled with gcc-14.2: add/remove: 6/12 grow/shrink: 59/50 up/down: 3389/-3560 (-171) Total: Before=22734393, After=22734222, chg -0.00% where 29 instances of code blocks involving POPCNT now gets inlined, resulting in the removal of several functions: format_is_yuv_semiplanar.part.isra 41 - -41 cdclk_divider 69 - -69 intel_joiner_adjust_timings 140 - -140 nl80211_send_wowlan_tcp_caps 369 - -369 nl80211_send_iftype_data 579 - -579 __do_sys_pidfd_send_signal 809 - -809 One noticeable change is: pcpu_page_first_chunk 1075 1060 -15 Where the compiler now inlines 4 more instances of POPCNT insns, but still manages to compile to a function with smaller code size. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250312123905.149298-3-ubizjak@gmail.com
2025-03-19x86/hweight: Use ASM_CALL_CONSTRAINT in inline asm()Uros Bizjak
Use ASM_CALL_CONSTRAINT to prevent inline asm() that includes call instruction from being scheduled before the frame pointer gets set up by the containing function. This unconstrained scheduling might cause objtool to print a "call without frame pointer save/setup" warning. Current versions of compilers don't seem to trigger this condition, but without this constraint there's nothing to prevent the compiler from scheduling the insn in front of frame creation. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250312123905.149298-2-ubizjak@gmail.com
2025-03-19x86/hweight: Use named operands in inline asm()Uros Bizjak
No functional change intended. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250312123905.149298-1-ubizjak@gmail.com
2025-03-19x86/stackprotector/64: Only export __ref_stack_chk_guard on CONFIG_SMPIngo Molnar
The __ref_stack_chk_guard symbol doesn't exist on UP: <stdin>:4:15: error: ‘__ref_stack_chk_guard’ undeclared here (not in a function) Fix the #ifdef around the entry.S export. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Uros Bizjak <ubizjak@gmail.com> Link: https://lore.kernel.org/r/20250123190747.745588-8-brgerst@gmail.com
2025-03-19x86/head/64: Avoid Clang < 17 stack protector in startup codeArd Biesheuvel
Clang versions before 17 will not honour -fdirect-access-external-data for the load of the stack cookie emitted into each function's prologue and epilogue, and will emit a GOT based reference instead, e.g., 4c 8b 2d 00 00 00 00 mov 0x0(%rip),%r13 18a: R_X86_64_REX_GOTPCRELX __ref_stack_chk_guard-0x4 65 49 8b 45 00 mov %gs:0x0(%r13),%rax This is inefficient, but at least, the linker will usually follow the rules of the x86 psABI, and relax the GOT load into a RIP-relative LEA instruction. This is still suboptimal, as the per-CPU load could use a RIP-relative reference directly, but at least it gets rid of the first load from memory. However, Boris reports that in some cases, when using distro builds of Clang/LLD 15, the first load gets relaxed into 49 c7 c6 20 c0 55 86 mov $0xffffffff8655c020,%r14 ffffffff8373bf0f: R_X86_64_32S __ref_stack_chk_guard 65 49 8b 06 mov %gs:(%r14),%rax instead, which is fine in principle, as MOV may be cheaper than LEA on some micro-architectures. However, such absolute references assume that the variable in question can be accessed via the kernel virtual mapping, and this is not guaranteed for the startup code residing in .head.text. This is therefore a true positive, that was caught using the recently introduced relocs check for absolute references in the startup code: Absolute reference to symbol '__ref_stack_chk_guard' not permitted in .head.text Work around the issue by disabling the stack protector in the startup code for Clang versions older than 17. Fixes: 80d47defddc0 ("x86/stackprotector/64: Convert to normal per-CPU variable") Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250312102740.602870-2-ardb+git@google.com
2025-03-19x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h>Uros Bizjak
Merge common x86_32 and x86_64 code in crash_setup_regs() using macros from <asm/asm.h>. The compiled object files before and after the patch are unchanged. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lore.kernel.org/r/20250306145227.55819-1-ubizjak@gmail.com
2025-03-19x86/runtime-const: Add the RUNTIME_CONST_PTR assembly macroKirill A. Shutemov
Add an assembly macro to refer runtime cost. It hides linker magic and makes assembly more readable. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250304153342.2016569-1-kirill.shutemov@linux.intel.com
2025-03-19x86/cpu/intel: Limit the non-architectural constant_tsc model checksSohil Mehta
X86_FEATURE_CONSTANT_TSC is a Linux-defined, synthesized feature flag. It is used across several vendors. Intel CPUs will set the feature when the architectural CPUID.80000007.EDX[1] bit is set. There are also some Intel CPUs that have the X86_FEATURE_CONSTANT_TSC behavior but don't enumerate it with the architectural bit. Those currently have a model range check. Today, virtually all of the CPUs that have the CPUID bit *also* match the "model >= 0x0e" check. This is confusing. Instead of an open-ended check, pick some models (INTEL_IVYBRIDGE and P4_WILLAMETTE) as the end of goofy CPUs that should enumerate the bit but don't. These models are relatively arbitrary but conservative pick for this. This makes it obvious that later CPUs (like Family 18+) no longer need to synthesize X86_FEATURE_CONSTANT_TSC. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20250219184133.816753-14-sohil.mehta@intel.com
2025-03-19x86/mm/pat: Replace Intel x86_model checks with VFM onesSohil Mehta
Introduce markers and names for some Family 6 and Family 15 models and replace x86_model checks with VFM ones. Since the VFM checks are closed ended and only applicable to Intel, get rid of the explicit Intel vendor check as well. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lore.kernel.org/r/20250219184133.816753-13-sohil.mehta@intel.com
2025-03-19x86/cpu/intel: Fix fast string initialization for extended FamiliesSohil Mehta
X86_FEATURE_REP_GOOD is a linux defined feature flag to track whether fast string operations should be used for copy_page(). It is also used as a second alternative for clear_page() if enhanced fast string operations (ERMS) are not available. X86_FEATURE_ERMS is an Intel-specific hardware-defined feature flag that tracks hardware support for Enhanced Fast strings. It is used to track whether Fast strings should be used for similar memory copy and memory clearing operations. On top of these, there is a FAST_STRING enable bit in the IA32_MISC_ENABLE MSR. It is typically controlled by the BIOS to provide a hint to the hardware and the OS on whether fast string operations are preferred. Commit: 161ec53c702c ("x86, mem, intel: Initialize Enhanced REP MOVSB/STOSB") introduced a mechanism to honor the BIOS preference for fast string operations and clear the above feature flags if needed. Unfortunately, the current initialization code for Intel to set and clear these bits is confusing at best and likely incorrect. X86_FEATURE_REP_GOOD is cleared in early_init_intel() if MISC_ENABLE.FAST_STRING is 0. But it gets set later on unconditionally for all Family 6 processors in init_intel(). This not only overrides the BIOS preference but also contradicts the earlier check. Fix this by combining the related checks and always relying on the BIOS provided preference for fast string operations. This simplification makes sure the upcoming Intel Family 18 and 19 models are covered as well. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Juergen Gross <jgross@suse.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250219184133.816753-12-sohil.mehta@intel.com
2025-03-19x86/smpboot: Fix INIT delay assignment for extended Intel FamiliesSohil Mehta
Some old crusty CPUs need an extra delay that slows down booting. See the comment above 'init_udelay' for details. Newer CPUs don't need the delay. Right now, for Intel, Family 6 and only Family 6 skips the delay. That leaves out both the Family 15 (Pentium 4s) and brand new Family 18/19 models. The omission of Family 15 (Pentium 4s) seems like an oversight and 18/19 do not need the delay. Skip the delay on all Intel processors Family 6 and beyond. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250219184133.816753-11-sohil.mehta@intel.com
2025-03-19x86/smpboot: Remove confusing quirk usage in INIT delaySohil Mehta
Very old multiprocessor systems required a 10 msec delay between asserting and de-asserting INIT but modern processors do not require this delay. Over time the usage of the "quirk" wording while setting the INIT delay has become misleading. The code comments suggest that modern processors need to be quirked, which clears the default init_udelay of 10 msec, while legacy processors don't need the quirk and continue to use the default init_udelay. With a lot more modern processors, the wording should be inverted if at all needed. Instead, simplify the comments and the code by getting rid of "quirk" usage altogether and clarifying the following: - Old legacy processors -> Set the "legacy" 10 msec delay - Modern processors -> Do not set any delay No functional change. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250219184133.816753-10-sohil.mehta@intel.com
2025-03-19x86/acpi/cstate: Improve Intel Family model checksSohil Mehta
Update the Intel Family checks to consistently use Family 15 instead of Family 0xF. Also, get rid of one of last usages of x86_model by using the new VFM checks. Update the incorrect comment since the check has changed since the initial commit: ee1ca48fae7e ("ACPI: Disable ARB_DISABLE on platforms where it is not needed") The two changes were: - 3e2ada5867b7 ("ACPI: fix Compaq Evo N800c (Pentium 4m) boot hang regression") removed the P4 - Family 15. - 03a05ed11529 ("ACPI: Use the ARB_DISABLE for the CPU which model id is less than 0x0f.") got rid of CORE_YONAH - Family 6, model E. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/20250219184133.816753-9-sohil.mehta@intel.com
2025-03-19x86/cpu/intel: Replace Family 5 model checks with VFM onesSohil Mehta
Introduce names for some Family 5 models and convert some of the checks to be VFM based. Also, to keep the file sorted by family, move Family 5 to the top of the header file. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20250219184133.816753-8-sohil.mehta@intel.com
2025-03-19x86/cpu/intel: Replace Family 15 checks with VFM onesSohil Mehta
Introduce names for some old pentium 4 models and replace the x86_model checks with VFM ones. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20250219184133.816753-7-sohil.mehta@intel.com
2025-03-19x86/cpu/intel: Replace early Family 6 checks with VFM onesSohil Mehta
Introduce names for some old pentium models and replace the x86_model checks with VFM ones. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20250219184133.816753-6-sohil.mehta@intel.com
2025-03-19x86/mtrr: Modify a x86_model check to an Intel VFM checkSohil Mehta
Simplify one of the last few Intel x86_model checks in arch/x86 by substituting it with a VFM one. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20250219184133.816753-5-sohil.mehta@intel.com
2025-03-19x86/microcode: Update the Intel processor flag scan checkSohil Mehta
The Family model check to read the processor flag MSR is misleading and potentially incorrect. It doesn't consider Family while comparing the model number. The original check did have a Family number but it got lost/moved during refactoring. intel_collect_cpu_info() is called through multiple paths such as early initialization, CPU hotplug as well as IFS image load. Some of these flows would be error prone due to the ambiguous check. Correct the processor flag scan check to use a Family number and update it to a VFM based one to make it more readable. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20250219184133.816753-4-sohil.mehta@intel.com
2025-03-19x86/cpu/intel: Fix the MOVSL alignment preference for extended FamiliesSohil Mehta
The alignment preference for 32-bit MOVSL based bulk memory move has been 8-byte for a long time. However this preference is only set for Family 6 and 15 processors. Use the same preference for upcoming Family numbers 18 and 19. Also, use a simpler VFM based check instead of switching based on Family numbers. Refresh the comment to reflect the new check. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Juergen Gross <jgross@suse.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250219184133.816753-3-sohil.mehta@intel.com
2025-03-19x86/apic: Fix 32-bit APIC initialization for extended Intel FamiliesSohil Mehta
APIC detection is currently limited to a few specific Families and will not match the upcoming Families >=18. Extend the check to include all Families 6 or greater. Also convert it to a VFM check to make it simpler. Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20250219184133.816753-2-sohil.mehta@intel.com
2025-03-19x86/cpuid: Use u32 in instead of uint32_t in <asm/cpuid/api.h>Ingo Molnar
Use u32 instead of uint32_t in hypervisor_cpuid_base(). Yes, uint32_t is used in Xen code et al, but this is a core x86 architecture header and we should standardize on the type that is being used overwhelmingly in related x86 architecture code. The two types are the same so there should be no build warnings. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: "Ahmed S. Darwish" <darwi@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250317221824.3738853-6-mingo@kernel.org
2025-03-19x86/cpuid: Standardize on u32 in <asm/cpuid/api.h>Ingo Molnar
Convert all uses of 'unsigned int' to 'u32' in <asm/cpuid/api.h>. This is how a lot of the call sites are doing it, and the two types are equivalent in the C sense - but 'u32' better expresses that these are expressions of an immutable hardware ABI. Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Xin Li (Intel) <xin@zytor.com> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: "Ahmed S. Darwish" <darwi@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250317221824.3738853-5-mingo@kernel.org
2025-03-19x86/cpuid: Clean up <asm/cpuid/api.h>Ingo Molnar
- Include <asm/cpuid/types.h> first, as is customary. This also has the side effect of build-testing the header dependency assumptions in the types header. - No newline necessary after the SPDX line - Newline necessary after inline function definitions - Rename native_cpuid_reg() to NATIVE_CPUID_REG(): it's a CPP macro, whose name we capitalize in such cases. - Prettify the CONFIG_PARAVIRT_XXL inclusion block a bit - Standardize register references in comments to EAX/EBX/ECX/etc., from the hodgepodge of references. - s/cpus/CPUs because why add noise to common acronyms? Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: "Ahmed S. Darwish" <darwi@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250317221824.3738853-4-mingo@kernel.org
2025-03-19x86/cpuid: Clean up <asm/cpuid/types.h>Ingo Molnar
- We have 0x0d, 0x9 and 0x1d as literals for the CPUID_LEAF definitions, pick a single, consistent style of 0xZZ literals. - Likewise, harmonize the style of the 'struct cpuid_regs' list of registers with that of 'enum cpuid_regs_idx'. Because while computers don't care about unnecessary visual noise, humans do. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: "Ahmed S. Darwish" <darwi@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250317221824.3738853-3-mingo@kernel.org
2025-03-19x86/cpuid: Refactor <asm/cpuid.h>Ahmed S. Darwish
In preparation for future commits where CPUID headers will be expanded, refactor the CPUID header <asm/cpuid.h> into: asm/cpuid/ ├── api.h └── types.h Move the CPUID data structures into <asm/cpuid/types.h> and the access APIs into <asm/cpuid/api.h>. Let <asm/cpuid.h> be just an include of <asm/cpuid/api.h> so that existing call sites do not break. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: "Ahmed S. Darwish" <darwi@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250317221824.3738853-2-mingo@kernel.org
2025-03-19x86/syscall/32: Add comment to conditionalBrian Gerst
Add a CONFIG_X86_FRED comment, since this conditional is nested. Suggested-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20250314151220.862768-8-brgerst@gmail.com
2025-03-19x86/syscall: Remove stray semicolonsBrian Gerst
No functional change. Suggested-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20250314151220.862768-7-brgerst@gmail.com
2025-03-19x86/syscall: Move sys_ni_syscall()Brian Gerst
Move sys_ni_syscall() to kernel/process.c, and remove the now empty entry/common.c No functional changes. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20250314151220.862768-6-brgerst@gmail.com
2025-03-19x86/syscall/x32: Move x32 syscall tableBrian Gerst
Since commit: 2e958a8a510d ("x86/entry/x32: Rename __x32_compat_sys_* to __x64_compat_sys_*") the ABI prefix for x32 syscalls is the same as native 64-bit syscalls. Move the x32 syscall table to syscall_64.c No functional changes. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20250314151220.862768-5-brgerst@gmail.com
2025-03-19x86/syscall/64: Move 64-bit syscall dispatch codeBrian Gerst
Move the 64-bit syscall dispatch code to syscall_64.c. No functional changes. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20250314151220.862768-4-brgerst@gmail.com
2025-03-19x86/syscall/32: Move 32-bit syscall dispatch codeBrian Gerst
Move the 32-bit syscall dispatch code to syscall_32.c. No functional changes. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20250314151220.862768-3-brgerst@gmail.com
2025-03-19x86/xen: Move Xen upcall handlerBrian Gerst
Move the upcall handler to Xen-specific files. No functional changes. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Juergen Gross <jgross@suse.com> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20250314151220.862768-2-brgerst@gmail.com
2025-03-19x86/amd_node: Add a smn_read_register() helperMario Limonciello
Some of the ACP drivers will poll registers through SMN using read_poll_timeout() which requires returning the result of the register read as the argument. Add a helper to do just that. Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250217231747.1656228-2-superm1@kernel.org
2025-03-19x86/amd_node: Add support for debugfs access to SMN registersMario Limonciello
There are certain registers on AMD Zen systems that can only be accessed through SMN. Introduce a new interface that provides debugfs files for accessing SMN. As this introduces the capability for userspace to manipulate the hardware in unpredictable ways, taint the kernel when writing. Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250130-wip-x86-amd-nb-cleanup-v4-3-b5cc997e471b@amd.com
2025-03-19x86/amd_node: Add SMN offsets to exclusive region accessMario Limonciello
Offsets 0x60 and 0x64 are used internally by kernel drivers that call the amd_smn_read() and amd_smn_write() functions. If userspace accesses the regions at the same time as the kernel it may cause malfunctions in drivers using the offsets. Add these offsets to the exclusions so that the kernel is tainted if a non locked down userspace tries to access them. Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250130-wip-x86-amd-nb-cleanup-v4-2-b5cc997e471b@amd.com
2025-03-19x86/amd_node, platform/x86/amd/hsmp: Have HSMP use SMN through AMD_NODEYazen Ghannam
The HSMP interface is just an SMN interface with different offsets. Define an HSMP wrapper in the SMN code and have the HSMP platform driver use that rather than a local solution. Also, remove the "root" member from AMD_NB, since there are no more users of it. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Carlos Bilbao <carlos.bilbao@kernel.org> Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20250130-wip-x86-amd-nb-cleanup-v4-1-b5cc997e471b@amd.com
2025-03-19x86/mtrr: Use str_enabled_disabled() helper in print_mtrr_state()Thorsten Blum
Remove hard-coded strings by using the str_enabled_disabled() helper function. Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/all/20250117144900.171684-2-thorsten.blum%40linux.dev
2025-03-19x86/entry: Add __init to ia32_emulation_override_cmdline()Vitaly Kuznetsov
ia32_emulation_override_cmdline() is an early_param() arg and these are only needed at boot time. In fact, all other early_param() functions in arch/x86 seem to have '__init' annotation and ia32_emulation_override_cmdline() is the only exception. Fixes: a11e097504ac ("x86: Make IA32_EMULATION boot time configurable") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Nikolay Borisov <nik.borisov@suse.com> Link: https://lore.kernel.org/all/20241210151650.1746022-1-vkuznets%40redhat.com
2025-03-19x86/cpufeatures: Warn about unmet CPU feature dependenciesSohil Mehta
Currently, the cpuid_deps[] table is only exercised when a particular feature is explicitly disabled and clear_cpu_cap() is called. However, some of these listed dependencies might already be missing during boot. These types of errors shouldn't generally happen in production environments, but they could sometimes sneak through, especially when VMs and Kconfigs are in the mix. Also, the kernel might introduce artificial dependencies between unrelated features, such as making LAM depend on LASS. Unexpected failures can occur when the kernel tries to use such features. Add a simple boot-time scan of the cpuid_deps[] table to detect the missing dependencies. One option is to disable all of such features during boot, but that may cause regressions in existing systems. For now, just warn about the missing dependencies to create awareness. As a trade-off between spamming the kernel log and keeping track of all the features that have been warned about, only warn about the first missing dependency. Any subsequent unmet dependency will only be logged after the first one has been resolved. Features are typically represented through unsigned integers within the kernel, though some of them have user-friendly names if they are exposed via /proc/cpuinfo. Show the friendlier name if available, otherwise display the X86_FEATURE_* numerals to make it easier to identify the feature. Suggested-by: Tony Luck <tony.luck@intel.com> Suggested-by: Ingo Molnar <mingo@redhat.com> Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Juergen Gross <jgross@suse.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20250313201608.3304135-1-sohil.mehta@intel.com
generated by cgit v1.2.3 (git 2.39.1) at 2025-07-30 08:37:41 +0000