kernel/linux.git/arch/x86/tools, branch v6.12.80

x86/tools: Drop duplicate unlikely() definition in insn_decoder_test.c

2025-06-27T10:11:41+00:00

commit f710202b2a45addea3dcdcd862770ecbaf6597ef upstream. After commit c104c16073b7 ("Kunit to check the longest symbol length"), there is a warning when building with clang because there is now a definition of unlikely from compiler.h in tools/include/linux, which conflicts with the one in the instruction decoder selftest: arch/x86/tools/insn_decoder_test.c:15:9: warning: 'unlikely' macro redefined [-Wmacro-redefined] Remove the second unlikely() definition, as it is no longer necessary, clearing up the warning. Fixes: c104c16073b7 ("Kunit to check the longest symbol length") Signed-off-by: Nathan Chancellor Signed-off-by: Ingo Molnar Acked-by: Shuah Khan Link: https://lore.kernel.org/r/20250318-x86-decoder-test-fix-unlikely-redef-v1-1-74c84a7bf05b@kernel.org Signed-off-by: Greg Kroah-Hartman

Kunit to check the longest symbol length

2025-06-27T10:11:41+00:00

commit c104c16073b7fdb3e4eae18f66f4009f6b073d6f upstream. The longest length of a symbol (KSYM_NAME_LEN) was increased to 512 in the reference [1]. This patch adds kunit test suite to check the longest symbol length. These tests verify that the longest symbol length defined is supported. This test can also help other efforts for longer symbol length, like [2]. The test suite defines one symbol with the longest possible length. The first test verify that functions with names of the created symbol, can be called or not. The second test, verify that the symbols are created (or not) in the kernel symbol table. [1] https://lore.kernel.org/lkml/20220802015052.10452-6-ojeda@kernel.org/ [2] https://lore.kernel.org/lkml/20240605032120.3179157-1-song@kernel.org/ Link: https://lore.kernel.org/r/20250302221518.76874-1-sergio.collado@gmail.com Tested-by: Martin Rodriguez Reboredo Reviewed-by: Shuah Khan Reviewed-by: Rae Moar Signed-off-by: Sergio González Collado Link: https://github.com/Rust-for-Linux/linux/issues/504 Reviewed-by: Rae Moar Acked-by: David Gow Signed-off-by: Shuah Khan Signed-off-by: Greg Kroah-Hartman

Merge tag 'perf-urgent-2024-05-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-05-19T18:32:42+00:00

Pull perf event updates from Ingo Molnar: - Extend the x86 instruction decoder with APX and other new instructions - Misc cleanups * tag 'perf-urgent-2024-05-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/cstate: Remove unused 'struct perf_cstate_msr' perf/x86/rapl: Rename 'maxdie' to nr_rapl_pmu and 'dieid' to rapl_pmu_idx x86/insn: Add support for APX EVEX instructions to the opcode map x86/insn: Add support for APX EVEX to the instruction decoder logic x86/insn: x86/insn: Add support for REX2 prefix to the instruction decoder opcode map x86/insn: Add support for REX2 prefix to the instruction decoder logic x86/insn: Add misc new Intel instructions x86/insn: Add VEX versions of VPDPBUSD, VPDPBUSDS, VPDPWSSD and VPDPWSSDS x86/insn: Fix PUSH instruction in x86 instruction decoder opcode map x86/insn: Add Key Locker instructions to the opcode map

x86/insn: Add support for APX EVEX to the instruction decoder logic

2024-05-02T11:13:45+00:00

Intel Advanced Performance Extensions (APX) extends the EVEX prefix to support: - extended general purpose registers (EGPRs) i.e. r16 to r31 - Push-Pop Acceleration (PPX) hints - new data destination (NDD) register - suppress status flags writes (NF) of common instructions - new instructions Refer to the Intel Advanced Performance Extensions (Intel APX) Architecture Specification for details. The extended EVEX prefix does not need amended instruction decoder logic, except in one area. Some instructions are defined as SCALABLE which means the EVEX.W bit and EVEX.pp bits are used to determine operand size. Specifically, if an instruction is SCALABLE and EVEX.W is zero, then EVEX.pp value 0 (representing no prefix NP) means default operand size, whereas EVEX.pp value 1 (representing 66 prefix) means operand size override i.e. 16 bits Add an attribute (INAT_EVEX_SCALABLE) to identify such instructions, and amend the logic appropriately. Amend the awk script that generates the attribute tables from the opcode map, to recognise "(es)" as attribute INAT_EVEX_SCALABLE. Signed-off-by: Adrian Hunter Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240502105853.5338-8-adrian.hunter@intel.com

x86/insn: Add support for REX2 prefix to the instruction decoder logic

2024-05-02T11:13:44+00:00

Intel Advanced Performance Extensions (APX) uses a new 2-byte prefix named REX2 to select extended general purpose registers (EGPRs) i.e. r16 to r31. The REX2 prefix is effectively an extended version of the REX prefix. REX2 and EVEX are also used with PUSH/POP instructions to provide a Push-Pop Acceleration (PPX) hint. With PPX hints, a CPU will attempt to fast-forward register data between matching PUSH and POP instructions. REX2 is valid only with opcodes in maps 0 and 1. Similar extension for other maps is provided by the EVEX prefix, covered in a separate patch. Some opcodes in maps 0 and 1 are reserved under REX2. One of these is used for a new 64-bit absolute direct jump instruction JMPABS. Refer to the Intel Advanced Performance Extensions (Intel APX) Architecture Specification for details. Define a code value for the REX2 prefix (INAT_PFX_REX2), and add attribute flags for opcodes reserved under REX2 (INAT_NO_REX2) and to identify opcodes (only JMPABS) that require a mandatory REX2 prefix (INAT_REX2_VARIANT). Amend logic to read the REX2 prefix and get the opcode attribute for the map number (0 or 1) encoded in the REX2 prefix. Amend the awk script that generates the attribute tables from the opcode map, to recognise "REX2" as attribute INAT_PFX_REX2, and "(!REX2)" as attribute INAT_NO_REX2, and "(REX2)" as attribute INAT_REX2_VARIANT. Signed-off-by: Adrian Hunter Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240502105853.5338-6-adrian.hunter@intel.com

x86/build: Clean up arch/x86/tools/relocs.c a bit

2024-03-24T04:01:35+00:00

So: - Follow Documentation/CodingStyle for: - curly braces - variable definitions - return statements - etc. - Fix unnecessary linebreaks - Don't split user-visible error strings over multiple lines ... - It's fine to use vertical alignment to make code more readable, but it should be internally consistent for definitions visible on a single page ... - There's 40+ die() statements that are basically asserts and never trigger. Make them single-line, to move them out of sight as much as possible. Signed-off-by: Ingo Molnar Cc: linux-kernel@vger.kernel.org

x86/boot: Ignore relocations in .notes sections in walk_relocs() too

2024-03-22T08:48:59+00:00

Commit: aaa8736370db ("x86, relocs: Ignore relocations in .notes section") ... only started ignoring the .notes sections in print_absolute_relocs(), but the same logic should also by applied in walk_relocs() to avoid such relocations. [ mingo: Fixed various typos in the changelog, removed extra curly braces from the code. ] Fixes: aaa8736370db ("x86, relocs: Ignore relocations in .notes section") Fixes: 5ead97c84fa7 ("xen: Core Xen implementation") Fixes: da1a679cde9b ("Add /sys/kernel/notes") Signed-off-by: Guixiong Wei Signed-off-by: Ingo Molnar Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20240317150547.24910-1-weiguixiong@bytedance.com

x86, relocs: Ignore relocations in .notes section

2024-03-01T06:34:42+00:00

When building with CONFIG_XEN_PV=y, .text symbols are emitted into the .notes section so that Xen can find the "startup_xen" entry point. This information is used prior to booting the kernel, so relocations are not useful. In fact, performing relocations against the .notes section means that the KASLR base is exposed since /sys/kernel/notes is world-readable. To avoid leaking the KASLR base without breaking unprivileged tools that are expecting to read /sys/kernel/notes, skip performing relocations in the .notes section. The values readable in .notes are then identical to those found in System.map. Reported-by: Guixiong Wei Closes: https://lore.kernel.org/all/20240218073501.54555-1-guixiongwei@gmail.com/ Fixes: 5ead97c84fa7 ("xen: Core Xen implementation") Fixes: da1a679cde9b ("Add /sys/kernel/notes") Reviewed-by: Juergen Gross Signed-off-by: Kees Cook

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

2024-01-09T01:22:02+00:00

Pull x86 build updates from Ingo Molnar: - Update the objdump & instruction decoder self-test code for better LLVM toolchain compatibility - Rework CONFIG_X86_PAE dependencies, for better readability and higher robustness. - Misc cleanups * tag 'x86-build-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/tools: objdump_reformat.awk: Skip bad instructions from llvm-objdump x86/Kconfig: Rework CONFIG_X86_PAE dependency x86/tools: Remove chkobjdump.awk x86/tools: objdump_reformat.awk: Allow for spaces x86/tools: objdump_reformat.awk: Ensure regex matches fwait

x86/tools: objdump_reformat.awk: Skip bad instructions from llvm-objdump

2024-01-04T09:04:02+00:00

When running the instruction decoder selftest with LLVM=1 and CONFIG_PVH=y, there is a series of warnings: arch/x86/tools/insn_decoder_test: warning: Found an x86 instruction decoder bug, please report this. arch/x86/tools/insn_decoder_test: warning: ffffffff81000050 ea arch/x86/tools/insn_decoder_test: warning: objdump says 1 bytes, but insn_get_length() says 7 arch/x86/tools/insn_decoder_test: warning: Decoded and checked 7214721 instructions with 1 failures GNU objdump outputs "(bad)" instead of "", which is already handled in the bad_expr regex, so there is no warning. $ objdump -d arch/x86/platform/pvh/head.o | grep -E '50:\s+ea' 50: ea (bad) $ llvm-objdump -d arch/x86/platform/pvh/head.o | grep -E '50:\s+ea' 50: ea Add "" to the bad_expr regex to clear up the warning, allowing the instruction decoder selftest to fully pass with llvm-objdump. Signed-off-by: Nathan Chancellor Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20231205-objdump_reformat-awk-handle-llvm-objdump-bad_expr-v1-1-b4a74f39396f@kernel.org