user/sven/linux.git/arch/x86/Kbuild, branch master

x86/kbuild: Incorporate boot/startup/ via Kbuild makefile

2025-09-03T15:59:59Z

Using core-y is not the correct way to get kbuild to descend into arch/x86/boot/startup. For instance, building an individual object does not work as expected when the pattern rule is local to the Makefile $ make arch/x86/boot/startup/map_kernel.pi.o GEN Makefile CALL /home/ardb/linux/scripts/checksyscalls.sh DESCEND objtool INSTALL libsubcmd_headers make[3]: *** No rule to make target 'arch/x86/boot/startup/map_kernel.pi.o'. Stop. make[2]: *** [/home/ardb/linux/scripts/Makefile.build:461: arch/x86] Error 2 make[1]: *** [/home/ardb/linux/Makefile:2011: .] Error 2 make: *** [/home/ardb/linux/Makefile:248: __sub-make] Error 2 So use obj-y from arch.x86/Kbuild instead, which makes things work as expected. Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/20250828102202.1849035-42-ardb+git@google.com

tracing: Disable branch profiling in noinstr code

2025-03-22T08:49:26Z

CONFIG_TRACE_BRANCH_PROFILING inserts a call to ftrace_likely_update() for each use of likely() or unlikely(). That breaks noinstr rules if the affected function is annotated as noinstr. Disable branch profiling for files with noinstr functions. In addition to some individual files, this also includes the entire arch/x86 subtree, as well as the kernel/entry, drivers/cpuidle, and drivers/idle directories, all of which are noinstr-heavy. Due to the nature of how sched binaries are built by combining multiple .c files into one, branch profiling is disabled more broadly across the sched code than would otherwise be needed. This fixes many warnings like the following: vmlinux.o: warning: objtool: do_syscall_64+0x40: call to ftrace_likely_update() leaves .noinstr.text section vmlinux.o: warning: objtool: __rdgsbase_inactive+0x33: call to ftrace_likely_update() leaves .noinstr.text section vmlinux.o: warning: objtool: handle_bug.isra.0+0x198: call to ftrace_likely_update() leaves .noinstr.text section ... Reported-by: Ingo Molnar Suggested-by: Steven Rostedt Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Acked-by: Thomas Gleixner Cc: Linus Torvalds Link: https://lore.kernel.org/r/fb94fc9303d48a5ed370498f54500cc4c338eb6d.1742586676.git.jpoimboe@kernel.org

x86/build: Use obj-y to descend into arch/x86/virt/

2024-03-30T09:41:49Z

Commit c33621b4c5ad ("x86/virt/tdx: Wire up basic SEAMCALL functions") introduced a new instance of core-y instead of the standardized obj-y syntax. X86 Makefiles descend into subdirectories of arch/x86/virt inconsistently; into arch/x86/virt/ via core-y defined in arch/x86/Makefile, but into arch/x86/virt/svm/ via obj-y defined in arch/x86/Kbuild. This is problematic when you build a single object in parallel because multiple threads attempt to build the same file. $ make -j$(nproc) arch/x86/virt/vmx/tdx/seamcall.o [ snip ] AS arch/x86/virt/vmx/tdx/seamcall.o AS arch/x86/virt/vmx/tdx/seamcall.o fixdep: error opening file: arch/x86/virt/vmx/tdx/.seamcall.o.d: No such file or directory make[4]: *** [scripts/Makefile.build:362: arch/x86/virt/vmx/tdx/seamcall.o] Error 2 Use the obj-y syntax, as it works correctly. Signed-off-by: Masahiro Yamada Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240330060554.18524-1-masahiroy@kernel.org

x86/sev: Add SEV-SNP host initialization support

2024-01-29T16:20:23Z

The memory integrity guarantees of SEV-SNP are enforced through a new structure called the Reverse Map Table (RMP). The RMP is a single data structure shared across the system that contains one entry for every 4K page of DRAM that may be used by SEV-SNP VMs. The APM Volume 2 section on Secure Nested Paging (SEV-SNP) details a number of steps needed to detect/enable SEV-SNP and RMP table support on the host: - Detect SEV-SNP support based on CPUID bit - Initialize the RMP table memory reported by the RMP base/end MSR registers and configure IOMMU to be compatible with RMP access restrictions - Set the MtrrFixDramModEn bit in SYSCFG MSR - Set the SecureNestedPagingEn and VMPLEn bits in the SYSCFG MSR - Configure IOMMU RMP table entry format is non-architectural and it can vary by processor. It is defined by the PPR document for each respective CPU family. Restrict SNP support to CPU models/families which are compatible with the current RMP table entry format to guard against any undefined behavior when running on other system types. Future models/support will handle this through an architectural mechanism to allow for broader compatibility. SNP host code depends on CONFIG_KVM_AMD_SEV config flag which may be enabled even when CONFIG_AMD_MEM_ENCRYPT isn't set, so update the SNP-specific IOMMU helpers used here to rely on CONFIG_KVM_AMD_SEV instead of CONFIG_AMD_MEM_ENCRYPT. Signed-off-by: Brijesh Singh Co-developed-by: Ashish Kalra Signed-off-by: Ashish Kalra Co-developed-by: Tom Lendacky Signed-off-by: Tom Lendacky Co-developed-by: Borislav Petkov (AMD) Signed-off-by: Borislav Petkov (AMD) Co-developed-by: Michael Roth Signed-off-by: Michael Roth Link: https://lore.kernel.org/r/20240126041126.1927228-5-michael.roth@amd.com

x86/cc: Move arch/x86/{kernel/cc_platform.c => coco/core.c}

2022-02-23T17:25:58Z

Move cc_platform.c to arch/x86/coco/. The directory is going to be the home space for code related to confidential computing. Intel TDX code will land here. AMD SEV code will also eventually be moved there. No functional changes. Signed-off-by: Kirill A. Shutemov Signed-off-by: Borislav Petkov Reviewed-by: Tom Lendacky Link: https://lore.kernel.org/r/20220222185740.26228-3-kirill.shutemov@linux.intel.com

kbuild: use more subdir- for visiting subdirectories while cleaning

2021-10-24T04:49:46Z

Documentation/kbuild/makefiles.rst suggests to use "archclean" for cleaning arch/$(SRCARCH)/boot/, but it is not a hard requirement. Since commit d92cc4d51643 ("kbuild: require all architectures to have arch/$(SRCARCH)/Kbuild"), we can use the "subdir- += boot" trick for all architectures. This can take advantage of the parallel option (-j) for "make clean". I also cleaned up the comments in arch/$(SRCARCH)/Makefile. The "archdep" target no longer exists. Signed-off-by: Masahiro Yamada Reviewed-by: Kees Cook Acked-by: Geert Uytterhoeven Acked-by: Michael Ellerman (powerpc)

treewide: Add SPDX license identifier - Kbuild

2019-05-30T18:32:33Z

Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0 Reported-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman Reviewed-by: Kate Stewart Signed-off-by: Greg Kroah-Hartman

KVM: x86: Allow Qemu/KVM to use PVH entry point

2018-12-13T18:41:49Z

For certain applications it is desirable to rapidly boot a KVM virtual machine. In cases where legacy hardware and software support within the guest is not needed, Qemu should be able to boot directly into the uncompressed Linux kernel binary without the need to run firmware. There already exists an ABI to allow this for Xen PVH guests and the ABI is supported by Linux and FreeBSD: https://xenbits.xen.org/docs/unstable/misc/pvh.html This patch enables Qemu to use that same entry point for booting KVM guests. Signed-off-by: Maran Wilson Suggested-by: Konrad Rzeszutek Wilk Suggested-by: Boris Ostrovsky Tested-by: Boris Ostrovsky Reviewed-by: Juergen Gross Signed-off-by: Boris Ostrovsky

xen/pvh: Move PVH entry code out of Xen specific tree

2018-12-13T18:41:49Z

Once hypervisors other than Xen start using the PVH entry point for starting VMs, we would like the option of being able to compile PVH entry capable kernels without enabling CONFIG_XEN and all the code that comes along with that. To allow that, we are moving the PVH code out of Xen and into files sitting at a higher level in the tree. This patch is not introducing any code or functional changes, just moving files from one location to another. Signed-off-by: Maran Wilson Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Juergen Gross Signed-off-by: Boris Ostrovsky

Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-09-07T16:25:15Z

Pull x86 platform updates from Ingo Molnar: "The main changes include various Hyper-V optimizations such as faster hypercalls and faster/better TLB flushes - and there's also some Intel-MID cleanups" * 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tracing/hyper-v: Trace hyperv_mmu_flush_tlb_others() x86/hyper-v: Support extended CPU ranges for TLB flush hypercalls x86/platform/intel-mid: Make several arrays static, to make code smaller MAINTAINERS: Add missed file for Hyper-V x86/hyper-v: Use hypercall for remote TLB flush hyper-v: Globalize vp_index x86/hyper-v: Implement rep hypercalls hyper-v: Use fast hypercall for HVCALL_SIGNAL_EVENT x86/hyper-v: Introduce fast hypercall implementation x86/hyper-v: Make hv_do_hypercall() inline x86/hyper-v: Include hyperv/ only when CONFIG_HYPERV is set x86/platform/intel-mid: Make 'bt_sfi_data' const x86/platform/intel-mid: Make IRQ allocation a bit more flexible x86/platform/intel-mid: Group timers callbacks together