kernel.git/arch/x86/kernel/head_64.S, branch linux-5.13.y

Merge tag 'x86_build_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-12-14T21:54:50Z

Pull x86 build updates from Borislav Petkov: "Two x86 build fixes: - Fix the vmlinux size check on 64-bit along with adding useful clarifications on the topic (Arvind Sankar) - Remove -m16 workaround now that the GCC versions that need it are unsupported (Nick Desaulniers)" * tag 'x86_build_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/build: Remove -m16 workaround for unsupported versions of GCC x86/build: Fix vmlinux size check on 64-bit

Merge tag 'x86_cleanups_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-12-14T21:45:26Z

Pull x86 cleanups from Borislav Petkov: "Another branch with a nicely negative diffstat, just the way I like 'em: - Remove all uses of TIF_IA32 and TIF_X32 and reclaim the two bits in the end (Gabriel Krisman Bertazi) - All kinds of minor cleanups all over the tree" * tag 'x86_cleanups_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) x86/ia32_signal: Propagate __user annotation properly x86/alternative: Update text_poke_bp() kernel-doc comment x86/PCI: Make a kernel-doc comment a normal one x86/asm: Drop unused RDPID macro x86/boot/compressed/64: Use TEST %reg,%reg instead of CMP $0,%reg x86/head64: Remove duplicate include x86/mm: Declare 'start' variable where it is used x86/head/64: Remove unused GET_CR2_INTO() macro x86/boot: Remove unused finalize_identity_maps() x86/uaccess: Document copy_from_user_nmi() x86/dumpstack: Make show_trace_log_lvl() static x86/mtrr: Fix a kernel-doc markup x86/setup: Remove unused MCA variables x86, libnvdimm/test: Remove COPY_MC_TEST x86: Reclaim TIF_IA32 and TIF_X32 x86/mm: Convert mmu context ia32_compat into a proper flags field x86/elf: Use e_machine to check for x32/ia32 in setup_additional_pages() elf: Expose ELF header on arch_setup_additional_pages() x86/elf: Use e_machine to select start_thread for x32 elf: Expose ELF header in compat_start_thread() ...

x86/head/64: Remove unused GET_CR2_INTO() macro

2020-11-18T17:09:38Z

Commit 4b47cdbda6f1 ("x86/head/64: Move early exception dispatch to C code") removed the usage of GET_CR2_INTO(). Drop the definition as well, and related definitions in paravirt.h and asm-offsets.h Signed-off-by: Arvind Sankar Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20201005151208.2212886-3-nivedita@alum.mit.edu

x86/build: Fix vmlinux size check on 64-bit

2020-10-29T20:54:35Z

Commit b4e0409a36f4 ("x86: check vmlinux limits, 64-bit") added a check that the size of the 64-bit kernel is less than KERNEL_IMAGE_SIZE. The check uses (_end - _text), but this is not enough. The initial PMD used in startup_64() (level2_kernel_pgt) can only map upto KERNEL_IMAGE_SIZE from __START_KERNEL_map, not from _text, and the modules area (MODULES_VADDR) starts at KERNEL_IMAGE_SIZE. The correct check is what is currently done for 32-bit, since LOAD_OFFSET is defined appropriately for the two architectures. Just check (_end - LOAD_OFFSET) against KERNEL_IMAGE_SIZE unconditionally. Note that on 32-bit, the limit is not strict: KERNEL_IMAGE_SIZE is not really used by the main kernel. The higher the kernel is located, the less the space available for the vmalloc area. However, it is used by KASLR in the compressed stub to limit the maximum address of the kernel to a safe value. Clean up various comments to clarify that despite the name, KERNEL_IMAGE_SIZE is not a limit on the size of the kernel image, but a limit on the maximum virtual address that the image can occupy. Signed-off-by: Arvind Sankar Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20201029161903.2553528-1-nivedita@alum.mit.edu

x86/head/64: Check SEV encryption before switching to kernel page-table

2020-10-29T17:09:59Z

When SEV is enabled, the kernel requests the C-bit position again from the hypervisor to build its own page-table. Since the hypervisor is an untrusted source, the C-bit position needs to be verified before the kernel page-table is used. Call sev_verify_cbit() before writing the CR3. [ bp: Massage. ] Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Reviewed-by: Tom Lendacky Link: https://lkml.kernel.org/r/20201028164659.27002-5-joro@8bytes.org

x86/head/64: Don't call verify_cpu() on starting APs

2020-09-09T09:33:20Z

The APs are not ready to handle exceptions when verify_cpu() is called in secondary_startup_64(). Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Reviewed-by: Kees Cook Link: https://lkml.kernel.org/r/20200907131613.12703-69-joro@8bytes.org

x86/sev-es: Setup GHCB-based boot #VC handler

2020-09-09T09:32:27Z

Add the infrastructure to handle #VC exceptions when the kernel runs on virtual addresses and has mapped a GHCB. This handler will be used until the runtime #VC handler takes over. Since the handler runs very early, disable instrumentation for sev-es.c. [ bp: Make vc_ghcb_invalidate() __always_inline so that it can be inlined in noinstr functions like __sev_es_nmi_complete(). ] Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200908123816.GB3764@8bytes.org

x86/sev-es: Setup an early #VC handler

2020-09-09T08:45:24Z

Setup an early handler for #VC exceptions. There is no GHCB mapped yet, so just re-use the vc_no_ghcb_handler(). It can only handle CPUID exit-codes, but that should be enough to get the kernel through verify_cpu() and __startup_64() until it runs on virtual addresses. Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov [ boot failure Error: kernel_ident_mapping_init() failed. ] Reported-by: kernel test robot Link: https://lkml.kernel.org/r/20200908123517.GA3764@8bytes.org

x86/head/64: Move early exception dispatch to C code

2020-09-07T20:49:18Z

Move the assembly coded dispatch between page-faults and all other exceptions to C code to make it easier to maintain and extend. Also change the return-type of early_make_pgtable() to bool and make it static. Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200907131613.12703-36-joro@8bytes.org

x86/head/64: Install a CPU bringup IDT

2020-09-07T20:18:38Z

Add a separate bringup IDT for the CPU bringup code that will be used until the kernel switches to the idt_table. There are two reasons for a separate IDT: 1) When the idt_table is set up and the secondary CPUs are booted, it contains entries (e.g. IST entries) which require certain CPU state to be set up. This includes a working TSS (for IST), MSR_GS_BASE (for stack protector) or CR4.FSGSBASE (for paranoid_entry) path. By using a dedicated IDT for early boot this state need not to be set up early. 2) The idt_table is static to idt.c, so any function using/modifying must be in idt.c too. That means that all compiler driven instrumentation like tracing or KASAN is also active in this code. But during early CPU bringup the environment is not set up for this instrumentation to work correctly. To avoid all of these hassles and make early exception handling robust, use a dedicated bringup IDT. The IDT is loaded two times, first on the boot CPU while the kernel is still running on direct mapped addresses, and again later after the switch to kernel addresses has happened. The second IDT load happens on the boot and secondary CPUs. Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200907131613.12703-34-joro@8bytes.org