linux-dev/arch/x86/boot/compressed/misc.c, branch linus/master

Merge tag 'x86_tdx_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-05-24T00:51:12Z

Pull Intel TDX support from Borislav Petkov: "Intel Trust Domain Extensions (TDX) support. This is the Intel version of a confidential computing solution called Trust Domain Extensions (TDX). This series adds support to run the kernel as part of a TDX guest. It provides similar guest protections to AMD's SEV-SNP like guest memory and register state encryption, memory integrity protection and a lot more. Design-wise, it differs from AMD's solution considerably: it uses a software module which runs in a special CPU mode called (Secure Arbitration Mode) SEAM. As the name suggests, this module serves as sort of an arbiter which the confidential guest calls for services it needs during its lifetime. Just like AMD's SNP set, this series reworks and streamlines certain parts of x86 arch code so that this feature can be properly accomodated" * tag 'x86_tdx_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits) x86/tdx: Fix RETs in TDX asm x86/tdx: Annotate a noreturn function x86/mm: Fix spacing within memory encryption features message x86/kaslr: Fix build warning in KASLR code in boot stub Documentation/x86: Document TDX kernel architecture ACPICA: Avoid cache flush inside virtual machines x86/tdx/ioapic: Add shared bit for IOAPIC base address x86/mm: Make DMA memory shared for TD guest x86/mm/cpa: Add support for TDX shared memory x86/tdx: Make pages shared in ioremap() x86/topology: Disable CPU online/offline control for TDX guests x86/boot: Avoid #VE during boot for TDX platforms x86/boot: Set CR0.NE early and keep it set during the boot x86/acpi/x86/boot: Add multiprocessor wake-up support x86/boot: Add a trampoline for booting APs via firmware handoff x86/tdx: Wire up KVM hypercalls x86/tdx: Port I/O: Add early boot support x86/tdx: Port I/O: Add runtime hypercalls x86/boot: Port I/O: Add decompression-time support for TDX x86/boot: Port I/O: Allow to hook up alternative helpers ...

x86/boot: Put globals that are accessed early into the .data section

2022-04-20T18:10:54Z

The helpers in arch/x86/boot/compressed/efi.c might be used during early boot to access the EFI system/config tables, and in some cases these EFI helpers might attempt to print debug/error messages, before console_init() has been called. __putstr() checks some variables to avoid printing anything before the console has been initialized, but this isn't enough since those variables live in .bss, which may not have been cleared yet. This can lead to a triple-fault occurring, primarily when booting in legacy/CSM mode (where EFI helpers will attempt to print some debug messages). Fix this by declaring these globals in .data section instead so there is no dependency on .bss being cleared before accessing them. Fixes: c01fce9cef849 ("x86/compressed: Add SEV-SNP feature detection/setup") Reported-by: Borislav Petkov Suggested-by: Thomas Lendacky Signed-off-by: Michael Roth Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220420152613.145077-1-michael.roth@amd.com

x86/boot: Port I/O: Allow to hook up alternative helpers

2022-04-07T15:27:52Z

Port I/O instructions trigger #VE in the TDX environment. In response to the exception, kernel emulates these instructions using hypercalls. But during early boot, on the decompression stage, it is cumbersome to deal with #VE. It is cleaner to go to hypercalls directly, bypassing #VE handling. Add a way to hook up alternative port I/O helpers in the boot stub with a new pio_ops structure. For now, set the ops structure to just call the normal I/O operation functions. out*()/in*() macros redefined to use pio_ops callbacks. It eliminates need in changing call sites. io_delay() changed to use port I/O helper instead of inline assembly. Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen Reviewed-by: Dave Hansen Link: https://lkml.kernel.org/r/20220405232939.73860-16-kirill.shutemov@linux.intel.com

x86/tdx: Detect TDX at early kernel decompression time

2022-04-07T15:27:51Z

The early decompression code does port I/O for its console output. But, handling the decompression-time port I/O demands a different approach from normal runtime because the IDT required to support #VE based port I/O emulation is not yet set up. Paravirtualizing I/O calls during the decompression step is acceptable because the decompression code doesn't have a lot of call sites to IO instruction. To support port I/O in decompression code, TDX must be detected before the decompression code might do port I/O. Detect whether the kernel runs in a TDX guest. Add an early_is_tdx_guest() interface to query the cached TDX guest status in the decompression code. TDX is detected with CPUID. Make cpuid_count() accessible outside boot/cpuflags.c. TDX detection in the main kernel is very similar. Move common bits into . The actual port I/O paravirtualization will come later in the series. Signed-off-by: Kuppuswamy Sathyanarayanan Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen Reviewed-by: Tony Luck Reviewed-by: Dave Hansen Link: https://lkml.kernel.org/r/20220405232939.73860-13-kirill.shutemov@linux.intel.com

fortify: Detect struct member overflows in memmove() at compile-time

2022-02-14T00:50:06Z

As done for memcpy(), also update memmove() to use the same tightened compile-time checks under CONFIG_FORTIFY_SOURCE. Signed-off-by: Kees Cook

x86/boot/compressed: Avoid duplicate malloc() implementations

2021-10-27T09:07:59Z

The early malloc() and free() implementation in include/linux/decompress/mm.h (which is also included by the static decompressors) is static. This is fine when the only thing interested in using malloc() is the decompression code, but the x86 early boot environment may use malloc() in a couple places, leading to a potential collision when the static copies of the available memory region ("malloc_ptr") gets reset to the global "free_mem_ptr" value. As it happened, the existing usage pattern was accidentally safe because each user did 1 malloc() and 1 free() before returning and were not nested: extract_kernel() (misc.c) choose_random_location() (kaslr.c) mem_avoid_init() handle_mem_options() malloc() ... free() ... parse_elf() (misc.c) malloc() ... free() Once the future FGKASLR series is added, however, it will insert additional malloc() calls local to fgkaslr.c in the middle of parse_elf()'s malloc()/free() pair: parse_elf() (misc.c) malloc() if (...) { layout_randomized_image(output, &ehdr, phdrs); malloc() <- boom ... else layout_image(output, &ehdr, phdrs); free() To avoid collisions, there must be a single implementation of malloc(). Adjust include/linux/decompress/mm.h so that visibility can be controlled, provide prototypes in misc.h, and implement the functions in misc.c. This also results in a small size savings: $ size vmlinux.before vmlinux.after text data bss dec hex filename 8842314 468 178320 9021102 89a6ae vmlinux.before 8842240 468 178320 9021028 89a664 vmlinux.after Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20211013175742.1197608-4-keescook@chromium.org

x86/boot/compressed: Enable -Wundef

2021-05-12T19:39:56Z

A discussion around -Wundef showed that there were still a few boolean Kconfigs where #if was used rather than #ifdef to guard different code. Kconfig doesn't define boolean configs, which can result in -Wundef warnings. arch/x86/boot/compressed/Makefile resets the CFLAGS used for this directory, and doesn't re-enable -Wundef as the top level Makefile does. If re-added, with RANDOMIZE_BASE and X86_NEED_RELOCS disabled, the following warnings are visible. arch/x86/boot/compressed/misc.h:82:5: warning: 'CONFIG_RANDOMIZE_BASE' is not defined, evaluates to 0 [-Wundef] ^ arch/x86/boot/compressed/misc.c:175:5: warning: 'CONFIG_X86_NEED_RELOCS' is not defined, evaluates to 0 [-Wundef] ^ Simply fix these and re-enable this warning for this directory. Suggested-by: Nathan Chancellor Suggested-by: Joe Perches Signed-off-by: Nick Desaulniers Signed-off-by: Ingo Molnar Acked-by: Kees Cook Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20210422190450.3903999-1-ndesaulniers@google.com

Merge tag 'x86_boot_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-04-26T16:24:06Z

Pull x86 boot updates from Borislav Petkov: "Consolidation and cleanup of the early memory reservations, along with a couple of gcc11 warning fixes" * tag 'x86_boot_for_v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/setup: Move trim_snb_memory() later in setup_arch() to fix boot hangs x86/setup: Merge several reservations of start of memory x86/setup: Consolidate early memory reservations x86/boot/compressed: Avoid gcc-11 -Wstringop-overread warning x86/boot/tboot: Avoid Wstringop-overread-warning

x86/boot/compressed: Avoid gcc-11 -Wstringop-overread warning

2021-03-22T23:16:25Z

GCC gets confused by the comparison of a pointer to an integer literal, with the assumption that this is an offset from a NULL pointer and that dereferencing it is invalid: In file included from arch/x86/boot/compressed/misc.c:18: In function ‘parse_elf’, inlined from ‘extract_kernel’ at arch/x86/boot/compressed/misc.c:442:2: arch/x86/boot/compressed/../string.h:15:23: error: ‘__builtin_memcpy’ reading 64 bytes from a region of size 0 [-Werror=stringop-overread] 15 | #define memcpy(d,s,l) __builtin_memcpy(d,s,l) | ^~~~~~~~~~~~~~~~~~~~~~~ arch/x86/boot/compressed/misc.c:283:9: note: in expansion of macro ‘memcpy’ 283 | memcpy(&ehdr, output, sizeof(ehdr)); | ^~~~~~ I could not find any good workaround for this, but as this is only a warning for a failure during early boot, removing the line entirely works around the warning. Signed-off-by: Arnd Bergmann Signed-off-by: Ingo Molnar Cc: Linus Torvalds Cc: Martin Sebor Link: https://lore.kernel.org/r/20210322160253.4032422-2-arnd@kernel.org

x86/boot/compressed/64: Cleanup exception handling before booting kernel

2021-03-18T15:44:36Z

Disable the exception handling before booting the kernel to make sure any exceptions that happen during early kernel boot are not directed to the pre-decompression code. Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210312123824.306-2-joro@8bytes.org