kernel/arch/x86/boot/boot.h, branch linux-rolling-stable

x86/{boot,mtrr}: Remove unused function declarations

2025-11-22T20:26:36Z

Commits 28be1b454c2b ("x86/boot: Remove unused copy_*_gs() functions") 34d2819f2078 ("x86, mtrr: Remove unused mtrr/state.c") removed the functions but left the prototypes. Remove them. [ bp: Merge into a single patch. ] Signed-off-by: Yue Haibing Signed-off-by: Borislav Petkov (AMD) Link: https://patch.msgid.link/20251120121037.1479334-1-yuehaibing@huawei.com

x86/asm: Remove code depending on __GCC_ASM_FLAG_OUTPUTS__

2025-09-08T13:38:06Z

The minimum supported GCC version is 8.1, which supports flag output operands and always defines __GCC_ASM_FLAG_OUTPUTS__ macro. Remove code depending on __GCC_ASM_FLAG_OUTPUTS__ and use the "=@ccCOND" flag output operand directly. Use the equivalent "=@ccz" instead of "=@cce" flag output operand for CMPXCHG8B and CMPXCHG16B instructions. These instructions set a single flag bit - the Zero flag - and "=@ccz" is used to distinguish the CC user from comparison instructions, where set ZERO flag indeed means that the values are equal. Signed-off-by: Uros Bizjak Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20250905121723.GCaLrU04lP2A50PT-B@fat_crate.local

Merge branch 'x86/boot' into x86/core, to merge dependent commits

2025-05-13T08:35:27Z

Prepare to resolve conflicts with an upstream series of fixes that conflict with pending x86 changes: 6f5bf947bab0 Merge tag 'its-for-linus-20250509' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Signed-off-by: Ingo Molnar

x86/asm: Replace "REP; NOP" with PAUSE mnemonic

2025-04-18T08:19:25Z

Current minimum required version of binutils is 2.25, which supports PAUSE instruction mnemonic. Replace "REP; NOP" with this proper mnemonic. No functional change intended. Reviewed-by: Nikolay Borisov Signed-off-by: Uros Bizjak Signed-off-by: Ingo Molnar Cc: H. Peter Anvin Link: https://lore.kernel.org/r/20250418080805.83679-2-ubizjak@gmail.com

x86/boot: Remove semicolon from "rep" prefixes

2025-04-18T07:32:57Z

Minimum version of binutils required to compile the kernel is 2.25. This version correctly handles the "rep" prefixes, so it is possible to remove the semicolon, which was used to support ancient versions of GNU as. Due to the semicolon, the compiler considers "rep; insn" (or its alternate "rep\n\tinsn" form) as two separate instructions. Removing the semicolon makes asm length calculations more accurate, consequently making scheduling and inlining decisions of the compiler more accurate. Removing the semicolon also enables assembler checks involving "rep" prefixes. Trying to assemble e.g. "rep addl %eax, %ebx" results in: Error: invalid instruction `add' after `rep' Signed-off-by: Uros Bizjak Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Brian Gerst Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kees Cook Cc: Linus Torvalds Cc: Martin Mares Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250418071437.4144391-1-ubizjak@gmail.com

x86/headers: Replace ASSEMBLY with ASSEMBLER in non-UAPI headers

2025-03-19T10:47:30Z

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 , and that mentioned this macro in comments with some missing underscores. Signed-off-by: Thomas Huth Signed-off-by: Ingo Molnar Cc: Brian Gerst Cc: Juergen Gross Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Link: https://lore.kernel.org/r/20250314071013.1575167-38-thuth@redhat.com

x86/boot: Remove unused function atou()

2024-11-07T17:08:23Z

I can't find any sign of atou() having been used. Remove it. Signed-off-by: Dr. David Alan Gilbert Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240913005753.1392431-1-linux@treblig.org

Merge tag 'x86_build_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-05-24T01:15:44Z

Pull x86 build updates from Borislav Petkov: - Add a "make x86_debug.config" target which enables a bunch of useful config debug options when trying to debug an issue - A gcc-12 build warnings fix * tag 'x86_build_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Wrap literal addresses in absolute_pointer() x86/configs: Add x86 debugging Kconfig fragment plus docs

x86/boot: Wrap literal addresses in absolute_pointer()

2022-05-19T10:47:30Z

GCC 11 (incorrectly[1]) assumes that literal values cast to (void *) should be treated like a NULL pointer with an offset, and raises diagnostics when doing bounds checking under -Warray-bounds. GCC 12 got "smarter" about finding these: In function 'rdfs8', inlined from 'vga_recalc_vertical' at /srv/code/arch/x86/boot/video-mode.c:124:29, inlined from 'set_mode' at /srv/code/arch/x86/boot/video-mode.c:163:3: /srv/code/arch/x86/boot/boot.h:114:9: warning: array subscript 0 is outside array bounds of 'u8[0]' {aka 'unsigned char[]'} [-Warray-bounds] 114 | asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr)); | ^~~ This has been solved in other places[2] already by using the recently added absolute_pointer() macro. Do the same here. [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578 [2] https://lore.kernel.org/all/20210912160149.2227137-1-linux@roeck-us.net/ Signed-off-by: Kees Cook Signed-off-by: Borislav Petkov Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/20220227195918.705219-1-keescook@chromium.org

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