kernel/arch/x86/include/asm/bug.h, branch linux-rolling-stable

Merge tag 'x86-urgent-2025-12-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-12-21T22:41:29Z

Pull x86 fixes from Ingo Molnar: - Fix FPU core dumps on certain CPU models - Fix htmldocs build warning - Export TLB tracing event name via header - Remove unused constant from - Fix comments - Fix whitespace noise in documentation - Fix variadic structure's definition to un-confuse UBSAN - Fix posted MSI interrupts irq_retrigger() bug - Fix asm build failure with older GCC builds * tag 'x86-urgent-2025-12-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/bug: Fix old GCC compile fails x86/msi: Make irq_retrigger() functional for posted MSI x86/platform/uv: Fix UBSAN array-index-out-of-bounds mm: Remove tlb_flush_reason::NR_TLB_FLUSH_REASONS from x86/mm/tlb/trace: Export the TLB_REMOTE_WRONG_CPU enum in x86/sgx: Remove unmatched quote in __sgx_encl_extend function comment x86/boot/Documentation: Fix whitespace noise in boot.rst x86/fpu: Fix FPU state core dump truncation on CPUs with no extended xfeatures x86/boot/Documentation: Fix htmldocs build warning due to malformed table in boot.rst

x86/bug: Fix old GCC compile fails

2025-12-18T10:55:40Z

For some mysterious reasons the GCC 8 and 9 preprocessor manages to sporadically fumble _ASM_BYTES(0x0f, 0x0b): $ grep ".byte[ ]*0x0f" defconfig-build/drivers/net/wireless/realtek/rtlwifi/base.s 1: .byte0x0f,0x0b ; 1: .byte 0x0f,0x0b ; which makes the assembler upset and all that. While there are more _ASM_BYTES() users (notably the NOP instructions), those don't seem affected. Therefore replace the offending ASM_UD2 with one using the ud2 mnemonic. Reported-by: Jean Delvare Suggested-by: Uros Bizjak Fixes: 85a2d4a890dc ("x86,ibt: Use UDB instead of 0xEA") Cc: stable@kernel.org Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251218104659.GT3911114@noisy.programming.kicks-ass.net

arch/x86: replace "__auto_type" with "auto"

2025-12-08T23:32:15Z

Replace instances of "__auto_type" with "auto" in: arch/x86/include/asm/bug.h arch/x86/include/asm/string_64.h arch/x86/include/asm/uaccess_64.h Signed-off-by: H. Peter Anvin (Intel)

objtool: Remove newlines and tabs from annotation macros

2025-12-03T18:42:37Z

Remove newlines and tabs from the annotation macros so the invoking code can insert them as needed to match the style of the surrounding code. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://patch.msgid.link/66305834c2eb78f082217611b756231ae9c0b555.1764694625.git.jpoimboe@kernel.org

x86/bugs: Make i386 use GENERIC_BUG_RELATIVE_POINTERS

2025-11-27T08:32:48Z

Linus figured less #ifdef is more better and making x86-32 use GENERIC_BUG_RELATIVE_POINTERS removes one layer of macro magic from the bug.h bits. Suggested-by: Linus Torvalds Signed-off-by: Peter Zijlstra (Intel)

x86/bug: Fix BUG_FORMAT vs KASLR

2025-11-27T08:32:47Z

Encoding a relative NULL pointer doesn't work for KASLR, when the whole kernel image gets shifted, the __bug_table and the target string get shifted by the same amount and the relative offset is preserved. However when the target is an absolute 0 value and the __bug_table gets moved about, the end result in a pointer equivalent to kaslr_offset(), not NULL. Notably, this will generate SHN_UNDEF relocations, and Ard would really like to not have those at all. Use the empty string to denote no-string. Suggested-by: Linus Torvalds Cc: Ard Biesheuvel Signed-off-by: Peter Zijlstra (Intel)

x86_64/bug: Inline the UD1

2025-11-24T19:23:25Z

(Ab)use the static_call infrastructure to convert all: call __WARN_trap instances into the desired: ud1 (%edx), %rdi eliminating the CALL/RET, but more importantly, fixing the fact that all WARNs will have: RIP: 0010:__WARN_trap+0 Basically, by making it a static_call trampoline call, objtool will collect the callsites, and then the inline rewrite will hit the special case and replace the code with the magic instruction. Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251110115758.456717741@infradead.org

x86/bug: Implement WARN_ONCE()

2025-11-24T19:23:25Z

Implement WARN_ONCE like WARN using BUGFLAG_ONCE. Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251110115758.339309119@infradead.org

x86_64/bug: Implement __WARN_printf()

2025-11-24T19:23:05Z

The basic idea is to have __WARN_printf() be a vararg function such that the compiler can do the optimal calling convention for us. This function body will be a #UD and then set up a va_list in the exception from pt_regs. But because the trap will be in a called function, the bug_entry must be passed in. Have that be the first argument, with the format tucked away inside the bug_entry. The comments should clarify the real fun details. The big downside is that all WARNs will now show: RIP: 0010:__WARN_trap:+0 One possible solution is to simply discard the top frame when unwinding. A follow up patch takes care of this slightly differently by abusing the x86 static_call implementation. This changes (with the next patches): WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET, "corrupted preempt_count: %s/%d/0x%x\n", from: cmpl $2, %ecx #, _7 jne .L1472 ... .L1472: cmpb $0, __already_done.11(%rip) je .L1513 ... .L1513 movb $1, __already_done.11(%rip) movl 1424(%r14), %edx # _15->pid, _15->pid leaq 1912(%r14), %rsi #, _17 movq $.LC43, %rdi #, call __warn_printk # ud2 .pushsection __bug_table,"aw" 2: .long 1b - . # bug_entry::bug_addr .long .LC1 - . # bug_entry::file .word 5093 # bug_entry::line .word 2313 # bug_entry::flags .org 2b + 12 .popsection .pushsection .discard.annotate_insn,"M", @progbits, 8 .long 1b - . .long 8 # ANNOTYPE_REACHABLE .popsection into: cmpl $2, %ecx #, _7 jne .L1442 #, ... .L1442: lea (2f)(%rip), %rdi 1: .pushsection __bug_table,"aw" 2: .long 1b - . # bug_entry::bug_addr .long .LC43 - . # bug_entry::format .long .LC1 - . # bug_entry::file .word 5093 # bug_entry::line .word 2323 # bug_entry::flags .org 2b + 16 .popsection movl 1424(%r14), %edx # _19->pid, _19->pid leaq 1912(%r14), %rsi #, _13 ud1 (%edx), %rdi Notably, by pushing everything into the exception handler it can take care of the ONCE thing. Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251110115758.213813530@infradead.org

x86/bug: Use BUG_FORMAT for DEBUG_BUGVERBOSE_DETAILED

2025-11-24T19:22:21Z

Since we have an explicit format string, use it for the condition string instead of frobbing it in the file string. Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251110115758.097401406@infradead.org