Merge tag 'x86-urgent-2026-10-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:

 - Don't apply va_align to hugetlb mappings on AMD F15h systems
   that have custom va_align.bits values (Laurent Wandrebeck)

 - Fix PMD teardown handling regression flagged by lockdep
   (Mikhail Gavrilov)

 - Hide ptrace header register offset macros behind __ASSEMBLER__ or
   __FRAME_OFFSETS, to fix user-space build errors that may trigger
   if they happen to shadow these short and generic macro names
   (Nick Desaulniers)

* tag 'x86-urgent-2026-10-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  {x86,um}/uapi/ptrace: Guard register offset macros with __ASSEMBLER__ or __FRAME_OFFSETS
  x86/mm: Drop unnecessary PMD page copy when freeing
  x86/mm: Don't apply va_align to hugetlb mappings on AMD F15h

5 files changed, 29 insertions, 33 deletions

diff --git a/arch/x86/include/uapi/asm/ptrace-abi.h b/arch/x86/include/uapi/asm/ptrace-abi.h
index 5823584de..3656955c6 100644
--- a/arch/x86/include/uapi/asm/ptrace-abi.h
+++ b/arch/x86/include/uapi/asm/ptrace-abi.h
@@ -2,6 +2,7 @@
 #ifndef _ASM_X86_PTRACE_ABI_H
 #define _ASM_X86_PTRACE_ABI_H
 
+#if defined(__ASSEMBLER__) || defined(__FRAME_OFFSETS)
 #ifdef __i386__
 
 #define EBX 0
@@ -25,7 +26,6 @@
 
 #else /* __i386__ */
 
-#if defined(__ASSEMBLER__) || defined(__FRAME_OFFSETS)
 /*
  * C ABI says these regs are callee-preserved. They aren't saved on kernel entry
  * unless syscall needs a complete, fully filled "struct pt_regs".
@@ -57,12 +57,12 @@
 #define EFLAGS 144
 #define RSP 152
 #define SS 160
-#endif /* __ASSEMBLER__ */
 
 /* top of stack page */
 #define FRAME_SIZE 168
 
 #endif /* !__i386__ */
+#endif /* defined(__ASSEMBLER__) || defined(__FRAME_OFFSETS) */
 
 /* Arbitrarily choose the same ptrace numbers as used by the Sparc code. */
 #define PTRACE_GETREGS            12
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 776ae6fa7..4c078827f 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -50,9 +50,16 @@ static unsigned long get_align_mask(struct file *filp)
  * value before calling vm_unmapped_area() or ORed directly to the
  * address.
  */
-static unsigned long get_align_bits(void)
+static unsigned long get_align_bits(struct file *filp)
 {
-	return va_align.bits & get_align_mask(NULL);
+	/*
+	 * va_align.bits is smaller than the huge page size and will
+	 * lead to misaligned huge pages. Ignore it for huge mappings.
+	 */
+	if (is_file_hugepages(filp))
+		return 0;
+
+	return va_align.bits & get_align_mask(filp);
 }
 
 static int __init control_va_addr_alignment(char *str)
@@ -157,7 +164,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len,
 	}
 	if (filp) {
 		info.align_mask = get_align_mask(filp);
-		info.align_offset += get_align_bits();
+		info.align_offset += get_align_bits(filp);
 	}
 
 	return vm_unmapped_area(&info);
@@ -222,7 +229,7 @@ get_unmapped_area:
 
 	if (filp) {
 		info.align_mask = get_align_mask(filp);
-		info.align_offset += get_align_bits();
+		info.align_offset += get_align_bits(filp);
 	}
 	addr = vm_unmapped_area(&info);
 	if (!(addr & ~PAGE_MASK))
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index cb03f5a2b..4a105f283 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -705,47 +705,37 @@ int pmd_clear_huge(pmd_t *pmd)
 }
 
 #ifdef CONFIG_X86_64
-/**
- * pud_free_pmd_page - Clear PUD entry and free PMD page
- * @pud: Pointer to a PUD
- * @addr: Virtual address associated with PUD
- *
- * Context: The PUD range has been unmapped and TLB purged.
- * Return: 1 if clearing the entry succeeded. 0 otherwise.
- *
- * NOTE: Callers must allow a single page allocation.
+/*
+ * Given a PUD poitner, detach and free the pointed-to
+ * PMD page and any PTE page children. The entire range
+ * under the PUD must not have any valid translations
+ * and the TLB must have already been flushed.
  */
 int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 {
-	pmd_t *pmd, *pmd_sv;
 	struct ptdesc *pt;
+	pmd_t *pmd;
 	int i;
 
 	pmd = pud_pgtable(*pud);
-	pmd_sv = (pmd_t *)__get_free_page(GFP_KERNEL);
-	if (!pmd_sv)
-		return 0;
-
-	for (i = 0; i < PTRS_PER_PMD; i++) {
-		pmd_sv[i] = pmd[i];
-		if (!pmd_none(pmd[i]))
-			pmd_clear(&pmd[i]);
-	}
 
+	/* Detach the PMD page: */
 	pud_clear(pud);
 
-	/* INVLPG to clear all paging-structure caches */
+	/*
+	 * PMD and all its descendents are unreachable
+	 * via normal page walks. Make them unreachable
+	 * in cached mid-level walks too:
+	 */
 	flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1);
 
 	for (i = 0; i < PTRS_PER_PMD; i++) {
-		if (!pmd_none(pmd_sv[i])) {
-			pt = page_ptdesc(pmd_page(pmd_sv[i]));
+		if (!pmd_none(pmd[i])) {
+			pt = page_ptdesc(pmd_page(pmd[i]));
 			pagetable_dtor_free(pt);
 		}
 	}
 
-	free_page((unsigned long)pmd_sv);
-
 	pmd_free(&init_mm, pmd);
 
 	return 1;
diff --git a/arch/x86/um/asm/ptrace.h b/arch/x86/um/asm/ptrace.h
index 2641d28d1..439c4151f 100644
--- a/arch/x86/um/asm/ptrace.h
+++ b/arch/x86/um/asm/ptrace.h
@@ -13,9 +13,7 @@ enum {
 };
 
 #include <linux/compiler.h>
-#ifndef CONFIG_X86_32
-#define __FRAME_OFFSETS /* Needed to get the R* macros */
-#endif
+#define __FRAME_OFFSETS /* Needed to get the register macros */
 #include <asm/ptrace-generic.h>
 
 #define user_mode(r) UPT_IS_USER(&(r)->regs)
diff --git a/arch/x86/um/ptrace_32.c b/arch/x86/um/ptrace_32.c
index 3af3cb821..9e9155b0e 100644
--- a/arch/x86/um/ptrace_32.c
+++ b/arch/x86/um/ptrace_32.c
@@ -7,6 +7,7 @@
 #include <linux/sched.h>
 #include <linux/uaccess.h>
 #include <linux/regset.h>
+#define __FRAME_OFFSETS
 #include <asm/ptrace-abi.h>
 #include <registers.h>
 #include <skas.h>