From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- include/asm-generic/pgtable-nop4d.h | 58 +++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 include/asm-generic/pgtable-nop4d.h (limited to 'include/asm-generic/pgtable-nop4d.h') diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h new file mode 100644 index 000000000..89c21f84c --- /dev/null +++ b/include/asm-generic/pgtable-nop4d.h @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _PGTABLE_NOP4D_H +#define _PGTABLE_NOP4D_H + +#ifndef __ASSEMBLER__ + +#define __PAGETABLE_P4D_FOLDED 1 + +typedef struct { pgd_t pgd; } p4d_t; + +#define P4D_SHIFT PGDIR_SHIFT +#define PTRS_PER_P4D 1 +#define P4D_SIZE (1UL << P4D_SHIFT) +#define P4D_MASK (~(P4D_SIZE-1)) + +/* + * The "pgd_xxx()" functions here are trivial for a folded two-level + * setup: the p4d is never bad, and a p4d always exists (as it's folded + * into the pgd entry) + */ +static inline int pgd_none(pgd_t pgd) { return 0; } +static inline int pgd_bad(pgd_t pgd) { return 0; } +static inline int pgd_present(pgd_t pgd) { return 1; } +static inline void pgd_clear(pgd_t *pgd) { } +#define p4d_ERROR(p4d) (pgd_ERROR((p4d).pgd)) + +#define pgd_populate(mm, pgd, p4d) do { } while (0) +#define pgd_populate_safe(mm, pgd, p4d) do { } while (0) +/* + * (p4ds are folded into pgds so this doesn't get actually called, + * but the define is needed for a generic inline function.) + */ +#define set_pgd(pgdptr, pgdval) set_p4d((p4d_t *)(pgdptr), (p4d_t) { pgdval }) + +static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address) +{ + return (p4d_t *)pgd; +} + +#define p4d_val(x) (pgd_val((x).pgd)) +#define __p4d(x) ((p4d_t) { __pgd(x) }) + +#define pgd_page(pgd) (p4d_page((p4d_t){ pgd })) +#define pgd_page_vaddr(pgd) ((unsigned long)(p4d_pgtable((p4d_t){ pgd }))) + +/* + * allocating and freeing a p4d is trivial: the 1-entry p4d is + * inside the pgd, so has no extra memory associated with it. + */ +#define p4d_alloc_one(mm, address) NULL +#define p4d_free(mm, x) do { } while (0) +#define p4d_free_tlb(tlb, x, a) do { } while (0) + +#undef p4d_addr_end +#define p4d_addr_end(addr, end) (end) + +#endif /* __ASSEMBLER__ */ +#endif /* _PGTABLE_NOP4D_H */ -- cgit v1.3.1