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 --- arch/x86/boot/cpu.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 arch/x86/boot/cpu.c (limited to 'arch/x86/boot/cpu.c') diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c new file mode 100644 index 000000000..feb6dbd7c --- /dev/null +++ b/arch/x86/boot/cpu.c @@ -0,0 +1,86 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007-2008 rPath, Inc. - All Rights Reserved + * + * ----------------------------------------------------------------------- */ + +/* + * arch/x86/boot/cpu.c + * + * Check for obligatory CPU features and abort if the features are not + * present. + */ + +#include "boot.h" +#include "cpustr.h" + +static char *cpu_name(int level) +{ + static char buf[6]; + + if (level == 64) { + return "x86-64"; + } else { + if (level == 15) + level = 6; + sprintf(buf, "i%d86", level); + return buf; + } +} + +static void show_cap_strs(u32 *err_flags) +{ + int i, j; + const unsigned char *msg_strs = (const unsigned char *)x86_cap_strs; + for (i = 0; i < NCAPINTS; i++) { + u32 e = err_flags[i]; + for (j = 0; j < 32; j++) { + if (msg_strs[0] < i || + (msg_strs[0] == i && msg_strs[1] < j)) { + /* Skip to the next string */ + msg_strs += 2; + while (*msg_strs++) + ; + } + if (e & 1) { + if (msg_strs[0] == i && + msg_strs[1] == j && + msg_strs[2]) + printf("%s ", msg_strs+2); + else + printf("%d:%d ", i, j); + } + e >>= 1; + } + } +} + +int validate_cpu(void) +{ + u32 *err_flags; + int cpu_level, req_level; + + check_cpu(&cpu_level, &req_level, &err_flags); + + if (cpu_level < req_level) { + printf("This kernel requires an %s CPU, ", + cpu_name(req_level)); + printf("but only detected an %s CPU.\n", + cpu_name(cpu_level)); + return -1; + } + + if (err_flags) { + puts("This kernel requires the following features " + "not present on the CPU:\n"); + show_cap_strs(err_flags); + putchar('\n'); + return -1; + } else if (check_knl_erratum()) { + return -1; + } else { + return 0; + } +} -- cgit v1.3.1