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/cmdline.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 156 insertions(+) create mode 100644 arch/x86/boot/cmdline.c (limited to 'arch/x86/boot/cmdline.c') diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c new file mode 100644 index 000000000..21d56ae83 --- /dev/null +++ b/arch/x86/boot/cmdline.c @@ -0,0 +1,156 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * ----------------------------------------------------------------------- */ + +/* + * Simple command-line parser for early boot. + */ + +#include "boot.h" + +static inline int myisspace(u8 c) +{ + return c <= ' '; /* Close enough approximation */ +} + +/* + * Find a non-boolean option, that is, "option=argument". In accordance + * with standard Linux practice, if this option is repeated, this returns + * the last instance on the command line. + * + * Returns the length of the argument (regardless of if it was + * truncated to fit in the buffer), or -1 on not found. + */ +int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *buffer, int bufsize) +{ + addr_t cptr; + char c; + int len = -1; + const char *opptr = NULL; + char *bufptr = buffer; + enum { + st_wordstart, /* Start of word/after whitespace */ + st_wordcmp, /* Comparing this word */ + st_wordskip, /* Miscompare, skip */ + st_bufcpy /* Copying this to buffer */ + } state = st_wordstart; + + if (!cmdline_ptr) + return -1; /* No command line */ + + cptr = cmdline_ptr & 0xf; + set_fs(cmdline_ptr >> 4); + + while (cptr < 0x10000 && (c = rdfs8(cptr++))) { + switch (state) { + case st_wordstart: + if (myisspace(c)) + break; + + /* else */ + state = st_wordcmp; + opptr = option; + fallthrough; + + case st_wordcmp: + if (c == '=' && !*opptr) { + len = 0; + bufptr = buffer; + state = st_bufcpy; + } else if (myisspace(c)) { + state = st_wordstart; + } else if (c != *opptr++) { + state = st_wordskip; + } + break; + + case st_wordskip: + if (myisspace(c)) + state = st_wordstart; + break; + + case st_bufcpy: + if (myisspace(c)) { + state = st_wordstart; + } else { + if (len < bufsize-1) + *bufptr++ = c; + len++; + } + break; + } + } + + if (bufsize) + *bufptr = '\0'; + + return len; +} + +/* + * Find a boolean option (like quiet,noapic,nosmp....) + * + * Returns the position of that option (starts counting with 1) + * or 0 on not found + */ +int __cmdline_find_option_bool(unsigned long cmdline_ptr, const char *option) +{ + addr_t cptr; + char c; + int pos = 0, wstart = 0; + const char *opptr = NULL; + enum { + st_wordstart, /* Start of word/after whitespace */ + st_wordcmp, /* Comparing this word */ + st_wordskip, /* Miscompare, skip */ + } state = st_wordstart; + + if (!cmdline_ptr) + return -1; /* No command line */ + + cptr = cmdline_ptr & 0xf; + set_fs(cmdline_ptr >> 4); + + while (cptr < 0x10000) { + c = rdfs8(cptr++); + pos++; + + switch (state) { + case st_wordstart: + if (!c) + return 0; + else if (myisspace(c)) + break; + + state = st_wordcmp; + opptr = option; + wstart = pos; + fallthrough; + + case st_wordcmp: + if (!*opptr) + if (!c || myisspace(c)) + return wstart; + else + state = st_wordskip; + else if (!c) + return 0; + else if (c != *opptr++) + state = st_wordskip; + break; + + case st_wordskip: + if (!c) + return 0; + else if (myisspace(c)) + state = st_wordstart; + break; + } + } + + return 0; /* Buffer overrun */ +} -- cgit v1.3.1