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 --- rust/helpers/atomic_ext.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 rust/helpers/atomic_ext.c (limited to 'rust/helpers/atomic_ext.c') diff --git a/rust/helpers/atomic_ext.c b/rust/helpers/atomic_ext.c new file mode 100644 index 000000000..c267d5190 --- /dev/null +++ b/rust/helpers/atomic_ext.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include + +#define GEN_READ_HELPER(tname, type) \ +__rust_helper type rust_helper_atomic_##tname##_read(type *ptr) \ +{ \ + return READ_ONCE(*ptr); \ +} + +#define GEN_SET_HELPER(tname, type) \ +__rust_helper void rust_helper_atomic_##tname##_set(type *ptr, type val) \ +{ \ + WRITE_ONCE(*ptr, val); \ +} + +#define GEN_READ_ACQUIRE_HELPER(tname, type) \ +__rust_helper type rust_helper_atomic_##tname##_read_acquire(type *ptr) \ +{ \ + return smp_load_acquire(ptr); \ +} + +#define GEN_SET_RELEASE_HELPER(tname, type) \ +__rust_helper void rust_helper_atomic_##tname##_set_release(type *ptr, type val)\ +{ \ + smp_store_release(ptr, val); \ +} + +#define GEN_READ_SET_HELPERS(tname, type) \ + GEN_READ_HELPER(tname, type) \ + GEN_SET_HELPER(tname, type) \ + GEN_READ_ACQUIRE_HELPER(tname, type) \ + GEN_SET_RELEASE_HELPER(tname, type) \ + +GEN_READ_SET_HELPERS(i8, s8) +GEN_READ_SET_HELPERS(i16, s16) +GEN_READ_SET_HELPERS(ptr, const void *) + +/* + * xchg helpers depend on ARCH_SUPPORTS_ATOMIC_RMW and on the + * architecture provding xchg() support for i8 and i16. + * + * The architectures that currently support Rust (x86_64, armv7, + * arm64, riscv, and loongarch) satisfy these requirements. + */ +#define GEN_XCHG_HELPER(tname, type, suffix) \ +__rust_helper type \ +rust_helper_atomic_##tname##_xchg##suffix(type *ptr, type new) \ +{ \ + return xchg##suffix(ptr, new); \ +} + +#define GEN_XCHG_HELPERS(tname, type) \ + GEN_XCHG_HELPER(tname, type, ) \ + GEN_XCHG_HELPER(tname, type, _acquire) \ + GEN_XCHG_HELPER(tname, type, _release) \ + GEN_XCHG_HELPER(tname, type, _relaxed) \ + +GEN_XCHG_HELPERS(i8, s8) +GEN_XCHG_HELPERS(i16, s16) +GEN_XCHG_HELPERS(ptr, const void *) + +/* + * try_cmpxchg helpers depend on ARCH_SUPPORTS_ATOMIC_RMW and on the + * architecture provding try_cmpxchg() support for i8 and i16. + * + * The architectures that currently support Rust (x86_64, armv7, + * arm64, riscv, and loongarch) satisfy these requirements. + */ +#define GEN_TRY_CMPXCHG_HELPER(tname, type, suffix) \ +__rust_helper bool \ +rust_helper_atomic_##tname##_try_cmpxchg##suffix(type *ptr, type *old, type new)\ +{ \ + return try_cmpxchg##suffix(ptr, old, new); \ +} + +#define GEN_TRY_CMPXCHG_HELPERS(tname, type) \ + GEN_TRY_CMPXCHG_HELPER(tname, type, ) \ + GEN_TRY_CMPXCHG_HELPER(tname, type, _acquire) \ + GEN_TRY_CMPXCHG_HELPER(tname, type, _release) \ + GEN_TRY_CMPXCHG_HELPER(tname, type, _relaxed) \ + +GEN_TRY_CMPXCHG_HELPERS(i8, s8) +GEN_TRY_CMPXCHG_HELPERS(i16, s16) +GEN_TRY_CMPXCHG_HELPERS(ptr, const void *) -- cgit v1.3.1