kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 333 insertions, 0 deletions

diff --git a/fs/smb/server/smb2ops.c b/fs/smb/server/smb2ops.c
new file mode 100644
index 000000000..c9a32ee09
--- /dev/null
+++ b/fs/smb/server/smb2ops.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (C) 2016 Namjae Jeon <linkinjeon@kernel.org>
+ *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/slab.h>
+#include "glob.h"
+
+#include "auth.h"
+#include "connection.h"
+#include "smb_common.h"
+#include "server.h"
+#include "stats.h"
+
+static struct smb_version_values smb21_server_values = {
+	.version_string = SMB21_VERSION_STRING,
+	.protocol_id = SMB21_PROT_ID,
+	.req_capabilities = SMB2_GLOBAL_CAP_LARGE_MTU,
+	.max_read_size = SMB21_DEFAULT_IOSIZE,
+	.max_write_size = SMB21_DEFAULT_IOSIZE,
+	.max_trans_size = SMB21_DEFAULT_IOSIZE,
+	.max_credits = SMB2_MAX_CREDITS,
+	.large_lock_type = 0,
+	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE,
+	.shared_lock_type = SMB2_LOCKFLAG_SHARED,
+	.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
+	.header_size = sizeof(struct smb2_hdr),
+	.max_header_size = MAX_SMB2_HDR_SIZE,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
+	.lock_cmd = SMB2_LOCK,
+	.cap_unix = 0,
+	.cap_nt_find = SMB2_NT_FIND,
+	.cap_large_files = SMB2_LARGE_FILES,
+	.create_lease_size = sizeof(struct create_lease),
+	.create_durable_size = sizeof(struct create_durable_rsp),
+	.create_mxac_size = sizeof(struct create_mxac_rsp),
+	.create_disk_id_size = sizeof(struct create_disk_id_rsp),
+	.create_posix_size = sizeof(struct create_posix_rsp),
+};
+
+static struct smb_version_values smb30_server_values = {
+	.version_string = SMB30_VERSION_STRING,
+	.protocol_id = SMB30_PROT_ID,
+	.req_capabilities = SMB2_GLOBAL_CAP_LARGE_MTU,
+	.max_read_size = SMB3_DEFAULT_IOSIZE,
+	.max_write_size = SMB3_DEFAULT_IOSIZE,
+	.max_trans_size = SMB3_DEFAULT_TRANS_SIZE,
+	.max_credits = SMB2_MAX_CREDITS,
+	.large_lock_type = 0,
+	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE,
+	.shared_lock_type = SMB2_LOCKFLAG_SHARED,
+	.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
+	.header_size = sizeof(struct smb2_hdr),
+	.max_header_size = MAX_SMB2_HDR_SIZE,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
+	.lock_cmd = SMB2_LOCK,
+	.cap_unix = 0,
+	.cap_nt_find = SMB2_NT_FIND,
+	.cap_large_files = SMB2_LARGE_FILES,
+	.create_lease_size = sizeof(struct create_lease_v2),
+	.create_durable_size = sizeof(struct create_durable_rsp),
+	.create_durable_v2_size = sizeof(struct create_durable_rsp_v2),
+	.create_mxac_size = sizeof(struct create_mxac_rsp),
+	.create_disk_id_size = sizeof(struct create_disk_id_rsp),
+	.create_posix_size = sizeof(struct create_posix_rsp),
+};
+
+static struct smb_version_values smb302_server_values = {
+	.version_string = SMB302_VERSION_STRING,
+	.protocol_id = SMB302_PROT_ID,
+	.req_capabilities = SMB2_GLOBAL_CAP_LARGE_MTU,
+	.max_read_size = SMB3_DEFAULT_IOSIZE,
+	.max_write_size = SMB3_DEFAULT_IOSIZE,
+	.max_trans_size = SMB3_DEFAULT_TRANS_SIZE,
+	.max_credits = SMB2_MAX_CREDITS,
+	.large_lock_type = 0,
+	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE,
+	.shared_lock_type = SMB2_LOCKFLAG_SHARED,
+	.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
+	.header_size = sizeof(struct smb2_hdr),
+	.max_header_size = MAX_SMB2_HDR_SIZE,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
+	.lock_cmd = SMB2_LOCK,
+	.cap_unix = 0,
+	.cap_nt_find = SMB2_NT_FIND,
+	.cap_large_files = SMB2_LARGE_FILES,
+	.create_lease_size = sizeof(struct create_lease_v2),
+	.create_durable_size = sizeof(struct create_durable_rsp),
+	.create_durable_v2_size = sizeof(struct create_durable_rsp_v2),
+	.create_mxac_size = sizeof(struct create_mxac_rsp),
+	.create_disk_id_size = sizeof(struct create_disk_id_rsp),
+	.create_posix_size = sizeof(struct create_posix_rsp),
+};
+
+static struct smb_version_values smb311_server_values = {
+	.version_string = SMB311_VERSION_STRING,
+	.protocol_id = SMB311_PROT_ID,
+	.req_capabilities = SMB2_GLOBAL_CAP_LARGE_MTU,
+	.max_read_size = SMB3_DEFAULT_IOSIZE,
+	.max_write_size = SMB3_DEFAULT_IOSIZE,
+	.max_trans_size = SMB3_DEFAULT_TRANS_SIZE,
+	.max_credits = SMB2_MAX_CREDITS,
+	.large_lock_type = 0,
+	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE,
+	.shared_lock_type = SMB2_LOCKFLAG_SHARED,
+	.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
+	.header_size = sizeof(struct smb2_hdr),
+	.max_header_size = MAX_SMB2_HDR_SIZE,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
+	.lock_cmd = SMB2_LOCK,
+	.cap_unix = 0,
+	.cap_nt_find = SMB2_NT_FIND,
+	.cap_large_files = SMB2_LARGE_FILES,
+	.create_lease_size = sizeof(struct create_lease_v2),
+	.create_durable_size = sizeof(struct create_durable_rsp),
+	.create_durable_v2_size = sizeof(struct create_durable_rsp_v2),
+	.create_mxac_size = sizeof(struct create_mxac_rsp),
+	.create_disk_id_size = sizeof(struct create_disk_id_rsp),
+	.create_posix_size = sizeof(struct create_posix_rsp),
+};
+
+static struct smb_version_ops smb2_0_server_ops = {
+	.get_cmd_val		=	get_smb2_cmd_val,
+	.inc_reqs		=	ksmbd_counter_inc_reqs,
+	.init_rsp_hdr		=	init_smb2_rsp_hdr,
+	.set_rsp_status		=	set_smb2_rsp_status,
+	.allocate_rsp_buf       =       smb2_allocate_rsp_buf,
+	.set_rsp_credits	=	smb2_set_rsp_credits,
+	.check_user_session	=	smb2_check_user_session,
+	.get_ksmbd_tcon		=	smb2_get_ksmbd_tcon,
+	.is_sign_req		=	smb2_is_sign_req,
+	.check_sign_req		=	smb2_check_sign_req,
+	.set_sign_rsp		=	smb2_set_sign_rsp
+};
+
+static struct smb_version_ops smb3_0_server_ops = {
+	.get_cmd_val		=	get_smb2_cmd_val,
+	.inc_reqs		=	ksmbd_counter_inc_reqs,
+	.init_rsp_hdr		=	init_smb2_rsp_hdr,
+	.set_rsp_status		=	set_smb2_rsp_status,
+	.allocate_rsp_buf       =       smb2_allocate_rsp_buf,
+	.set_rsp_credits	=	smb2_set_rsp_credits,
+	.check_user_session	=	smb2_check_user_session,
+	.get_ksmbd_tcon		=	smb2_get_ksmbd_tcon,
+	.is_sign_req		=	smb2_is_sign_req,
+	.check_sign_req		=	smb3_check_sign_req,
+	.set_sign_rsp		=	smb3_set_sign_rsp,
+	.generate_signingkey	=	ksmbd_gen_smb30_signingkey,
+	.generate_encryptionkey	=	ksmbd_gen_smb30_encryptionkey,
+	.is_transform_hdr	=	smb3_is_transform_hdr,
+	.decrypt_req		=	smb3_decrypt_req,
+	.encrypt_resp		=	smb3_encrypt_resp
+};
+
+static struct smb_version_ops smb3_11_server_ops = {
+	.get_cmd_val		=	get_smb2_cmd_val,
+	.inc_reqs		=	ksmbd_counter_inc_reqs,
+	.init_rsp_hdr		=	init_smb2_rsp_hdr,
+	.set_rsp_status		=	set_smb2_rsp_status,
+	.allocate_rsp_buf       =       smb2_allocate_rsp_buf,
+	.set_rsp_credits	=	smb2_set_rsp_credits,
+	.check_user_session	=	smb2_check_user_session,
+	.get_ksmbd_tcon		=	smb2_get_ksmbd_tcon,
+	.is_sign_req		=	smb2_is_sign_req,
+	.check_sign_req		=	smb3_check_sign_req,
+	.set_sign_rsp		=	smb3_set_sign_rsp,
+	.generate_signingkey	=	ksmbd_gen_smb311_signingkey,
+	.generate_encryptionkey	=	ksmbd_gen_smb311_encryptionkey,
+	.is_transform_hdr	=	smb3_is_transform_hdr,
+	.decrypt_req		=	smb3_decrypt_req,
+	.encrypt_resp		=	smb3_encrypt_resp
+};
+
+static struct smb_version_cmds smb2_0_server_cmds[NUMBER_OF_SMB2_COMMANDS] = {
+	[SMB2_NEGOTIATE_HE]	=	{ .proc = smb2_negotiate_request, },
+	[SMB2_SESSION_SETUP_HE] =	{ .proc = smb2_sess_setup, },
+	[SMB2_TREE_CONNECT_HE]  =	{ .proc = smb2_tree_connect,},
+	[SMB2_TREE_DISCONNECT_HE]  =	{ .proc = smb2_tree_disconnect,},
+	[SMB2_LOGOFF_HE]	=	{ .proc = smb2_session_logoff,},
+	[SMB2_CREATE_HE]	=	{ .proc = smb2_open},
+	[SMB2_QUERY_INFO_HE]	=	{ .proc = smb2_query_info},
+	[SMB2_QUERY_DIRECTORY_HE] =	{ .proc = smb2_query_dir},
+	[SMB2_CLOSE_HE]		=	{ .proc = smb2_close},
+	[SMB2_ECHO_HE]		=	{ .proc = smb2_echo},
+	[SMB2_SET_INFO_HE]      =       { .proc = smb2_set_info},
+	[SMB2_READ_HE]		=	{ .proc = smb2_read},
+	[SMB2_WRITE_HE]		=	{ .proc = smb2_write},
+	[SMB2_FLUSH_HE]		=	{ .proc = smb2_flush},
+	[SMB2_CANCEL_HE]	=	{ .proc = smb2_cancel},
+	[SMB2_LOCK_HE]		=	{ .proc = smb2_lock},
+	[SMB2_IOCTL_HE]		=	{ .proc = smb2_ioctl},
+	[SMB2_OPLOCK_BREAK_HE]	=	{ .proc = smb2_oplock_break},
+	[SMB2_CHANGE_NOTIFY_HE]	=	{ .proc = smb2_notify},
+};
+
+/**
+ * init_smb2_1_server() - initialize a smb server connection with smb2.1
+ *			command dispatcher
+ * @conn:	connection instance
+ */
+void init_smb2_1_server(struct ksmbd_conn *conn)
+{
+	conn->vals = &smb21_server_values;
+	conn->ops = &smb2_0_server_ops;
+	conn->cmds = smb2_0_server_cmds;
+	conn->max_cmds = ARRAY_SIZE(smb2_0_server_cmds);
+	conn->signing_algorithm = SIGNING_ALG_HMAC_SHA256_LE;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_LEASES)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_LEASING;
+}
+
+/**
+ * init_smb3_0_server() - initialize a smb server connection with smb3.0
+ *			command dispatcher
+ * @conn:	connection instance
+ */
+void init_smb3_0_server(struct ksmbd_conn *conn)
+{
+	conn->vals = &smb30_server_values;
+	conn->ops = &smb3_0_server_ops;
+	conn->cmds = smb2_0_server_cmds;
+	conn->max_cmds = ARRAY_SIZE(smb2_0_server_cmds);
+	conn->signing_algorithm = SIGNING_ALG_AES_CMAC_LE;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_LEASES)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_LEASING |
+			SMB2_GLOBAL_CAP_DIRECTORY_LEASING;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_ENCRYPTION &&
+	    conn->cli_cap & SMB2_GLOBAL_CAP_ENCRYPTION)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_ENCRYPTION;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_ENCRYPTION ||
+	    (!(server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_ENCRYPTION_OFF) &&
+	     conn->cli_cap & SMB2_GLOBAL_CAP_ENCRYPTION))
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_ENCRYPTION;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB3_MULTICHANNEL)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_MULTI_CHANNEL;
+}
+
+/**
+ * init_smb3_02_server() - initialize a smb server connection with smb3.02
+ *			command dispatcher
+ * @conn:	connection instance
+ */
+void init_smb3_02_server(struct ksmbd_conn *conn)
+{
+	conn->vals = &smb302_server_values;
+	conn->ops = &smb3_0_server_ops;
+	conn->cmds = smb2_0_server_cmds;
+	conn->max_cmds = ARRAY_SIZE(smb2_0_server_cmds);
+	conn->signing_algorithm = SIGNING_ALG_AES_CMAC_LE;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_LEASES)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_LEASING |
+			SMB2_GLOBAL_CAP_DIRECTORY_LEASING;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_ENCRYPTION ||
+	    (!(server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_ENCRYPTION_OFF) &&
+	     conn->cli_cap & SMB2_GLOBAL_CAP_ENCRYPTION))
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_ENCRYPTION;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB3_MULTICHANNEL)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_MULTI_CHANNEL;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_DURABLE_HANDLE)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_PERSISTENT_HANDLES;
+}
+
+/**
+ * init_smb3_11_server() - initialize a smb server connection with smb3.11
+ *			command dispatcher
+ * @conn:	connection instance
+ */
+int init_smb3_11_server(struct ksmbd_conn *conn)
+{
+	conn->vals = &smb311_server_values;
+	conn->ops = &smb3_11_server_ops;
+	conn->cmds = smb2_0_server_cmds;
+	conn->max_cmds = ARRAY_SIZE(smb2_0_server_cmds);
+	conn->signing_algorithm = SIGNING_ALG_AES_CMAC_LE;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_LEASES)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_LEASING |
+			SMB2_GLOBAL_CAP_DIRECTORY_LEASING;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB3_MULTICHANNEL)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_MULTI_CHANNEL;
+
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_DURABLE_HANDLE)
+		conn->vals->req_capabilities |= SMB2_GLOBAL_CAP_PERSISTENT_HANDLES;
+
+	INIT_LIST_HEAD(&conn->preauth_sess_table);
+	return 0;
+}
+
+void init_smb2_max_read_size(unsigned int sz)
+{
+	sz = clamp_val(sz, SMB3_MIN_IOSIZE, SMB3_MAX_IOSIZE);
+	smb21_server_values.max_read_size = sz;
+	smb30_server_values.max_read_size = sz;
+	smb302_server_values.max_read_size = sz;
+	smb311_server_values.max_read_size = sz;
+}
+
+void init_smb2_max_write_size(unsigned int sz)
+{
+	sz = clamp_val(sz, SMB3_MIN_IOSIZE, SMB3_MAX_IOSIZE);
+	smb21_server_values.max_write_size = sz;
+	smb30_server_values.max_write_size = sz;
+	smb302_server_values.max_write_size = sz;
+	smb311_server_values.max_write_size = sz;
+}
+
+void init_smb2_max_trans_size(unsigned int sz)
+{
+	sz = clamp_val(sz, SMB3_MIN_IOSIZE, SMB3_MAX_IOSIZE);
+	smb21_server_values.max_trans_size = sz;
+	smb30_server_values.max_trans_size = sz;
+	smb302_server_values.max_trans_size = sz;
+	smb311_server_values.max_trans_size = sz;
+}
+
+void init_smb2_max_credits(unsigned int sz)
+{
+	smb21_server_values.max_credits = sz;
+	smb30_server_values.max_credits = sz;
+	smb302_server_values.max_credits = sz;
+	smb311_server_values.max_credits = sz;
+}