From: Song Liu <songliubraving@fb.com>
Date: Fri, 12 Nov 2021 07:02:43 -0800
Subject: bpf: Introduce btf_tracing_ids
Patch-mainline: v5.17-rc1
Git-commit: d19ddb476a539fd78ad1028ae13bb38506286931
References: jsc#PED-1368

Similar to btf_sock_ids, btf_tracing_ids provides btf ID for task_struct,
file, and vm_area_struct via easy to understand format like
btf_tracing_ids[BTF_TRACING_TYPE_[TASK|file|VMA]].

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211112150243.1270987-3-songliubraving@fb.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 include/linux/btf_ids.h       |   14 +++++++++++++-
 kernel/bpf/bpf_task_storage.c |    4 ++--
 kernel/bpf/btf.c              |    8 ++++----
 kernel/bpf/stackmap.c         |    2 +-
 kernel/bpf/task_iter.c        |   12 ++++++------
 kernel/bpf/verifier.c         |    2 +-
 kernel/trace/bpf_trace.c      |    4 ++--
 7 files changed, 29 insertions(+), 17 deletions(-)

--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -189,6 +189,18 @@ MAX_BTF_SOCK_TYPE,
 extern u32 btf_sock_ids[];
 #endif
 
-extern u32 btf_task_struct_ids[];
+#define BTF_TRACING_TYPE_xxx	\
+	BTF_TRACING_TYPE(BTF_TRACING_TYPE_TASK, task_struct)	\
+	BTF_TRACING_TYPE(BTF_TRACING_TYPE_FILE, file)		\
+	BTF_TRACING_TYPE(BTF_TRACING_TYPE_VMA, vm_area_struct)
+
+enum {
+#define BTF_TRACING_TYPE(name, type) name,
+BTF_TRACING_TYPE_xxx
+#undef BTF_TRACING_TYPE
+MAX_BTF_TRACING_TYPE,
+};
+
+extern u32 btf_tracing_ids[];
 
 #endif
--- a/kernel/bpf/bpf_task_storage.c
+++ b/kernel/bpf/bpf_task_storage.c
@@ -323,7 +323,7 @@ const struct bpf_func_proto bpf_task_sto
 	.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
 	.arg1_type = ARG_CONST_MAP_PTR,
 	.arg2_type = ARG_PTR_TO_BTF_ID,
-	.arg2_btf_id = &btf_task_struct_ids[0],
+	.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
 	.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
 	.arg4_type = ARG_ANYTHING,
 };
@@ -334,5 +334,5 @@ const struct bpf_func_proto bpf_task_sto
 	.ret_type = RET_INTEGER,
 	.arg1_type = ARG_CONST_MAP_PTR,
 	.arg2_type = ARG_PTR_TO_BTF_ID,
-	.arg2_btf_id = &btf_task_struct_ids[0],
+	.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
 };
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6354,10 +6354,10 @@ const struct bpf_func_proto bpf_btf_find
 	.arg4_type	= ARG_ANYTHING,
 };
 
-BTF_ID_LIST_GLOBAL(btf_task_struct_ids, 3)
-BTF_ID(struct, task_struct)
-BTF_ID(struct, file)
-BTF_ID(struct, vm_area_struct)
+BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
+#define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
+BTF_TRACING_TYPE_xxx
+#undef BTF_TRACING_TYPE
 
 /* BTF ID set registration API for modules */
 
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -489,7 +489,7 @@ const struct bpf_func_proto bpf_get_task
 	.gpl_only	= false,
 	.ret_type	= RET_INTEGER,
 	.arg1_type	= ARG_PTR_TO_BTF_ID,
-	.arg1_btf_id	= &btf_task_struct_ids[0],
+	.arg1_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
 	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
 	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
 	.arg4_type	= ARG_ANYTHING,
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -622,7 +622,7 @@ const struct bpf_func_proto bpf_find_vma
 	.func		= bpf_find_vma,
 	.ret_type	= RET_INTEGER,
 	.arg1_type	= ARG_PTR_TO_BTF_ID,
-	.arg1_btf_id	= &btf_task_struct_ids[0],
+	.arg1_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
 	.arg2_type	= ARG_ANYTHING,
 	.arg3_type	= ARG_PTR_TO_FUNC,
 	.arg4_type	= ARG_PTR_TO_STACK_OR_NULL,
@@ -652,19 +652,19 @@ static int __init task_iter_init(void)
 		init_irq_work(&work->irq_work, do_mmap_read_unlock);
 	}
 
-	task_reg_info.ctx_arg_info[0].btf_id = btf_task_struct_ids[0];
+	task_reg_info.ctx_arg_info[0].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_TASK];
 	ret = bpf_iter_reg_target(&task_reg_info);
 	if (ret)
 		return ret;
 
-	task_file_reg_info.ctx_arg_info[0].btf_id = btf_task_struct_ids[0];
-	task_file_reg_info.ctx_arg_info[1].btf_id = btf_task_struct_ids[1];
+	task_file_reg_info.ctx_arg_info[0].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_TASK];
+	task_file_reg_info.ctx_arg_info[1].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_FILE];
 	ret =  bpf_iter_reg_target(&task_file_reg_info);
 	if (ret)
 		return ret;
 
-	task_vma_reg_info.ctx_arg_info[0].btf_id = btf_task_struct_ids[0];
-	task_vma_reg_info.ctx_arg_info[1].btf_id = btf_task_struct_ids[2];
+	task_vma_reg_info.ctx_arg_info[0].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_TASK];
+	task_vma_reg_info.ctx_arg_info[1].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_VMA];
 	return bpf_iter_reg_target(&task_vma_reg_info);
 }
 late_initcall(task_iter_init);
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6164,7 +6164,7 @@ static int set_find_vma_callback_state(s
 	callee->regs[BPF_REG_2].type = PTR_TO_BTF_ID;
 	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
 	callee->regs[BPF_REG_2].btf =  btf_vmlinux;
-	callee->regs[BPF_REG_2].btf_id = btf_task_struct_ids[2];
+	callee->regs[BPF_REG_2].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_VMA],
 
 	/* pointer to stack or null */
 	callee->regs[BPF_REG_3] = caller->regs[BPF_REG_4];
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -764,7 +764,7 @@ const struct bpf_func_proto bpf_get_curr
 	.func		= bpf_get_current_task_btf,
 	.gpl_only	= true,
 	.ret_type	= RET_PTR_TO_BTF_ID,
-	.ret_btf_id	= &btf_task_struct_ids[0],
+	.ret_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
 };
 
 BPF_CALL_1(bpf_task_pt_regs, struct task_struct *, task)
@@ -779,7 +779,7 @@ const struct bpf_func_proto bpf_task_pt_
 	.func		= bpf_task_pt_regs,
 	.gpl_only	= true,
 	.arg1_type	= ARG_PTR_TO_BTF_ID,
-	.arg1_btf_id	= &btf_task_struct_ids[0],
+	.arg1_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
 	.ret_type	= RET_PTR_TO_BTF_ID,
 	.ret_btf_id	= &bpf_task_pt_regs_ids[0],
 };