[PATCH v6 8/9] sframe: Initialize debug info for kernel sections

[Dylan Hatch]

Setup the optional unwinder debug information for kernel .sframe
sections. Modules are indicated by the format "(<module-name>)".

Suggested-by: Jens Remus <jremus at linux.ibm.com>
Signed-off-by: Dylan Hatch <dylanbhatch at google.com>
---
 kernel/unwind/sframe.c       |  4 ++++
 kernel/unwind/sframe_debug.h | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index e8ede0343cb2..d256e72620fe 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -1036,6 +1036,8 @@ void __init init_sframe_table(void)
 	kernel_sfsec.text_start		= (unsigned long)_stext;
 	kernel_sfsec.text_end		= (unsigned long)_etext;
 
+	dbg_init(&kernel_sfsec);
+
 	if (WARN_ON(sframe_read_header(&kernel_sfsec)))
 		return;
 	if (WARN_ON(sframe_validate_section(&kernel_sfsec)))
@@ -1099,6 +1101,8 @@ void sframe_module_init(struct module *mod, void *sframe, size_t sframe_size,
 	sec->text_start   = (unsigned long)text;
 	sec->text_end     = (unsigned long)text + text_size;
 
+	dbg_init(sec);
+
 	if (WARN_ON(sframe_read_header(sec)))
 		return;
 	if (WARN_ON(sframe_sort_fdes(sec)))
diff --git a/kernel/unwind/sframe_debug.h b/kernel/unwind/sframe_debug.h
index e568be4172b1..6c7ab3aa7c9e 100644
--- a/kernel/unwind/sframe_debug.h
+++ b/kernel/unwind/sframe_debug.h
@@ -32,6 +32,19 @@ static inline void dbg_init(struct sframe_section *sec)
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 
+	if (sec->sec_type == SFRAME_KERNEL) {
+		if (sec == &kernel_sfsec) {
+			sec->filename = kstrdup("(vmlinux)", GFP_KERNEL);
+		} else {
+			struct module *mod = container_of(sec, struct module,
+							  arch.sframe_sec);
+			sec->filename = kasprintf(GFP_KERNEL, "(%s)",
+						  mod->name);
+		}
+
+		return;
+	}
+
 	guard(mmap_read_lock)(mm);
 	vma = vma_lookup(mm, sec->sframe_start);
 	if (!vma)
-- 
2.54.0.563.g4f69b47b94-goog