[PATCH v7 07/11] sframe: Add debug helpers with object name

[Dylan Hatch]

Include the object name for kernel .sframe sections, indicated by the
format "(<module-name>)".

Suggested-by: Jens Remus <jremus at linux.ibm.com>
Reviewed-by: Jens Remus <jremus at linux.ibm.com>
Signed-off-by: Dylan Hatch <dylanbhatch at google.com>

---

Changes since v6:
 - Compute objname of sec on the fly to avoid allocating/storing an
   extra string in struct sframe_section for the name.
 - Squash dbg_print_header() definition, and add calls from
   init_sframe_table() and sframe_module_init().
---
 kernel/unwind/sframe.c       | 11 +++++++----
 kernel/unwind/sframe_debug.h | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 4 deletions(-)
 create mode 100644 kernel/unwind/sframe_debug.h

diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
index e6542bb678585..c4715befb59b5 100644
--- a/kernel/unwind/sframe.c
+++ b/kernel/unwind/sframe.c
@@ -15,6 +15,7 @@
 #include <asm/sections.h>
 
 #include "sframe.h"
+#include "sframe_debug.h"
 
 static bool sframe_init __ro_after_init;
 struct sframe_section kernel_sfsec __ro_after_init;
@@ -497,7 +498,7 @@ static int sframe_read_header(struct sframe_section *sec)
 
 	header_end = sec->sframe_start + sizeof(struct sframe_header);
 	if (header_end >= sec->sframe_end) {
-		pr_debug("header struct doesn't fit in section\n");
+		dbg_sec(sec, "header struct doesn't fit in section\n");
 		return -EINVAL;
 	}
 
@@ -507,12 +508,12 @@ static int sframe_read_header(struct sframe_section *sec)
 	    shdr->preamble.version != SFRAME_VERSION_3 ||
 	    !(shdr->preamble.flags & SFRAME_F_FDE_FUNC_START_PCREL) ||
 	    shdr->auxhdr_len) {
-		pr_debug("bad/unsupported sframe header\n");
+		dbg_sec(sec, "bad/unsupported sframe header\n");
 		return -EINVAL;
 	}
 
 	if (!shdr->num_fdes || !shdr->num_fres) {
-		pr_debug("no fde/fre entries\n");
+		dbg_sec(sec, "no fde/fre entries\n");
 		return -EINVAL;
 	}
 
@@ -524,7 +525,7 @@ static int sframe_read_header(struct sframe_section *sec)
 	fres_end   = fres_start + shdr->fre_len;
 
 	if (fres_start < fdes_end || fres_end > sec->sframe_end) {
-		pr_debug("inconsistent fde/fre offsets\n");
+		dbg_sec(sec, "inconsistent fde/fre offsets\n");
 		return -EINVAL;
 	}
 
@@ -551,6 +552,7 @@ void __init init_sframe_table(void)
 	}
 
 	sframe_init = true;
+	dbg_print_header(&kernel_sfsec);
 }
 
 #ifdef CONFIG_MODULES
@@ -611,6 +613,7 @@ void sframe_module_init(struct module *mod, void *sframe, size_t sframe_size)
 
 	/* Ensure SFrame is initialized when sframe_find() happens */
 	WRITE_ONCE(mod->arch.sframe_init, true);
+	dbg_print_header(sec);
 }
 
 #endif
diff --git a/kernel/unwind/sframe_debug.h b/kernel/unwind/sframe_debug.h
new file mode 100644
index 0000000000000..114a4ff4899ef
--- /dev/null
+++ b/kernel/unwind/sframe_debug.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _SFRAME_DEBUG_H
+#define _SFRAME_DEBUG_H
+
+#include <linux/sframe.h>
+#include "sframe.h"
+
+#ifdef CONFIG_MODULES
+
+#define objname(sec) ((sec) == &kernel_sfsec					\
+		     ? "vmlinux"						\
+		     : container_of((sec), struct module, arch.sframe_sec)->name)
+
+#else
+
+#define objname(...) "vmlinux"
+
+#endif
+
+#define dbg_sec(sec, fmt, ...)						\
+	pr_debug("(%s): " fmt, objname(sec), ##__VA_ARGS__)
+
+static __always_inline void dbg_print_header(struct sframe_section *sec)
+{
+	unsigned long fdes_end;
+
+	fdes_end = sec->fdes_start + (sec->num_fdes * sizeof(struct sframe_fde_v3));
+
+	dbg_sec(sec, "SEC:0x%lx-0x%lx fdes:0x%lx-0x%lx fres:0x%lx-0x%lx ra_off:%d fp_off:%d\n",
+		sec->sframe_start, sec->sframe_end, sec->fdes_start, fdes_end, sec->fres_start,
+		sec->fres_end, sec->ra_off, sec->fp_off);
+}
+
+#endif /* _SFRAME_DEBUG_H */
-- 
2.55.0.1082.g2b9226bbc0-goog