[RFC PATCH 1/2] pgo: Update .profraw file format to version 7

[RFC PATCH 1/2] pgo: Update .profraw file format to version 7

[Jarmo Tiitto]

Recent LLVM-13 can't read the version 5 profile file any more
so update the format to .profraw file version 7.

This version adds binary_ids_size entry to struct llvm_prf_header
and it is output as zero.

This is enough to fix processing the profile data on LLVM-13 tools.

Signed-off-by: Jarmo Tiitto <jarmo.tiitto@gmail.com>
---
 kernel/pgo/fs.c  | 1 +
 kernel/pgo/pgo.h | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/pgo/fs.c b/kernel/pgo/fs.c
index 3c5aa7c2a4ce..77d23f869503 100644
--- a/kernel/pgo/fs.c
+++ b/kernel/pgo/fs.c
@@ -62,6 +62,7 @@ static void prf_fill_header(void **buffer)
 #endif
 	header->version = LLVM_VARIANT_MASK_IR_PROF | LLVM_INSTR_PROF_RAW_VERSION;
 	header->data_size = prf_data_count();
+	header->binary_ids_size = 0;
 	header->padding_bytes_before_counters = 0;
 	header->counters_size = prf_cnts_count();
 	header->padding_bytes_after_counters = 0;
diff --git a/kernel/pgo/pgo.h b/kernel/pgo/pgo.h
index 04fbf3bcde1e..45eeff9ab6c4 100644
--- a/kernel/pgo/pgo.h
+++ b/kernel/pgo/pgo.h
@@ -43,7 +43,7 @@
 		 (u64)'R' << 8  |	\
 		 (u64)129)
 
-#define LLVM_INSTR_PROF_RAW_VERSION		5
+#define LLVM_INSTR_PROF_RAW_VERSION 7
 #define LLVM_INSTR_PROF_DATA_ALIGNMENT		8
 #define LLVM_INSTR_PROF_IPVK_FIRST		0
 #define LLVM_INSTR_PROF_IPVK_LAST		1
@@ -56,6 +56,7 @@
  * struct llvm_prf_header - represents the raw profile header data structure.
  * @magic: the magic token for the file format.
  * @version: the version of the file format.
+ * @binary_ids_size: the number of binary ids. (since LLVM_INSTR_PROF_RAW_VERSION >= 7)
  * @data_size: the number of entries in the profile data section.
  * @padding_bytes_before_counters: the number of padding bytes before the
  *   counters.
@@ -72,6 +73,7 @@
 struct llvm_prf_header {
 	u64 magic;
 	u64 version;
+	u64 binary_ids_size;
 	u64 data_size;
 	u64 padding_bytes_before_counters;
 	u64 counters_size;
-- 
2.34.0

[RFC PATCH 2/2] pgo: Make module.lds.S linker script to merge __llvm_prf_ sections.

[Jarmo Tiitto]

The compiler leaves many duplicate instances of __llvm_prf_* sections
in final module objects and they confuse the kernel module loader.
Fix this by providing module.lds.S linker script that merges the split
sections like vmlinux.lds.S currently does.

Signed-off-by: Jarmo Tiitto <jarmo.tiitto@gmail.com>
---
I'm not sure the linker script is entirely correct and
it propably needs more work.
---
 scripts/module.lds.S | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index 04c5685c25cf..83ca5825c0c3 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -60,6 +60,39 @@ SECTIONS {
 		*(.text .text.[0-9a-zA-Z_]* .text..L.cfi*)
 	}
 #endif
+#ifdef CONFIG_PGO_CLANG
+	/*
+	 * With CONFIG_PGO_CLANG the compiler may split __llvm_prf_xxx
+	 * objects into multiple sections. Merge them in final .ko object.
+	 * However leave .rela__llvm_prf_data sections as-is
+	 * since they are needed by the module loader.
+	 */
+	__llvm_prf_data : AT(ADDR(__llvm_prf_data)) {
+		__llvm_prf_data_start = .;
+		KEEP(*(SORT(__llvm_prf_data)))
+		__llvm_prf_data_end = .;
+	}
+	__llvm_prf_cnts : AT(ADDR(__llvm_prf_cnts)) {
+		__llvm_prf_cnts_start = .;
+		KEEP(*(SORT(__llvm_prf_cnts)))
+		__llvm_prf_cnts_end = .;
+	}
+	__llvm_prf_names : AT(ADDR(__llvm_prf_names)) {
+		__llvm_prf_names_start = .;
+		KEEP(*(SORT(__llvm_prf_names)))
+		__llvm_prf_names_end = .;
+	}
+	__llvm_prf_vals : AT(ADDR(__llvm_prf_vals)) {
+		__llvm_prf_vals_start = .;
+		KEEP(*(SORT(__llvm_prf_vals)))
+		__llvm_prf_vals_end = .;
+	}
+	__llvm_prf_vnds : AT(ADDR(__llvm_prf_vnds)) {
+		__llvm_prf_vnds_start = .;
+		KEEP(*(SORT(__llvm_prf_vnds)))
+		__llvm_prf_vnds_end = .;
+	}
+#endif
 }
 
 /* bring in arch-specific sections */
-- 
2.34.0

[RFC PATCH 1/2] pgo: Update .profraw file format to version 7

[Jarmo Tiitto]

Recent LLVM-13 can't read the version 5 profile file any more
so update the format to .profraw file version 7.

This version adds binary_ids_size entry to struct llvm_prf_header
and it is output as zero.

This is enough to fix processing the profile data on LLVM-13 tools.

Signed-off-by: Jarmo Tiitto <jarmo.tiitto@gmail.com>
---
 kernel/pgo/fs.c  | 1 +
 kernel/pgo/pgo.h | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/pgo/fs.c b/kernel/pgo/fs.c
index 3c5aa7c2a4ce..77d23f869503 100644
--- a/kernel/pgo/fs.c
+++ b/kernel/pgo/fs.c
@@ -62,6 +62,7 @@ static void prf_fill_header(void **buffer)
 #endif
 	header->version = LLVM_VARIANT_MASK_IR_PROF | LLVM_INSTR_PROF_RAW_VERSION;
 	header->data_size = prf_data_count();
+	header->binary_ids_size = 0;
 	header->padding_bytes_before_counters = 0;
 	header->counters_size = prf_cnts_count();
 	header->padding_bytes_after_counters = 0;
diff --git a/kernel/pgo/pgo.h b/kernel/pgo/pgo.h
index 04fbf3bcde1e..45eeff9ab6c4 100644
--- a/kernel/pgo/pgo.h
+++ b/kernel/pgo/pgo.h
@@ -43,7 +43,7 @@
 		 (u64)'R' << 8  |	\
 		 (u64)129)
 
-#define LLVM_INSTR_PROF_RAW_VERSION		5
+#define LLVM_INSTR_PROF_RAW_VERSION 7
 #define LLVM_INSTR_PROF_DATA_ALIGNMENT		8
 #define LLVM_INSTR_PROF_IPVK_FIRST		0
 #define LLVM_INSTR_PROF_IPVK_LAST		1
@@ -56,6 +56,7 @@
  * struct llvm_prf_header - represents the raw profile header data structure.
  * @magic: the magic token for the file format.
  * @version: the version of the file format.
+ * @binary_ids_size: the number of binary ids. (since LLVM_INSTR_PROF_RAW_VERSION >= 7)
  * @data_size: the number of entries in the profile data section.
  * @padding_bytes_before_counters: the number of padding bytes before the
  *   counters.
@@ -72,6 +73,7 @@
 struct llvm_prf_header {
 	u64 magic;
 	u64 version;
+	u64 binary_ids_size;
 	u64 data_size;
 	u64 padding_bytes_before_counters;
 	u64 counters_size;
-- 
2.34.0