kpatch/0016-create-diff-object-add-jump-label-support.patch

From 7d73bf5fe9d4c551424eb4868cd7081cbf0334d1 Mon Sep 17 00:00:00 2001
From: Zhipeng Xie <xiezhipeng1@huawei.com>
Date: Mon, 2 Mar 2020 04:35:07 -0500
Subject: [PATCH 16/37] create-diff-object: add jump label support

This patch processes the __jump_table special section, and
only the jump_lable used by the changed functions will be
included in __jump_table section and solve this limitation.
(The livepatch in kernel should also be modified that processing
the tracepoint again after the dynamic relocation by livepatch.)

Signed-off-by: Zhipeng Xie <xiezhipeng1@huawei.com>
---
 kpatch-build/create-diff-object.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index 9c70fee..9334cf9 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -70,6 +70,7 @@ enum subsection {
 enum loglevel loglevel = NORMAL;
 
 bool KLP_ARCH;
+char *KEEP_JUMP_LABEL = NULL;
 
 /*******************
  * Data structures
@@ -2399,6 +2400,8 @@ static bool should_keep_jump_label(struct lookup_table *lookup,
 		if (tracepoint || dynamic_debug)
 			return false;
 
+		if (KEEP_JUMP_LABEL)
+			return true;
 		/*
 		 * This will be upgraded to an error after all jump labels have
 		 * been reported.
@@ -2429,6 +2432,8 @@ static bool should_keep_jump_label(struct lookup_table *lookup,
 		if (tracepoint || dynamic_debug)
 			return false;
 
+		if (KEEP_JUMP_LABEL)
+			return true;
 		/*
 		 * This will be upgraded to an error after all jump labels have
 		 * been reported.
@@ -3027,8 +3032,7 @@ static void kpatch_process_special_sections(struct kpatch_elf *kelf,
 		 * labels and enable tracepoints in a patched function.
 		 */
 		list_for_each_entry(sec, &kelf->sections, list) {
-			if (strcmp(sec->name, "__jump_table") &&
-			    strcmp(sec->name, "__tracepoints") &&
+			if (strcmp(sec->name, "__tracepoints") &&
 			    strcmp(sec->name, "__tracepoints_ptrs") &&
 			    strcmp(sec->name, "__tracepoints_strings"))
 				continue;
@@ -4009,6 +4013,7 @@ int main(int argc, char *argv[])
 	char *parent_symtab, *mod_symvers, *patch_name, *output_obj;
 	char *no_profiling_calls = NULL;
 
+	KEEP_JUMP_LABEL = getenv("KEEP_JUMP_LABEL");
 	memset(&arguments, 0, sizeof(arguments));
 	argp_parse (&argp, argc, argv, 0, NULL, &arguments);
 	if (arguments.debug)
-- 
2.33.0