From b5745d7ea68ad13c98c7180d4b6b69e43ef33d55 Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Fri, 5 Jul 2019 11:45:50 -0500
Subject: [PATCH] Add support for R_X86_64_PLT32

Starting with binutils 2.31, the Linux kernel may have R_X86_64_PLT32
relocations. Make sure we support them. This should be as simple as
treating R_X86_64_PLT32 exactly like R_X86_64_PC32 everywhere. For more
details see upstream commit torvalds/linux@b21ebf2.

This also fixes the following issue seen on Fedora 29:

```
$ kpatch-build/kpatch-build -t vmlinux ./test/integration/fedora-27/convert-global-local.patch
Using cache at /home/jpoimboe/.kpatch/src
Testing patch file(s)
Reading special section data
Building original source
Building patched source
Extracting new and modified ELF sections
ERROR: slub.o: 1 function(s) can not be patched
slub.o: function __kmalloc has no fentry/mcount call, unable to patch
/home/jpoimboe/git/kpatch/kpatch-build/create-diff-object: unreconcilable difference
ERROR: 1 error(s) encountered. Check /home/jpoimboe/.kpatch/build.log for more details.
```

Fixes #975.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 kmod/core/core.c                  | 1 +
 kpatch-build/create-diff-object.c | 3 ++-
 kpatch-build/kpatch-elf.c         | 4 +++-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/kmod/core/core.c b/kmod/core/core.c
index a91d417..4d60d79 100644
--- a/kmod/core/core.c
+++ b/kmod/core/core.c
@@ -700,6 +700,7 @@ static int kpatch_write_relocations(struct kpatch_module *kpmod,
 		case R_X86_64_NONE:
 			continue;
 		case R_X86_64_PC32:
+		case R_X86_64_PLT32:
 			loc = dynrela->dest;
 			val = (u32)(dynrela->src + dynrela->addend -
 				    dynrela->dest);
diff --git a/kpatch-build/create-diff-object.c b/kpatch-build/create-diff-object.c
index 61fc571..3b366fe 100644
--- a/kpatch-build/create-diff-object.c
+++ b/kpatch-build/create-diff-object.c
@@ -1288,7 +1288,8 @@ static void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
 #ifdef __powerpc64__
 			add_off = 0;
 #else
-			if (rela->type == R_X86_64_PC32) {
+			if (rela->type == R_X86_64_PC32 ||
+			    rela->type == R_X86_64_PLT32) {
 				struct insn insn;
 				rela_insn(sec, rela, &insn);
 				add_off = (long)insn.next_byte -
diff --git a/kpatch-build/kpatch-elf.c b/kpatch-build/kpatch-elf.c
index 7f90e36..848a715 100644
--- a/kpatch-build/kpatch-elf.c
+++ b/kpatch-build/kpatch-elf.c
@@ -332,7 +332,9 @@ static void kpatch_find_func_profiling_calls(struct kpatch_elf *kelf)
 #else
 		rela = list_first_entry(&sym->sec->rela->relas, struct rela,
 					list);
-		if ((rela->type != R_X86_64_NONE && rela->type != R_X86_64_PC32) ||
+		if ((rela->type != R_X86_64_NONE &&
+		     rela->type != R_X86_64_PC32 &&
+		     rela->type != R_X86_64_PLT32) ||
 		    strcmp(rela->sym->name, "__fentry__"))
 			continue;