From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 29 Oct 2020 11:34:16 +0000 (+0100)
Subject: 4.19-stable patches
X-Git-Tag: v4.19.154~28
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c801afb7690bf99788d4ff4a48b19507a78adfd2;p=thirdparty%2Fkernel%2Fstable-queue.git

4.19-stable patches

added patches:
	objtool-support-clang-non-section-symbols-in-orc-generation.patch
---

diff --git a/queue-4.19/objtool-support-clang-non-section-symbols-in-orc-generation.patch b/queue-4.19/objtool-support-clang-non-section-symbols-in-orc-generation.patch
new file mode 100644
index 00000000000..865d5b766e6
--- /dev/null
+++ b/queue-4.19/objtool-support-clang-non-section-symbols-in-orc-generation.patch
@@ -0,0 +1,92 @@
+From e81e0724432542af8d8c702c31e9d82f57b1ff31 Mon Sep 17 00:00:00 2001
+From: Josh Poimboeuf <jpoimboe@redhat.com>
+Date: Wed, 1 Apr 2020 13:23:27 -0500
+Subject: objtool: Support Clang non-section symbols in ORC generation
+
+From: Josh Poimboeuf <jpoimboe@redhat.com>
+
+commit e81e0724432542af8d8c702c31e9d82f57b1ff31 upstream.
+
+When compiling the kernel with AS=clang, objtool produces a lot of
+warnings:
+
+  warning: objtool: missing symbol for section .text
+  warning: objtool: missing symbol for section .init.text
+  warning: objtool: missing symbol for section .ref.text
+
+It then fails to generate the ORC table.
+
+The problem is that objtool assumes text section symbols always exist.
+But the Clang assembler is aggressive about removing them.
+
+When generating relocations for the ORC table, objtool always tries to
+reference instructions by their section symbol offset.  If the section
+symbol doesn't exist, it bails.
+
+Do a fallback: when a section symbol isn't available, reference a
+function symbol instead.
+
+Reported-by: Dmitry Golovin <dima@golovin.in>
+Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Tested-by: Nathan Chancellor <natechancellor@gmail.com>
+Reviewed-by: Miroslav Benes <mbenes@suse.cz>
+Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://github.com/ClangBuiltLinux/linux/issues/669
+Link: https://lkml.kernel.org/r/9a9cae7fcf628843aabe5a086b1a3c5bf50f42e8.1585761021.git.jpoimboe@redhat.com
+Cc: Nick Desaulniers <ndesaulniers@google.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ tools/objtool/orc_gen.c |   33 ++++++++++++++++++++++++++-------
+ 1 file changed, 26 insertions(+), 7 deletions(-)
+
+--- a/tools/objtool/orc_gen.c
++++ b/tools/objtool/orc_gen.c
+@@ -100,11 +100,6 @@ static int create_orc_entry(struct secti
+ 	struct orc_entry *orc;
+ 	struct rela *rela;
+ 
+-	if (!insn_sec->sym) {
+-		WARN("missing symbol for section %s", insn_sec->name);
+-		return -1;
+-	}
+-
+ 	/* populate ORC data */
+ 	orc = (struct orc_entry *)u_sec->data->d_buf + idx;
+ 	memcpy(orc, o, sizeof(*orc));
+@@ -117,8 +112,32 @@ static int create_orc_entry(struct secti
+ 	}
+ 	memset(rela, 0, sizeof(*rela));
+ 
+-	rela->sym = insn_sec->sym;
+-	rela->addend = insn_off;
++	if (insn_sec->sym) {
++		rela->sym = insn_sec->sym;
++		rela->addend = insn_off;
++	} else {
++		/*
++		 * The Clang assembler doesn't produce section symbols, so we
++		 * have to reference the function symbol instead:
++		 */
++		rela->sym = find_symbol_containing(insn_sec, insn_off);
++		if (!rela->sym) {
++			/*
++			 * Hack alert.  This happens when we need to reference
++			 * the NOP pad insn immediately after the function.
++			 */
++			rela->sym = find_symbol_containing(insn_sec,
++							   insn_off - 1);
++		}
++		if (!rela->sym) {
++			WARN("missing symbol for insn at offset 0x%lx\n",
++			     insn_off);
++			return -1;
++		}
++
++		rela->addend = insn_off - rela->sym->offset;
++	}
++
+ 	rela->type = R_X86_64_PC32;
+ 	rela->offset = idx * sizeof(int);
+