Merge branch 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:
 "The biggest changes in this cycle were the vmlinux.o optimizations by
   Peter Zijlstra, which are preparatory and optimization work to run
   objtool against the much richer vmlinux.o object file, to perform
   new, whole-program section based logic. That work exposed a handful
   of problems with the existing code, which fixes and optimizations are
   merged here. The complete 'vmlinux.o and noinstr' work is still work
   in progress, targeted for v5.8.

  There's also assorted fixes and enhancements from Josh Poimboeuf.

  In particular I'd like to draw attention to commit 644592d328370,
  which turns fatal objtool errors into failed kernel builds. This
  behavior is IMO now justified on multiple grounds (it's easy currently
  to not notice an essentially corrupted kernel build), and the commit
  has been in -next testing for several weeks, but there could still be
  build failures with old or weird toolchains. Should that be widespread
  or high profile enough then I'd suggest a quick revert, to not hold up
  the merge window"

* 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  objtool: Re-arrange validate_functions()
  objtool: Optimize find_rela_by_dest_range()
  objtool: Delete cleanup()
  objtool: Optimize read_sections()
  objtool: Optimize find_symbol_by_name()
  objtool: Resize insn_hash
  objtool: Rename find_containing_func()
  objtool: Optimize find_symbol_*() and read_symbols()
  objtool: Optimize find_section_by_name()
  objtool: Optimize find_section_by_index()
  objtool: Add a statistics mode
  objtool: Optimize find_symbol_by_index()
  x86/kexec: Make relocate_kernel_64.S objtool clean
  x86/kexec: Use RIP relative addressing
  objtool: Rename func_for_each_insn_all()
  objtool: Rename func_for_each_insn()
  objtool: Introduce validate_return()
  objtool: Improve call destination function detection
  objtool: Fix clang switch table edge case
  objtool: Add relocation check for alternative sections
  ...

2 files changed, 8 insertions, 5 deletions

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 9b294c13809a..8be5926cce51 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -28,7 +28,6 @@ KASAN_SANITIZE_dumpstack_$(BITS).o			:= n
 KASAN_SANITIZE_stacktrace.o				:= n
 KASAN_SANITIZE_paravirt.o				:= n
 
-OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o	:= y
 OBJECT_FILES_NON_STANDARD_test_nx.o			:= y
 OBJECT_FILES_NON_STANDARD_paravirt_patch.o		:= y
 
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index ef3ba99068d3..a4d9a261425b 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -9,6 +9,8 @@
 #include <asm/kexec.h>
 #include <asm/processor-flags.h>
 #include <asm/pgtable_types.h>
+#include <asm/nospec-branch.h>
+#include <asm/unwind_hints.h>
 
 /*
  * Must be relocatable PIC code callable as a C function
@@ -39,6 +41,7 @@
 	.align PAGE_SIZE
 	.code64
 SYM_CODE_START_NOALIGN(relocate_kernel)
+	UNWIND_HINT_EMPTY
 	/*
 	 * %rdi indirection_page
 	 * %rsi page_list
@@ -105,6 +108,7 @@ SYM_CODE_START_NOALIGN(relocate_kernel)
 SYM_CODE_END(relocate_kernel)
 
 SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
+	UNWIND_HINT_EMPTY
 	/* set return address to 0 if not preserving context */
 	pushq	$0
 	/* store the start address on the stack */
@@ -192,14 +196,12 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
 1:
 	popq	%rdx
 	leaq	PAGE_SIZE(%r10), %rsp
+	ANNOTATE_RETPOLINE_SAFE
 	call	*%rdx
 
 	/* get the re-entry point of the peer system */
 	movq	0(%rsp), %rbp
-	call	1f
-1:
-	popq	%r8
-	subq	$(1b - relocate_kernel), %r8
+	leaq	relocate_kernel(%rip), %r8
 	movq	CP_PA_SWAP_PAGE(%r8), %r10
 	movq	CP_PA_BACKUP_PAGES_MAP(%r8), %rdi
 	movq	CP_PA_TABLE_PAGE(%r8), %rax
@@ -212,6 +214,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
 SYM_CODE_END(identity_mapped)
 
 SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
+	UNWIND_HINT_EMPTY
 	movq	RSP(%r8), %rsp
 	movq	CR4(%r8), %rax
 	movq	%rax, %cr4
@@ -233,6 +236,7 @@ SYM_CODE_END(virtual_mapped)
 
 	/* Do the copies */
 SYM_CODE_START_LOCAL_NOALIGN(swap_pages)
+	UNWIND_HINT_EMPTY
 	movq	%rdi, %rcx 	/* Put the page_list in %rcx */
 	xorl	%edi, %edi
 	xorl	%esi, %esi