From fc8bd77d6476d7733ace9e03093b4acaee6e0605 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 16 Mar 2020 10:13:45 +0100 Subject: x86/kexec: Use RIP relative addressing Normally identity_mapped is not visible to objtool, due to: arch/x86/kernel/Makefile:OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o := y However, when we want to run objtool on vmlinux.o there is no hiding it: vmlinux.o: warning: objtool: .text+0x4c0f1: unsupported intra-function call Replace the (i386 inspired) pattern: call 1f 1: popq %r8 subq $(1b - relocate_kernel), %r8 With a x86_64 RIP-relative LEA: leaq relocate_kernel(%rip), %r8 Suggested-by: Brian Gerst Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200324160924.143334345@infradead.org --- arch/x86/kernel/relocate_kernel_64.S | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index ef3ba99068d3..cc5c8b9048b5 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -196,10 +196,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped) /* get the re-entry point of the peer system */ movq 0(%rsp), %rbp - call 1f -1: - popq %r8 - subq $(1b - relocate_kernel), %r8 + leaq relocate_kernel(%rip), %r8 movq CP_PA_SWAP_PAGE(%r8), %r10 movq CP_PA_BACKUP_PAGES_MAP(%r8), %rdi movq CP_PA_TABLE_PAGE(%r8), %rax -- cgit From 36cc552055a5f95bab479533b4ebbad6a6cea0e1 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 24 Mar 2020 15:35:42 +0100 Subject: x86/kexec: Make relocate_kernel_64.S objtool clean Having fixed the biggest objtool issue in this file; fix up the rest and remove the exception. Suggested-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200324160924.202621656@infradead.org --- arch/x86/kernel/Makefile | 1 - arch/x86/kernel/relocate_kernel_64.S | 7 +++++++ 2 files changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 9b294c13809a..8be5926cce51 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -28,7 +28,6 @@ KASAN_SANITIZE_dumpstack_$(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 cc5c8b9048b5..a4d9a261425b 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -9,6 +9,8 @@ #include #include #include +#include +#include /* * 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 */ @@ -192,6 +196,7 @@ 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 */ @@ -209,6 +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 @@ -230,6 +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 -- cgit