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From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de, jpoimboe@redhat.com
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	peterz@infradead.org, mhiramat@kernel.org, mbenes@suse.cz,
	brgerst@gmail.com
Subject: [PATCH v2 04/19] x86/kexec: Use RIP relative addressing
Date: Tue, 17 Mar 2020 18:02:38 +0100	[thread overview]
Message-ID: <20200317170909.999544119@infradead.org> (raw)
In-Reply-To: 20200317170234.897520633@infradead.org

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 <brgerst@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kernel/relocate_kernel_64.S |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- 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_ma
 
 	/* 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



  parent reply	other threads:[~2020-03-17 17:12 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-17 17:02 [PATCH v2 00/19] objtool: vmlinux.o and noinstr validation Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 01/19] objtool: Introduce validate_return() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 02/19] objtool: Rename func_for_each_insn() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 03/19] objtool: Rename func_for_each_insn_all() Peter Zijlstra
2020-03-17 17:02 ` Peter Zijlstra [this message]
2020-03-17 17:02 ` [PATCH v2 05/19] objtool: Optimize find_symbol_by_index() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 06/19] objtool: Add a statistics mode Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 07/19] objtool: Optimize find_section_by_index() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 08/19] objtool: Optimize find_section_by_name() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 09/19] objtool: Optimize find_symbol_*() and read_symbols() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 10/19] objtool: Rename find_containing_func() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 11/19] objtool: Resize insn_hash Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 12/19] objtool: Optimize find_symbol_by_name() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 13/19] objtool: Optimize read_sections() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 14/19] objtool: Delete cleanup() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 15/19] objtool: Optimize find_rela_by_dest_range() Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 16/19] objtool: Implement noinstr validation Peter Zijlstra
2020-03-17 21:00   ` Josh Poimboeuf
2020-03-18  9:03     ` Peter Zijlstra
2020-03-18 10:06       ` Peter Zijlstra
2020-03-18 13:21   ` Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 17/19] objtool: Optimize !vmlinux.o again Peter Zijlstra
2020-03-18 13:20   ` Peter Zijlstra
2020-03-20 16:20     ` Miroslav Benes
2020-03-21 15:14       ` Peter Zijlstra
2020-03-21 16:11         ` Peter Zijlstra
2020-03-23  7:27           ` Miroslav Benes
2020-03-17 17:02 ` [PATCH v2 18/19] objtool: Use sec_offset_hash() for insn_hash Peter Zijlstra
2020-03-17 17:02 ` [PATCH v2 19/19] objtool: Detect loading function pointers across noinstr Peter Zijlstra
2020-03-17 23:39   ` kbuild test robot
2020-03-17 23:43     ` Nick Desaulniers
2020-03-18 11:02       ` Peter Zijlstra
2020-03-18  7:18   ` kbuild test robot
2020-03-17 21:05 ` [PATCH v2 00/19] objtool: vmlinux.o and noinstr validation Josh Poimboeuf
2020-03-18 13:18 ` [RFC][PATCH v2 20/19] kbuild/objtool: Add objtool-vmlinux.o pass Peter Zijlstra
2020-03-18 14:13   ` Peter Zijlstra
2020-03-18 18:34   ` Josh Poimboeuf

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