From cde07a4e4434ddfb9b1616ac971edf6d66329804 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf <jpoimboe@redhat.com> Date: Thu, 21 Jan 2021 15:29:28 -0600 Subject: [PATCH] x86/xen: Support objtool validation in xen-asm.S The OBJECT_FILES_NON_STANDARD annotation is used to tell objtool to ignore a file. File-level ignores won't work when validating vmlinux.o. Tweak the ELF metadata and unwind hints to allow objtool to follow the code. Cc: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/8b042a09c69e8645f3b133ef6653ba28f896807d.1611263462.git.jpoimboe@redhat.com --- arch/x86/xen/Makefile | 1 - arch/x86/xen/xen-asm.S | 29 +++++++++++++++++++---------- 2 files changed, 19 insertions(+), 11 deletions(-) diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile index fc5c5ba4aacb..40b5779fce21 100644 --- a/arch/x86/xen/Makefile +++ b/arch/x86/xen/Makefile @@ -1,5 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 -OBJECT_FILES_NON_STANDARD_xen-asm.o := y ifdef CONFIG_FUNCTION_TRACER # Do not profile debug and lowlevel utilities diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S index 1cb0e84b9161..a05e80b552c0 100644 --- a/arch/x86/xen/xen-asm.S +++ b/arch/x86/xen/xen-asm.S @@ -14,6 +14,7 @@ #include <asm/thread_info.h> #include <asm/asm.h> #include <asm/frame.h> +#include <asm/unwind_hints.h> #include <xen/interface/xen.h> @@ -146,6 +147,7 @@ SYM_FUNC_END(xen_read_cr2_direct); .macro xen_pv_trap name SYM_CODE_START(xen_\name) + UNWIND_HINT_EMPTY pop %rcx pop %r11 jmp \name @@ -184,6 +186,7 @@ xen_pv_trap asm_exc_xen_hypervisor_callback SYM_CODE_START(xen_early_idt_handler_array) i = 0 .rept NUM_EXCEPTION_VECTORS + UNWIND_HINT_EMPTY pop %rcx pop %r11 jmp early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE @@ -210,11 +213,13 @@ hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32 * rsp->rax } */ SYM_CODE_START(xen_iret) + UNWIND_HINT_EMPTY pushq $0 jmp hypercall_iret SYM_CODE_END(xen_iret) SYM_CODE_START(xen_sysret64) + UNWIND_HINT_EMPTY /* * We're already on the usermode stack at this point, but * still with the kernel gs, so we can easily switch back. @@ -250,7 +255,8 @@ SYM_CODE_END(xen_sysret64) */ /* Normal 64-bit system call target */ -SYM_FUNC_START(xen_syscall_target) +SYM_CODE_START(xen_syscall_target) + UNWIND_HINT_EMPTY popq %rcx popq %r11 @@ -263,12 +269,13 @@ SYM_FUNC_START(xen_syscall_target) movq $__USER_CS, 1*8(%rsp) jmp entry_SYSCALL_64_after_hwframe -SYM_FUNC_END(xen_syscall_target) +SYM_CODE_END(xen_syscall_target) #ifdef CONFIG_IA32_EMULATION /* 32-bit compat syscall target */ -SYM_FUNC_START(xen_syscall32_target) +SYM_CODE_START(xen_syscall32_target) + UNWIND_HINT_EMPTY popq %rcx popq %r11 @@ -281,10 +288,11 @@ SYM_FUNC_START(xen_syscall32_target) movq $__USER32_CS, 1*8(%rsp) jmp entry_SYSCALL_compat_after_hwframe -SYM_FUNC_END(xen_syscall32_target) +SYM_CODE_END(xen_syscall32_target) /* 32-bit compat sysenter target */ -SYM_FUNC_START(xen_sysenter_target) +SYM_CODE_START(xen_sysenter_target) + UNWIND_HINT_EMPTY /* * NB: Xen is polite and clears TF from EFLAGS for us. This means * that we don't need to guard against single step exceptions here. @@ -301,17 +309,18 @@ SYM_FUNC_START(xen_sysenter_target) movq $__USER32_CS, 1*8(%rsp) jmp entry_SYSENTER_compat_after_hwframe -SYM_FUNC_END(xen_sysenter_target) +SYM_CODE_END(xen_sysenter_target) #else /* !CONFIG_IA32_EMULATION */ -SYM_FUNC_START_ALIAS(xen_syscall32_target) -SYM_FUNC_START(xen_sysenter_target) +SYM_CODE_START(xen_syscall32_target) +SYM_CODE_START(xen_sysenter_target) + UNWIND_HINT_EMPTY lea 16(%rsp), %rsp /* strip %rcx, %r11 */ mov $-ENOSYS, %rax pushq $0 jmp hypercall_iret -SYM_FUNC_END(xen_sysenter_target) -SYM_FUNC_END_ALIAS(xen_syscall32_target) +SYM_CODE_END(xen_sysenter_target) +SYM_CODE_END(xen_syscall32_target) #endif /* CONFIG_IA32_EMULATION */