From: Shivank Garg <shivankg@amd.com>
To: Brendan Jackman <jackmanb@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Alexandre Chartre <alexandre.chartre@oracle.com>,
Liran Alon <liran.alon@oracle.com>,
Jan Setje-Eilers <jan.setjeeilers@oracle.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>,
Lorenzo Stoakes <lstoakes@gmail.com>,
David Hildenbrand <david@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>,
Michal Hocko <mhocko@kernel.org>,
Khalid Aziz <khalid.aziz@oracle.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Valentin Schneider <vschneid@redhat.com>,
Paul Turner <pjt@google.com>, Reiji Watanabe <reijiw@google.com>,
Junaid Shahid <junaids@google.com>,
Ofir Weisse <oweisse@google.com>,
Yosry Ahmed <yosryahmed@google.com>,
Patrick Bellasi <derkling@google.com>,
KP Singh <kpsingh@google.com>,
Alexandra Sandulescu <aesa@google.com>,
Matteo Rizzo <matteorizzo@google.com>,
Jann Horn <jannh@google.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kvm@vger.kernel.org
Subject: Re: [PATCH 26/26] KVM: x86: asi: Add some mitigations on address space transitions
Date: Tue, 20 Aug 2024 16:22:18 +0530 [thread overview]
Message-ID: <49849e0b-5ed6-44a4-94b3-1d5dd54b9a29@amd.com> (raw)
In-Reply-To: <20240712-asi-rfc-24-v1-26-144b319a40d8@google.com>
Hi Brendan,
> .:: Minor issues
>
> - fill_return_buffer() causes an “unreachable instruction” objtool
> warning. I haven’t investigated this.
> +
> +.pushsection .noinstr.text, "ax"
> +SYM_CODE_START(fill_return_buffer)
> + __FILL_RETURN_BUFFER(%_ASM_AX,RSB_CLEAR_LOOPS)
> + RET
> +SYM_CODE_END(fill_return_buffer)
> +.popsection
>
I'm getting this error when buiding the ASI patchset:
OBJCOPY modules.builtin.modinfo
GEN modules.builtin
GEN .vmlinux.objs
MODPOST Module.symvers
ERROR: modpost: "fill_return_buffer" [arch/x86/kvm/kvm.ko] undefined!
make[2]: *** [scripts/Makefile.modpost:145: Module.symvers] Error 1
make[1]: *** [/home/shivank/linux/Makefile:1871: modpost] Error 2
make: *** [Makefile:240: __sub-make] Error 2
I'm wondering if we need to annotate the asm code with
UNWIND_HINT_FUNC and EXPORT the fill_return_buffer and to avoid this?
---
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index db5b8ee01efe..4084ab49e2a7 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -399,7 +399,9 @@ EXPORT_SYMBOL(__x86_return_thunk)
.pushsection .noinstr.text, "ax"
SYM_CODE_START(fill_return_buffer)
+ UNWIND_HINT_FUNC
__FILL_RETURN_BUFFER(%_ASM_AX,RSB_CLEAR_LOOPS)
RET
SYM_CODE_END(fill_return_buffer)
+__EXPORT_THUNK(fill_return_buffer)
.popsection
---
This solved the issue for me.
Thanks,
Shivank
next prev parent reply other threads:[~2024-08-20 10:52 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-12 17:00 [PATCH 00/26] Address Space Isolation (ASI) 2024 Brendan Jackman
2024-07-12 17:00 ` [PATCH 01/26] mm: asi: Make some utility functions noinstr compatible Brendan Jackman
2024-10-25 11:41 ` Borislav Petkov
2024-10-25 13:21 ` Brendan Jackman
2024-10-29 17:38 ` Junaid Shahid
2024-10-29 19:12 ` Thomas Gleixner
2024-11-01 1:44 ` Junaid Shahid
2024-11-01 10:06 ` Brendan Jackman
2024-11-01 20:27 ` Thomas Gleixner
2024-11-05 21:40 ` Junaid Shahid
2024-12-13 14:45 ` Brendan Jackman
2024-07-12 17:00 ` [PATCH 02/26] x86: Create CONFIG_MITIGATION_ADDRESS_SPACE_ISOLATION Brendan Jackman
2024-07-22 7:55 ` Geert Uytterhoeven
2024-07-12 17:00 ` [PATCH 03/26] mm: asi: Introduce ASI core API Brendan Jackman
2024-07-12 17:00 ` [PATCH 04/26] objtool: let some noinstr functions make indirect calls Brendan Jackman
2024-07-12 17:00 ` [PATCH 05/26] mm: asi: Add infrastructure for boot-time enablement Brendan Jackman
2024-07-12 17:00 ` [PATCH 06/26] mm: asi: ASI support in interrupts/exceptions Brendan Jackman
2024-07-12 17:00 ` [PATCH 07/26] mm: asi: Switch to unrestricted address space before a context switch Brendan Jackman
2024-07-12 17:00 ` [PATCH 08/26] mm: asi: Use separate PCIDs for restricted address spaces Brendan Jackman
2024-07-12 17:00 ` [PATCH 09/26] mm: asi: Make __get_current_cr3_fast() ASI-aware Brendan Jackman
2024-07-12 17:00 ` [PATCH 10/26] mm: asi: Avoid warning from NMI userspace accesses in ASI context Brendan Jackman
2024-07-14 3:59 ` kernel test robot
2024-07-12 17:00 ` [PATCH 11/26] mm: asi: ASI page table allocation functions Brendan Jackman
2024-07-12 17:00 ` [PATCH 12/26] mm: asi: asi_exit() on PF, skip handling if address is accessible Brendan Jackman
2024-07-12 17:00 ` [PATCH 13/26] mm: asi: Functions to map/unmap a memory range into ASI page tables Brendan Jackman
2024-07-12 17:00 ` [PATCH 14/26] mm: asi: Add basic infrastructure for global non-sensitive mappings Brendan Jackman
2024-07-12 17:00 ` [PATCH 15/26] mm: Add __PAGEFLAG_FALSE Brendan Jackman
2024-07-12 17:00 ` [PATCH 16/26] mm: asi: Map non-user buddy allocations as nonsensitive Brendan Jackman
2024-08-21 13:59 ` Brendan Jackman
2024-07-12 17:00 ` [PATCH 17/26] mm: asi: Map kernel text and static data " Brendan Jackman
2024-07-12 17:00 ` [PATCH 18/26] mm: asi: Map vmalloc/vmap data as nonsesnitive Brendan Jackman
2024-07-13 15:53 ` kernel test robot
2024-07-12 17:00 ` [PATCH 19/26] percpu: clean up all mappings when pcpu_map_pages() fails Brendan Jackman
2024-07-16 1:33 ` Yosry Ahmed
2024-07-12 17:00 ` [PATCH 20/26] mm: asi: Map dynamic percpu memory as nonsensitive Brendan Jackman
2024-07-12 17:00 ` [PATCH 21/26] KVM: x86: asi: Restricted address space for VM execution Brendan Jackman
2024-07-12 17:00 ` [PATCH 22/26] KVM: x86: asi: Stabilize CR3 when potentially accessing with ASI Brendan Jackman
2024-07-12 17:00 ` [PATCH 23/26] mm: asi: Stabilize CR3 in switch_mm_irqs_off() Brendan Jackman
2024-07-12 17:00 ` [PATCH 24/26] mm: asi: Make TLB flushing correct under ASI Brendan Jackman
2024-07-12 17:00 ` [PATCH 25/26] mm: asi: Stop ignoring asi=on cmdline flag Brendan Jackman
2024-07-12 17:00 ` [PATCH 26/26] KVM: x86: asi: Add some mitigations on address space transitions Brendan Jackman
2024-07-14 5:02 ` kernel test robot
2024-08-20 10:52 ` Shivank Garg [this message]
2024-08-21 9:38 ` Brendan Jackman
2024-08-21 16:00 ` Shivank Garg
2024-07-12 17:09 ` [PATCH 00/26] Address Space Isolation (ASI) 2024 Brendan Jackman
2024-09-11 16:37 ` Brendan Jackman
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