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From: David Brazdil <dbrazdil@google.com>
To: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
	Christoph Lameter <cl@linux.com>, Arnd Bergmann <arnd@arndb.de>,
	James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
	linux-arch@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH v2 00/10] Independent per-CPU data section for nVHE
Date: Wed, 16 Sep 2020 13:24:12 +0100	[thread overview]
Message-ID: <20200916122412.elxfxbdygvmdgrj5@google.com> (raw)
In-Reply-To: <20200916115404.rhv4dkyjz35e4x25@google.com>

> I was also wondering about another approach - using the PERCPU_SECTION macro
> unchanged in the hyp linker script. It would lay out a single .data..percpu and
> we would then prefix it with .hyp and the symbols with __kvm_nvhe_ as with
> everything else. WDYT? Haven't tried that yet, could be a naive idea. 

Seems to work. Can't use PERCPU_SECTION directly because then we couldn't
rename it in the same linker script, but if we just unwrap that one layer
we can use PERCPU_INPUT. No global macro changes needed.

Let me know what you think.

------8<------
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 5904a4de9f40..9e6bf21268f1 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -195,11 +195,9 @@ SECTIONS
        PERCPU_SECTION(L1_CACHE_BYTES)

        /* KVM nVHE per-cpu section */
-       #undef PERCPU_SECTION_NAME
-       #undef PERCPU_SYMBOL_NAME
-       #define PERCPU_SECTION_NAME(suffix)     CONCAT3(.hyp, PERCPU_SECTION_BASE_NAME, suffix)
-       #define PERCPU_SYMBOL_NAME(name)        __kvm_nvhe_ ## name
-       PERCPU_SECTION(L1_CACHE_BYTES)
+       . = ALIGN(PAGE_SIZE);
+       .hyp.data..percpu : { *(.hyp.data..percpu) }
+       . = ALIGN(PAGE_SIZE);

        .rela.dyn : ALIGN(8) {
                *(.rela .rela*)
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
index 7d8c3fa004f4..1d8e4f7edc29 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S
@@ -4,6 +4,10 @@
  * Written by David Brazdil <dbrazdil@google.com>
  */

+#include <asm-generic/vmlinux.lds.h>
+#include <asm/cache.h>
+#include <asm/memory.h>
+
 /*
  * Defines an ELF hyp section from input section @NAME and its subsections.
  */
@@ -11,9 +15,9 @@

 SECTIONS {
        HYP_SECTION(.text)
-       HYP_SECTION(.data..percpu)
-       HYP_SECTION(.data..percpu..first)
-       HYP_SECTION(.data..percpu..page_aligned)
-       HYP_SECTION(.data..percpu..read_mostly)
-       HYP_SECTION(.data..percpu..shared_aligned)
+
+       .hyp..data..percpu : {
+               __per_cpu_load = .;
+               PERCPU_INPUT(L1_CACHE_BYTES)
+       }
 }
-----8<------

David

  reply	other threads:[~2020-09-16 21:01 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-03  9:17 David Brazdil
2020-09-03  9:17 ` [PATCH v2 01/10] Macros to override naming of percpu symbols and sections David Brazdil
2020-09-03  9:17 ` [PATCH v2 02/10] kvm: arm64: Partially link nVHE hyp code, simplify HYPCOPY David Brazdil
2020-09-10  9:54   ` Andrew Scull
2020-09-14 13:09   ` Will Deacon
2020-09-03  9:17 ` [PATCH v2 03/10] kvm: arm64: Remove __hyp_this_cpu_read David Brazdil
2020-09-10 11:12   ` Andrew Scull
2020-09-17  8:34     ` David Brazdil
2020-09-03  9:17 ` [PATCH v2 04/10] kvm: arm64: Remove hyp_adr/ldr_this_cpu David Brazdil
2020-09-10 12:34   ` Andrew Scull
2020-09-03  9:17 ` [PATCH v2 05/10] kvm: arm64: Add helpers for accessing nVHE hyp per-cpu vars David Brazdil
2020-09-03  9:17 ` [PATCH v2 06/10] kvm: arm64: Duplicate arm64_ssbd_callback_required for nVHE hyp David Brazdil
2020-09-03  9:17 ` [PATCH v2 07/10] kvm: arm64: Create separate instances of kvm_host_data for VHE/nVHE David Brazdil
2020-09-03  9:17 ` [PATCH v2 08/10] kvm: arm64: Mark hyp stack pages reserved David Brazdil
2020-09-03  9:17 ` [PATCH v2 09/10] kvm: arm64: Set up hyp percpu data for nVHE David Brazdil
2020-09-03  9:17 ` [PATCH v2 10/10] kvm: arm64: Remove unnecessary hyp mappings David Brazdil
2020-09-10 14:07   ` Andrew Scull
2020-09-16 13:35     ` David Brazdil
2020-09-14 17:40 ` [PATCH v2 00/10] Independent per-CPU data section for nVHE Will Deacon
2020-09-16 11:54   ` David Brazdil
2020-09-16 12:24     ` David Brazdil [this message]
2020-09-16 12:39       ` Will Deacon
2020-09-16 12:40         ` David Brazdil

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