linux-kernel - [PATCH v7 3/4] arm64: Make use of memblock_isolate

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Date:   Fri, 10 Mar 2023 10:45:38 +0100
From:   Alexandre Ghiti <alexghiti@...osinc.com>
To:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Mike Rapoport <rppt@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Anup Patel <anup@...infault.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-riscv@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-mm@...ck.org
Cc:     Alexandre Ghiti <alexghiti@...osinc.com>
Subject: [PATCH v7 3/4] arm64: Make use of memblock_isolate_memory for the linear mapping

In order to isolate the kernel text mapping, we used some sort of hack
to isolate the kernel text range which consisted in marking this region
as not mappable with memblock_mark_nomap. Simply use the newly introduced
memblock_isolate_memory function which does exactly the same but does not
uselessly mark the region as not mappable.

Signed-off-by: Alexandre Ghiti <alexghiti@...osinc.com>
---
 arch/arm64/mm/mmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 6f9d8898a025..408dc852805c 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -552,7 +552,7 @@ static void __init map_mem(pgd_t *pgdp)
 	 * So temporarily mark them as NOMAP to skip mappings in
 	 * the following for-loop
 	 */
-	memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
+	memblock_isolate_memory(kernel_start, kernel_end - kernel_start);
 
 #ifdef CONFIG_KEXEC_CORE
 	if (crash_mem_map) {
@@ -568,6 +568,7 @@ static void __init map_mem(pgd_t *pgdp)
 	for_each_mem_range(i, &start, &end) {
 		if (start >= end)
 			break;
+
 		/*
 		 * The linear map must allow allocation tags reading/writing
 		 * if MTE is present. Otherwise, it has the same attributes as
@@ -589,7 +590,6 @@ static void __init map_mem(pgd_t *pgdp)
 	 */
 	__map_memblock(pgdp, kernel_start, kernel_end,
 		       PAGE_KERNEL, NO_CONT_MAPPINGS);
-	memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
 
 	/*
 	 * Use page-level mappings here so that we can shrink the region
-- 
2.37.2