linux-kernel - [PATCH] arm64: add early fixmap initialization flag

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Message-Id: <20240217140326.2367186-1-skseofh@gmail.com>
Date: Sat, 17 Feb 2024 23:03:26 +0900
From: skseofh@...il.com
To: catalin.marinas@....com,
	will@...nel.org
Cc: ryan.roberts@....com,
	mark.rutland@....com,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Daero Lee <skseofh@...il.com>
Subject: [PATCH] arm64: add early fixmap initialization flag

From: Daero Lee <skseofh@...il.com>

early_fixmap_init may be called multiple times. Since there is no
change in the page table after early fixmap initialization, an
initialization flag was added.

Signed-off-by: Daero Lee <skseofh@...il.com>
---
 arch/arm64/mm/fixmap.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c
index c0a3301203bd..fbdd5f30f3a1 100644
--- a/arch/arm64/mm/fixmap.c
+++ b/arch/arm64/mm/fixmap.c
@@ -32,6 +32,8 @@ static pte_t bm_pte[NR_BM_PTE_TABLES][PTRS_PER_PTE] __page_aligned_bss;
 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
 
+static int early_fixmap_initialized __initdata;
+
 static inline pte_t *fixmap_pte(unsigned long addr)
 {
 	return &bm_pte[BM_PTE_TABLE_IDX(addr)][pte_index(addr)];
@@ -100,10 +102,15 @@ void __init early_fixmap_init(void)
 	unsigned long addr = FIXADDR_TOT_START;
 	unsigned long end = FIXADDR_TOP;
 
+	if (early_fixmap_initialized)
+		return;
+
 	pgd_t *pgdp = pgd_offset_k(addr);
 	p4d_t *p4dp = p4d_offset(pgdp, addr);
 
 	early_fixmap_init_pud(p4dp, addr, end);
+
+	early_fixmap_initialized = 1;
 }
 
 /*
-- 
2.25.1