linux-kernel - [RESEND PATCH v4 4/6] arm64/mm: Make swapper_pg

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Date:   Wed, 18 Jul 2018 18:17:25 +0800
From:   Jun Yao <yaojun8558363@...il.com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     catalin.marinas@....com, will.deacon@....com, james.morse@....com,
        linux-kernel@...r.kernel.org
Subject: [RESEND PATCH v4 4/6] arm64/mm: Make swapper_pg_dir smaller

We setup final page tables in swapper_pg_dir, which just contains
PGD. And the PUD/PMD are allocated dynamically. So we can make it
smaller.

Signed-off-by: Jun Yao <yaojun8558363@...il.com>
---
 arch/arm64/kernel/vmlinux.lds.S | 2 +-
 arch/arm64/mm/mmu.c             | 8 --------
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 61d7cee3eaa6..2446911f4262 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -237,7 +237,7 @@ SECTIONS
 	. += RESERVED_TTBR0_SIZE;
 #endif
 	swapper_pg_dir = .;
-	. += SWAPPER_DIR_SIZE;
+	. += PAGE_SIZE;
 	swapper_pg_end = .;
 
 	__pecoff_data_size = ABSOLUTE(. - __initdata_begin);
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 088a591e4ea4..1d16104aa0b9 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -633,14 +633,6 @@ void __init paging_init(void)
 	map_mem(swapper_pg_dir);
 	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
 	init_mm.pgd = swapper_pg_dir;
-
-	/*
-	 * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd
-	 * allocated with it.
-	 */
-	memblock_free(__pa_symbol(swapper_pg_dir) + PAGE_SIZE,
-		      __pa_symbol(swapper_pg_end) - __pa_symbol(swapper_pg_dir)
-		      - PAGE_SIZE);
 }
 
 void __init set_init_mm_pgd(pgd_t *pgd)
-- 
2.17.1