linux-kernel - [PATCH 3/4] migrate swapper_pg

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Message-Id: <20180529043808.27896-1-yaojun8558363@gmail.com>
Date:   Tue, 29 May 2018 12:38:08 +0800
From:   YaoJun <yaojun8558363@...il.com>
To:     kernel-hardening@...ts.openwall.com
Cc:     linux-kernel@...r.kernel.org,
        linux-security-module@...r.kernel.org, jmorris@...ei.org
Subject: [PATCH 3/4] migrate swapper_pg_dir

Because tramp_map_kernel/tramp_unmap_kernel macro update
ttbr1 by add/sub offset, so we need to migrate both
swapper_pg_dir and tramp_pg_dir. Before doing that, make
tramp_pg_dir and swapper_pg_dir adjacent.

---
 arch/arm64/kernel/entry.S       |  4 ++--
 arch/arm64/kernel/vmlinux.lds.S | 10 +++++-----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index ec2ee720e33e..b35425feaf56 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -1004,7 +1004,7 @@ __ni_sys_trace:
 
 	.macro tramp_map_kernel, tmp
 	mrs	\tmp, ttbr1_el1
-	add	\tmp, \tmp, #(PAGE_SIZE + RESERVED_TTBR0_SIZE)
+	add	\tmp, \tmp, #(PAGE_SIZE)
 	bic	\tmp, \tmp, #USER_ASID_FLAG
 	msr	ttbr1_el1, \tmp
 #ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003
@@ -1023,7 +1023,7 @@ alternative_else_nop_endif
 
 	.macro tramp_unmap_kernel, tmp
 	mrs	\tmp, ttbr1_el1
-	sub	\tmp, \tmp, #(PAGE_SIZE + RESERVED_TTBR0_SIZE)
+	sub	\tmp, \tmp, #(PAGE_SIZE)
 	orr	\tmp, \tmp, #USER_ASID_FLAG
 	msr	ttbr1_el1, \tmp
 	/*
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 0221aca6493d..a094156e05a4 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -219,15 +219,15 @@ SECTIONS
 	idmap_pg_dir = .;
 	. += IDMAP_DIR_SIZE;
 
-#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-	tramp_pg_dir = .;
-	. += PAGE_SIZE;
-#endif
-
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
 	reserved_ttbr0 = .;
 	. += RESERVED_TTBR0_SIZE;
 #endif
+
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+	tramp_pg_dir = .;
+	. += PAGE_SIZE;
+#endif
 	swapper_pg_dir = .;
 	. += SWAPPER_DIR_SIZE;
 	swapper_pg_end = .;
-- 
2.17.0