From: Joey Gouly <joey.gouly@arm.com>
To: <linux-arm-kernel@lists.infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
nd@arm.com, Will Deacon <will@kernel.org>,
Joey Gouly <joey.gouly@arm.com>
Subject: [PATCH 2/2] arm64: vmlinux.ld.S: add assertion for tramp_pg_dir offset
Date: Tue, 2 Feb 2021 12:36:58 +0000 [thread overview]
Message-ID: <20210202123658.22308-3-joey.gouly@arm.com> (raw)
In-Reply-To: <20210202123658.22308-1-joey.gouly@arm.com>
Add TRAMP_SWAPPER_OFFSET and use that instead of hardcoding
the offset between swapper_pg_dir and tramp_pg_dir.
Then use TRAMP_SWAPPER_OFFSET to assert that the offset is
correct at link time.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
---
arch/arm64/include/asm/memory.h | 6 ++++++
arch/arm64/kernel/entry.S | 4 ++--
arch/arm64/kernel/vmlinux.lds.S | 5 +++++
3 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 300f728fa288..f9aa9fa8806e 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -165,6 +165,12 @@
*/
#define RESERVED_SWAPPER_OFFSET (PAGE_SIZE)
+/*
+ * Open-coded (swapper_pg_dir - tramp_pg_dir) as this cannot be calculated
+ * until link time.
+ */
+#define TRAMP_SWAPPER_OFFSET (2 * PAGE_SIZE)
+
#ifndef __ASSEMBLY__
#include <linux/bitops.h>
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index c9bae73f2621..c6aee646eb6b 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -805,7 +805,7 @@ SYM_CODE_END(ret_to_user)
// Move from tramp_pg_dir to swapper_pg_dir
.macro tramp_map_kernel, tmp
mrs \tmp, ttbr1_el1
- add \tmp, \tmp, #(2 * PAGE_SIZE)
+ add \tmp, \tmp, #TRAMP_SWAPPER_OFFSET
bic \tmp, \tmp, #USER_ASID_FLAG
msr ttbr1_el1, \tmp
#ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003
@@ -825,7 +825,7 @@ alternative_else_nop_endif
// Move from swapper_pg_dir to tramp_pg_dir
.macro tramp_unmap_kernel, tmp
mrs \tmp, ttbr1_el1
- sub \tmp, \tmp, #(2 * PAGE_SIZE)
+ sub \tmp, \tmp, #TRAMP_SWAPPER_OFFSET
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 a03a5300bce9..68f76a96c60b 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -319,3 +319,8 @@ ASSERT(_text == KIMAGE_VADDR, "HEAD is misaligned")
ASSERT(swapper_pg_dir - reserved_pg_dir == RESERVED_SWAPPER_OFFSET,
"RESERVED_SWAPPER_OFFSET is wrong!")
+
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+ASSERT(swapper_pg_dir - tramp_pg_dir == TRAMP_SWAPPER_OFFSET,
+ "TRAMP_SWAPPER_OFFSET is wrong!")
+#endif
--
2.17.1
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next prev parent reply other threads:[~2021-02-02 12:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 12:36 [PATCH 0/2] Introduce macros for the offsets to reserved_pg_dir and tramp_pg_dir Joey Gouly
2021-02-02 12:36 ` [PATCH 1/2] arm64: vmlinux.ld.S: add assertion for reserved_pg_dir offset Joey Gouly
2021-02-02 12:36 ` Joey Gouly [this message]
2021-02-03 12:28 ` [PATCH 0/2] Introduce macros for the offsets to reserved_pg_dir and tramp_pg_dir Mark Rutland
2021-02-03 21:31 ` Will Deacon
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