linux-kernel - [PATCH v6 36/38] KVM: arm64: Page-align the .hyp sections

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Message-Id: <20210319100146.1149909-37-qperret@google.com>
Date:   Fri, 19 Mar 2021 10:01:44 +0000
From:   Quentin Perret <qperret@...gle.com>
To:     catalin.marinas@....com, will@...nel.org, maz@...nel.org,
        james.morse@....com, julien.thierry.kdev@...il.com,
        suzuki.poulose@....com
Cc:     android-kvm@...gle.com, seanjc@...gle.com, mate.toth-pal@....com,
        linux-kernel@...r.kernel.org, robh+dt@...nel.org,
        linux-arm-kernel@...ts.infradead.org, kernel-team@...roid.com,
        kvmarm@...ts.cs.columbia.edu, tabba@...gle.com, ardb@...nel.org,
        mark.rutland@....com, dbrazdil@...gle.com, qperret@...gle.com
Subject: [PATCH v6 36/38] KVM: arm64: Page-align the .hyp sections

We will soon unmap the .hyp sections from the host stage 2 in Protected
nVHE mode, which obviously works with at least page granularity, so make
sure to align them correctly.

Acked-by: Will Deacon <will@...nel.org>
Signed-off-by: Quentin Perret <qperret@...gle.com>
---
 arch/arm64/kernel/vmlinux.lds.S | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index e96173ce211b..709d2c433c5e 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -15,9 +15,11 @@
 
 #define HYPERVISOR_DATA_SECTIONS				\
 	HYP_SECTION_NAME(.rodata) : {				\
+		. = ALIGN(PAGE_SIZE);				\
 		__hyp_rodata_start = .;				\
 		*(HYP_SECTION_NAME(.data..ro_after_init))	\
 		*(HYP_SECTION_NAME(.rodata))			\
+		. = ALIGN(PAGE_SIZE);				\
 		__hyp_rodata_end = .;				\
 	}
 
@@ -72,21 +74,14 @@ ENTRY(_text)
 jiffies = jiffies_64;
 
 #define HYPERVISOR_TEXT					\
-	/*						\
-	 * Align to 4 KB so that			\
-	 * a) the HYP vector table is at its minimum	\
-	 *    alignment of 2048 bytes			\
-	 * b) the HYP init code will not cross a page	\
-	 *    boundary if its size does not exceed	\
-	 *    4 KB (see related ASSERT() below)		\
-	 */						\
-	. = ALIGN(SZ_4K);				\
+	. = ALIGN(PAGE_SIZE);				\
 	__hyp_idmap_text_start = .;			\
 	*(.hyp.idmap.text)				\
 	__hyp_idmap_text_end = .;			\
 	__hyp_text_start = .;				\
 	*(.hyp.text)					\
 	HYPERVISOR_EXTABLE				\
+	. = ALIGN(PAGE_SIZE);				\
 	__hyp_text_end = .;
 
 #define IDMAP_TEXT					\
@@ -322,11 +317,12 @@ SECTIONS
 #include "image-vars.h"
 
 /*
- * The HYP init code and ID map text can't be longer than a page each,
- * and should not cross a page boundary.
+ * The HYP init code and ID map text can't be longer than a page each. The
+ * former is page-aligned, but the latter may not be with 16K or 64K pages, so
+ * it should also not cross a page boundary.
  */
-ASSERT(__hyp_idmap_text_end - (__hyp_idmap_text_start & ~(SZ_4K - 1)) <= SZ_4K,
-	"HYP init code too big or misaligned")
+ASSERT(__hyp_idmap_text_end - __hyp_idmap_text_start <= PAGE_SIZE,
+	"HYP init code too big")
 ASSERT(__idmap_text_end - (__idmap_text_start & ~(SZ_4K - 1)) <= SZ_4K,
 	"ID map text too big or misaligned")
 #ifdef CONFIG_HIBERNATION
-- 
2.31.0.rc2.261.g7f71774620-goog