Linux-ARM-Kernel Archive on lore.kernel.org
 help / color / mirror / Atom feed
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 1/2] arm64: vmlinux.ld.S: add assertion for reserved_pg_dir offset
Date: Tue, 2 Feb 2021 12:36:57 +0000	[thread overview]
Message-ID: <20210202123658.22308-2-joey.gouly@arm.com> (raw)
In-Reply-To: <20210202123658.22308-1-joey.gouly@arm.com>

Add RESERVED_SWAPPER_OFFSET and use that instead of hardcoding
the offset between swapper_pg_dir and reserved_pg_dir.

Then use RESERVED_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/asm-uaccess.h | 4 ++--
 arch/arm64/include/asm/memory.h      | 6 ++++++
 arch/arm64/include/asm/uaccess.h     | 2 +-
 arch/arm64/kernel/vmlinux.lds.S      | 3 +++
 4 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h
index 9990059be106..ccedf548dac9 100644
--- a/arch/arm64/include/asm/asm-uaccess.h
+++ b/arch/arm64/include/asm/asm-uaccess.h
@@ -15,10 +15,10 @@
 	.macro	__uaccess_ttbr0_disable, tmp1
 	mrs	\tmp1, ttbr1_el1			// swapper_pg_dir
 	bic	\tmp1, \tmp1, #TTBR_ASID_MASK
-	sub	\tmp1, \tmp1, #PAGE_SIZE		// reserved_pg_dir just before swapper_pg_dir
+	sub	\tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET	// reserved_pg_dir
 	msr	ttbr0_el1, \tmp1			// set reserved TTBR0_EL1
 	isb
-	add	\tmp1, \tmp1, #PAGE_SIZE
+	add	\tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET
 	msr	ttbr1_el1, \tmp1		// set reserved ASID
 	isb
 	.endm
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 99d7e1494aaa..300f728fa288 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -159,6 +159,12 @@
 #define IOREMAP_MAX_ORDER	(PMD_SHIFT)
 #endif
 
+/*
+ *  Open-coded (swapper_pg_dir - reserved_pg_dir) as this cannot be calculated
+ *  until link time.
+ */
+#define RESERVED_SWAPPER_OFFSET	(PAGE_SIZE)
+
 #ifndef __ASSEMBLY__
 
 #include <linux/bitops.h>
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index f0fe0cc6abe0..0deb88467111 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -87,7 +87,7 @@ static inline void __uaccess_ttbr0_disable(void)
 	ttbr = read_sysreg(ttbr1_el1);
 	ttbr &= ~TTBR_ASID_MASK;
 	/* reserved_pg_dir placed before swapper_pg_dir */
-	write_sysreg(ttbr - PAGE_SIZE, ttbr0_el1);
+	write_sysreg(ttbr - RESERVED_SWAPPER_OFFSET, ttbr0_el1);
 	isb();
 	/* Set reserved ASID */
 	write_sysreg(ttbr, ttbr1_el1);
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 4c0b0c89ad59..a03a5300bce9 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -316,3 +316,6 @@ ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == PAGE_SIZE,
  * If padding is applied before .head.text, virt<->phys conversions will fail.
  */
 ASSERT(_text == KIMAGE_VADDR, "HEAD is misaligned")
+
+ASSERT(swapper_pg_dir - reserved_pg_dir == RESERVED_SWAPPER_OFFSET,
+       "RESERVED_SWAPPER_OFFSET is wrong!")
-- 
2.17.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  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 ` Joey Gouly [this message]
2021-02-02 12:36 ` [PATCH 2/2] arm64: vmlinux.ld.S: add assertion for tramp_pg_dir offset Joey Gouly
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210202123658.22308-2-joey.gouly@arm.com \
    --to=joey.gouly@arm.com \
    --cc=catalin.marinas@arm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=mark.rutland@arm.com \
    --cc=nd@arm.com \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox