From: Miles Chen <miles.chen@mediatek.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Russell King <linux@armlinux.org.uk>,
Minchan Kim <minchan@kernel.org>
Cc: <linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>,
<linux-mediatek@lists.infradead.org>, <wsd_upstream@mediatek.com>,
Miles Chen <miles.chen@mediatek.com>,
Suren Baghdasaryan <surenb@google.com>
Subject: [PATCH v2 4/4] arm: replace vector mem type with read-only type
Date: Fri, 23 Oct 2020 17:14:37 +0800 [thread overview]
Message-ID: <20201023091437.8225-5-miles.chen@mediatek.com> (raw)
In-Reply-To: <20201023091437.8225-1-miles.chen@mediatek.com>
Since kernel no longer writes to the vector, try to replace
the vector mem type with read-only type and remove L_PTE_MT_VECTORS.
from Catalin in [1]:
"
> I don't think this matters since the kernel no longer writes to the
> vectors page at run-time but it needs cleaning up a bit (and testing in
> case I missed something). IOW, do we still need a dedicated mapping type
> for the vectors or we can simply use the read-only user page attributes?
"
[1] https://lore.kernel.org/patchwork/patch/986574/
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
---
arch/arm/include/asm/pgtable-2level.h | 1 -
arch/arm/mm/mmu.c | 7 +++----
arch/arm/mm/proc-macros.S | 2 +-
3 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h
index 385e7a32394e..438359d3675f 100644
--- a/arch/arm/include/asm/pgtable-2level.h
+++ b/arch/arm/include/asm/pgtable-2level.h
@@ -163,7 +163,6 @@
#define L_PTE_MT_WRITETHROUGH (_AT(pteval_t, 0x02) << 2) /* 0010 */
#define L_PTE_MT_WRITEBACK (_AT(pteval_t, 0x03) << 2) /* 0011 */
#define L_PTE_MT_DEV_SHARED (_AT(pteval_t, 0x04) << 2) /* 0100 */
-#define L_PTE_MT_VECTORS (_AT(pteval_t, 0x05) << 2) /* 0101 */
#define L_PTE_MT_MINICACHE (_AT(pteval_t, 0x06) << 2) /* 0110 (sa1100, xscale) */
#define L_PTE_MT_WRITEALLOC (_AT(pteval_t, 0x07) << 2) /* 0111 */
#if defined(CONFIG_CPU_V7) || defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V6K)
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index ab69250a86bc..0b6b377e2cce 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -536,12 +536,11 @@ static void __init build_mem_type_table(void)
#ifndef CONFIG_ARM_LPAE
/*
- * We don't use domains on ARMv6 (since this causes problems with
- * v6/v7 kernels), so we must use a separate memory type for user
- * r/o, kernel r/w to map the vectors page.
+ * We no longer write to the vector pages ar run-time, to
+ * use read-only user page attribute for vector.
*/
if (cpu_arch == CPU_ARCH_ARMv6)
- vecs_pgprot |= L_PTE_MT_VECTORS;
+ vecs_pgprot |= L_PTE_RDONLY;
/*
* Check is it with support for the PXN bit
diff --git a/arch/arm/mm/proc-macros.S b/arch/arm/mm/proc-macros.S
index dde1d6374250..f3e6551b4a7e 100644
--- a/arch/arm/mm/proc-macros.S
+++ b/arch/arm/mm/proc-macros.S
@@ -137,7 +137,7 @@
.long PTE_CACHEABLE @ L_PTE_MT_WRITETHROUGH
.long PTE_CACHEABLE | PTE_BUFFERABLE @ L_PTE_MT_WRITEBACK
.long PTE_BUFFERABLE @ L_PTE_MT_DEV_SHARED
- .long PTE_CACHEABLE | PTE_BUFFERABLE | PTE_EXT_APX @ L_PTE_MT_VECTORS
+ .long 0x00 @ unused
.long 0x00 @ L_PTE_MT_MINICACHE (not present)
.long PTE_EXT_TEX(1) | PTE_CACHEABLE | PTE_BUFFERABLE @ L_PTE_MT_WRITEALLOC
.long 0x00 @ unused
--
2.18.0
next prev parent reply other threads:[~2020-10-23 9:15 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 9:14 [PATCH v2 0/4] arm: support get_user_pages_fast Miles Chen
2020-10-23 9:14 ` [PATCH v2 1/4] arm: mm: use strict p[gum]d types Miles Chen
2020-10-23 9:14 ` [PATCH v2 2/4] arm: mm: reordering memory type table Miles Chen
2020-10-23 10:16 ` Russell King - ARM Linux admin
2020-10-27 8:03 ` Miles Chen
2020-10-23 9:14 ` [PATCH v2 3/4] arm: mm: introduce L_PTE_SPECIAL Miles Chen
2020-10-23 10:08 ` Russell King - ARM Linux admin
2020-10-27 7:45 ` Miles Chen
2020-10-27 9:11 ` Russell King - ARM Linux admin
2020-11-01 12:48 ` Miles Chen
2020-10-23 9:14 ` Miles Chen [this message]
2020-10-23 10:12 ` [PATCH v2 4/4] arm: replace vector mem type with read-only type Russell King - ARM Linux admin
2020-10-27 7:41 ` Miles Chen
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