This is a note to let you know that I've just added the patch titled
riscv: Start of DRAM should at least be aligned on PMD size for the direct mapping
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
riscv-start-of-dram-should-at-least-be-aligned-on-pmd-size-for-the-direct-mapping.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c3bcc65d4d2e8292c435322cbc34c318d06b8b6c Mon Sep 17 00:00:00 2001
From: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Date: Tue, 4 Jul 2023 14:18:37 +0200
Subject: riscv: Start of DRAM should at least be aligned on PMD size for the direct mapping
From: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
commit c3bcc65d4d2e8292c435322cbc34c318d06b8b6c upstream.
So that we do not end up mapping the whole linear mapping using 4K
pages, which is slow at boot time, and also very likely at runtime.
So make sure we align the start of DRAM on a PMD boundary.
Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Reported-by: Song Shuai <suagrfillet@xxxxxxxxx>
Fixes: 3335068f8721 ("riscv: Use PUD/P4D/PGD pages for the linear mapping")
Tested-by: Song Shuai <suagrfillet@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230704121837.248976-1-alexghiti@xxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/riscv/mm/init.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 9ce504737d18..ad845c3aa9b2 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -214,8 +214,13 @@ static void __init setup_bootmem(void)
memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
phys_ram_end = memblock_end_of_DRAM();
+
+ /*
+ * Make sure we align the start of the memory on a PMD boundary so that
+ * at worst, we map the linear mapping with PMD mappings.
+ */
if (!IS_ENABLED(CONFIG_XIP_KERNEL))
- phys_ram_base = memblock_start_of_DRAM();
+ phys_ram_base = memblock_start_of_DRAM() & PMD_MASK;
/*
* In 64-bit, any use of __va/__pa before this point is wrong as we
--
2.41.0
Patches currently in stable-queue which might be from alexghiti@xxxxxxxxxxxx are
queue-6.4/riscv-start-of-dram-should-at-least-be-aligned-on-pmd-size-for-the-direct-mapping.patch
