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authorAlexandre Ghiti <alex@ghiti.fr>2021-04-11 12:41:44 -0400
committerPalmer Dabbelt <palmerdabbelt@google.com>2021-04-26 08:25:04 -0700
commit2bfc6cd81bd17e4306e24ee47b9554c967bcb499 (patch)
treec06ff6ac90cb7735bb0871aa357c5d2b8049a6dc /arch/riscv/boot/loader.lds.S
parent8a07ac39f87d6c762006398029762c40e4d9d075 (diff)
downloadlinux-2bfc6cd81bd17e4306e24ee47b9554c967bcb499.tar.gz
riscv: Move kernel mapping outside of linear mapping
This is a preparatory patch for relocatable kernel and sv48 support. The kernel used to be linked at PAGE_OFFSET address therefore we could use the linear mapping for the kernel mapping. But the relocated kernel base address will be different from PAGE_OFFSET and since in the linear mapping, two different virtual addresses cannot point to the same physical address, the kernel mapping needs to lie outside the linear mapping so that we don't have to copy it at the same physical offset. The kernel mapping is moved to the last 2GB of the address space, BPF is now always after the kernel and modules use the 2GB memory range right before the kernel, so BPF and modules regions do not overlap. KASLR implementation will simply have to move the kernel in the last 2GB range and just take care of leaving enough space for BPF. In addition, by moving the kernel to the end of the address space, both sv39 and sv48 kernels will be exactly the same without needing to be relocated at runtime. Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> [Palmer: Squash the STRICT_RWX fix, and a !MMU fix] Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv/boot/loader.lds.S')
-rw-r--r--arch/riscv/boot/loader.lds.S3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/riscv/boot/loader.lds.S b/arch/riscv/boot/loader.lds.S
index 47a5003c2e28..62d94696a19c 100644
--- a/arch/riscv/boot/loader.lds.S
+++ b/arch/riscv/boot/loader.lds.S
@@ -1,13 +1,14 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <asm/page.h>
+#include <asm/pgtable.h>
OUTPUT_ARCH(riscv)
ENTRY(_start)
SECTIONS
{
- . = PAGE_OFFSET;
+ . = KERNEL_LINK_ADDR;
.payload : {
*(.payload)