From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
The current RISC-V's mm layout is based on a 2MB offset and wasting
memory. Remove 2MB offset and map PAGE_OFFSET at start_of_DRAM.
Then we could reduce the memory reserved for opensbi in the next
patch.
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Anup Patel <anup.patel@xxxxxxx>
Cc: Atish Patra <atishp@xxxxxxxxxxxx>
---
arch/riscv/include/asm/page.h | 8 ++++++++
arch/riscv/kernel/head.S | 10 +++-------
arch/riscv/kernel/vmlinux.lds.S | 5 ++---
arch/riscv/mm/init.c | 11 ++++++++---
4 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index b3e5ff0125fe..299147c78b4a 100644
--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -16,6 +16,14 @@
#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE - 1))
+#if __riscv_xlen == 64
+/* Image load offset(2MB) from start of RAM */
+#define LOAD_OFFSET 0x200000
+#else
+/* Image load offset(4MB) from start of RAM */
+#define LOAD_OFFSET 0x400000
+#endif
+
#ifdef CONFIG_64BIT
#define HUGE_MAX_HSTATE 2
#else
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index f52f01ecbeea..a6ac892d2ccf 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -61,13 +61,7 @@ ENTRY(_start)
/* Image load offset (0MB) from start of RAM for M-mode */
.dword 0
#else
-#if __riscv_xlen == 64
- /* Image load offset(2MB) from start of RAM */
- .dword 0x200000
-#else
- /* Image load offset(4MB) from start of RAM */
- .dword 0x400000
-#endif
+ .dword LOAD_OFFSET
#endif
/* Effective size of kernel image */
.dword _end - _start
@@ -94,6 +88,8 @@ relocate:
la a1, kernel_map
XIP_FIXUP_OFFSET a1
REG_L a1, KERNEL_MAP_VIRT_ADDR(a1)
+ li a2, LOAD_OFFSET
+ add a1, a1, a2
la a2, _start
sub a1, a1, a2
add ra, ra, a1
diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
index 5104f3a871e3..75b7c72cd4bd 100644
--- a/arch/riscv/kernel/vmlinux.lds.S
+++ b/arch/riscv/kernel/vmlinux.lds.S
@@ -11,10 +11,9 @@
#else
#include <asm/pgtable.h>
-#define LOAD_OFFSET KERNEL_LINK_ADDR
-#include <asm/vmlinux.lds.h>
#include <asm/page.h>
+#include <asm/vmlinux.lds.h>
#include <asm/cache.h>
#include <asm/thread_info.h>
#include <asm/set_memory.h>
@@ -32,7 +31,7 @@ PECOFF_FILE_ALIGNMENT = 0x200;
SECTIONS
{
/* Beginning of code and text segment */
- . = LOAD_OFFSET;
+ . = LOAD_OFFSET + KERNEL_LINK_ADDR;
_start = .;
HEAD_TEXT_SECTION
. = ALIGN(PAGE_SIZE);
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 24b2b8044602..920e78f8c3e4 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -221,6 +221,11 @@ static void __init setup_bootmem(void)
if (!IS_ENABLED(CONFIG_BUILTIN_DTB))
memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
+ /*
+ * Reserve OpenSBI region and depends on PMP to deny accesses.
+ */
+ memblock_reserve(__pa(PAGE_OFFSET), LOAD_OFFSET);
+
early_init_fdt_scan_reserved_mem();
dma_contiguous_reserve(dma32_phys_limit);
if (IS_ENABLED(CONFIG_64BIT))
@@ -604,7 +609,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
kernel_map.va_kernel_xip_pa_offset = kernel_map.virt_addr - kernel_map.xiprom;
#else
- kernel_map.phys_addr = (uintptr_t)(&_start);
+ kernel_map.phys_addr = (uintptr_t)(&_start) - LOAD_OFFSET;
kernel_map.size = (uintptr_t)(&_end) - kernel_map.phys_addr;
#endif
kernel_map.va_pa_offset = PAGE_OFFSET - kernel_map.phys_addr;
@@ -645,8 +650,8 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
create_pmd_mapping(trampoline_pmd, kernel_map.virt_addr,
kernel_map.xiprom, PMD_SIZE, PAGE_KERNEL_EXEC);
#else
- create_pmd_mapping(trampoline_pmd, kernel_map.virt_addr,
- kernel_map.phys_addr, PMD_SIZE, PAGE_KERNEL_EXEC);
+ create_pmd_mapping(trampoline_pmd, kernel_map.virt_addr + LOAD_OFFSET,
+ kernel_map.phys_addr + LOAD_OFFSET, PMD_SIZE, PAGE_KERNEL_EXEC);
#endif
#else
/* Setup trampoline PGD */
--
2.25.1
