riscv64: use wider default range for kernel text and modules

bcoles · Mar 30, 2024 · 3e60aad · 3e60aad
1 parent e26d4da
commit 3e60aad
Showing 1 changed file with 17 additions and 4 deletions.
diff --git a/src/kasld.h b/src/kasld.h
@@ -373,7 +373,11 @@
 /* -----------------------------------------------------------------------------
  * RISC-V 64-bit (riscv64)
  * -----------------------------------------------------------------------------
- * https://docs.kernel.org/riscv/vm-layout.html
+ * KASLR support added in commit f57805555834494e8cad729d01d86ba326d64959 in
+ * v6.6-rc1~10^2~5 on 2023-11-08.
+ * https://github.com/torvalds/linux/commit/f57805555834494e8cad729d01d86ba326d64959
+ * https://www.kernel.org/doc/html/next/riscv/vm-layout.html
+ * https://www.kernel.org/doc/html/next/riscv/boot.html
  */
 #elif (defined(__riscv) || defined(__riscv__)) && __riscv_xlen == 64
 
@@ -386,16 +390,23 @@
 // https://elixir.bootlin.com/linux/v6.1.1/source/arch/riscv/mm/init.c#L976
 #define phys_to_virt(x) ((unsigned long)(x) + (PAGE_OFFSET - 0x80000000ul))
 
-#define KERNEL_VAS_START 0xff00000000000000ul
+// VAS start with SV57 (5-level page tables): 0xff1bffff_fea00000
+// VAS start with SV48 (4-level page tables): 0xffff8d7f_fea00000
+// VAS start with SV39 (3-level page tables): 0xffffffc6_fea00000
+#define KERNEL_VAS_START 0xff10000000000000ul
 #define KERNEL_VAS_END   0xfffffffffffffffful
 
-#define KERNEL_BASE_MIN  0xffffffff80000000ul
+// common:
+// 0xffffffe0_00000000
+// 0xffffffff_80000000
+#define KERNEL_BASE_MIN  0xffffffe000000000ul
 #define KERNEL_BASE_MAX  0xffffffffff000000ul
 
 // Modules are located below kernel: KERNEL_LINK_ADDR - 2GB (0x80000000)
 // https://elixir.bootlin.com/linux/v6.1.1/source/arch/riscv/include/asm/pgtable.h#L52
+// 0xffffffd0_00000000 is also common
 #define MODULES_START    KERNEL_VAS_START - 0x80000000ul
-#define MODULES_END      KERNEL_BASE_MIN
+#define MODULES_END      0xfffffffffffffffful
 
 // https://elixir.bootlin.com/linux/v6.2-rc2/source/arch/riscv/include/asm/efi.h#L41
 #define KERNEL_ALIGN 2 * MB
@@ -407,6 +418,8 @@
 /* -----------------------------------------------------------------------------
  * RISC-V 32-bit (riscv32)
  * -----------------------------------------------------------------------------
+ * Linux for RISCV 32-bit does not support KASLR
+ * https://elixir.bootlin.com/linux/v6.8.2/source/arch/riscv/Kconfig#L819
  */
 #elif (defined(__riscv) || defined(__riscv__)) && __riscv_xlen == 32