riscv: Extend sv39 linear mapping max size to 128G

This harmonizes all virtual addressing modes which can now all map (PGDIR_SIZE * PTRS_PER_PGD) / 4 of physical memory. The RISCV implementation of KASAN requires that the boundary between shallow mappings are aligned on an 8G boundary. In this case we need VMALLOC_START to be 8G aligned. So although we only need to move the start of the linear mapping down by 4GiB to allow 128GiB to be mapped, we actually move it down by 8GiB (creating a 4GiB hole between the linear mapping and KASAN shadow space) to maintain the alignment requirement. Signed-off-by: Stuart Menefy <stuart.menefy@codasip.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20240630110550.1731929-1-stuart.menefy@codasip.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

riscv: Extend sv39 linear mapping max size to 128G
This harmonizes all virtual addressing modes which can now all map (PGDIR_SIZE * PTRS_PER_PGD) / 4 of physical memory. The RISCV implementation of KASAN requires that the boundary between shallow mappings are aligned on an 8G boundary. In this case we need VMALLOC_START to be 8G aligned. So although we only need to move the start of the linear mapping down by 4GiB to allow 128GiB to be mapped, we actually move it down by 8GiB (creating a 4GiB hole between the linear mapping and KASAN shadow space) to maintain the alignment requirement. Signed-off-by: Stuart Menefy <stuart.menefy@codasip.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20240630110550.1731929-1-stuart.menefy@codasip.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>
5c8405d7 · Stuart Menefy · Palmer Dabbelt · 3aa1a7d0 · 5c8405d7 · 5c8405d7
Commit 5c8405d7 authored Jun 30, 2024 by Stuart Menefy Committed by Palmer Dabbelt Jul 26, 2024
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Documentation/arch/riscv/vm-layout.rst Documentation/arch/riscv/vm-layout.rst +6 -5

arch/riscv/include/asm/page.h arch/riscv/include/asm/page.h +1 -1

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--- a/Documentation/arch/riscv/vm-layout.rst
+++ b/Documentation/arch/riscv/vm-layout.rst
@@ -47,11 +47,12 @@ RISC-V Linux Kernel SV39
                                                              | Kernel-space virtual memory, shared between all processes:
  ____________________________________________________________|___________________________________________________________
                    |            |                  |         |
-   ffffffc6fea00000 | -228    GB | ffffffc6feffffff |    6 MB | fixmap
-   ffffffc6ff000000 | -228    GB | ffffffc6ffffffff |   16 MB | PCI io
-   ffffffc700000000 | -228    GB | ffffffc7ffffffff |    4 GB | vmemmap
-   ffffffc800000000 | -224    GB | ffffffd7ffffffff |   64 GB | vmalloc/ioremap space
-   ffffffd800000000 | -160    GB | fffffff6ffffffff |  124 GB | direct mapping of all physical memory
+   ffffffc4fea00000 | -236    GB | ffffffc4feffffff |    6 MB | fixmap
+   ffffffc4ff000000 | -236    GB | ffffffc4ffffffff |   16 MB | PCI io
+   ffffffc500000000 | -236    GB | ffffffc5ffffffff |    4 GB | vmemmap
+   ffffffc600000000 | -232    GB | ffffffd5ffffffff |   64 GB | vmalloc/ioremap space
+   ffffffd600000000 | -168    GB | fffffff5ffffffff |  128 GB | direct mapping of all physical memory
+                    |            |                  |         |
   fffffff700000000 |  -36    GB | fffffffeffffffff |   32 GB | kasan
  __________________|____________|__________________|_________|____________________________________________________________
                                                              |

--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -37,7 +37,7 @@
 * define the PAGE_OFFSET value for SV48 and SV39.
 */
 #define PAGE_OFFSET_L4		_AC(0xffffaf8000000000, UL)
-#define PAGE_OFFSET_L3		_AC(0xffffffd800000000, UL)
+#define PAGE_OFFSET_L3		_AC(0xffffffd600000000, UL)
 #else
 #define PAGE_OFFSET		_AC(CONFIG_PAGE_OFFSET, UL)
 #endif /* CONFIG_64BIT */