[PATCH v2 7/9] riscv: Align the sv39 linear map to 16 GiB

Samuel Holland
2024-10-22T02:12:36Z

The KASAN implementation on RISC-V requires the shadow memory for the
vmemmap and linear map regions to be aligned to a PMD boundary (1 GiB).
For KASAN_GENERIC (KASAN_SHADOW_SCALE_SHIFT == 3), this enforces 8 GiB
alignment for the memory regions themselves. KASAN_SW_TAGS uses 16-byte
granules (KASAN_SHADOW_SCALE_SHIFT == 4), so now the memory regions must
be aligned to a 16 GiB boundary.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---

(no changes since v1)

Documentation/arch/riscv/vm-layout.rst | 10 +++++-----
arch/riscv/include/asm/page.h | 2 +-
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/arch/riscv/vm-layout.rst b/Documentation/arch/riscv/vm-layout.rst
index eabec99b5852..c0778c421b34 100644
--- a/Documentation/arch/riscv/vm-layout.rst
+++ b/Documentation/arch/riscv/vm-layout.rst
@@ -47,11 +47,11 @@ RISC-V Linux Kernel SV39
| Kernel-space virtual memory, shared between all processes:
____________________________________________________________|___________________________________________________________
| | | |
- 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
+ ffffffc2fea00000 | -244 GB | ffffffc2feffffff | 6 MB | fixmap
+ ffffffc2ff000000 | -244 GB | ffffffc2ffffffff | 16 MB | PCI io
+ ffffffc300000000 | -244 GB | ffffffc3ffffffff | 4 GB | vmemmap
+ ffffffc400000000 | -240 GB | ffffffd3ffffffff | 64 GB | vmalloc/ioremap space
+ ffffffd400000000 | -176 GB | fffffff3ffffffff | 128 GB | direct mapping of all physical memory
| | | |
fffffff700000000 | -36 GB | fffffffeffffffff | 32 GB | kasan
__________________|____________|__________________|_________|____________________________________________________________
diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index 32d308a3355f..6e2f79cf77c5 100644
--- 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(0xffffffd600000000, UL)
+#define PAGE_OFFSET_L3 _AC(0xffffffd400000000, UL)
#else
#define PAGE_OFFSET _AC(CONFIG_PAGE_OFFSET, UL)
#endif /* CONFIG_64BIT */
--
2.45.1