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| author | Samuel Holland <samuel.holland@sifive.com> | 2024-03-27 17:38:13 +0300 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2024-05-16 22:59:58 +0300 |
| commit | ad5643cf2f699989daa85d909403febd6712fccb (patch) | |
| tree | 0130bf91b6942e48a2f5b40ca9892462a0eaae62 /arch/riscv | |
| parent | 9ad6bb3298d1c008bb36b1f4fa9ea896d2904b5a (diff) | |
| download | linux-ad5643cf2f699989daa85d909403febd6712fccb.tar.xz | |
riscv: Define TASK_SIZE_MAX for __access_ok()
TASK_SIZE_MAX should be set to a constant value, at least the largest
valid userspace address under any runtime configuration. This optimizes
the check in __access_ok(), which no longer needs to compute the runtime
value of TASK_SIZE. The check does not need to be exact, as long as it
accepts all valid userspace addresses and rejects all valid kernel
addresses; well-behaved programs will never fail the access_ok() check.
For RISC-V, which requires all virtual addresses to be sign extended,
the optimal choice is LONG_MAX because it simplifies the limit
comparison to a sign bit test.
This removes about half of the references to pgtable_l[45]_enabled.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240327143858.711792-3-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv')
| -rw-r--r-- | arch/riscv/include/asm/pgtable.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index f5cc8bcc7f8d..762a85551764 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -870,6 +870,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte) */ #ifdef CONFIG_64BIT #define TASK_SIZE_64 (PGDIR_SIZE * PTRS_PER_PGD / 2) +#define TASK_SIZE_MAX LONG_MAX #ifdef CONFIG_COMPAT #define TASK_SIZE_32 (_AC(0x80000000, UL) - PAGE_SIZE) |