diff options
| author | Leonardo Bras <leobras@redhat.com> | 2024-01-03 13:00:19 -0300 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2024-03-19 16:39:36 -0700 |
| commit | 6be7ee4bebd14b8e7e040a5e7fd6aec3d9167c72 (patch) | |
| tree | 0d10e98b0b0e0ba00342229f266cdd5bc37111d7 /arch | |
| parent | b85ea95d086471afb4ad062012a4d73cd328fa86 (diff) | |
riscv: Improve arch_get_mmap_end() macro
This macro caused me some confusion, which took some reviewer's time to
make it clear, so I propose adding a short comment in code to avoid
confusion in the future.
Also, added some improvements to the macro, such as removing the
assumption of VA_USER_SV57 being the largest address space.
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20240103160024.70305-3-leobras@redhat.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/riscv/include/asm/processor.h | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index f19f861cda54..2278e2a8362a 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -18,15 +18,21 @@ #define DEFAULT_MAP_WINDOW (UL(1) << (MMAP_VA_BITS - 1)) #define STACK_TOP_MAX TASK_SIZE_64 +/* + * addr is a hint to the maximum userspace address that mmap should provide, so + * this macro needs to return the largest address space available so that + * mmap_end < addr, being mmap_end the top of that address space. + * See Documentation/arch/riscv/vm-layout.rst for more details. + */ #define arch_get_mmap_end(addr, len, flags) \ ({ \ unsigned long mmap_end; \ typeof(addr) _addr = (addr); \ if ((_addr) == 0 || (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())) \ mmap_end = STACK_TOP_MAX; \ - else if ((_addr) >= VA_USER_SV57) \ - mmap_end = STACK_TOP_MAX; \ - else if ((((_addr) >= VA_USER_SV48)) && (VA_BITS >= VA_BITS_SV48)) \ + else if (((_addr) >= VA_USER_SV57) && (VA_BITS >= VA_BITS_SV57)) \ + mmap_end = VA_USER_SV57; \ + else if (((_addr) >= VA_USER_SV48) && (VA_BITS >= VA_BITS_SV48)) \ mmap_end = VA_USER_SV48; \ else \ mmap_end = VA_USER_SV39; \ |