Unverified Commit 6be7ee4b authored by Leonardo Bras's avatar Leonardo Bras Committed by Palmer Dabbelt
Browse files

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: default avatarLeonardo Bras <leobras@redhat.com>
Reviewed-by: default avatarGuo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20240103160024.70305-3-leobras@redhat.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent b85ea95d

arch/riscv/include/asm/processor.h

+9 −3
Original line number Diff line number Diff line
@@ -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;			\