RE: [PATCH V2 2/4] riscv: mm: Fixup compat arch_get_mmap_end

[David Laight]

From: guoren@xxxxxxxxxx <guoren@xxxxxxxxxx>
> Sent: 21 December 2023 15:47
> 
> From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> 
> When the task is in COMPAT mode, the arch_get_mmap_end should be 2GB,
> not TASK_SIZE_64. The TASK_SIZE has contained is_compat_mode()
> detection, so change the definition of STACK_TOP_MAX to TASK_SIZE
> directly.

Why 2G ?

IIRC for 32-bit native x86 the limit is 3G, but in compat mode
it is (just under) 4G.

There is a special mmap option (for programs like wine) to
limit mmap() to 2G.

	David

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