Re: [PATCH] linux-user/sh4: allow full 32-bit address space

Hi Michael,

On Thu, 2026-07-30 at 09:45 +0300, Michael Tokarev wrote:
> On 7/27/26 14:48, Laurent Vivier wrote:
> > On real SH4 hardware, the address space is split between user mode
> > (U0, 0x00000000-0x7fffffff) and kernel mode (P1-P4, 0x80000000-0xffffffff),
> > so TARGET_VIRT_ADDR_SPACE_BITS was set to 31 for CONFIG_USER_ONLY.
> > 
> > However, qemu-user does not emulate the MMU, so this limit is not needed.
> > The only effect is to restrict reserved_va to 2 GB, causing OOM failures
> > for memory-intensive builds (e.g. webkit2gtk on Debian sh4 buildds).
> > 
> > Set TARGET_VIRT_ADDR_SPACE_BITS to 32 unconditionally, like most other
> > 32-bit targets. Also fix the TASK_UNMAPPED_BASE macro to use 1ull instead
> > of 1u to avoid undefined behavior when shifting by 32.
> 
> Should I pick this one for the stable series too?  So it will find its
> way to debian too, for example, so sh4 buildd(s) will feel a bit better? :)

Yes, please. I have already built local packages with the patch that I am going
to deploy on the buildds once they have finished building the current queue.

If the patch is part of the official package, I don't risk accidentally removing
the patched package again with a future update.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
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