Re: [Qemu-devel] [PATCH 09/10] mipsn32-linux-user: Restrict address space to 31-bits.

[Richard Henderson]

On 2013-02-11 09:44, Peter Maydell wrote:
> > >-# ifdef TARGET_MIPS
> > >+# if HOST_LONG_BITS == 64 \
> > >+     && (defined(TARGET_ABI_MIPSO32) || defined(TARGET_ABI_MIPSN32))
> > >  /* MIPS only supports 31 bits of virtual address space for user space */
> > >-unsigned long reserved_va = 0x77000000;
> > >-# else
> > >+unsigned long reserved_va = 0x7f000000;
> > >+# elif (TARGET_LONG_BITS == 32) && (HOST_LONG_BITS == 64)
> > >  unsigned long reserved_va = 0xf7000000;
> > >-# endif
> > >  #else
> > >  unsigned long reserved_va;
> > >  #endif
> > >-#endif
> > >+#endif /* CONFIG_USE_GUEST_BASE */
> Maybe clearer to pull out the "#if HOST_LONG_BITS == 64" into
> its own #if rather than having it as an && term in both the #if
> and the #elif?

In which case you get two "base" (unsigned long reserved_va;) cases, 
which didn't look clearer at all.  The only other thing I can think to 
do is

#if HLB == 64
# if MIPS
#  define RESERVED_MAX 0x7f000000
# elif TLB == 32
#  define RESERVED_MAX 0xf7000000
# endif
#endif
#ifndef RESERVED_MAX
# define RESERVED_MAX 0
#endif

unsigned long reserved_va = RESERVED_MAX;


r~