On Friday 30 November 2007, Carlo Marcelo Arenas Belon wrote: > On Fri, Nov 30, 2007 at 04:28:09PM +0000, Paul Brook wrote: > > On Friday 30 November 2007, Carlo Marcelo Arenas Belon wrote: > > > The following patch enforces that the sh4 target is 32 bit to prevent > > > qemu to expand incorrectly to a 64 bit wide cpu if compiled in a 64 bit > > > host. > > > > This is wrong. As the comment in cpu-defs.h says, target_phys_addr_t may > > need to be bigger than the actual target address space. > > > > What exactly are you trying to fix? > > in a generic way, that the CPU width of the host (as defined by the size of > the type that is used to store a target_phys_addr_t) that is used to build > the emulator affects in any way the size of the emulated target physical > address size or its representation. > > in the sh4 specific case, it doesn't make sense for sh4 to print an access > error to a physical address that is 64 bit long when it is a 32 bit CPU and > that is what would happen unless the patch is applied. > > if anything the following definition from cpu-defs.h is invalid for a > representation of a 32 bit physical address : > > #define TARGET_FMT_plx "%016" PRIx64
Before you can fix that you probably need to fix the bits of qemu (TLB code) that store a host pointer in a phys_addr_t. Or at least distance TARGET_PHYS_ADDR_BITS from the definition of phys_addr_t, and include appropriate comments. In that case TARGET_PHYS_ADDR_BITS could be a precise value, rather than the next multiple of 32. e.g. I think sparc32 has a 40-bit physical address space. Paul