• Arnd Bergmann's avatar
    ARM: make xscale iwmmxt code multiplatform aware · d33c43ac
    Arnd Bergmann authored
    In a multiplatform configuration, we may end up building a kernel for
    both Marvell PJ1 and an ARMv4 CPU implementation. In that case, the
    xscale-cp0 code is built with gcc -march=armv4{,t}, which results in a
    build error from the coprocessor instructions.
    
    Since we know this code will only have to run on an actual xscale
    processor, we can simply build the entire file for ARMv5TE.
    
    Related to this, we need to handle the iWMMXT initialization sequence
    differently during boot, to ensure we don't try to touch xscale
    specific registers on other CPUs from the xscale_cp0_init initcall.
    cpu_is_xscale() used to be hardcoded to '1' in any configuration that
    enables any XScale-compatible core, but this breaks once we can have a
    combined kernel with MMP1 and something else.
    
    In this patch, I replace the existing cpu_is_xscale() macro with a new
    cpu_is_xscale_family() macro that evaluates true for xscale, xsc3 and
    mohawk, which makes the behavior more deterministic.
    
    The two existing users of cpu_is_xscale() are modified accordingly,
    but slightly change behavior for kernels that enable CPU_MOHAWK without
    also enabling CPU_XSCALE or CPU_XSC3. Previously, these would leave leave
    PMD_BIT4 in the page tables untouched, now they clear it as we've always
    done for kernels that enable both MOHAWK and the support for the older
    CPU types.
    
    Since the previous behavior was inconsistent, I assume it was
    unintentional.
    Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
    d33c43ac
mmu.c 42.9 KB