On Jul 23, 2014, at 1:46 PM, Joerg Sonnenberger <jo...@britannica.bec.de> wrote:
> On Tue, Jul 22, 2014 at 10:40:02PM +0100, Alexander Nasonov wrote: >> Matt Thomas wrote: >>> >>> On Jul 22, 2014, at 2:27 PM, Alexander Nasonov <al...@yandex.ru> wrote: >>>> I allocate with the X flag and it seems to work: >>>> >>>> /* in sljitExecAllocator.c */ >>>> return (void *)uvm_km_alloc(module_map, size, >>>> PAGE_SIZE, UVM_KMF_WIRED | UVM_KMF_ZERO | UVM_KMF_EXEC); >>> >>> ok. Then you need don't a hook for cache flushing >>> >>> pmap_protect(vm_map_pamp(module_map), va, size) will do that for you. >>> At least for arm/mips/ppc/vax. (e.g. changing a writeable exec page >>> to read-only automatically causes it exec cleaned). >> >> sljit allocates 64K exec chucks which are managed by a special allocator. >> You need to run pmap_protect for each chunk. I think it's cheaper to >> flush icache. > > Wouldn't it be preferable to have *two* mappings for the code? One which > is writeable and another which is executable? won’t give you cleaning by the pmap since that’s done by pmap_protect.
