d343041caa
Introduce explicit abstractions for different mapping types, handling the instantiation, forking, pagefaults and freeing of anonymous memory, direct physical mappings, shared memory and physically contiguous anonymous memory as separate types, making region.c more generic. Also some other genericification like merging the 3 munmap cases into one. COW and SMAP safemap code is still implicit in region.c.
73 lines
1.9 KiB
C
73 lines
1.9 KiB
C
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/* This file implements the methods of direct physical mapping.
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*
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* A direct physical mapping is done by accepting the physical
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* memory address and range from the caller and allowing direct
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* access to it. Most significantly, no physical memory is allocated
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* when it's mapped or freed when it's unmapped. E.g. device memory.
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*/
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#include "vm.h"
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/* These functions are static so as to not pollute the
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* global namespace, and are accessed through their function
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* pointers.
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*/
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static int phys_reference(struct phys_region *pr);
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static int phys_unreference(struct phys_region *pr);
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static int phys_writable(struct phys_region *pr);
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static int phys_pagefault(struct vmproc *vmp, struct vir_region *region,
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struct phys_region *ph, int write);
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static int phys_copy(struct vir_region *vr, struct vir_region *newvr);
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struct mem_type mem_type_directphys = {
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.name = "physical memory mapping",
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.ev_reference = phys_reference,
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.ev_copy = phys_copy,
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.ev_unreference = phys_unreference,
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.writable = phys_writable,
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.ev_pagefault = phys_pagefault
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};
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static int phys_reference(struct phys_region *pr)
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{
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panic("%s", __FUNCTION__);
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return OK;
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}
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static int phys_unreference(struct phys_region *pr)
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{
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return OK;
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}
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static int phys_pagefault(struct vmproc *vmp, struct vir_region *region,
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struct phys_region *ph, int write)
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{
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phys_bytes arg = region->param.phys, phmem;
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assert(arg != MAP_NONE);
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assert(ph->ph->phys == MAP_NONE);
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phmem = arg + ph->offset;
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assert(phmem != MAP_NONE);
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ph->ph->phys = phmem;
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return OK;
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}
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static int phys_writable(struct phys_region *pr)
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{
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assert(pr->ph->refcount > 0);
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return pr->ph->phys != MAP_NONE;
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}
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void phys_setphys(struct vir_region *vr, phys_bytes phys)
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{
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vr->param.phys = phys;
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}
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static int phys_copy(struct vir_region *vr, struct vir_region *newvr)
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{
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newvr->param.phys = vr->param.phys;
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return OK;
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}
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