On Sun, Apr 02, 2023 at 07:29:02PM +0000, Miod Vallat wrote:
> pmap_copy() is an optional pmap interface which has never been
> implemented. In pure Mary Kondo style, we should thank it for the joy it
> brought to CSRG people, and move it to the recycling bin - it's not
> going to be implemented anytime soon.
In Mach (Tevanian's thesis) it was described as:
"This routine is only advisory and need not do anything"
ok jsg@
>
> Index: share/man/man9/pmap.9
> ===================================================================
> RCS file: /OpenBSD/src/share/man/man9/pmap.9,v
> retrieving revision 1.19
> diff -u -p -r1.19 pmap.9
> --- share/man/man9/pmap.9 16 Dec 2019 10:34:04 -0000 1.19
> +++ share/man/man9/pmap.9 2 Apr 2023 19:23:11 -0000
> @@ -49,8 +49,7 @@
> .Nm pmap_growkernel ,
> .Nm pmap_update ,
> .Nm pmap_collect ,
> -.Nm pmap_virtual_space ,
> -.Nm pmap_copy
> +.Nm pmap_virtual_space
> .Nd machine dependent interface to the MMU
> .Sh SYNOPSIS
> .In machine/pmap.h
> @@ -366,9 +365,6 @@ it contains no valid mappings.
> .Fn pmap_collect "pmap_t pmap"
> .Ft void
> .Fn pmap_virtual_space "vaddr_t *vstartp" "vaddr_t *vendp"
> -.Ft void
> -.Fn pmap_copy "pmap_t dst_pmap" "pmap_t src_pmap" "vaddr_t dst_addr" \
> - "vsize_t len" "vaddr_t src_addr"
> .nr nS 0
> .Pp
> Wired memory allocation before the virtual memory system is bootstrapped
> @@ -398,26 +394,6 @@ is not expected to be used for some time
> module a chance to prioritize.
> The initial bounds of the kernel virtual address space are returned by
> .Fn pmap_virtual_space .
> -.Pp
> -The
> -.Fn pmap_copy
> -function copies the range specified by
> -.Fa src_addr
> -and
> -.Fa src_len
> -from
> -.Fa src_pmap
> -to the range described by
> -.Fa dst_addr
> -and
> -.Fa dst_len
> -in
> -.Fa dst_map .
> -.Fn pmap_copy
> -is called during a
> -.Xr fork 2
> -operation to give the child process an initial set of low-level
> -mappings.
> .Sh SEE ALSO
> .Xr fork 2 ,
> .Xr uvm_init 9
> Index: sys/arch/alpha/alpha/pmap.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/alpha/alpha/pmap.c,v
> retrieving revision 1.89
> diff -u -p -r1.89 pmap.c
> --- sys/arch/alpha/alpha/pmap.c 6 Feb 2023 11:16:22 -0000 1.89
> +++ sys/arch/alpha/alpha/pmap.c 2 Apr 2023 19:23:11 -0000
> @@ -2017,17 +2017,6 @@ pmap_extract(pmap_t pmap, vaddr_t va, pa
> }
>
> /*
> - * pmap_copy: [ INTERFACE ]
> - *
> - * Copy the mapping range specified by src_addr/len
> - * from the source map to the range dst_addr/len
> - * in the destination map.
> - *
> - * This routine is only advisory and need not do anything.
> - */
> -/* call deleted in <machine/pmap.h> */
> -
> -/*
> * pmap_collect: [ INTERFACE ]
> *
> * Garbage collects the physical map system for pages which are no
> Index: sys/arch/alpha/include/pmap.h
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/alpha/include/pmap.h,v
> retrieving revision 1.44
> diff -u -p -r1.44 pmap.h
> --- sys/arch/alpha/include/pmap.h 6 Feb 2023 11:16:22 -0000 1.44
> +++ sys/arch/alpha/include/pmap.h 2 Apr 2023 19:23:11 -0000
> @@ -155,7 +155,6 @@ void pmap_do_tlb_shootdown(struct cpu_in
> #define pmap_resident_count(pmap)
> ((pmap)->pm_stats.resident_count)
> #define pmap_wired_count(pmap) ((pmap)->pm_stats.wired_count)
>
> -#define pmap_copy(dp, sp, da, l, sa) /* nothing */
> #define pmap_update(pmap) /* nothing (yet) */
>
> #define pmap_proc_iflush(p, va, len) /* nothing */
> Index: sys/arch/amd64/amd64/pmap.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/amd64/amd64/pmap.c,v
> retrieving revision 1.162
> diff -u -p -r1.162 pmap.c
> --- sys/arch/amd64/amd64/pmap.c 30 Jan 2023 11:21:26 -0000 1.162
> +++ sys/arch/amd64/amd64/pmap.c 2 Apr 2023 19:23:11 -0000
> @@ -2257,17 +2257,6 @@ pmap_collect(struct pmap *pmap)
> }
> #endif
>
> -/*
> - * pmap_copy: copy mappings from one pmap to another
> - *
> - * => optional function
> - * void pmap_copy(dst_pmap, src_pmap, dst_addr, len, src_addr)
> - */
> -
> -/*
> - * defined as macro in pmap.h
> - */
> -
> void
> pmap_enter_special(vaddr_t va, paddr_t pa, vm_prot_t prot)
> {
> Index: sys/arch/amd64/include/pmap.h
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/amd64/include/pmap.h,v
> retrieving revision 1.85
> diff -u -p -r1.85 pmap.h
> --- sys/arch/amd64/include/pmap.h 31 Jan 2023 15:18:54 -0000 1.85
> +++ sys/arch/amd64/include/pmap.h 2 Apr 2023 19:23:11 -0000
> @@ -369,7 +369,6 @@ extern const long nbpd[], nkptpmax[];
>
> #define pmap_clear_modify(pg) pmap_clear_attrs(pg, PG_M)
> #define pmap_clear_reference(pg) pmap_clear_attrs(pg, PG_U)
> -#define pmap_copy(DP,SP,D,L,S)
> #define pmap_is_modified(pg) pmap_test_attrs(pg, PG_M)
> #define pmap_is_referenced(pg) pmap_test_attrs(pg, PG_U)
> #define pmap_move(DP,SP,D,L,S)
> Index: sys/arch/arm/include/pmap.h
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/arm/include/pmap.h,v
> retrieving revision 1.53
> diff -u -p -r1.53 pmap.h
> --- sys/arch/arm/include/pmap.h 31 Jan 2023 15:18:54 -0000 1.53
> +++ sys/arch/arm/include/pmap.h 2 Apr 2023 19:23:11 -0000
> @@ -240,7 +240,6 @@ extern struct pmap kernel_pmap_store;
> (((pg)->mdpage.pvh_attrs & PVF_REF) != 0)
>
> #define pmap_deactivate(p) do { /* nothing */ } while (0)
> -#define pmap_copy(dp, sp, da, l, sa) do { /* nothing */ } while (0)
>
> #define pmap_unuse_final(p) do { /* nothing */ } while (0)
> #define pmap_remove_holes(vm) do { /* nothing */ } while (0)
> Index: sys/arch/arm64/arm64/pmap.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/arm64/arm64/pmap.c,v
> retrieving revision 1.93
> diff -u -p -r1.93 pmap.c
> --- sys/arch/arm64/arm64/pmap.c 27 Mar 2023 19:02:47 -0000 1.93
> +++ sys/arch/arm64/arm64/pmap.c 2 Apr 2023 19:23:11 -0000
> @@ -1927,13 +1927,6 @@ pmap_clear_reference(struct vm_page *pg)
> }
>
> void
> -pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vaddr_t dst_addr,
> - vsize_t len, vaddr_t src_addr)
> -{
> - /* NOOP */
> -}
> -
> -void
> pmap_unwire(pmap_t pm, vaddr_t va)
> {
> struct pte_desc *pted;
> Index: sys/arch/hppa/include/pmap.h
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/hppa/include/pmap.h,v
> retrieving revision 1.54
> diff -u -p -r1.54 pmap.h
> --- sys/arch/hppa/include/pmap.h 24 Jan 2023 16:51:06 -0000 1.54
> +++ sys/arch/hppa/include/pmap.h 2 Apr 2023 19:23:11 -0000
> @@ -102,7 +102,6 @@ struct vm_page *pmap_unmap_direct(vaddr_
> #define pmap_kernel() (&kernel_pmap_store)
> #define pmap_resident_count(pmap)
> ((pmap)->pm_stats.resident_count)
> #define pmap_update(pm) (void)(pm)
> -#define pmap_copy(dpmap,spmap,da,len,sa)
>
> #define PG_PMAP_MOD PG_PMAP0 /* modified */
> #define PG_PMAP_REF PG_PMAP1 /* referenced */
> Index: sys/arch/i386/i386/pmap.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/i386/i386/pmap.c,v
> retrieving revision 1.220
> diff -u -p -r1.220 pmap.c
> --- sys/arch/i386/i386/pmap.c 30 Jan 2023 10:49:05 -0000 1.220
> +++ sys/arch/i386/i386/pmap.c 2 Apr 2023 19:23:11 -0000
> @@ -2263,17 +2263,6 @@ pmap_collect(struct pmap *pmap)
> }
>
> /*
> - * pmap_copy: copy mappings from one pmap to another
> - *
> - * => optional function
> - * void pmap_copy(dst_pmap, src_pmap, dst_addr, len, src_addr)
> - */
> -
> -/*
> - * defined as macro in pmap.h
> - */
> -
> -/*
> * pmap_enter: enter a mapping into a pmap
> *
> * => must be done "now" ... no lazy-evaluation
> Index: sys/arch/i386/i386/pmapae.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/i386/i386/pmapae.c,v
> retrieving revision 1.68
> diff -u -p -r1.68 pmapae.c
> --- sys/arch/i386/i386/pmapae.c 30 Jan 2023 10:49:05 -0000 1.68
> +++ sys/arch/i386/i386/pmapae.c 2 Apr 2023 19:23:11 -0000
> @@ -820,8 +820,6 @@ pmap_bootstrap_pae(void)
> * => we should not be holding any pv_head locks (in case we are forced
> * to call pmap_steal_ptp())
> * => we may need to lock pv_head's if we have to steal a PTP
> - * => just_try: true if we want a PTP, but not enough to steal one
> - * from another pmap (e.g. during optional functions like pmap_copy)
> */
>
> struct vm_page *
> @@ -1670,17 +1668,6 @@ pmap_unwire_pae(struct pmap *pmap, vaddr
> }
> #endif
> }
> -
> -/*
> - * pmap_copy: copy mappings from one pmap to another
> - *
> - * => optional function
> - * void pmap_copy(dst_pmap, src_pmap, dst_addr, len, src_addr)
> - */
> -
> -/*
> - * defined as macro in pmap.h
> - */
>
> /*
> * pmap_enter: enter a mapping into a pmap
> Index: sys/arch/i386/include/pmap.h
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/i386/include/pmap.h,v
> retrieving revision 1.92
> diff -u -p -r1.92 pmap.h
> --- sys/arch/i386/include/pmap.h 31 Jan 2023 15:18:54 -0000 1.92
> +++ sys/arch/i386/include/pmap.h 2 Apr 2023 19:23:11 -0000
> @@ -205,7 +205,6 @@ extern struct pool pmap_pv_pool;
>
> #define pmap_clear_modify(pg) pmap_clear_attrs(pg, PG_M)
> #define pmap_clear_reference(pg) pmap_clear_attrs(pg, PG_U)
> -#define pmap_copy(DP,SP,D,L,S)
> #define pmap_is_modified(pg) pmap_test_attrs(pg, PG_M)
> #define pmap_is_referenced(pg) pmap_test_attrs(pg, PG_U)
> #define pmap_valid_entry(E) ((E) & PG_V) /* is PDE or PTE valid? */
> Index: sys/arch/m88k/include/pmap.h
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/m88k/include/pmap.h,v
> retrieving revision 1.28
> diff -u -p -r1.28 pmap.h
> --- sys/arch/m88k/include/pmap.h 12 Feb 2023 07:02:43 -0000 1.28
> +++ sys/arch/m88k/include/pmap.h 2 Apr 2023 19:23:11 -0000
> @@ -51,7 +51,6 @@ extern apr_t kernel_apr, userland_apr;
> #define pmap_resident_count(pmap) ((pmap)->pm_stats.resident_count)
> #define pmap_wired_count(pmap) ((pmap)->pm_stats.wired_count)
>
> -#define pmap_copy(dp,sp,d,l,s) do { /* nothing */ } while (0)
> #define pmap_update(pmap) do { /* nothing */ } while (0)
>
> #define pmap_clear_modify(pg) pmap_unsetbit(pg, PG_M)
> Index: sys/arch/mips64/mips64/pmap.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/mips64/mips64/pmap.c,v
> retrieving revision 1.124
> diff -u -p -r1.124 pmap.c
> --- sys/arch/mips64/mips64/pmap.c 11 Jan 2023 03:19:52 -0000 1.124
> +++ sys/arch/mips64/mips64/pmap.c 2 Apr 2023 19:23:11 -0000
> @@ -1407,22 +1407,6 @@ pmap_extract(pmap_t pmap, vaddr_t va, pa
> }
>
> /*
> - * Copy the range specified by src_addr/len
> - * from the source map to the range dst_addr/len
> - * in the destination map.
> - *
> - * This routine is only advisory and need not do anything.
> - */
> -void
> -pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vaddr_t dst_addr, vsize_t len,
> - vaddr_t src_addr)
> -{
> -
> - DPRINTF(PDB_FOLLOW,("pmap_copy(%p, %p, %p, 0x%lx, %p)\n",
> - dst_pmap, src_pmap, (void *)dst_addr, len, (void *)src_addr));
> -}
> -
> -/*
> * pmap_zero_page zeros the specified (machine independent) page.
> */
> void
> Index: sys/arch/powerpc/include/pmap.h
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/powerpc/include/pmap.h,v
> retrieving revision 1.63
> diff -u -p -r1.63 pmap.h
> --- sys/arch/powerpc/include/pmap.h 31 Jan 2023 15:18:55 -0000 1.63
> +++ sys/arch/powerpc/include/pmap.h 2 Apr 2023 19:23:11 -0000
> @@ -148,7 +148,6 @@ int pmap_copyinsn(pmap_t, vaddr_t, uint3
> void pmap_real_memory(vaddr_t *start, vsize_t *size);
>
> int pte_spill_v(struct pmap *pm, u_int32_t va, u_int32_t dsisr, int
> exec_fault);
> -#define pmap_copy(dst_pmap, src_pmap, dst_addr, len, src_addr) ;
> int reserve_dumppages(caddr_t p);
>
> #define pmap_unuse_final(p) /* nothing */
> Index: sys/arch/powerpc64/powerpc64/pmap.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/powerpc64/powerpc64/pmap.c,v
> retrieving revision 1.59
> diff -u -p -r1.59 pmap.c
> --- sys/arch/powerpc64/powerpc64/pmap.c 25 Jan 2023 09:53:53 -0000
> 1.59
> +++ sys/arch/powerpc64/powerpc64/pmap.c 2 Apr 2023 19:23:11 -0000
> @@ -1047,12 +1047,6 @@ pmap_init(void)
> pmap_initialized = 1;
> }
>
> -void
> -pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vaddr_t dst_addr,
> - vsize_t len, vaddr_t src_addr)
> -{
> -}
> -
> int
> pmap_enter(pmap_t pm, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
> {
> Index: sys/arch/riscv64/riscv64/pmap.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/riscv64/riscv64/pmap.c,v
> retrieving revision 1.29
> diff -u -p -r1.29 pmap.c
> --- sys/arch/riscv64/riscv64/pmap.c 11 Jan 2023 11:10:25 -0000 1.29
> +++ sys/arch/riscv64/riscv64/pmap.c 2 Apr 2023 19:23:11 -0000
> @@ -1862,13 +1862,6 @@ pmap_clear_reference(struct vm_page *pg)
> }
>
> void
> -pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vaddr_t dst_addr,
> - vsize_t len, vaddr_t src_addr)
> -{
> - /* NOOP */
> -}
> -
> -void
> pmap_unwire(pmap_t pm, vaddr_t va)
> {
> struct pte_desc *pted;
> Index: sys/arch/sh/include/pmap.h
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/sh/include/pmap.h,v
> retrieving revision 1.19
> diff -u -p -r1.19 pmap.h
> --- sys/arch/sh/include/pmap.h 8 Mar 2023 04:43:07 -0000 1.19
> +++ sys/arch/sh/include/pmap.h 2 Apr 2023 19:23:11 -0000
> @@ -65,7 +65,6 @@ void pmap_bootstrap(void);
> #define pmap_kernel() (&__pmap_kernel)
> #define pmap_deactivate(pmap) do { /* nothing */ } while (0)
> #define pmap_update(pmap) do { /* nothing */ } while (0)
> -#define pmap_copy(dp,sp,d,l,s) do { /* nothing */ } while (0)
> #define pmap_wired_count(pmap) ((pmap)->pm_stats.wired_count)
> #define pmap_resident_count(pmap)
> ((pmap)->pm_stats.resident_count)
>
> Index: sys/arch/sparc64/sparc64/pmap.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/arch/sparc64/sparc64/pmap.c,v
> retrieving revision 1.110
> diff -u -p -r1.110 pmap.c
> --- sys/arch/sparc64/sparc64/pmap.c 24 Jan 2023 07:26:34 -0000 1.110
> +++ sys/arch/sparc64/sparc64/pmap.c 2 Apr 2023 19:23:11 -0000
> @@ -1528,19 +1528,6 @@ pmap_release(struct pmap *pm)
> }
>
> /*
> - * Copy the range specified by src_addr/len
> - * from the source map to the range dst_addr/len
> - * in the destination map.
> - *
> - * This routine is only advisory and need not do anything.
> - */
> -void
> -pmap_copy(struct pmap *dst_pmap, struct pmap *src_pmap, vaddr_t dst_addr,
> - vsize_t len, vaddr_t src_addr)
> -{
> -}
> -
> -/*
> * Garbage collects the physical map system for
> * pages which are no longer used.
> * Success need not be guaranteed -- that is, there
> Index: sys/uvm/uvm_map.c
> ===================================================================
> RCS file: /OpenBSD/src/sys/uvm/uvm_map.c,v
> retrieving revision 1.313
> diff -u -p -r1.313 uvm_map.c
> --- sys/uvm/uvm_map.c 24 Feb 2023 15:17:48 -0000 1.313
> +++ sys/uvm/uvm_map.c 2 Apr 2023 19:23:11 -0000
> @@ -3716,15 +3716,6 @@ uvm_mapent_forkshared(struct vmspace *ne
> old_entry->end - old_entry->start, 0, old_entry->protection,
> old_entry->max_protection, old_map, old_entry, dead);
>
> - /*
> - * pmap_copy the mappings: this routine is optional
> - * but if it is there it will reduce the number of
> - * page faults in the new proc.
> - */
> - if (!UVM_ET_ISHOLE(new_entry))
> - pmap_copy(new_map->pmap, old_map->pmap, new_entry->start,
> - (new_entry->end - new_entry->start), new_entry->start);
> -
> return (new_entry);
> }
>
> @@ -3805,8 +3796,6 @@ uvm_mapent_forkcopy(struct vmspace *new_
> * resolve all copy-on-write faults now
> * (note that there is nothing to do if
> * the old mapping does not have an amap).
> - * XXX: is it worthwhile to bother with
> - * pmap_copy in this case?
> */
> if (old_entry->aref.ar_amap)
> amap_cow_now(new_map, new_entry);
> @@ -3821,12 +3810,7 @@ uvm_mapent_forkcopy(struct vmspace *new_
> * fork operation.
> *
> * if we do not write-protect the parent, then
> - * we must be sure to write-protect the child
> - * after the pmap_copy() operation.
> - *
> - * XXX: pmap_copy should have some way of telling
> - * us that it didn't do anything so we can avoid
> - * calling pmap_protect needlessly.
> + * we must be sure to write-protect the child.
> */
> if (!UVM_ET_ISNEEDSCOPY(old_entry)) {
> if (old_entry->max_protection & PROT_WRITE) {
> @@ -3854,15 +3838,6 @@ uvm_mapent_forkcopy(struct vmspace *new_
> else
> protect_child = FALSE;
> }
> - /*
> - * copy the mappings
> - * XXX: need a way to tell if this does anything
> - */
> - if (!UVM_ET_ISHOLE(new_entry))
> - pmap_copy(new_map->pmap, old_map->pmap,
> - new_entry->start,
> - (old_entry->end - old_entry->start),
> - old_entry->start);
>
> /* protect the child's mappings if necessary */
> if (protect_child) {
> @@ -4526,13 +4501,6 @@ uvm_map_extract(struct vm_map *srcmap, v
> newentry->protection != PROT_NONE)
> newentry->protection = newentry->max_protection;
> newentry->protection &= ~PROT_EXEC;
> -
> - /*
> - * Step 2: perform pmap copy.
> - * (Doing this in the loop saves one RB traversal.)
> - */
> - pmap_copy(kernel_map->pmap, srcmap->pmap,
> - cp_start - start + dstaddr, cp_len, cp_start);
> }
> pmap_update(kernel_map->pmap);
>
> Index: sys/uvm/uvm_pmap.h
> ===================================================================
> RCS file: /OpenBSD/src/sys/uvm/uvm_pmap.h,v
> retrieving revision 1.32
> diff -u -p -r1.32 uvm_pmap.h
> --- sys/uvm/uvm_pmap.h 1 Jan 2023 19:49:18 -0000 1.32
> +++ sys/uvm/uvm_pmap.h 2 Apr 2023 19:23:11 -0000
> @@ -128,9 +128,6 @@ boolean_t pmap_clear_reference(struct v
> #if !defined(pmap_collect) && defined(__HAVE_PMAP_COLLECT)
> void pmap_collect(pmap_t);
> #endif
> -#if !defined(pmap_copy)
> -void pmap_copy(pmap_t, pmap_t, vaddr_t, vsize_t, vaddr_t);
> -#endif
> #if !defined(pmap_copy_page)
> void pmap_copy_page(struct vm_page *, struct vm_page *);
> #endif
>
>
