From b9a59e483225093dec4e28ee5841b5b7f5e73562 Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Mon, 3 Mar 2014 00:50:33 +0100 Subject: Keep two virtual pages as mapping windows to access physical memory PCI devices expose their memory etc. way beyond last_phys_addr. Userland drivers opening /dev/mem need to open those too, even if phystokv() will not work for them. * i386/intel/pmap.h (pmap_mapwindow_t): New type. (pmap_get_mapwindow, pmap_put_mapwindow): New prototypes. (PMAP_NMAPWINDOWS): New macro. * i386/intel/pmap.c (mapwindows): New array. (pmap_get_mapwindow, pmap_put_mapwindow): New functions. (pmap_bootstrap, pmap_virtual_space): Reserve virtual pages for the mapping windows. * i386/i386/phys.c: Include (INTEL_PTE_W, INTEL_PTE_R): New macros (pmap_zero_page, pmap_copy_page, copy_to_phys, copy_from_phys): Use `pmap_get_mapwindow' to temporarily map physical pages beyond last_phys_addr. --- i386/i386/phys.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++--- i386/intel/pmap.c | 43 +++++++++++++++++++++++++++++- i386/intel/pmap.h | 10 +++++++ 3 files changed, 127 insertions(+), 5 deletions(-) diff --git a/i386/i386/phys.c b/i386/i386/phys.c index ed4a309..d4bd6c3 100644 --- a/i386/i386/phys.c +++ b/i386/i386/phys.c @@ -37,8 +37,12 @@ #include #include +#include #include +#define INTEL_PTE_W(p) (INTEL_PTE_VALID | INTEL_PTE_WRITE | INTEL_PTE_REF | INTEL_PTE_MOD | pa_to_pte(p)) +#define INTEL_PTE_R(p) (INTEL_PTE_VALID | INTEL_PTE_REF | pa_to_pte(p)) + /* * pmap_zero_page zeros the specified (machine independent) page. */ @@ -47,7 +51,21 @@ pmap_zero_page(p) vm_offset_t p; { assert(p != vm_page_fictitious_addr); - memset((void *)phystokv(p), 0, PAGE_SIZE); + vm_offset_t v; + pmap_mapwindow_t *map; + + if (p >= phys_last_addr) + { + map = pmap_get_mapwindow(INTEL_PTE_W(p)); + v = map->vaddr; + } + else + v = phystokv(p); + + memset((void*) v, 0, PAGE_SIZE); + + if (p >= phys_last_addr) + pmap_put_mapwindow(map); } /* @@ -57,10 +75,33 @@ void pmap_copy_page(src, dst) vm_offset_t src, dst; { + vm_offset_t src_addr_v, dst_addr_v; + pmap_mapwindow_t *src_map, *dst_map; assert(src != vm_page_fictitious_addr); assert(dst != vm_page_fictitious_addr); - memcpy((void *)phystokv(dst), (void *)phystokv(src), PAGE_SIZE); + if (src >= phys_last_addr) + { + src_map = pmap_get_mapwindow(INTEL_PTE_R(src)); + src_addr_v = src_map->vaddr; + } + else + src_addr_v = phystokv(src); + + if (dst >= phys_last_addr) + { + dst_map = pmap_get_mapwindow(INTEL_PTE_W(dst)); + dst_addr_v = dst_map->vaddr; + } + else + dst_addr_v = phystokv(dst); + + memcpy((void *) dst_addr_v, (void *) src_addr_v, PAGE_SIZE); + + if (src >= phys_last_addr) + pmap_put_mapwindow(src_map); + if (dst >= phys_last_addr) + pmap_put_mapwindow(dst_map); } /* @@ -73,8 +114,23 @@ copy_to_phys(src_addr_v, dst_addr_p, count) vm_offset_t src_addr_v, dst_addr_p; int count; { + vm_offset_t dst_addr_v; + pmap_mapwindow_t *dst_map; assert(dst_addr_p != vm_page_fictitious_addr); - memcpy((void *)phystokv(dst_addr_p), (void *)src_addr_v, count); + assert(pa_to_pte(dst_addr_p + count-1) == pa_to_pte(dst_addr_p)); + + if (dst_addr_p >= phys_last_addr) + { + dst_map = pmap_get_mapwindow(INTEL_PTE_W(dst_addr_p)); + dst_addr_v = dst_map->vaddr; + } + else + dst_addr_v = phystokv(dst_addr_p); + + memcpy((void *)dst_addr_v, (void *)src_addr_v, count); + + if (dst_addr_p >= phys_last_addr) + pmap_put_mapwindow(dst_map); } /* @@ -88,8 +144,23 @@ copy_from_phys(src_addr_p, dst_addr_v, count) vm_offset_t src_addr_p, dst_addr_v; int count; { + vm_offset_t src_addr_v; + pmap_mapwindow_t *src_map; assert(src_addr_p != vm_page_fictitious_addr); - memcpy((void *)dst_addr_v, (void *)phystokv(src_addr_p), count); + assert(pa_to_pte(src_addr_p + count-1) == pa_to_pte(src_addr_p)); + + if (src_addr_p >= phys_last_addr) + { + src_map = pmap_get_mapwindow(INTEL_PTE_R(src_addr_p)); + src_addr_v = src_map->vaddr; + } + else + src_addr_v = phystokv(src_addr_p); + + memcpy((void *)dst_addr_v, (void *)src_addr_v, count); + + if (src_addr_p >= phys_last_addr) + pmap_put_mapwindow(src_map); } /* diff --git a/i386/intel/pmap.c b/i386/intel/pmap.c index 2943d26..a3d9630 100644 --- a/i386/intel/pmap.c +++ b/i386/intel/pmap.c @@ -419,6 +419,12 @@ unsigned int inuse_ptepages_count = 0; /* debugging */ */ pt_entry_t *kernel_page_dir; +/* + * Two slots for temporary physical page mapping, to allow for + * physical-to-physical transfers. + */ +static pmap_mapwindow_t mapwindows[PMAP_NMAPWINDOWS]; + static inline pt_entry_t * pmap_pde(const pmap_t pmap, vm_offset_t addr) { @@ -774,6 +780,12 @@ void pmap_bootstrap(void) } for (; pte < ptable+NPTES; pte++) { + if (va >= kernel_virtual_end - PMAP_NMAPWINDOWS * PAGE_SIZE); + { + pmap_mapwindow_t *win = &mapwindows[atop(va - (kernel_virtual_end - PMAP_NMAPWINDOWS * PAGE_SIZE))]; + win->entry = pte; + win->vaddr = va; + } WRITE_PTE(pte, 0); va += INTEL_PGBYTES; } @@ -884,12 +896,41 @@ void pmap_clear_bootstrap_pagetable(pt_entry_t *base) { } #endif /* MACH_PV_PAGETABLES */ +/* + * Create a temporary mapping for a given physical entry + * + * This can be used to access physical pages which are not mapped 1:1 by + * phystokv(). + */ +pmap_mapwindow_t *pmap_get_mapwindow(pt_entry_t entry) +{ + pmap_mapwindow_t *map; + + /* Find an empty one. */ + for (map = &mapwindows[0]; map < &mapwindows[sizeof (mapwindows) / sizeof (*mapwindows)]; map++) + if (!(*map->entry)) + break; + assert(map < &mapwindows[sizeof (mapwindows) / sizeof (*mapwindows)]); + + WRITE_PTE(map->entry, entry); + return map; +} + +/* + * Destroy a temporary mapping for a physical entry + */ +void pmap_put_mapwindow(pmap_mapwindow_t *map) +{ + WRITE_PTE(map->entry, 0); + PMAP_UPDATE_TLBS(kernel_pmap, map->vaddr, map->vaddr + PAGE_SIZE); +} + void pmap_virtual_space(startp, endp) vm_offset_t *startp; vm_offset_t *endp; { *startp = kernel_virtual_start; - *endp = kernel_virtual_end; + *endp = kernel_virtual_end - PMAP_NMAPWINDOWS * PAGE_SIZE; } /* diff --git a/i386/intel/pmap.h b/i386/intel/pmap.h index 047a384..382cd5f 100644 --- a/i386/intel/pmap.h +++ b/i386/intel/pmap.h @@ -192,6 +192,16 @@ extern void pmap_clear_bootstrap_pagetable(pt_entry_t *addr); #define set_pmap(pmap) set_cr3(kvtophys((vm_offset_t)(pmap)->dirbase)) #endif /* PAE */ +typedef struct { + pt_entry_t *entry; + vm_offset_t vaddr; +} pmap_mapwindow_t; + +extern pmap_mapwindow_t *pmap_get_mapwindow(pt_entry_t entry); +extern void pmap_put_mapwindow(pmap_mapwindow_t *map); + +#define PMAP_NMAPWINDOWS 2 + #if NCPUS > 1 /* * List of cpus that are actively using mapped memory. 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