diff options
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/arch/amd64/amd64/pmap.c | 33 | ||||
| -rw-r--r-- | sys/include/vm/pmap.h | 5 |
2 files changed, 38 insertions, 0 deletions
diff --git a/sys/arch/amd64/amd64/pmap.c b/sys/arch/amd64/amd64/pmap.c index 6047699..108cd91 100644 --- a/sys/arch/amd64/amd64/pmap.c +++ b/sys/arch/amd64/amd64/pmap.c @@ -30,6 +30,7 @@ #include <sys/types.h> #include <sys/param.h> #include <sys/cdefs.h> +#include <sys/errno.h> #include <machine/tlb.h> #include <machine/vas.h> #include <vm/pmap.h> @@ -191,6 +192,38 @@ pmap_update_tbl(struct vas vas, vaddr_t va, uint64_t val) return 0; } +int +pmap_new_vas(struct vas *res) +{ + const struct vas *kvas = &g_kvas; + struct vas new_vas; + uint64_t *src, *dest; + + new_vas.cr3_flags = kvas->cr3_flags; + new_vas.top_level = vm_alloc_frame(1); + if (new_vas.top_level == 0) + return -ENOMEM; + + src = PHYS_TO_VIRT(kvas->top_level); + dest = PHYS_TO_VIRT(new_vas.top_level); + + /* + * Keep the higher half but zero out the lower + * half for user programs. + */ + for (int i = 0; i < 512; ++i) { + if (i < 256) { + dest[i] = 0; + continue; + } + + dest[i] = src[i]; + } + + *res = new_vas; + return 0; +} + struct vas pmap_read_vas(void) { diff --git a/sys/include/vm/pmap.h b/sys/include/vm/pmap.h index ec669a8..dccfe0d 100644 --- a/sys/include/vm/pmap.h +++ b/sys/include/vm/pmap.h @@ -52,6 +52,11 @@ struct vas pmap_read_vas(void); void pmap_switch_vas(struct vas vas); /* + * Create a new virtual address space. + */ +int pmap_new_vas(struct vas *res); + +/* * Create a virtual memory mapping of a single page. */ int pmap_map(struct vas vas, vaddr_t va, paddr_t pa, vm_prot_t prot); |