rename abi to sys. better memory allocation

23 files changed, 586 insertions, 261 deletions

diff --git a/abi/permission.h b/abi/permission.h
deleted file mode 100644
index 10bc6a3..0000000
--- a/abi/permission.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#ifndef JOVE_ABI_PERMISSION_H
-#define JOVE_ABI_PERMISSION_H 1
-
-#define PERM_MEM_PD 1 /* Permission to write to any PD. */
-#define PERM_MEM_MAP 2 /* Permission to map physical pages. */
-#define PERM_MEM_ALLOC 4 /* Permission to allocate and free physical memory.*/
-
-#endif
diff --git a/abi/syscall.h b/abi/syscall.h
deleted file mode 100644
index e336fe6..0000000
--- a/abi/syscall.h
+++ /dev/null
@@ -1,48 +0,0 @@
-#ifndef JOVE_ABI_SYSCALL_H
-#define JOVE_ABI_SYSCALL_H 1
-
-#include <stdint.h>
-
-typedef struct syscall {
-    int id;
-} syscall_t;
-
-struct syscall_log {
-    syscall_t syscall;
-    const char *message;
-};
-
-struct syscall_mem_takefree {
-    syscall_t syscall;
-    uintptr_t npages;
-};
-
-enum
-{
-    SYSCALL_LOG = 0,
-    SYSCALL_TID,
-
-    SYSCALL_MEM_TAKEFREE,
-
-    SYSCALL_COUNT
-};
-
-#define _SYSCALL(data) \
-    intmax_t ax; \
-    __asm__ volatile("movq %0, %%rdi\nsyscall": "=a"(ax): "r"(data): "memory"); \
-    return ax
-
-int _syscall_log(const char *message) {
-    struct syscall_log syscall_data = {
-        .syscall = (syscall_t){ .id = SYSCALL_LOG },
-        .message = message
-    };
-    _SYSCALL(&syscall_data);
-}
-
-intmax_t _syscall_tid(void) {
-    syscall_t syscall_data = { SYSCALL_TID };
-    _SYSCALL(&syscall_data);
-}
-
-#endif
diff --git a/arch/x86_64/elf.c b/arch/x86_64/elf.c
index 60b8f13..969cbf0 100644
--- a/arch/x86_64/elf.c
+++ b/arch/x86_64/elf.c
@@ -37,7 +37,15 @@ elf_load(const void *data, size_t len)
         struct ELF_phdr *phdr = &phdrs[phdri];
         void *pdata = (void*)phdr->p_vaddr;
             
-        mem_ensure_range(phdr->p_vaddr, phdr->p_vaddr + phdr->p_memsz, true, true);
+        mem_ensure_range(
+                phdr->p_vaddr,
+                phdr->p_vaddr + phdr->p_memsz, 
+                (page_flags_t) {
+                    .present = true,
+                    .writeable = true,
+                    .useraccess = true,
+                    .executable = true
+                });
         if(phdr->p_type == PT_LOAD)
         {
             memcpy(pdata, (void*)((uintptr_t)data + phdr->p_offset), phdr->p_filesz);
diff --git a/arch/x86_64/paging.c b/arch/x86_64/paging.c
index 9e8a5ed..dc27ca2 100644
--- a/arch/x86_64/paging.c
+++ b/arch/x86_64/paging.c
@@ -1,9 +1,10 @@
 #include "paging.h"
 #include "interrupt.h"
-#include <stddef.h>
-#include "lib/jove.h"
 #include "io/log.h"
+#include "lib/jove.h"
 #include "lib/string.h"
+#include "lib/hashtable.h"
+#include "mem/memory.h"
 #include "boot/boot.h"
 
 extern void *_kernel_end;
@@ -12,9 +13,16 @@ PAGEALIGN static uint64_t s_kernel_initial_pml4[512];
 PAGEALIGN static uint64_t s_kernel_initial_pml3[2][512];
 PAGEALIGN static uint64_t s_kernel_initial_pml2[2][512];
 PAGEALIGN static uint64_t s_kernel_initial_pml1[2][512];
-static struct PageDirectory s_kernel_initial_pd;
+static intmax_t s_next_pdid = 0;
+static page_directory_t s_kernel_initial_pd;
+
+page_directory_t *current_page_directory;
 
-struct PageDirectory *mem_current_pd;
+struct PageStateCache {
+    page_directory_t *pd;
+    size_t pmli[4];
+    pmle_t *pml[4];
+} s_state_cache;
 
 physptr_t
 mem_linear_tophys_koffset(uintptr_t virt)
@@ -29,17 +37,20 @@ mem_phys_tolinear(physptr_t phys)
 }
 
 static size_t
-s_paging_pmle(size_t l, uintptr_t addr)
+s_paging_pmli(size_t l, uintptr_t addr)
 {
     size_t shift = (12 + (9 * l));
     return (addr & (0x1FFULL << shift)) >> shift;
 }
 
-static union PageEntry*
-s_paging_fetch_table(union PageEntry *pt, size_t l, uintptr_t virt)
+static pmle_t*
+s_paging_fetch_table(pmle_t *pml, size_t l, uintptr_t virt)
 {
-    size_t pmle = s_paging_pmle(l, virt);
-    union PageEntry entry = pt[pmle];
+    size_t pmli = s_paging_pmli(l, virt);
+    if(s_state_cache.pmli[l] == pmli && s_state_cache.pml[l] != NULL)
+        return s_state_cache.pml[l];
+
+    pmle_t entry = pml[pmli];
     bool entry_new = false;
     if(!entry.p) {
         entry_new = true;
@@ -47,122 +58,134 @@ s_paging_fetch_table(union PageEntry *pt, size_t l, uintptr_t virt)
         entry.p = 1;
         entry.rw = 1;
         entry.us = 1;
-        pt[pmle] = entry;
+        pml[pmli] = entry;
     }
-    union PageEntry *table = (union PageEntry*)(mem_phys_tolinear(entry.paddr << 12));
-    if(entry_new) memset(table, 0, PAGESIZE);
+    pmle_t *table = (pmle_t*)(mem_phys_tolinear(entry.paddr << 12));
+    if(entry_new) memset(table, 0, PAGE_SIZE);
+
+    s_state_cache.pmli[l] = pmli;
+    s_state_cache.pml[l] = table;
     return table;
 }
 
-static union PageEntry*
-s_paging_get_table(union PageEntry *pt, size_t l, uintptr_t virt)
+static void
+s_paging_cache_tables(page_directory_t *pd, uintptr_t virt)
 {
-    if(pt == NULL) return NULL;
-    size_t pmle = s_paging_pmle(l, virt);
-    union PageEntry entry = pt[pmle];
-    if(!entry.p) return NULL;
-    return (union PageEntry*)(mem_phys_tolinear(entry.paddr << 12));
+    pmle_t *pml4 = (pmle_t*)pd->virt;
+    if(s_state_cache.pd != pd) memset(&s_state_cache, 0, sizeof(s_state_cache));
+
+    pmle_t *pml3 = s_paging_fetch_table(pml4, 3, virt);
+    pmle_t *pml2 = s_paging_fetch_table(pml3, 2, virt);
+    pmle_t *pml1 = s_paging_fetch_table(pml2, 1, virt);
 }
 
-physptr_t
-mem_linear_tophys(uintptr_t virt)
+static pmle_t*
+s_paging_get_table(pmle_t *pt, size_t l, uintptr_t virt)
 {
-    struct PageDirectory *pd = mem_current_pd;
-    union PageEntry *pml3 = s_paging_get_table(pd->pml4_vaddr, 3, virt);
-    union PageEntry *pml2 = s_paging_get_table(pd->pml4_vaddr, 3, virt);
-    union PageEntry *pml1 = s_paging_get_table(pd->pml4_vaddr, 3, virt);
-    if(pml1 == NULL) return 0;
-
-    size_t pml1i = s_paging_pmle(0, virt);
+    if(pt == NULL) return NULL;
+    size_t pmli = s_paging_pmli(l, virt);
+    if(s_state_cache.pmli[l] == pmli && s_state_cache.pml[l] != NULL)
+        return s_state_cache.pml[l];
 
-    if(!pml1[pml1i].p) return 0;
-    return pml1[pml1i].paddr << 12;
+    pmle_t entry = pt[pmli];
+    if(!entry.p) return NULL;
+    return (pmle_t*)(mem_phys_tolinear(entry.paddr << 12));
 }
 
-bool
-mem_check_ptr(const void *ptr)
+page_mapping_t
+mem_get_mapping_as(page_directory_t *pd, uintptr_t addr)
 {
-    if(ptr == NULL) return false;
-    return mem_linear_tophys((uintptr_t)ptr) != 0;
-}
+    spinlock_acquire(pd->lock);
+    page_mapping_t mapping = { 0 };
+    
+    pmle_t *pml4 = (pmle_t*)pd->virt;
+    if(s_state_cache.pd != pd) memset(&s_state_cache, 0, sizeof(s_state_cache));
 
-void
-mem_paging_map4k(struct PageDirectory *pd, physptr_t phys, uintptr_t virt, uint8_t flg)
-{
-    union PageEntry *pml3 = s_paging_fetch_table(pd->pml4_vaddr, 3, virt);
-    union PageEntry *pml2 = s_paging_fetch_table(pml3, 2, virt);
-    union PageEntry *pml1 = s_paging_fetch_table(pml2, 1, virt);
-    size_t pml1e = s_paging_pmle(0, virt);
-
-    pml1[pml1e] = (union PageEntry) {
-        .p = (flg & 1) > 0,
-        .rw = (flg & 2) > 0,
-        .us = (flg & 4) > 0,
-        .paddr = phys >> 12
+    pmle_t *pml3 = s_paging_get_table(pml4, 3, addr);
+    pmle_t *pml2 = s_paging_get_table(pml3, 2, addr);
+    pmle_t *pml1 = s_paging_get_table(pml2, 1, addr);
+    if(pml1 == NULL) goto release_return;
+
+    size_t pml1i = s_paging_pmli(0, addr);
+    pmle_t pml1e = pml1[pml1i];
+
+    mapping = (page_mapping_t) {
+        .phys = (pml1e.paddr << 12) & ~PAGE_MASK,
+        .pf = {
+            .present = pml1e.p,
+            .writeable = pml1e.rw,
+            .useraccess = pml1e.us,
+            .executable = !pml1e.xd
+        }
     };
+release_return:
+    spinlock_release(pd->lock);
+    return mapping;
 }
 
-union PageEntry
-mem_paging_fetch4k(struct PageDirectory *pd, uintptr_t virt)
-{
-    union PageEntry *pml3 = s_paging_fetch_table(pd->pml4_vaddr, 3, virt);
-    union PageEntry *pml2 = s_paging_fetch_table(pml3, 2, virt);
-    union PageEntry *pml1 = s_paging_fetch_table(pml2, 1, virt);
-    return pml1[s_paging_pmle(0, virt)];
-}
+page_mapping_t mem_get_mapping(uintptr_t addr)
+{ return mem_get_mapping_as(current_page_directory, addr); }
 
-void
-mem_pd_ensure_4k(struct PageDirectory *pd, uintptr_t virt, uint8_t flg)
-{
-    union PageEntry pml1e = mem_paging_fetch4k(pd, virt);
-    if(!pml1e.p) {
-        uintptr_t phys = mem_phys_alloc(1);
-        mem_paging_map4k(pd, phys, virt, flg);
-    }
-}
 
-void
-mem_pd_ensure_range(struct PageDirectory *pd, uintptr_t from, uintptr_t to, uint8_t flg)
+bool
+mem_check_ptr(const void *ptr)
 {
-    from &= ~0xFFF;
-    for(; from < to; from += PAGESIZE)
-        mem_pd_ensure_4k(pd, from, flg);
+    return mem_get_mapping((uintptr_t)ptr).pf.present != 0;
 }
 
 void
-mem_ensure_range_for(void *pd, uintptr_t from, uintptr_t to, bool rw, bool user)
+mem_set_mapping_as(page_directory_t *pd, page_mapping_t mapping, uintptr_t virt)
 {
-    mem_pd_ensure_range((struct PageDirectory*)pd, from, to, 1 | (rw << 1) | (user << 2));
+    spinlock_acquire(pd->lock);
+    s_paging_cache_tables(pd, virt);
+    pmle_t *pml1 = s_state_cache.pml[0];
+    size_t pml1i = s_paging_pmli(0, virt);
+
+    pml1[pml1i] = (pmle_t) {
+        .p = mapping.pf.present,
+        .rw = mapping.pf.writeable,
+        .us = mapping.pf.useraccess,
+        .xd = !mapping.pf.executable,
+        .paddr = mapping.phys >> 12
+    };
+    spinlock_release(pd->lock);
 }
 
+void mem_set_mapping(page_mapping_t mapping, uintptr_t virt)
+{ mem_set_mapping_as(current_page_directory, mapping, virt); }
+
 void
-mem_ensure_range(uintptr_t from, uintptr_t to, bool rw, bool user)
+mem_ensure_range_as(page_directory_t *pd, uintptr_t from, uintptr_t to, page_flags_t flg)
 {
-    mem_ensure_range_for(mem_current_pd, from, to, rw, user);
-}
+    spinlock_acquire(pd->lock);
+    from &= ~(PAGE_SIZE - 1);
 
-void mem_pd_new(struct PageDirectory *pd)
-{
-    physptr_t pml4p = mem_phys_alloc(1);
-    union PageEntry *pml4 = (union PageEntry*)mem_phys_tolinear(pml4p);
-    memset(pml4, 0, PAGESIZE);
-    memcpy(&pml4[256], &pd->pml4_vaddr[256], PAGESIZE / 2);
-
-    *pd = (struct PageDirectory){
-        .pml4_vaddr = pml4,
-        .pml4_paddr = pml4p,
-        .references = 1
-    };
-}
+    if(to < from) to = from;
+    size_t pages = (to - from) >> 12;
+    if(pages == 0) pages = 1;
+    for(size_t i = 0; i < pages; i++) {
+        uintptr_t waddr = from + (i << 12);
+        s_paging_cache_tables(pd, waddr);
+        pmle_t *pml1 = s_state_cache.pml[1];
+        size_t pml1i = s_paging_pmli(0, waddr);
 
-void mem_pd_clone(struct PageDirectory *pd, struct PageDirectory *parent)
-{
-    mem_pd_new(pd);
-    for(size_t i = 0; i < 256; i++) {
-        //TODO: Impl pd cloning
+        if(!pml1[pml1i].p) {
+            physptr_t phys = mem_phys_alloc(1);
+            pml1[pml1i] = (pmle_t) {
+                .p = flg.present,
+                .rw = flg.writeable,
+                .us = flg.useraccess,
+                .xd = !flg.executable,
+                .paddr = phys >> 12
+            };
+        }
     }
+    spinlock_release(pd->lock);
 }
 
+void mem_ensure_range(uintptr_t from, uintptr_t to, page_flags_t flg)
+{ mem_ensure_range_as(current_page_directory, from, to, flg); }
+
 struct Registers*
 s_pagefault_handler(struct Registers *state)
 {
@@ -189,16 +212,17 @@ s_pagefault_handler(struct Registers *state)
 void
 mem_paging_setup(void)
 {
-    memset(s_kernel_initial_pml4, 0, PAGESIZE);
-    memset(s_kernel_initial_pml3, 0, 2 * PAGESIZE);
-    memset(s_kernel_initial_pml2, 0, 2 * PAGESIZE);
-    memset(s_kernel_initial_pml1, 0, PAGESIZE);
-    s_kernel_initial_pd = (struct PageDirectory){
-        .pml4_vaddr = (union PageEntry*)&s_kernel_initial_pml4,
-        .pml4_paddr = mem_linear_tophys_koffset((uintptr_t)&s_kernel_initial_pml4),
-        .references = 1
+    memset(s_kernel_initial_pml4, 0, PAGE_SIZE);
+    memset(s_kernel_initial_pml3, 0, 2 * PAGE_SIZE);
+    memset(s_kernel_initial_pml2, 0, 2 * PAGE_SIZE);
+    memset(s_kernel_initial_pml1, 0, PAGE_SIZE);
+    s_kernel_initial_pd = (page_directory_t){
+        .phys = mem_linear_tophys_koffset((uintptr_t)&s_kernel_initial_pml4),
+        .virt = (union PageEntry*)&s_kernel_initial_pml4,
+        .ref = 1,
+        .id = s_next_pdid++
     };
-    mem_current_pd = &s_kernel_initial_pd;
+    current_page_directory = &s_kernel_initial_pd;
 
     /* Map first few GiBs */
     s_kernel_initial_pml4[256] =
@@ -208,7 +232,7 @@ mem_paging_setup(void)
         mem_linear_tophys_koffset((uintptr_t)&s_kernel_initial_pml2[0])
         | 3;
     for(int i = 0; i < 512; i++) {
-        s_kernel_initial_pml2[0][i] = (i * (PAGESIZE * 512)) | 0x80 | 3;
+        s_kernel_initial_pml2[0][i] = (i * (PAGE_SIZE * 512)) | 0x80 | 3;
     }
 
     size_t kernel_pml4e = (boot_kernel_virtual_base >> (39));
@@ -225,9 +249,9 @@ mem_paging_setup(void)
     s_kernel_initial_pml2[1][kernel_pml2e] =
         mem_linear_tophys_koffset((uintptr_t)&s_kernel_initial_pml1[0]) | 3;
     for(int i = 0; i < kernel_npages; i++) {
-        s_kernel_initial_pml1[0][i] = (i * PAGESIZE) + boot_kernel_physical_address | 3;
+        s_kernel_initial_pml1[0][i] = (i * PAGE_SIZE) + boot_kernel_physical_address | 3;
     }
     
     int_set_handler(14, s_pagefault_handler);
-    __asm__ volatile("mov %0, %%cr3":: "r"(s_kernel_initial_pd.pml4_paddr));
+    __asm__ volatile("mov %0, %%cr3":: "r"(s_kernel_initial_pd.phys));
 }
diff --git a/arch/x86_64/paging.h b/arch/x86_64/paging.h
index 1e88a0b..28dfad2 100644
--- a/arch/x86_64/paging.h
+++ b/arch/x86_64/paging.h
@@ -2,9 +2,8 @@
 #define JOVE_ARCH_x86_64_PAGING_H 1
 
 #include <stdint.h>
-#include "mem/memory.h"
 
-union PageEntry
+typedef union PageMappingLevelEntry
 {
     struct {
         uint8_t p : 1; /* Present */
@@ -24,21 +23,6 @@ union PageEntry
         uint8_t xd : 1;
     }__attribute__((packed));
     uint64_t value;
-}__attribute__((packed));
-
-struct PageDirectory
-{
-    union PageEntry *pml4_vaddr;
-    physptr_t pml4_paddr;
-    size_t references;
-};
-
-extern struct PageDirectory *mem_current_pd;
-
-void mem_pd_new(struct PageDirectory *pd);
-void mem_pd_clone(struct PageDirectory *pd, struct PageDirectory *parent);
-
-void mem_pd_ensure_4k(struct PageDirectory *pd, uintptr_t virt, uint8_t flg);
-void mem_pd_ensure_range(struct PageDirectory *pd, uintptr_t from, uintptr_t to, uint8_t flg);
+} __attribute__((packed)) pmle_t;
 
 #endif
diff --git a/arch/x86_64/syscall_setup.S b/arch/x86_64/syscall_setup.S
index 972e345..4f5c6f0 100644
--- a/arch/x86_64/syscall_setup.S
+++ b/arch/x86_64/syscall_setup.S
@@ -6,12 +6,11 @@
 syscall_entry:
     swapgs
     movq %rsp, %rax
-    movq (_kernel_task_bp), %rsp
+    movq _kernel_task_bp, %rsp
     pushq %rax
     pushq %rbp
     pushq %rcx
     pushq %r11
-    movq %rsp, %rbp
     call syscall_handler
     popq %r11
     popq %rcx
diff --git a/arch/x86_64/tasking.c b/arch/x86_64/tasking.c
index fe6ecdb..9b29330 100644
--- a/arch/x86_64/tasking.c
+++ b/arch/x86_64/tasking.c
@@ -1,4 +1,4 @@
-#include "tsk/tasking.h"
+#include "usr/tasking.h"
 #include "mem/memory.h"
 #include "io/log.h"
 #include "lib/hashtable.h"
@@ -9,7 +9,6 @@
 
 struct TaskBody {
     struct Task base;
-    struct PageDirectory *pd;
     struct Registers state;
 };
 
@@ -44,7 +43,7 @@ tasking_setup(void)
         .base.id = s_task_id_next++,
         .base.kbp = ((uintptr_t)mem_slab_alloc(&s_kbp_cache)) + 0xFF0,
         .base.perm = (size_t)-1,
-        .pd = mem_current_pd
+        .base.pd = current_page_directory
     };
     hashtable_insert(&s_tasks, 0, ktask);
 
@@ -80,14 +79,8 @@ void
 task_free(struct Task *task)
 {
     struct TaskBody *body = (struct TaskBody*)task;
-    body->pd->references--;
+    task->pd->ref--;
     task->kbp -= 0xFFF;
     mem_slab_free(&s_kbp_cache, (void*)(task->kbp));
     klogf("Need impl for task_free\n");
 }
-
-void*
-task_get_pd(struct Task *task)
-{
-    return ((struct TaskBody*)task)->pd;
-}
diff --git a/lib/spinlock.h b/lib/spinlock.h
new file mode 100644
index 0000000..75af28a
--- /dev/null
+++ b/lib/spinlock.h
@@ -0,0 +1,27 @@
+#ifndef JOVE_LIB_SPINLOCK_H
+#define JOVE_LIB_SPINLOCK_H 1
+
+#include <stdatomic.h>
+
+typedef struct Spinlock
+{
+    atomic_flag flg;
+    
+    const char *locker_file;
+    const char *locker_func;
+    int locker_line;
+} spinlock_t;
+
+#define spinlock_acquire(lock) \
+    while(atomic_flag_test_and_set_explicit(&lock.flg, memory_order_acquire)) \
+        __builtin_ia32_pause(); \
+    lock.locker_file = __FILE__; \
+    lock.locker_func = __FUNCTION__; \
+    lock.locker_line = __LINE__
+
+#define spinlock_release(lock) \
+    atomic_flag_clear_explicit(&lock.flg, memory_order_release); \
+    lock.locker_file = lock.locker_func = NULL; \
+    lock.locker_line = -1
+
+#endif
diff --git a/main.c b/main.c
index 9341489..91125af 100644
--- a/main.c
+++ b/main.c
@@ -3,8 +3,8 @@
 #include "mem/memory.h"
 #include "mem/zone.h"
 #include "boot/cmdline.h"
-#include "tsk/tasking.h"
 #include "ird/initrd.h"
+#include "usr/tasking.h"
 #include "usr/umode.h"
 #include "lib/jove.h"
 
@@ -12,15 +12,14 @@ void
 kernel_main(void)
 {
     serial_setup();
-    //arch_tables_setup();
+    arch_tables_setup();
 
     mem_setup();
 
     cmdline_kernel_setup();
+    initrd_setup();
 
     tasking_setup();
-
-    initrd_setup();
     umode_setup();
 
     kpanic("Reached end of kernel main\n");
diff --git a/mem/memory.h b/mem/memory.h
index 41323ed..251c6f5 100644
--- a/mem/memory.h
+++ b/mem/memory.h
@@ -1,36 +1,61 @@
 #ifndef JOVE_MEM_H
 #define JOVE_MEM_H 1
 
-#define PAGESIZE 4096ULL
+#define PAGE_SHIFT 12
+#define PAGE_SIZE (1 << PAGE_SHIFT)
+#define PAGE_MASK (PAGE_SIZE - 1)
+
 #define KiB 1024ULL
 #define MiB (KiB * KiB)
 #define GiB (MiB * KiB)
 #define TiB (GiB * KiB)
 
-#include <stddef.h>
-#include <stdint.h>
-#include <stdbool.h>
-typedef uintptr_t physptr_t;
+#include "lib/spinlock.h"
+#include "sys/types.h"
+
+typedef struct page_directory
+{
+    spinlock_t lock;
+    size_t id;
+    size_t ref;
+    physptr_t phys;
+    void *virt;
+} page_directory_t;
 
 #include "slab.h"
 
-/*Linear*/
-void mem_paging_setup(void);
+extern page_directory_t *current_page_directory;
 
-physptr_t mem_linear_tophys(uintptr_t virt);
+/**Setup the kernel structures responsible for handling physical memory translation.*/
+void mem_paging_setup(void);
 
-/**Check if pointer is within valid memory.
+/**Check if a given pointer is valid.
  * @param ptr pointer to check.
- * @return if the pointer is invalid.*/
+ * @return if the pointer is valid.*/
 bool mem_check_ptr(const void *ptr);
 
-/**Make sure the range indicated is available in memory.
- * If necessary, allocate new pages using the passed flags
- * @param from start of the range.
- * @param to end of the range.
- * @param rw flag to mark page is writeable.
- * @param user flag to mark page as user accessable*/
-void mem_ensure_range(uintptr_t from, uintptr_t to, bool rw, bool user);
+/** Return the physical memory mapping for the given address.
+ * @param pd page directory to get mapping in.
+ * @param addr address to get mapping for.
+ * @return HAL compliant page mapping.*/
+page_mapping_t mem_get_mapping_as(page_directory_t *pd, uintptr_t addr);
+
+/** Return the physical memory mapping for the given address.
+ * @param addr address to get mapping for.
+ * @return HAL compliant page mapping.*/
+page_mapping_t mem_get_mapping(uintptr_t addr);
+
+/** Map a page mapping to a given virtual address.
+ * @param pd pointer to the page directory to edit.
+ * @param mapping mapping to apply.
+ * @param virt virtual address to map to. */
+void mem_set_mapping_as(page_directory_t *pd, page_mapping_t mapping, uintptr_t virt);
+
+/** Map a page mapping to a given virtual address.
+ * @param pd pointer to the page directory to edit.
+ * @param mapping mapping to apply.
+ * @param virt virtual address to map to. */
+void mem_set_mapping(page_mapping_t mapping, uintptr_t virt);
 
 /** Make sure the range indicated is available in memory for specified pd
  * If necessary, allocate new pages using the passed flags
@@ -39,7 +64,15 @@ void mem_ensure_range(uintptr_t from, uintptr_t to, bool rw, bool user);
  * @param to end of the range
  * @param rw flag to mark page is writeable
  * @param user flag to mark page as user accessable*/
-void mem_ensure_range_for(void *pd, uintptr_t from, uintptr_t to, bool rw, bool user);
+void mem_ensure_range_as(page_directory_t *pd, uintptr_t from, uintptr_t to, page_flags_t flg);
+
+/**Make sure the range indicated is available in memory
+ * If necessary, allocate new pages using the passed flags
+ * @param from start of the range.
+ * @param to end of the range.
+ * @param rw flag to mark page is writeable.
+ * @param user flag to mark page as user accessable*/
+void mem_ensure_range(uintptr_t from, uintptr_t to, page_flags_t flg);
 
 void mem_slab_setup(void);
 void mem_slabcache_new(struct SlabCache *cache, char *name, size_t objsize);
@@ -53,7 +86,8 @@ void mem_free(void *ptr);
 /*Physical*/
 
 physptr_t mem_phys_alloc(size_t pages);
-void mem_phys_reserve(physptr_t start, size_t len);
+void mem_phys_reserve(physptr_t start, physptr_t end);
+void mem_phys_release(physptr_t start, physptr_t end);
 
 void mem_setup(void);
 
diff --git a/mem/phys.c b/mem/phys.c
index 00f3531..bf56b77 100644
--- a/mem/phys.c
+++ b/mem/phys.c
@@ -1,9 +1,39 @@
 #include "memory.h"
 #include "zone.h"
+#include "lib/jove.h"
+
+void
+mem_phys_reserve(physptr_t start, physptr_t end)
+{
+    size_t zone = mem_zone_for(start);
+    size_t limit = mem_zone_bound_upper(zone);
+
+    if(end > limit) {
+        mem_phys_reserve(limit, end);
+        end = limit;
+    }
+    mem_zone_resv(MEM_ZONE_STANDARD, start, end);
+}
+
+void 
+mem_phys_release(physptr_t start, physptr_t end)
+{
+    size_t zone = mem_zone_for(start);
+    size_t limit = mem_zone_bound_upper(zone);
+
+    if(end > limit) {
+        mem_phys_release(limit, end);
+        end = limit;
+    }
+    mem_zone_free(MEM_ZONE_STANDARD, start, end);
+}
 
 physptr_t
 mem_phys_alloc(size_t pages)
 {
-    physptr_t ptr = mem_zone_alloc(MEM_ZONE_STANDARD, pages);
-    return ptr;
+    if(mem_zone_pages_free(MEM_ZONE_HIGHER) >= pages)
+        return mem_zone_alloc(MEM_ZONE_HIGHER, pages);
+    if(mem_zone_pages_free(MEM_ZONE_STANDARD) >= pages)
+        return mem_zone_alloc(MEM_ZONE_STANDARD, pages);
+    kpanic("Kernel ran out of physical memory!\n");
 }
diff --git a/mem/slab.c b/mem/slab.c
index 75b8302..30bc23a 100644
--- a/mem/slab.c
+++ b/mem/slab.c
@@ -17,7 +17,15 @@ s_next_free(size_t width)
 {
     uintptr_t ret = s_addr_next_free;
     s_addr_next_free += width;
-    mem_ensure_range(ret, s_addr_next_free, true, false);
+    mem_ensure_range(
+            ret,
+            s_addr_next_free,
+            (page_flags_t) { 
+                .present = true,
+                .writeable = true,
+                .useraccess = false,
+                .executable = false
+            });
     return ret;
 }
 
@@ -36,7 +44,7 @@ s_get_free_listw(size_t slabw, size_t objw)
 static struct SlabDescriptor
 *s_slab_new(struct SlabCache *cache, struct SlabDescriptor *last)
 {
-    size_t slab_width = (cache->slab_pages * PAGESIZE);
+    size_t slab_width = (cache->slab_pages << PAGE_SHIFT);
     uintptr_t descr_base = s_next_free(slab_width);
     struct SlabDescriptor *descr = (struct SlabDescriptor*)descr_base;
 
@@ -122,7 +130,7 @@ mem_slab_free(struct SlabCache *cache, void *ptr)
     {
         uintptr_t base = (uintptr_t)slab->obj_base;
         uintptr_t limit = ((uintptr_t)slab->slab_base) 
-            + (cache->slab_pages * PAGESIZE);
+            + (cache->slab_pages << PAGE_SHIFT);
         if(addr > limit || addr < base) continue;
         if((addr - base) % cache->obj_size != 0) {
             klogf("Tried to free offset pointer %#016X in slab %s\n",
@@ -142,7 +150,7 @@ mem_slab_free(struct SlabCache *cache, void *ptr)
     {
         uintptr_t base = (uintptr_t)slab->obj_base;
         uintptr_t limit = ((uintptr_t)slab->slab_base) 
-            + (cache->slab_pages * PAGESIZE);
+            + (cache->slab_pages << PAGE_SHIFT);
         if(addr > limit || addr < base) continue;
         if((addr - base) % cache->obj_size != 0) {
             klogf("Tried to free offset pointer %#016X in slab %s\n",
@@ -189,7 +197,7 @@ mem_slab_setup(void)
 {
     s_addr_next_free = (uintptr_t)&_kernel_end;
     s_addr_next_free = ((s_addr_next_free >> 12) + 1) << 12;
-    s_get_free_listw(PAGESIZE - sizeof(struct SlabDescriptor), 32);
+    s_get_free_listw(PAGE_SIZE - sizeof(struct SlabDescriptor), 32);
 
     for(int i = 0; i < GENERIC_CACHEC; i++)
     {
diff --git a/mem/zone.c b/mem/zone.c
index 489383a..42a056e 100644
--- a/mem/zone.c
+++ b/mem/zone.c
@@ -2,9 +2,11 @@
 #include "memory.h"
 #include "boot/boot.h"
 #include "lib/string.h"
+#include "lib/jove.h"
+#include "sys/errno.h"
 #include "io/log.h"
 
-#define MEM_ZONE_STANDARD_PAGES  (MEM_ZONE_STANDARD_LIMIT >> 12)
+#define MEM_ZONE_STANDARD_PAGES  (MEM_ZONE_STANDARD_LIMIT >> PAGE_SHIFT)
 
 static uintmax_t 
     s_zone_standard_freemap_blocks_flat[BUDDY_BLOCKS_FOR(MEM_ZONE_STANDARD_PAGES)];
@@ -17,8 +19,6 @@ static struct PhysicalMemoryZone s_zones[MEM_ZONE_COUNT] =
         .name = "Standard",
         .base = MEM_ZONE_STANDARD_BASE,
         .limit = MEM_ZONE_STANDARD_LIMIT,
-        .npages_total = MEM_ZONE_STANDARD_PAGES,
-        .npages_free = 0,
         .freemap = { 
             .orders = MEM_BUDDY_ORDERS,
             .bits = MEM_ZONE_STANDARD_PAGES,
@@ -36,40 +36,89 @@ static struct PhysicalMemoryZone s_zones[MEM_ZONE_COUNT] =
     }
 };
 
+int
+mem_zone_for(uintptr_t addr)
+{
+    addr &= ~PAGE_MASK;
+    for(size_t zonei = 0; zonei < MEM_ZONE_COUNT; zonei++)
+    {
+        struct PhysicalMemoryZone *pmz = &s_zones[zonei];
+        if(addr >= pmz->base && addr < pmz->limit) return zonei;
+    }
+    return -ENOTFOUND;
+}
+
+uintptr_t 
+mem_zone_bound_lower(size_t zone)
+{
+    if(zone >= MEM_ZONE_COUNT) return 0;
+    return s_zones[zone].base;
+}
+
+uintptr_t 
+mem_zone_bound_upper(size_t zone)
+{
+    if(zone >= MEM_ZONE_COUNT) return 0;
+    return s_zones[zone].limit;
+}
+
+size_t
+mem_zone_pages_free(size_t zone)
+{
+    if(zone >= MEM_ZONE_COUNT) return 0;
+    return s_zones[zone].freemap.free;
+}
+
 void
+_zone_resv(struct PhysicalMemoryZone *zone, uintptr_t base, uintptr_t limit)
+{
+    buddy_mark_range(&zone->freemap, base >> PAGE_SHIFT, limit >> PAGE_SHIFT);
+}
+
+void
+_zone_free(struct PhysicalMemoryZone *zone, uintptr_t base, uintptr_t limit)
+{
+    buddy_free_range(&zone->freemap, base >> PAGE_SHIFT, limit >> PAGE_SHIFT);
+}
+
+int
 mem_zone_resv(size_t zone, uintptr_t base, uintptr_t limit)
 {
-    size_t base_off = base % PAGESIZE;
-    size_t limit_off = limit % PAGESIZE;
-    
-    if(base_off > 0) base += (PAGESIZE - base_off);
-    limit -= limit_off;
+    if(zone >= MEM_ZONE_COUNT) return -EINVAL;
 
-    buddy_mark_range(&s_zones[zone].freemap, base >> 12, limit >> 12);
+    size_t base_off = base % PAGE_SIZE;
+
+    size_t base_real = (base & ~PAGE_MASK) + (base_off > 0 ? PAGE_SIZE : 0);
+    size_t limit_real = limit & ~PAGE_MASK;
+    _zone_resv(&s_zones[zone], base_real, limit_real);
+    return 0;
 }
 
-void
+int
 mem_zone_free(size_t zone, uintptr_t base, uintptr_t limit)
 {
-    size_t base_off = base % PAGESIZE;
-    size_t limit_off = limit % PAGESIZE;
-    
-    if(base_off > 0) base += (PAGESIZE - base_off);
-    limit -= limit_off;
-
-    size_t npages = (limit - base) >> 12;
-    s_zones[zone].npages_free += npages;
-    buddy_free_range(&s_zones[zone].freemap, base >> 12, limit >> 12);
+    if(zone >= MEM_ZONE_COUNT) return -EINVAL;
+
+    size_t base_off = base % PAGE_SIZE;
+
+    size_t base_real = (base & ~PAGE_MASK) + (base_off > 0 ? PAGE_SIZE : 0);
+    size_t limit_real = limit & ~PAGE_MASK;
+    _zone_free(&s_zones[zone], base_real, limit_real);
+    return 0;
 }
 
 uintptr_t
 mem_zone_alloc(size_t zone, size_t pages)
-{   
+{
+    if(zone >= MEM_ZONE_COUNT) return 0;
+
     struct PhysicalMemoryZone *pmz = &s_zones[zone];
     intmax_t pagei = buddy_alloc(&pmz->freemap, pages);
-    if(pagei < 0) return 0;
+    if(pagei < 0) {
+        return 0;
+    }
 
-    return (((uintmax_t)pagei) << 12) + pmz->base;
+    return (((uintmax_t)pagei) << PAGE_SHIFT) + pmz->base;
 }
 
 void
diff --git a/mem/zone.h b/mem/zone.h
index 7e863bf..c0b0f52 100644
--- a/mem/zone.h
+++ b/mem/zone.h
@@ -22,23 +22,42 @@ struct PhysicalMemoryZone
     uintptr_t base;
     uintptr_t limit;
 
-    size_t npages_total;
-    size_t npages_free;
-
     struct BuddyMap freemap;
 };
 
+/**Return the zone index for the given address
+ * @param addr address to look up
+ * @return zone index*/
+int mem_zone_for(uintptr_t addr);
+
+/**Return the lower bound for the given zone index.
+ * @param zone index into zones.
+ * @return lower bound.*/
+uintptr_t mem_zone_bound_lower(size_t zone);
+
+/**Return the upper bound for the given zone index.
+ * @param zone index into zones.
+ * @return upper bound.*/
+uintptr_t mem_zone_bound_upper(size_t zone);
+
+/**Return the number of pages free in the given zone.
+ * @param zone index into zones.
+ * @return number of free pages.*/
+size_t mem_zone_pages_free(size_t zone);
+
 /** Using a given zone, reserve a range of physical addresses
  * @param zone identifier of zone to modify
  * @param base starting address to reserve
- * @param limit ending address to reserve*/
-void mem_zone_resv(size_t zone, uintptr_t base, uintptr_t limit);
+ * @param limit ending address to reserve
+ * @return error code or 0 if success */
+int mem_zone_resv(size_t zone, uintptr_t base, uintptr_t limit);
 
 /** Using a given zone, free a range of physical addresses
  * @param zone identifier of zone to modify
  * @param base starting address to free
- * @param limit ending address to free*/
-void mem_zone_free(size_t zone, uintptr_t base, uintptr_t limit);
+ * @param limit ending address to free
+ * @return error code or 0 if success*/
+int mem_zone_free(size_t zone, uintptr_t base, uintptr_t limit);
 
 /** Allocate a number of pages from the given zone
  * @param zone identifier of the zone to modify
diff --git a/sys/errno.h b/sys/errno.h
new file mode 100644
index 0000000..8d0c980
--- /dev/null
+++ b/sys/errno.h
@@ -0,0 +1,10 @@
+#ifndef _SYS_ERRNO_H
+#define _SYS_ERRNO_H 1
+
+#define ENOPERM 1
+#define EFAULT 2
+#define EINVAL 3
+#define ENOSYS 4
+#define ENOTFOUND 5
+
+#endif
diff --git a/sys/permission.h b/sys/permission.h
new file mode 100644
index 0000000..08bb765
--- /dev/null
+++ b/sys/permission.h
@@ -0,0 +1,11 @@
+#ifndef _SYS_PERMISSION_H
+#define _SYS_PERMISSION_H 1
+
+#define PERM_MEM_PHYS_RESV 1 /* Reserve physical memory. */
+#define PERM_MEM_PHYS_FREE 2 /* Free physical memory. */
+#define PERM_MEM_PHYS_ALLOC 4 /* Allocate physical memory. */
+
+#define PERM_MEM_VIRT_PD 8 /* Work on any PD. */
+#define PERM_MEM_VIRT_MAP 0x10 /* Map physical memory to virtual memory. */
+
+#endif
diff --git a/sys/syscall.h b/sys/syscall.h
new file mode 100644
index 0000000..d8b64bb
--- /dev/null
+++ b/sys/syscall.h
@@ -0,0 +1,69 @@
+#ifndef _SYS_SYSCALL_H
+#define _SYS_SYSCALL_H 1
+
+#include <stdint.h>
+#include <stddef.h>
+#include "types.h"
+
+typedef struct syscall {
+    int id;
+} syscall_t;
+
+struct syscall_log {
+    syscall_t syscall;
+    const char *message;
+};
+
+struct syscall_mem_phys_range_op {
+    syscall_t syscall;
+    uintptr_t base;
+    uintptr_t limit;
+};
+
+struct syscall_mem_phys_alloc {
+    syscall_t syscall;
+    size_t npages;
+    uintptr_t *result;
+};
+
+struct syscall_mem_virt_mapping {
+    syscall_t syscall;
+    linear_address_t addr;
+    page_mapping_t *result;
+};
+
+struct syscall_mem_virt_map {
+    syscall_t syscall;
+    linear_address_t addr;
+    page_mapping_t map;
+};
+
+struct syscall_mem_virt_alloc {
+    syscall_t syscall;
+    linear_address_t from;
+    uintptr_t to;
+    page_flags_t flg;
+};
+
+enum
+{
+    SYSCALL_LOG = 0,
+    SYSCALL_TID,
+
+    SYSCALL_MEM_PHYS_RESV,
+    SYSCALL_MEM_PHYS_FREE,
+    SYSCALL_MEM_PHYS_ALLOC,
+
+    SYSCALL_MEM_VIRT_MAPPING,
+    SYSCALL_MEM_VIRT_MAP,
+    SYSCALL_MEM_VIRT_ALLOC,
+
+    SYSCALL_COUNT
+};
+
+#define _SYSCALL(data) \
+    intmax_t ax; \
+    __asm__ volatile("movq %0, %%rdi\nsyscall": "=a"(ax): "r"(data): "memory"); \
+    return ax
+
+#endif
diff --git a/sys/types.h b/sys/types.h
new file mode 100644
index 0000000..0a519c5
--- /dev/null
+++ b/sys/types.h
@@ -0,0 +1,32 @@
+#ifndef _SYS_TYPES_H
+#define _SYS_TYPES_H 1
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+typedef intmax_t tid_t;
+
+typedef struct {
+    intmax_t tid;
+    uintmax_t addr;
+} linear_address_t;
+
+typedef uintptr_t physptr_t;
+
+typedef struct page_flags
+{
+    bool present;
+    bool writeable;
+    bool useraccess;
+    bool executable;
+} page_flags_t;
+
+typedef struct page_mapping
+{
+    physptr_t phys;
+    page_flags_t pf;
+} page_mapping_t;
+
+
+#endif
diff --git a/usr/syscall.c b/usr/syscall.c
index 8680845..fbc5fe7 100644
--- a/usr/syscall.c
+++ b/usr/syscall.c
@@ -1,11 +1,28 @@
 #include "syscall.h"
-#include "tsk/tasking.h"
+#include "sys/errno.h"
+#include "sys/permission.h"
+#include "usr/tasking.h"
 #include "mem/memory.h"
 #include "io/log.h"
 
+#define ENSURE_ADDR(ptr) \
+    if(!mem_check_ptr(ptr)) { klogf("User passed bad address %#016X\n", ptr); return -EFAULT; }
+
+#define ENSURE_PERM(p) \
+    if(!(task_current->perm & p)) return -ENOPERM
+
+#define PD_FOR_LINEAR_ADDRESS(addr) current_page_directory; \
+    if(addr.tid == -1) addr.tid = task_current->id; \
+    if(addr.tid != task_current->id) { \
+        ENSURE_PERM(PERM_MEM_VIRT_PD); \
+        struct Task *task = task_get(addr.tid); \
+        if(task == NULL) return -EFAULT; \
+        pd = task->pd; \
+    }
+
 int _syscall_handler_log(struct syscall_log *req)
 {
-    if(!mem_check_ptr(req->message)) return -1;
+    ENSURE_ADDR(req->message);
     klogf("%s", req->message);
     return 0;
 }
@@ -15,14 +32,73 @@ intmax_t _syscall_handler_tid(syscall_t *req)
     return task_current->id;
 }
 
+int _syscall_handler_mem_phys_resv(struct syscall_mem_phys_range_op *req)
+{
+    ENSURE_PERM(PERM_MEM_PHYS_RESV);
+    mem_phys_reserve(req->base, req->limit);
+    return 0;
+}
+
+int _syscall_handler_mem_phys_free(struct syscall_mem_phys_range_op *req)
+{
+    ENSURE_PERM(PERM_MEM_PHYS_FREE);
+    mem_phys_release(req->base, req->limit);
+    return 0;
+}
+
+int _syscall_handler_mem_phys_alloc(struct syscall_mem_phys_alloc *req)
+{
+    ENSURE_ADDR(req->result);
+    ENSURE_PERM(PERM_MEM_PHYS_ALLOC);
+    *req->result = mem_phys_alloc(req->npages);
+    return 0;
+}
+
+int _syscall_handler_mem_virt_mapping(struct syscall_mem_virt_mapping *req)
+{
+    ENSURE_ADDR(req->result);
+    ENSURE_PERM(PERM_MEM_VIRT_MAP);
+    page_directory_t *pd = PD_FOR_LINEAR_ADDRESS(req->addr);
+    *req->result = mem_get_mapping_as(pd, req->addr.addr);
+    return 0;
+}
+
+int _syscall_handler_mem_virt_map(struct syscall_mem_virt_map *req)
+{
+    ENSURE_PERM(PERM_MEM_VIRT_MAP);
+    page_directory_t *pd = PD_FOR_LINEAR_ADDRESS(req->addr);
+    mem_set_mapping_as(pd, req->map, req->addr.addr);
+    return 0;
+}
+
+int _syscall_handler_mem_virt_alloc(struct syscall_mem_virt_alloc *req)
+{
+    ENSURE_PERM(PERM_MEM_VIRT_MAP);
+    ENSURE_PERM(PERM_MEM_PHYS_ALLOC);
+    page_directory_t *pd = PD_FOR_LINEAR_ADDRESS(req->from);
+    mem_ensure_range_as(pd, req->from.addr, req->to, req->flg);
+    return 0;
+}
+
 void *_syscall_handlers[SYSCALL_COUNT] = {
-    _syscall_handler_log
+    _syscall_handler_log,
+    _syscall_handler_tid,
+
+    _syscall_handler_mem_phys_resv,
+    _syscall_handler_mem_phys_free,
+    _syscall_handler_mem_phys_alloc,
+
+    _syscall_handler_mem_virt_mapping,
+    _syscall_handler_mem_virt_map,
+    _syscall_handler_mem_virt_alloc,
 };
 
 int
 syscall_handler(syscall_t *req)
 {
-    if(!mem_check_ptr(req)) return -1;
-    if(req->id >= SYSCALL_COUNT) return -1;
+    ENSURE_ADDR(req);
+    if(req->id >= SYSCALL_COUNT) return -ENOSYS;
+
+    ENSURE_ADDR(_syscall_handlers[req->id]);
     return ((syscall_handler_t)(_syscall_handlers[req->id]))(req);
 }
diff --git a/usr/syscall.h b/usr/syscall.h
index fe7843c..5cc82b8 100644
--- a/usr/syscall.h
+++ b/usr/syscall.h
@@ -1,7 +1,7 @@
 #ifndef JOVE_USER_SYSCALL_H
 #define JOVE_USER_SYSCALL_H 1
 
-#include "abi/syscall.h"
+#include "sys/syscall.h"
 
 typedef int (*syscall_handler_t)(syscall_t*);
 
diff --git a/tsk/thread.c b/usr/tasking.c
index cb4df25..cb4df25 100644
--- a/tsk/thread.c
+++ b/usr/tasking.c
diff --git a/tsk/tasking.h b/usr/tasking.h
index b322682..4b11999 100644
--- a/tsk/tasking.h
+++ b/usr/tasking.h
@@ -3,8 +3,8 @@
 
 #include <stddef.h>
 #include <stdint.h>
-
-typedef size_t tid_t;
+#include "sys/types.h"
+#include "mem/memory.h"
 
 struct Task
 {
@@ -12,6 +12,8 @@ struct Task
     tid_t id;
     uintptr_t kbp;
     size_t perm;
+
+    page_directory_t *pd;
 };
 
 extern struct Task *task_current;
@@ -21,7 +23,6 @@ void tasking_setup(void);
 struct Task *task_new(struct Task *parent);
 struct Task *task_get(tid_t id);
 
-void *task_get_pd(struct Task *task);
 void task_perm_release(struct Task *task, size_t mask);
 
 #endif
diff --git a/usr/umode.c b/usr/umode.c
index 4ef5306..1105d9e 100644
--- a/usr/umode.c
+++ b/usr/umode.c
@@ -24,7 +24,15 @@ umode_setup(void)
         kpanic("Init file %s is incorrectly formatted (want ELF64)\n", init_path);
 
     void *user_stack = (void*)(0x00007FFFFFFFFFFF);
-    mem_ensure_range((uintptr_t)user_stack & ~0xFFF, (uintptr_t)user_stack, true, true);
+    mem_ensure_range(
+            (uintptr_t)user_stack & ~0xFFF,
+            (uintptr_t)user_stack,
+            (page_flags_t) {
+                .present = true,
+                .writeable = true,
+                .useraccess = true,
+                .executable = false
+            });
 
     klogf("User entry point %#016X\n", entry_point);
     umode_enter(entry_point, user_stack);