redo application paging and system calls, rename mercury to hilbert

34 files changed, 316 insertions, 344 deletions

diff --git a/.gitignore b/.gitignore
index 24524ee..d35ad13 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,5 @@
 .vscode/
-include/mercury/kernel/limine.hpp
+include/hilbert/kernel/limine.hpp
 limine
 obj
 out
diff --git a/applications/init/main.cpp b/applications/init/main.cpp
index e0019b5..1a39513 100644
--- a/applications/init/main.cpp
+++ b/applications/init/main.cpp
@@ -1,7 +1,7 @@
-#include <mercury/syscall.hpp>
+#include <hilbert/syscall.hpp>
 
-using mercury::syscall::encoded_color;
-using mercury::syscall::color;
+using hilbert::syscall::encoded_color;
+using hilbert::syscall::color;
 
 encoded_color *fb;
 uint32_t fb_width;
@@ -10,7 +10,7 @@ uint32_t fb_pitch;
 
 int main(int, char **) {
 
-  mercury::syscall::get_framebuffer(fb, fb_width, fb_height, fb_pitch);
+  hilbert::syscall::get_framebuffer(fb, fb_width, fb_height, fb_pitch);
   for (uint32_t y = 0; y < fb_height; ++y)
     for (uint32_t x = 0; x < fb_width; ++x) {
        color c = {
@@ -18,9 +18,8 @@ int main(int, char **) {
         .g = (uint8_t)(y * 255 / fb_height),
         .b = (uint8_t)(x * 255 / fb_width)
       };
-      fb[y * fb_pitch + x] = mercury::syscall::encode_color(c);
+      fb[y * fb_pitch + x] = hilbert::syscall::encode_color(c);
     }
-  mercury::syscall::draw_framebuffer();
 
   //*(int *)0x12345678 = 0;
   //fb_width = *(uint32_t *)0xffffffffc0000000;
diff --git a/applications/link.ld b/applications/link.ld
index eaba220..f8c09a2 100644
--- a/applications/link.ld
+++ b/applications/link.ld
@@ -18,13 +18,13 @@ SECTIONS {
     *(.text .text.*)
   } : rx
 
-  . = ALIGN(0x200000);
+  . = ALIGN(4096);
 
   .rodata : {
     *(.rodata .rodata.*)
   } : ro
 
-  . = ALIGN(0x200000);
+  . = ALIGN(4096);
 
   .data : {
     *(.data .data.*)
diff --git a/documentation/memory.txt b/documentation/memory.txt
index 581bd71..c000fa7 100644
--- a/documentation/memory.txt
+++ b/documentation/memory.txt
@@ -1,11 +1,11 @@
 only the first 32GiB of physical memory are considered. this can be changed
 with pram_pages in paging.cpp. vram layout is as follows:
 
-0x0000.0000.0000 - 0x0000.001f.ffff: always unmapped
-0x0000.0020.0000 - 0x0000.3fbf.ffff: available to user process
-0x0000.3fc0.0000 - 0x0000.3fdf.ffff: always unmapped
-0x0000.3fe0.0000 - 0x0000.3fff.ffff: user stack
-0x0000.4000.0000 - 0xffff.bfff.ffff: always unmapped
+0x0000.0000.0000 - 0x0000.0000.0fff: always unmapped
+0x0000.0000.1000 - 0x0000.001f.efff: user stack
+0x0000.001f.f000 - 0x0000.001f.ffff: always unmapped
+0x0000.0020.0000 - 0x007f.ffff.ffff: available to user process
+0x0080.0000.0000 - 0xffff.bfff.ffff: always unmapped
 0xffff.c000.0000 - 0xffff.ffdf.ffff: available to kernel
 0xffff.ffe0.0000 - 0xffff.ffe0.0fff: always unmapped
 0xffff.ffe0.1000 - 0xffff.ffef.efff: interrupt stack
diff --git a/documentation/syscalls.txt b/documentation/syscalls.txt
index cbba5e3..463f815 100644
--- a/documentation/syscalls.txt
+++ b/documentation/syscalls.txt
@@ -20,8 +20,3 @@ get framebuffer:
   esi out: pitch
   framebuffer is always 32 bpp. use the encode color syscall
   to encode colors. pitch is in dwords, not in bytes.
-
-draw framebuffer:
-  rax in: 2
-  this draws changes to the framebuffer gotten by the get framebuffer
-  system call. (currently, the entire thing is copied, not just changes.)
diff --git a/include/mercury/kernel/application.hpp b/include/hilbert/kernel/application.hpp
index bc4a763..dc2c9a3 100644
--- a/include/mercury/kernel/application.hpp
+++ b/include/hilbert/kernel/application.hpp
@@ -1,10 +1,12 @@
-#ifndef MERCURY_KERNEL_APPLICATION_HPP
-#define MERCURY_KERNEL_APPLICATION_HPP
+#ifndef HILBERT_KERNEL_APPLICATION_HPP
+#define HILBERT_KERNEL_APPLICATION_HPP
 
-#include <mercury/kernel/vfile.hpp>
+#include <hilbert/kernel/vfile.hpp>
 #include <cstdint>
 
-namespace mercury::kernel::application {
+//TODO: end application, threading.
+
+namespace hilbert::kernel::application {
 
   enum class app_state {
     running,
@@ -18,9 +20,10 @@ namespace mercury::kernel::application {
 
     uint64_t *p4;
     uint64_t *p3;
-    uint64_t *p2;
+    uint64_t *p2s[512];
+    uint64_t **p1s[512];
 
-    bool *p2es_to_free_on_exit;
+    bool **p1es_to_free_on_exit[512];
 
     uint64_t p4_paddr;
 
@@ -38,20 +41,15 @@ namespace mercury::kernel::application {
     } saved_regs;
 
     app_instance();
-    ~app_instance();
 
-    //2MiB page. vaddr and paddr must be aligned, and vaddr in valid range.
+    //vaddr and paddr must be aligned, and vaddr must be < 0x0080.0000.0000
     void map_page(uint64_t vaddr, uint64_t paddr,
       bool write, bool execute, bool free_pram_on_exit);
 
-    //2MiB pages. returns start of first page.
+    //returns start of first page.
     uint64_t get_free_vaddr_pages(uint64_t count);
 
-    void create_stack();
-
-    void set_instruction_pointer(uint64_t vaddr);
-
-    //2MiB pages; only lower half.
+    //in lower half
     uint64_t count_mapped_vram_pages();
 
   };
diff --git a/include/mercury/kernel/framebuffer.hpp b/include/hilbert/kernel/framebuffer.hpp
index 677a42a..c6725ae 100644
--- a/include/mercury/kernel/framebuffer.hpp
+++ b/include/hilbert/kernel/framebuffer.hpp
@@ -1,16 +1,14 @@
-#ifndef MERCURY_KERNEL_FRAMEBUFFER_HPP
-#define MERCURY_KERNEL_FRAMEBUFFER_HPP
+#ifndef HILBERT_KERNEL_FRAMEBUFFER_HPP
+#define HILBERT_KERNEL_FRAMEBUFFER_HPP
 
 #include <cstdint>
 
-namespace mercury::kernel::framebuffer {
+namespace hilbert::kernel::framebuffer {
 
-  extern uint32_t *vaddr;
   extern int width;
   extern int height;
-  extern int dword_pitch;
 
-  void init_framebuffer(uint64_t vaddr, uint64_t width, uint64_t height, uint64_t pitch);
+  void init_framebuffer(uint64_t paddr, uint64_t vaddr, uint64_t width, uint64_t height, uint64_t pitch);
 
   typedef uint32_t color;
   color encode_color(uint8_t r, uint8_t g, uint8_t b);
diff --git a/include/mercury/kernel/paging.hpp b/include/hilbert/kernel/paging.hpp
index f6d400a..2cf6f5c 100644
--- a/include/mercury/kernel/paging.hpp
+++ b/include/hilbert/kernel/paging.hpp
@@ -1,12 +1,12 @@
-#ifndef MERCURY_KERNEL_PAGING_HPP
-#define MERCURY_KERNEL_PAGING_HPP
+#ifndef HILBERT_KERNEL_PAGING_HPP
+#define HILBERT_KERNEL_PAGING_HPP
 
 #include <cstdint>
 
 //in paging.asm
 extern "C" [[noreturn]] void switch_to_kernel_p4(void (*and_then_jump_to)());
 
-namespace mercury::kernel::paging {
+namespace hilbert::kernel::paging {
 
   void mark_all_pram_used();
   void mark_all_vram_free();
@@ -16,11 +16,12 @@ namespace mercury::kernel::paging {
 
   uint64_t find_unmapped_vram_region(uint64_t page_count);
 
-  uint64_t encode_pte(
-    uint64_t addr, bool user, bool write, bool execute, bool ps);
+  uint64_t encode_pte(uint64_t addr, bool user, bool write, bool execute);
 
   void init_kernel_page_tables(uint64_t kernel_offset);
 
+  uint64_t take_pram_page();
+
   void map_kernel_stacks();
 
   void map_kernel_page(
@@ -39,8 +40,6 @@ namespace mercury::kernel::paging {
 
   extern uint64_t kernel_p4e;
 
-  uint64_t take_2mib_pram_page();
-
 }
 
 #endif
diff --git a/include/mercury/kernel/storage.hpp b/include/hilbert/kernel/storage.hpp
index 61e7d3b..ea40d86 100644
--- a/include/mercury/kernel/storage.hpp
+++ b/include/hilbert/kernel/storage.hpp
@@ -1,10 +1,10 @@
-#ifndef MERCURY_KERNEL_STORAGE_HPP
-#define MERCURY_KERNEL_STORAGE_HPP
+#ifndef HILBERT_KERNEL_STORAGE_HPP
+#define HILBERT_KERNEL_STORAGE_HPP
 
-#include <mercury/kernel/utility.hpp>
+#include <hilbert/kernel/utility.hpp>
 #include <cstdint>
 
-namespace mercury::kernel::storage {
+namespace hilbert::kernel::storage {
 
   typedef uint64_t node_id_t;
   typedef uint64_t directory_iter_t;
diff --git a/include/mercury/kernel/storage/bd/memory.hpp b/include/hilbert/kernel/storage/bd/memory.hpp
index e12d565..7702cb3 100644
--- a/include/mercury/kernel/storage/bd/memory.hpp
+++ b/include/hilbert/kernel/storage/bd/memory.hpp
@@ -1,9 +1,9 @@
-#ifndef MERCURY_KERNEL_STORAGE_BD_MEMORY_HPP
-#define MERCURY_KERNEL_STORAGE_BD_MEMORY_HPP
+#ifndef HILBERT_KERNEL_STORAGE_BD_MEMORY_HPP
+#define HILBERT_KERNEL_STORAGE_BD_MEMORY_HPP
 
-#include <mercury/kernel/storage.hpp>
+#include <hilbert/kernel/storage.hpp>
 
-namespace mercury::kernel::storage::bd {
+namespace hilbert::kernel::storage::bd {
 
   class memory : public block_device {
 
diff --git a/include/mercury/kernel/storage/fs/tarfs.hpp b/include/hilbert/kernel/storage/fs/tarfs.hpp
index 9e16207..80e6030 100644
--- a/include/mercury/kernel/storage/fs/tarfs.hpp
+++ b/include/hilbert/kernel/storage/fs/tarfs.hpp
@@ -1,9 +1,9 @@
-#ifndef MERCURY_KERNEL_STORAGE_FS_TARFS_HPP
-#define MERCURY_KERNEL_STORAGE_FS_TARFS_HPP
+#ifndef HILBERT_KERNEL_STORAGE_FS_TARFS_HPP
+#define HILBERT_KERNEL_STORAGE_FS_TARFS_HPP
 
-#include <mercury/kernel/storage.hpp>
+#include <hilbert/kernel/storage.hpp>
 
-namespace mercury::kernel::storage::fs {
+namespace hilbert::kernel::storage::fs {
 
   class tarfs_instance : public file_system_instance {
 
diff --git a/include/hilbert/kernel/syscall.hpp b/include/hilbert/kernel/syscall.hpp
new file mode 100644
index 0000000..c83e514
--- /dev/null
+++ b/include/hilbert/kernel/syscall.hpp
@@ -0,0 +1,13 @@
+#include <cstdint>
+
+namespace hilbert::kernel::syscall {
+
+  typedef void (*syscall_handler)(
+    uint64_t &rax, uint64_t &rdi, uint64_t &rsi, uint64_t &rdx);
+
+  void init_syscalls();
+
+  //assumes this rax has not been used yet and is < 256.
+  void add_syscall(uint64_t rax, syscall_handler handler);
+
+}
diff --git a/include/mercury/kernel/terminal.hpp b/include/hilbert/kernel/terminal.hpp
index 7b2d27a..78ddbe8 100644
--- a/include/mercury/kernel/terminal.hpp
+++ b/include/hilbert/kernel/terminal.hpp
@@ -1,12 +1,12 @@
-#ifndef MERCURY_KERNEL_TERMINAL_HPP
-#define MERCURY_KERNEL_TERMINAL_HPP
+#ifndef HILBERT_KERNEL_TERMINAL_HPP
+#define HILBERT_KERNEL_TERMINAL_HPP
 
-#include <mercury/kernel/framebuffer.hpp>
-#include <mercury/kernel/utility.hpp>
+#include <hilbert/kernel/framebuffer.hpp>
+#include <hilbert/kernel/utility.hpp>
 #include <cstddef>
 #include <cstdint>
 
-namespace mercury::kernel::terminal {
+namespace hilbert::kernel::terminal {
 
   extern uint8_t *termfont;
   extern uint64_t termfont_len;
diff --git a/include/mercury/kernel/utility.hpp b/include/hilbert/kernel/utility.hpp
index 3edd7d4..930264a 100644
--- a/include/mercury/kernel/utility.hpp
+++ b/include/hilbert/kernel/utility.hpp
@@ -1,10 +1,10 @@
-#ifndef MERCURY_KERNEL_UTILITY_HPP
-#define MERCURY_KERNEL_UTILITY_HPP
+#ifndef HILBERT_KERNEL_UTILITY_HPP
+#define HILBERT_KERNEL_UTILITY_HPP
 
 #include <optional>
 #include <cstdint>
 
-namespace mercury::kernel::utility {
+namespace hilbert::kernel::utility {
 
   template <class t>
   static inline t min(t a, t b) {
diff --git a/include/mercury/kernel/vfile.hpp b/include/hilbert/kernel/vfile.hpp
index ce72bb1..086b6ab 100644
--- a/include/mercury/kernel/vfile.hpp
+++ b/include/hilbert/kernel/vfile.hpp
@@ -1,15 +1,15 @@
-#ifndef MERCURY_KERNEL_VFILE_HPP
-#define MERCURY_KERNEL_VFILE_HPP
+#ifndef HILBERT_KERNEL_VFILE_HPP
+#define HILBERT_KERNEL_VFILE_HPP
 
-#include <mercury/kernel/storage.hpp>
-#include <mercury/kernel/utility.hpp>
+#include <hilbert/kernel/storage.hpp>
+#include <hilbert/kernel/utility.hpp>
 
 //TODO: mounts points.
 //maybe a two-way map between mount points and targets? one mount point per
 //target and vice versa. only directories may be mount points, and only file
 //system roots (which must be directories) may be targets.
 
-namespace mercury::kernel::vfile {
+namespace hilbert::kernel::vfile {
 
   //a canon path contains no . or empty directory names, and
   //contains no .. except for at the start of a relative path.
diff --git a/include/mercury/syscall.hpp b/include/hilbert/syscall.hpp
index f434d91..0e430d1 100644
--- a/include/mercury/syscall.hpp
+++ b/include/hilbert/syscall.hpp
@@ -1,9 +1,9 @@
-#ifndef MERCURY_SYSCALL_HPP
-#define MERCURY_SYSCALL_HPP
+#ifndef HILBERT_SYSCALL_HPP
+#define HILBERT_SYSCALL_HPP
 
 #include <cstdint>
 
-namespace mercury::syscall {
+namespace hilbert::syscall {
 
   typedef uint32_t encoded_color;
 
@@ -19,8 +19,6 @@ namespace mercury::syscall {
     uint32_t &width_out, uint32_t &height_out, uint32_t &pitch_out
   );
 
-  extern "C" void draw_framebuffer();
-
 }
 
 #endif
diff --git a/kernel/allocator.cpp b/kernel/allocator.cpp
index b04078c..807bc94 100644
--- a/kernel/allocator.cpp
+++ b/kernel/allocator.cpp
@@ -1,7 +1,7 @@
-#include <mercury/kernel/paging.hpp>
+#include <hilbert/kernel/paging.hpp>
 #include <cstddef>
 
-namespace mercury::kernel::allocator {
+namespace hilbert::kernel::allocator {
 
   struct free_entry {
     uint64_t start;
@@ -118,7 +118,7 @@ namespace mercury::kernel::allocator {
 
 }
 
-using namespace mercury::kernel::allocator;
+using namespace hilbert::kernel::allocator;
 
 void *_new(size_t len) {
   if (len == 0)
diff --git a/kernel/application.cpp b/kernel/application.cpp
index 19b1dbc..ed8795b 100644
--- a/kernel/application.cpp
+++ b/kernel/application.cpp
@@ -1,83 +1,87 @@
-#include <mercury/kernel/application.hpp>
-#include <mercury/kernel/paging.hpp>
+#include <hilbert/kernel/application.hpp>
+#include <hilbert/kernel/paging.hpp>
 
 //TODO - scheduling.
 
-namespace mercury::kernel::application {
+namespace hilbert::kernel::application {
 
-  app_instance::app_instance() : state(app_state::paused) {
+  app_instance::app_instance()
+    : state(app_state::paused), framebuffer_vaddr(0) {
 
-    framebuffer_vaddr = 0;
+    uint64_t p4_vaddr;
+    paging::map_new_kernel_page(p4_vaddr, p4_paddr);
+    p4 = (uint64_t *)p4_vaddr;
 
     uint64_t p3_paddr;
-    uint64_t p2_paddr;
-
-    uint64_t p4_vaddr;
     uint64_t p3_vaddr;
-    uint64_t p2_vaddr;
-
-    paging::map_new_kernel_page(p4_vaddr, p4_paddr);
     paging::map_new_kernel_page(p3_vaddr, p3_paddr);
-    paging::map_new_kernel_page(p2_vaddr, p2_paddr);
-
-    p4 = (uint64_t *)p4_vaddr;
     p3 = (uint64_t *)p3_vaddr;
-    p2 = (uint64_t *)p2_vaddr;
 
     for (int i = 1; i < 511; ++i)
       p4[i] = 0;
+    p4[0] = paging::encode_pte(p3_paddr, true, true, true);
     p4[511] = paging::kernel_p4e;
-    p4[0] = paging::encode_pte(p3_paddr, true, true, true, false);
 
-    for (int i = 1; i < 512; ++i)
+    for (int i = 0; i < 512; ++i) {
       p3[i] = 0;
-    p3[0] = paging::encode_pte(p2_paddr, true, true, true, false);
-
-    for (int i = 0; i < 512; ++i)
-      p2[i] = 0;
-
-    p2es_to_free_on_exit = new bool[512];
+      p2s[i] = 0;
+      p1s[i] = 0;
+      p1es_to_free_on_exit[i] = 0;
+    }
 
   }
 
-  app_instance::~app_instance() {
+  void app_instance::map_page(uint64_t vaddr, uint64_t paddr,
+    bool write, bool execute, bool free_pram_on_exit
+  ) {
 
-    for (int i = 1; i < 512; ++i)
-      if (p2[i] != 0 && p2es_to_free_on_exit[i]) {
-        uint64_t paddr = p2[i] & ~0x1fffffULL;
-        paging::mark_pram_region_free(paddr, paddr + 0x200000);
+    uint64_t i = ((vaddr / 4096) / 512) / 512;
+    uint64_t j = ((vaddr / 4096) / 512) % 512;
+    uint64_t k = (vaddr / 4096) % 512;
+
+    if (p2s[i] == 0) {
+      uint64_t p2_paddr;
+      uint64_t p2_vaddr;
+      paging::map_new_kernel_page(p2_vaddr, p2_paddr);
+      p3[i] = paging::encode_pte(p2_paddr, true, true, true);
+      p2s[i] = (uint64_t *)p2_vaddr;
+      p1s[i] = new uint64_t *[512];
+      p1es_to_free_on_exit[i] = new bool *[512];
+      for (int u = 0; u < 512; ++u) {
+        p2s[i][u] = 0;
+        p1s[i][u] = 0;
+        p1es_to_free_on_exit[i][u] = 0;
       }
+    }
 
-    delete[] p2es_to_free_on_exit;
-
-    uint64_t p2_paddr = p3[0] & ~0x1fffffULL;
-    paging::unmap_kernel_page((uint64_t)p2);
-    paging::mark_pram_region_free(p2_paddr, p2_paddr + 4096);
-
-    uint64_t p3_paddr = p4[0] & ~0x1fffffULL;
-    paging::unmap_kernel_page((uint64_t)p3);
-    paging::mark_pram_region_free(p3_paddr, p3_paddr + 4096);
-
-    paging::unmap_kernel_page((uint64_t)p4);
-    paging::mark_pram_region_free(p4_paddr, p4_paddr + 4096);
+    if (p2s[i][j] == 0) {
+      uint64_t p1_paddr;
+      uint64_t p1_vaddr;
+      paging::map_new_kernel_page(p1_vaddr, p1_paddr);
+      p2s[i][j] = paging::encode_pte(p1_paddr, true, true, true);
+      p1s[i][j] = (uint64_t *)p1_vaddr;
+      p1es_to_free_on_exit[i][j] = new bool[512];
+      for (int u = 0; u < 512; ++u) {
+        p1s[i][j][u] = 0;
+        p1es_to_free_on_exit[i][j][u] = false;
+      }
+    }
 
-  }
+    p1s[i][j][k] = paging::encode_pte(paddr, true, write, execute);
+    p1es_to_free_on_exit[i][j][k] = free_pram_on_exit;
 
-  void app_instance::map_page(uint64_t vaddr, uint64_t paddr,
-    bool write, bool execute, bool free_pram_on_exit
-  ) {
-    uint64_t i = vaddr / 0x200000;
-    p2[i] = paging::encode_pte(paddr, true, write, execute, true);
-    p2es_to_free_on_exit[i] = free_pram_on_exit;
   }
 
   uint64_t app_instance::get_free_vaddr_pages(uint64_t count) {
-    uint64_t start = 1;
+    uint64_t start = 0x200000 / 4096;
     uint64_t length = 0;
-    while (start + length < 510) {
+    while (start + length <= 0x8000000000 / 4096) {
       if (length == count)
-        return start * 0x200000;
-      if (p2[start + length] == 0)
+        return start * 4096;
+      int i = ((start + length) / 512) / 512;
+      int j = ((start + length) / 512) % 512;
+      int k = (start + length) % 512;
+      if (p1s[i] == 0 || p1s[i][j] == 0 || p1s[i][j][k] == 0)
         ++length;
       else {
         start += length + 1;
@@ -88,28 +92,15 @@ namespace mercury::kernel::application {
     return 0;
   }
 
-  void app_instance::create_stack() {
-    uint64_t stack_paddr = paging::take_2mib_pram_page();
-    map_page(0x3fe00000, stack_paddr, true, false, true);
-    for (int i = 0; i < 512; ++i) {
-      uint64_t vaddr = paging::find_unmapped_vram_region(1);
-      paging::map_kernel_page(stack_paddr + 512 * i, vaddr, true, false);
-      for (int j = 0; j < 4096 / 8; ++j)
-        *(uint64_t *)(vaddr + j * 8) = 0;
-      paging::unmap_kernel_page(vaddr);
-    }
-    saved_regs.rsp = 0x40000000;
-  }
-
-  void app_instance::set_instruction_pointer(uint64_t vaddr) {
-    saved_regs.rip = vaddr;
-  }
-
   uint64_t app_instance::count_mapped_vram_pages() {
     uint64_t count = 0;
-    for (int i = 1; i < 512; ++i)
-      if (p2[i] != 0)
-        ++count;
+    for (int i = 0; i < 512; ++i)
+      if (p1s[i] != 0)
+        for (int j = 0; j < 512; ++j)
+          if (p1s[i][j] != 0)
+            for (int k = 0; k < 512; ++k)
+              if (p1s[i][j][k] != 0)
+                ++count;
     return count;
   }
 
@@ -186,18 +177,19 @@ namespace mercury::kernel::application {
       READ(entry_start + 40, 8, &vsize)
       READ(entry_start + 4, 4, &flags)
 
-      if (vaddr & 0x1fffff)
+      if (vaddr & 4095)
         return create_app_result::app_corrupt;
       if (file.dir_entry.length < foffset + fsize)
         return create_app_result::app_corrupt;
       if (fsize > vsize)
         return create_app_result::app_corrupt;
-      if (vaddr == 0)
+
+      if (vaddr < 0x200000)
         return create_app_result::app_corrupt;
 
-      uint64_t vpages = (vsize - 1) / 0x200000 + 1;
+      uint64_t vpages = (vsize - 1) / 4096 + 1;
 
-      if (vaddr + vpages * 0x200000 > ((1 << 30) - (4 << 20)))
+      if (vaddr + vpages * 4096 > 0x8000000000)
         return create_app_result::app_corrupt;
 
       load_info info = {
@@ -217,47 +209,55 @@ namespace mercury::kernel::application {
     for (unsigned i = 0; i < load_infos.count; ++i) {
       const auto &info = load_infos.buffer[i];
       for (uint64_t j = 0; j < info.vpages; ++j) {
-        uint64_t paddr = paging::take_2mib_pram_page();
-        out->map_page(info.vaddr + j * 0x200000, paddr,
+        uint64_t paddr = paging::take_pram_page();
+        out->map_page(info.vaddr + j * 4096, paddr,
           info.writable, info.executable, true);
-        for (int k = 0; k < 512; ++k) {
-          uint64_t offset_in_segment = j * 0x200000 + k * 4096;
-          uint64_t kvaddr = paging::find_unmapped_vram_region(1);
-          paging::map_kernel_page(paddr + k * 4096, kvaddr, true, false);
-          storage::fs_result result = storage::fs_result::success;
-          if (info.fsize > offset_in_segment) {
-            if (info.fsize >= offset_in_segment + 4096)
-              result = file.read_file(
-                info.foffset + offset_in_segment, 4096, (void *)kvaddr);
-            else {
-              int to_read = info.fsize - offset_in_segment;
-              result = file.read_file(
-                info.foffset + offset_in_segment, to_read, (void *)kvaddr);
-              uint8_t *blank = (uint8_t *)(kvaddr + to_read);
-              for (int i = 0; i < 4096 - to_read; ++i)
-                blank[i] = 0;
-            }
-          }
+        uint64_t kvaddr = paging::find_unmapped_vram_region(1);
+        paging::map_kernel_page(paddr, kvaddr, true, false);
+        storage::fs_result result = storage::fs_result::success;
+        if (info.fsize > j * 4096) {
+          if (info.fsize >= j * 4096 + 4096)
+            result = file.read_file(
+              info.foffset + j * 4096, 4096, (void *)kvaddr);
           else {
-            uint8_t *blank = (uint8_t *)kvaddr;
-            for (int i = 0; i < 4096; ++i)
+            int to_read = info.fsize - j * 4096;
+            result = file.read_file(
+              info.foffset + j * 4096, to_read, (void *)kvaddr);
+            uint8_t *blank = (uint8_t *)(kvaddr + to_read);
+            for (int i = 0; i < 4096 - to_read; ++i)
               blank[i] = 0;
           }
-          paging::unmap_kernel_page(kvaddr);
-          if (result == storage::fs_result::device_error) {
-            delete out;
-            return create_app_result::device_error;
-          }
-          if (result == storage::fs_result::fs_corrupt) {
-            delete out;
-            return create_app_result::fs_corrupt;
-          }
+        }
+        else {
+          uint8_t *blank = (uint8_t *)kvaddr;
+          for (int i = 0; i < 4096; ++i)
+            blank[i] = 0;
+        }
+        paging::unmap_kernel_page(kvaddr);
+        if (result == storage::fs_result::device_error) {
+          delete out;
+          return create_app_result::device_error;
+        }
+        if (result == storage::fs_result::fs_corrupt) {
+          delete out;
+          return create_app_result::fs_corrupt;
         }
       }
     }
 
-    out->create_stack();
-    out->set_instruction_pointer(entry_point);
+    for (uint64_t vaddr = 0x1000; vaddr < 0x1ff000; vaddr += 4096) {
+      uint64_t paddr = paging::take_pram_page();
+      uint64_t kvaddr = paging::find_unmapped_vram_region(1);
+      paging::map_kernel_page(paddr, kvaddr, true, false);
+      uint8_t *p = (uint8_t *)kvaddr;
+      for (int i = 0; i < 4096; ++i)
+        p[i] = 0;
+      paging::unmap_kernel_page(kvaddr);
+      out->map_page(vaddr, paddr, true, false, true);
+    }
+
+    out->saved_regs.rsp = 0x1ff000;
+    out->saved_regs.rip = entry_point;
 
     return create_app_result::success;
 
diff --git a/kernel/entry.cpp b/kernel/entry.cpp
index cce8066..8ba585f 100644
--- a/kernel/entry.cpp
+++ b/kernel/entry.cpp
@@ -1,13 +1,13 @@
-#include <mercury/kernel/storage/bd/memory.hpp>
-#include <mercury/kernel/storage/fs/tarfs.hpp>
-#include <mercury/kernel/application.hpp>
-#include <mercury/kernel/framebuffer.hpp>
-#include <mercury/kernel/terminal.hpp>
-#include <mercury/kernel/limine.hpp>
-#include <mercury/kernel/paging.hpp>
-#include <mercury/kernel/vfile.hpp>
+#include <hilbert/kernel/storage/bd/memory.hpp>
+#include <hilbert/kernel/storage/fs/tarfs.hpp>
+#include <hilbert/kernel/application.hpp>
+#include <hilbert/kernel/framebuffer.hpp>
+#include <hilbert/kernel/terminal.hpp>
+#include <hilbert/kernel/limine.hpp>
+#include <hilbert/kernel/paging.hpp>
+#include <hilbert/kernel/vfile.hpp>
 
-using namespace mercury::kernel;
+using namespace hilbert::kernel;
 
 LIMINE_BASE_REVISION(1)
 
@@ -173,8 +173,8 @@ extern "C" [[noreturn]] void entry() {
   //set up framebuffer and terminal:
   //TODO: assumes framebuffer is 32-bpp rgb
 
-  framebuffer::init_framebuffer(
-    fb_vaddr, framebuffer->width, framebuffer->height, framebuffer->pitch);
+  framebuffer::init_framebuffer(fb_start, fb_vaddr,
+    framebuffer->width, framebuffer->height, framebuffer->pitch);
 
   //switch to kernel p4
 
diff --git a/kernel/framebuffer.cpp b/kernel/framebuffer.cpp
index a115e0b..dbd735f 100644
--- a/kernel/framebuffer.cpp
+++ b/kernel/framebuffer.cpp
@@ -1,20 +1,60 @@
-#include <mercury/kernel/framebuffer.hpp>
+#include <hilbert/kernel/application.hpp>
+#include <hilbert/kernel/framebuffer.hpp>
+#include <hilbert/kernel/syscall.hpp>
 
-namespace mercury::kernel::framebuffer {
+namespace hilbert::kernel::framebuffer {
 
-  uint32_t *vaddr;
+  static uint64_t paddr;
+  static uint32_t *vaddr;
   int width;
   int height;
-  int dword_pitch;
+  static int dword_pitch;
 
-  void init_framebuffer(
-    uint64_t vaddr, uint64_t width, uint64_t height, uint64_t pitch
+  void encode_color_syscall(
+    uint64_t &rax, uint64_t &rdi, uint64_t &rsi, uint64_t &rdx
   ) {
+    rax = (uint64_t)encode_color(
+      rdi & 0xff, (rdi >> 8) & 0xff, (rdi >> 16) & 0xff);
+    rdi = 0;
+    rsi = 0;
+    rdx = 0;
+  }
+
+  void get_framebuffer_syscall(
+    uint64_t &rax, uint64_t &rdi, uint64_t &rsi, uint64_t &rdx
+  ) {
+
+    auto *app = application::running_app;
+    if (app->framebuffer_vaddr == 0) {
+      uint64_t pages_needed = (dword_pitch * height * 4 - 1) / 4096 + 1;
+      uint64_t vaddr = app->get_free_vaddr_pages(pages_needed);
+      for (uint64_t i = 0; i < pages_needed; ++i)
+        app->map_page(vaddr + i * 4096, paddr + i * 4096, true, false, false);
+      app->framebuffer_vaddr = vaddr;
+    }
+
+    rax = app->framebuffer_vaddr;
+    rdi = (uint64_t)(uint32_t)width | ((uint64_t)(uint32_t)height << 32);
+    rsi = (uint32_t)dword_pitch;
+    rdx = 0;
+
+  }
+
+  void init_framebuffer(uint64_t paddr, uint64_t vaddr,
+    uint64_t width, uint64_t height, uint64_t pitch
+  ) {
+
     //TODO: assumes 32-bpp rgb
+
+    framebuffer::paddr = paddr;
     framebuffer::vaddr = (uint32_t *)vaddr;
     framebuffer::width = width;
     framebuffer::height = height;
     dword_pitch = pitch / 4;
+
+    syscall::add_syscall(0, &encode_color_syscall);
+    syscall::add_syscall(1, &get_framebuffer_syscall);
+
   }
 
   color encode_color(uint8_t r, uint8_t g, uint8_t b) {
diff --git a/kernel/interrupts.cpp b/kernel/interrupts.cpp
index 8ac986d..1a95f22 100644
--- a/kernel/interrupts.cpp
+++ b/kernel/interrupts.cpp
@@ -1,6 +1,6 @@
-#include <mercury/kernel/terminal.hpp>
+#include <hilbert/kernel/terminal.hpp>
 
-using namespace mercury::kernel;
+using namespace hilbert::kernel;
 
 struct [[gnu::packed]] exception_info_t {
 
diff --git a/kernel/paging.cpp b/kernel/paging.cpp
index 17b61f4..d8869fc 100644
--- a/kernel/paging.cpp
+++ b/kernel/paging.cpp
@@ -1,5 +1,5 @@
-#include <mercury/kernel/utility.hpp>
-#include <mercury/kernel/paging.hpp>
+#include <hilbert/kernel/utility.hpp>
+#include <hilbert/kernel/paging.hpp>
 
 //see also ../documentation/memory.txt
 
@@ -7,7 +7,7 @@ extern "C" {
   uint64_t __kernel_p4_paddr;
 }
 
-namespace mercury::kernel::paging {
+namespace hilbert::kernel::paging {
 
   static constexpr uint64_t kernel_vram_start = 0xffffffffc0000000;
   static constexpr uint64_t kernel_vram_end = 0xffffffffffe00000;
@@ -38,11 +38,9 @@ namespace mercury::kernel::paging {
 
   uint64_t kernel_p4e;
 
-  uint64_t encode_pte(
-    uint64_t addr, bool user, bool write, bool execute, bool ps
-  ) {
+  uint64_t encode_pte(uint64_t addr, bool user, bool write, bool execute) {
     return (addr & 0x0000ffffffffffff) | (execute ? 0 : (1ULL << 63))
-         | (ps << 7) | (user << 2) | (write << 1) | 1;
+         | (user << 2) | (write << 1) | 1;
   }
 
   void init_kernel_page_tables(uint64_t kernel_offset) {
@@ -50,15 +48,15 @@ namespace mercury::kernel::paging {
     for (int i = 0; i < 511; ++i)
       kernel_p4[i] = 0;
     kernel_p4e = encode_pte(
-      (uint64_t)kernel_p3 - kernel_offset, false, true, true, false);
+      (uint64_t)kernel_p3 - kernel_offset, false, true, true);
     kernel_p4[511] = kernel_p4e;
     for (int i = 0; i < 511; ++i)
       kernel_p3[i] = 0;
     kernel_p3[511] = encode_pte(
-      (uint64_t)kernel_p2 - kernel_offset, false, true, true, false);
+      (uint64_t)kernel_p2 - kernel_offset, false, true, true);
     for (int i = 0; i < 512; ++i)
       kernel_p2[i] = encode_pte(
-        (uint64_t)kernel_p1s + 4096 * i - kernel_offset, false, true, true, false);
+        (uint64_t)kernel_p1s + 4096 * i - kernel_offset, false, true, true);
     for (int i = 0; i < 512 * 512; ++i)
       kernel_p1s[i] = 0;
   }
@@ -66,7 +64,7 @@ namespace mercury::kernel::paging {
   void map_kernel_page(
       uint64_t paddr, uint64_t vaddr, bool write, bool execute) {
     uint64_t i = (vaddr - kernel_vram_start) / 4096;
-    kernel_p1s[i] = encode_pte(paddr, false, write, execute, false);
+    kernel_p1s[i] = encode_pte(paddr, false, write, execute);
   }
 
   void unmap_kernel_page(uint64_t vaddr) {
@@ -77,7 +75,7 @@ namespace mercury::kernel::paging {
     );
   }
 
-  static uint64_t take_pram_page() {
+  uint64_t take_pram_page() {
     for (uint64_t i = 0; i < pram_pages / 64; ++i)
       if (~pram_usage_bitmap[i] != 0)
         for (int j = 0; j < 64; ++j)
@@ -89,21 +87,6 @@ namespace mercury::kernel::paging {
     return 0;
   }
 
-  uint64_t take_2mib_pram_page() {
-    for (uint64_t i = 0; i < pram_pages / 512; ++i) {
-      for (int j = 0; j < 8; ++j)
-        if (pram_usage_bitmap[i * 8 + j] != 0)
-          goto next_i;
-      for (int j = 0; j < 8; ++j)
-        pram_usage_bitmap[i * 8 + j] = ~0ULL;
-      return 0x200000 * i;
-    next_i:
-      ;
-    }
-    //TODO: handle error
-    return 0;
-  }
-
   void map_kernel_stacks() {
     for (uint64_t vaddr = syscall_stack_bottom;
          vaddr < syscall_stack_top; vaddr += 4096)
diff --git a/kernel/storage.cpp b/kernel/storage.cpp
index f500f8e..b6b1a04 100644
--- a/kernel/storage.cpp
+++ b/kernel/storage.cpp
@@ -1,6 +1,6 @@
-#include <mercury/kernel/storage.hpp>
+#include <hilbert/kernel/storage.hpp>
 
-namespace mercury::kernel::storage {
+namespace hilbert::kernel::storage {
 
   bd_result block_device::load_cache_block(uint64_t i) {
 
diff --git a/kernel/storage/bd/memory.cpp b/kernel/storage/bd/memory.cpp
index 2f82099..d6a6719 100644
--- a/kernel/storage/bd/memory.cpp
+++ b/kernel/storage/bd/memory.cpp
@@ -1,6 +1,6 @@
-#include <mercury/kernel/storage/bd/memory.hpp>
+#include <hilbert/kernel/storage/bd/memory.hpp>
 
-namespace mercury::kernel::storage::bd {
+namespace hilbert::kernel::storage::bd {
 
   memory::memory(void *buffer, uint64_t buffer_len)
     : buffer((uint8_t *)buffer)
diff --git a/kernel/storage/fs/tarfs.cpp b/kernel/storage/fs/tarfs.cpp
index 4b752a2..fb1eff8 100644
--- a/kernel/storage/fs/tarfs.cpp
+++ b/kernel/storage/fs/tarfs.cpp
@@ -1,9 +1,9 @@
-#include <mercury/kernel/storage/fs/tarfs.hpp>
+#include <hilbert/kernel/storage/fs/tarfs.hpp>
 
 //in tarfs_instance, node_id_t and directory_iter_t refer to the number
 //of bytes into the block device that the info sector is located.
 
-namespace mercury::kernel::storage::fs {
+namespace hilbert::kernel::storage::fs {
 
 #define BD_TO_FS(expr) \
   { \
diff --git a/kernel/syscall.asm b/kernel/syscall.asm
index e4e0d77..c293402 100644
--- a/kernel/syscall.asm
+++ b/kernel/syscall.asm
@@ -4,51 +4,7 @@ global start_user_mode
 
 section .text
 
-extern syscall_encode_color
-
-encode_color_syscall:
-  call syscall_encode_color
-  mov edi, eax
-  xor rax, rax
-  mov eax, edi
-  xor rdi, rdi
-  xor rsi, rsi
-  xor rdx, rdx
-  jmp syscall_return
-
-extern syscall_get_fb_vaddr
-extern syscall_get_fb_dims
-extern syscall_get_fb_pitch
-
-get_framebuffer_syscall:
-  call syscall_get_fb_vaddr
-  push rax
-  call syscall_get_fb_dims
-  push rax
-  call syscall_get_fb_pitch
-  xor rsi, rsi
-  mov esi, eax
-  pop rdi
-  pop rax
-  xor rdx, rdx
-  jmp syscall_return
-
-extern syscall_copy_framebuffer
-
-draw_framebuffer_syscall:
-  call syscall_copy_framebuffer
-  xor rax, rax
-  xor rdi, rdi
-  xor rsi, rsi
-  xor rdx, rdx
-  jmp syscall_return
-
-bad_syscall:
-  xor rax, rax
-  xor rdi, rdi
-  xor rsi, rsi
-  xor rdx, rdx
-  jmp syscall_return
+extern do_syscall
 
 syscall_entry:
   mov r11, rsp
@@ -56,15 +12,23 @@ syscall_entry:
   push r11
   push rcx
 
-  cmp rax, 0
-  je encode_color_syscall
-  cmp rax, 1
-  je get_framebuffer_syscall
-  cmp rax, 2
-  je draw_framebuffer_syscall
-  jmp bad_syscall
+  push rdx
+  push rsi
+  push rdi
+  push rax
+
+  mov rdi, rsp
+  lea rsi, [rsp + 8]
+  lea rdx, [rsp + 16]
+  lea rcx, [rsp + 24]
+
+  call do_syscall
+
+  pop rax
+  pop rdi
+  pop rsi
+  pop rdx
 
-syscall_return:
   xor r8, r8
   xor r9, r9
   xor r10, r10
diff --git a/kernel/syscall.cpp b/kernel/syscall.cpp
index e91d12d..3aa4105 100644
--- a/kernel/syscall.cpp
+++ b/kernel/syscall.cpp
@@ -1,46 +1,36 @@
-#include <mercury/kernel/application.hpp>
-#include <mercury/kernel/framebuffer.hpp>
-#include <mercury/kernel/paging.hpp>
+#include <hilbert/kernel/application.hpp>
+#include <hilbert/kernel/framebuffer.hpp>
+#include <hilbert/kernel/syscall.hpp>
+#include <hilbert/kernel/paging.hpp>
 
-using namespace mercury::kernel;
+namespace hilbert::kernel::syscall {
 
-extern "C" uint32_t syscall_encode_color(uint32_t c) {
-  return (uint32_t)framebuffer::encode_color(
-    c & 0xff, (c >> 8) & 0xff, (c >> 16) & 0xff
-  );
-}
+  syscall_handler handlers[256];
 
-extern "C" uint64_t syscall_get_fb_vaddr() {
-  auto *app = application::running_app;
-  if (app->framebuffer_vaddr != 0)
-    return app->framebuffer_vaddr;
-  uint64_t fb_len = framebuffer::dword_pitch * framebuffer::height * 4;
-  uint64_t fb_pages = (fb_len - 1) / 0x200000 + 1;
-  uint64_t vaddr = app->get_free_vaddr_pages(fb_pages);
-  for (uint64_t i = 0; i < fb_pages; ++i) {
-    uint64_t paddr = paging::take_2mib_pram_page();
-    app->map_page(vaddr + i * 0x200000, paddr, true, false, true);
+  void init_syscalls() {
+    for (int i = 0; i < 256; ++i)
+      handlers[i] = 0;
   }
-  app->framebuffer_vaddr = vaddr;
-  return vaddr;
-}
 
-extern "C" uint64_t syscall_get_fb_dims() {
-  return (uint64_t)(uint32_t)framebuffer::width +
-    ((uint64_t)(uint32_t)framebuffer::height << 32);
-}
+  void add_syscall(uint64_t rax, syscall_handler handler) {
+    handlers[rax] = handler;
+  }
 
-extern "C" uint32_t syscall_get_fb_pitch() {
-  return (uint32_t)framebuffer::dword_pitch;
 }
 
-extern "C" void syscall_copy_framebuffer() {
-  auto *app = application::running_app;
-  if (app->framebuffer_vaddr != 0) {
-    const uint32_t *source = (const uint32_t *)app->framebuffer_vaddr;
-    for (int y = 0; y < framebuffer::height; ++y)
-      for (int x = 0; x < framebuffer::width; ++x)
-        framebuffer::vaddr[y * framebuffer::dword_pitch + x]
-          = source[y * framebuffer::dword_pitch + x];
+using namespace hilbert::kernel::syscall;
+
+extern "C" void do_syscall(
+  uint64_t &rax, uint64_t &rdi, uint64_t &rsi, uint64_t &rdx
+) {
+
+  if (rax < 256 && handlers[rax] != 0)
+    handlers[rax](rax, rdi, rsi, rdx);
+  else {
+    rax = 0;
+    rdi = 0;
+    rsi = 0;
+    rdx = 0;
   }
+
 }
diff --git a/kernel/terminal.cpp b/kernel/terminal.cpp
index 1074fe7..167e6cf 100644
--- a/kernel/terminal.cpp
+++ b/kernel/terminal.cpp
@@ -1,7 +1,7 @@
-#include <mercury/kernel/framebuffer.hpp>
-#include <mercury/kernel/terminal.hpp>
+#include <hilbert/kernel/framebuffer.hpp>
+#include <hilbert/kernel/terminal.hpp>
 
-namespace mercury::kernel::terminal {
+namespace hilbert::kernel::terminal {
 
   uint8_t *termfont;
   uint64_t termfont_len;
diff --git a/kernel/utility.cpp b/kernel/utility.cpp
index 865b817..249fb2c 100644
--- a/kernel/utility.cpp
+++ b/kernel/utility.cpp
@@ -1,6 +1,6 @@
-#include <mercury/kernel/utility.hpp>
+#include <hilbert/kernel/utility.hpp>
 
-namespace mercury::kernel::utility {
+namespace hilbert::kernel::utility {
 
   void mark_bitmap_region_zero(
       uint64_t *bitmap, uint64_t start_i, uint64_t end_i) {
diff --git a/kernel/vfile.cpp b/kernel/vfile.cpp
index 3b9dcb2..74cfbf9 100644
--- a/kernel/vfile.cpp
+++ b/kernel/vfile.cpp
@@ -1,9 +1,9 @@
-#include <mercury/kernel/vfile.hpp>
+#include <hilbert/kernel/vfile.hpp>
 
 //TODO: handle symlink loops nicely in vfile::get_child,
 //      vfile::get_children, and lookup_path.
 
-namespace mercury::kernel::vfile {
+namespace hilbert::kernel::vfile {
 
   void canon_path::parent() {
     if (segments.count != 0)
diff --git a/limine.cfg b/limine.cfg
index 505c8f4..4a411a1 100644
--- a/limine.cfg
+++ b/limine.cfg
@@ -1,5 +1,5 @@
 TIMEOUT=0
 
-:Mercury
+:Hilbert
 PROTOCOL=limine
 KERNEL_PATH=boot:///kernel.elf
diff --git a/makefile b/makefile
index 2d103b3..4c285f0 100644
--- a/makefile
+++ b/makefile
@@ -18,14 +18,14 @@ clean:
 
 dist-clean:
 	rm -rf limine
-	rm -f include/mercury/kernel/limine.hpp
+	rm -f include/hilbert/kernel/limine.hpp
 
 limine:
 	git clone --depth=1 -b v6.x-branch \
 	  https://github.com/limine-bootloader/limine.git limine
 	cd limine && ./bootstrap && ./configure -q --enable-bios --enable-bios-cd
 	+make -C limine
-	cp limine/limine.h include/mercury/kernel/limine.hpp
+	cp limine/limine.h include/hilbert/kernel/limine.hpp
 
 obj/kernel/entry.cpp.o: kernel/entry.cpp limine
 	@mkdir -p $(@D)
diff --git a/readme.txt b/readme.txt
index 7f4a2e2..ed4340e 100644
--- a/readme.txt
+++ b/readme.txt
@@ -1,4 +1,4 @@
-mercury is a 64-bit hobby operating system. to build and test it, you will need
+hilbert is a 64-bit hobby operating system. to build and test it, you will need
 some dependencies. these can be installed on debian with:
   apt install g++ gcc gdb git make nasm qemu-system-x86 xorriso
 then, just run "make -jx", replacing x with the number of threads to use while
diff --git a/stdlib/syscall.asm b/stdlib/syscall.asm
index eba7ec0..922ca1b 100644
--- a/stdlib/syscall.asm
+++ b/stdlib/syscall.asm
@@ -28,8 +28,3 @@ get_framebuffer:
   pop rcx
   mov dword [rcx], esi
   ret
-
-draw_framebuffer:
-  mov rax, 2
-  syscall
-  ret