Primitive ability to call kernel code from userspace.

1 files changed, 18 insertions, 122 deletions

diff --git a/src/kern/main.c b/src/kern/main.c
index 4ed67be..3af8beb 100644
--- a/src/kern/main.c
+++ b/src/kern/main.c
@@ -8,6 +8,7 @@
 #include "kern/mpu/mpu_manager.h"
 #include "kern/panic.h"
 #include "kern/priv.h"
+#include "user/syscall.h"
 
 void on_hard_fault()
 {
@@ -19,139 +20,34 @@ void on_systick() /* Overrides weak-symbol on_systick. */
   klogf("Systick\n");
 }
 
-#ifdef ARCH_STM32L4
+void configure_mpu()
+{
+  configure_flash_region((void*)0x08000000, REGION_SIZE_256Kb, NOT_PRIVILEGED);
+  configure_ram_region((void*)SRAM1_BASE, REGION_SIZE_64Kb, NOT_PRIVILEGED);
+  configure_ram_region((void*)SRAM2_BASE, REGION_SIZE_16Kb, NOT_PRIVILEGED);
+  configure_peripheral_region((void*)0x40000000, REGION_SIZE_512Mb, PRIVILEGED);
+  mpu_set_enabled(1);
+}
 
-int thing_in_sram_1;
+#ifdef ARCH_STM32L4
 
 /* Main function. This gets executed from the interrupt vector defined above. */
 int main()
 {
-  klogf("Hello, World! Clock Mhz: %d\n", (uint32_t)get_clock_mhz());
-  klogf("Heap Start: %p\n", &HEAP_START);
-  klogf("Heap End  : %p\n", &HEAP_STOP);
-
-  klogf("mpu: %p\n", &MPU);
-  klogf("mpu.type_r: %p\n", MPU.type_r);
-  klogf("mpu.ctrl_r: %p\n", MPU.ctrl_r);
-  klogf("mpu.rn_r: %p\n", MPU.rn_r);
-
-  thing_in_sram_1 = 0xdeadbeef;
-
-  uint32_t control;
-  asm volatile("mrs %0, control" : "=r"(control) :);
-
-  /* Set the countdown to start from 10,000,0000. */
-  SCB.strv_r = 10000000 / 20;
-
-  /* Enable interrupts. */
-  // regset(SCB.stcs_r, scb_tickint, 1);
-
-  /* Start the systick. */
-  regset(SCB.stcs_r, scb_enable, 1);
-
-
-  klogf("&thing_in_sram_1: %p\n", &thing_in_sram_1);
-  klogf(" thing_in_sram_1: %p\n", thing_in_sram_1);
-  mpu_set_enabled(0);
-
-  memory_region_opts_t memopts = { 0 };
-  memopts.region = (void*) 0x08000000 /* Flash base */ ;
-  memopts.bufferable = 0;
-  memopts.cacheable = 1;
-  memopts.sharable = 0;
-  memopts.tex = 0;
-  memopts.size = REGION_SIZE_256Kb;
-  memopts.perms = ACCESS_PERMS_ONLY_PRIV_RO;
-  memopts.subregion_disable = 0;
-  memopts.executable = 1;
-  memopts.enable = 1;
+  configure_mpu();
 
-  mpu_configure_region(0, &memopts);
+  klogf("Outside of usermode, I can still log stuff using klogf()\n");
 
-  memopts.region = (void*) SRAM1_BASE;
-  memopts.bufferable = 0;
-  memopts.cacheable = 1;
-  memopts.sharable = 0;
-  memopts.tex = 0;
-  memopts.size = REGION_SIZE_64Kb;
-  memopts.perms = ACCESS_PERMS_FULL;
-  memopts.subregion_disable = 0;
-  memopts.executable = 1;
-  memopts.enable = 1;
-
-  mpu_configure_region(1, &memopts);
-
-  memopts.region = (void*) SRAM2_BASE;
-  memopts.bufferable = 0;
-  memopts.cacheable = 1;
-  memopts.sharable = 0;
-  memopts.tex = 0;
-  memopts.size = REGION_SIZE_16Kb;
-  memopts.perms = ACCESS_PERMS_FULL;
-  memopts.subregion_disable = 0;
-  memopts.executable = 1;
-  memopts.enable = 1;
-
-  mpu_configure_region(2, &memopts);
-
-  memopts.region = (void*) 0x40000000 /* Peripheral base. */;
-  memopts.bufferable = 1;
-  memopts.cacheable = 0;
-  memopts.sharable = 1;
-  memopts.tex = 0;
-  memopts.size = REGION_SIZE_512Mb;
-  memopts.perms = ACCESS_PERMS_ONLY_PRIV;
-  memopts.subregion_disable = 0;
-  memopts.executable = 0;
-  memopts.enable = 1;
-
-  mpu_configure_region(3, &memopts);
-
-  for (uint32_t i = 0; i < 8; ++ i) {
-    MPU.rn_r = i;
-    klogf("--- %d ---\n", i);
-    klogf("mpu: %p\n", &MPU);
-    klogf("mpu.type_r: %p\n", MPU.type_r);
-    klogf("mpu.ctrl_r: %p\n", MPU.ctrl_r);
-    klogf("mpu.rn_r: %p\n", MPU.rn_r);
-    klogf("mpu.ras_r: %p\n", MPU.ras_r);
-    klogf("mpu.rba_r: %p\n", MPU.rba_r);
-  }
-
-  // memopts.region = (void*) (SRAM1_BASE);
-  // memopts.bufferable = 0;
-  // memopts.cacheable = 1;
-  // memopts.sharable = 1;
-  // memopts.tex = 0;
-  // memopts.size = REGION_SIZE_16Kb;
-  // memopts.perms = ACCESS_PERMS_NO_ACCESS;
-
-  klogf("CONTROL: %p\n", get_control_register());
-  klogf("CONTROL: %p\n", get_control_register());
-  klogf("MPU not enabled\n");
-
-  volatile int x;
-  klogf("x location: %p\n", &x);
-
-  // mpu_set_enabled(1);
-
-  x = 5;
-  klogf("Still alive?\n");
-
-  klogf("Entering User Mode\n");
   enter_user_mode();
 
-  asm volatile (
-      "svc #21\n"
-      );
-
-  klogf("Should Kernel Panic\n");
+  logs("Now that I'm in user mode, I have to log stuff using a system call\n");
+  logs(
+      "because I no longer have direct accss to USART2 and cannot use\n"
+      "klogf()\n");
 
-  for(;;);
-  // klogf("MPU enabled\n");
 
-  // klogf("&thing_in_sram_1: %p\n", &thing_in_sram_1);
-  // klogf(" thing_in_sram_1: %p\n", thing_in_sram_1);
+  for (;;)
+    ;
 }
 
 #endif