SYSCALL naked assembly working

[cortex-from-scratch] / syscall.c

diff --git a/syscall.c b/syscall.c
new file mode 100644 (file)
index 0000000..f6e1cba
--- /dev/null
+++ b/syscall.c
@@ -0,0 +1,130 @@
+/* (CC-BY-NC-SA) ROBIN KRENS - ROBIN @ ROBINKRENS.NL
+ * 
+ * $LOG$
+ * 2019/9/20 - ROBIN KRENS      
+ * Initial version 
+ * 
+ * $DESCRIPTION$
+ * 
+ * |----------------------------|
+ * | SYSTEM CALL       | #     |
+ * |--------------------|-------|
+ * | THEOS_getenv      |       |
+ * | THEOS_killenv     |       |
+ * | THEOS_setenv      |       |
+ * | THEOS_newenv      |       |
+ * | THEOS_cputs       |       |
+ * | THEOS_omnigod     |       |
+ * | THEOS_brk         |       |
+ * | THEOS_time                |       |
+ * | THEOS_magic       |       |
+ * |----------------------------|
+ *
+ * TODO: include in header enum
+ * */
+
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include <sys/robsys.h>
+#include <sys/mmap.h>
+
+#include <lib/stdio.h>
+#include <lib/string.h>
+#include <lib/regfunc.h>
+#include <lib/tinyprintf.h>
+
+
+/* the function gets called for 
+ * */
+__attribute__ ((naked))
+void * __svc_handler__(int x) {
+
+       uint8_t svc_nr;
+
+       asm volatile (
+       "tst lr, #4" "\n\t"
+       "ite eq" "\n\t"
+       "mrseq r0, msp" "\n\t"
+       "mrsne r0, psp" "\n\t"
+       "ldr r0, [r0, #24]" "\n\t"
+       "ldrb %0, [r0, #-2]" : "=r" (svc_nr) );
+
+       printf("SYSTEM CALL NR: %d", svc_nr);
+
+       for(;;);
+
+       volatile uint32_t * sp;
+       
+       asm volatile (
+       "tst lr, #4" "\n\t" 
+       "ite eq" "\n\t"
+       "mrseq %0, msp" "\n\t" 
+       "mrsne r0, psp" : "=r" (sp) );
+
+
+       for (int i = 0; (sp + i) < 0x20010000; i++) {
+               printf("ADDRESS: %p, VALUE: %x\n", (sp + i), *(sp + i));
+       }
+
+       for (;;);       
+       //asm ("mov %0, pc" : "=r" (link_register));
+       //printf("%x\n", link_register);
+       
+       volatile uint32_t * svc_number = (uint32_t *) 0x20022222;
+       *svc_number = sp[-6];
+       //              = sp[6];
+       //uint8_t tmp  = link_register[-2];
+       printf("SVC nr: %x", *svc_number);
+       //printf("%d, %d, %d, %d, %d, %d\n", msp[6], msp[0], msp[1], msp[2], msp[3], msp[4]);
+       
+       for (;;);
+       //return NULL;  
+       return 0;
+
+}
+
+void syscall(unsigned int * args) {
+
+       uint32_t svc_number = 99;
+       printf("SYSCALL NR: %x", svc_number);
+
+       for(;;);
+       /* switch(SYSCALL_NO) {
+               case THEOS_cputs:
+                       kernel_cputs(a1, a2);
+                       break;
+               default:
+                       for (;;);
+       } */
+
+}
+
+void syscall_init() {
+
+
+       /* SVC is located at position 11 in the interrupt vector table  */
+//     extern void * _syscall;
+       extern void * hardfault;
+
+       ivt_set_gate(11, __svc_handler__, 0);
+
+
+}
+
+static void kernel_cputs(char * s, size_t l) {
+
+       // TODO
+}
+
+
+void kernel_omnigod() {
+
+       /* */
+
+}
+
+
+