diff options
Diffstat (limited to 'src/arm/PL0')
-rw-r--r-- | src/arm/PL0/PL0_test.c | 34 | ||||
-rw-r--r-- | src/arm/PL0/PL0_test.ld | 19 | ||||
-rw-r--r-- | src/arm/PL0/PL0_utils.c | 19 | ||||
-rw-r--r-- | src/arm/PL0/PL0_utils.h | 6 | ||||
-rw-r--r-- | src/arm/PL0/svc.S | 5 |
5 files changed, 83 insertions, 0 deletions
diff --git a/src/arm/PL0/PL0_test.c b/src/arm/PL0/PL0_test.c new file mode 100644 index 0000000..0bfebc7 --- /dev/null +++ b/src/arm/PL0/PL0_test.c @@ -0,0 +1,34 @@ +#include "PL0_utils.h" + +// entry point - must remain the only function in the file! +void PL0_main(void) +{ + // If loading program to userspace and handling of svc are + // implemented correctly, this shall get printed + puts("Hello userspace! Type 'f' if you want me to try accessing " + "kernel memory!"); + + while (1) + { + char c = getchar(); + + if (c == '\r') + putchar('\n'); + + putchar(c); + + if (c == 'f') + { + // if we're indeed in PL0, we should trigger the abort + // handler now, when trying to access memory we're not + // allowed to + puts("Attempting to read kernel memory from userspace :d"); + char first_kernel_byte[2]; + + first_kernel_byte[0] = *(char*) 0x0; + first_kernel_byte[1] = '\0'; + + puts(first_kernel_byte); + } + } +} diff --git a/src/arm/PL0/PL0_test.ld b/src/arm/PL0/PL0_test.ld new file mode 100644 index 0000000..b1d06f4 --- /dev/null +++ b/src/arm/PL0/PL0_test.ld @@ -0,0 +1,19 @@ +/* linker script for creating the example userspace program PL0_test + */ + +/* no ENTRY() statement - this executable is run by jumping to it */ + +SECTIONS +{ + /* my thought up address userspace programs should run from */ + . = 0xaaa00000; + + __start = .; + .another_weird_section_name_that_doesnt_matter : + { + /* have entry point at the beginning */ + KEEP(PL0_test.o) + *(*) + } + __end = .; +} diff --git a/src/arm/PL0/PL0_utils.c b/src/arm/PL0/PL0_utils.c new file mode 100644 index 0000000..d83edb9 --- /dev/null +++ b/src/arm/PL0/PL0_utils.c @@ -0,0 +1,19 @@ +#include <stddef.h> +#include <stdint.h> + +#include "svc_interface.h" +#include "PL0_utils.h" + +// most generic definition possible +// the actual function defined in svc.S +uint32_t svc(enum svc_type, ...); + +void putchar(char character) +{ + svc(UART_PUTCHAR, character); +} + +char getchar(void) +{ + return svc(UART_GETCHAR); +} diff --git a/src/arm/PL0/PL0_utils.h b/src/arm/PL0/PL0_utils.h new file mode 100644 index 0000000..c26a100 --- /dev/null +++ b/src/arm/PL0/PL0_utils.h @@ -0,0 +1,6 @@ +#ifndef PL0_UTILS_H +#define PL0_UTILS_H + +#include "io.h" + +#endif // PL0_UTILS_H diff --git a/src/arm/PL0/svc.S b/src/arm/PL0/svc.S new file mode 100644 index 0000000..65200d8 --- /dev/null +++ b/src/arm/PL0/svc.S @@ -0,0 +1,5 @@ +.global svc + +svc: + svc #0 + mov pc, lr |