diff options
Diffstat (limited to 'task/umode_vma.c')
-rw-r--r-- | task/umode_vma.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/task/umode_vma.c b/task/umode_vma.c new file mode 100644 index 0000000..880e047 --- /dev/null +++ b/task/umode_vma.c @@ -0,0 +1,37 @@ +#include "umode_vma.h" +#include "arch/processor.h" +#include "api/errno.h" +#include "print.h" + +__attribute__((naked)) +int +_umode_vma_fail(void) +{ + __asm__ volatile(" \ + movq %%rbp, %%rsp; \ + popq %%rbp; \ + mov $1, %%eax; \ + retq":::); +} + +int +user_vma_read(void *dest, const void *src, size_t w) +{ + if((uintptr_t)src > USERLAND_MEMORY_LIMIT) return -EACCESS; + + _exrtab_push((void*)_umode_vma_fail); + for(size_t i = 0; i < w; i++) ((char*)dest)[i] = ((const char*)src)[i]; + _exrtab_pop(); + return 0; +} + +int +user_vma_write(void *dest, const void *src, size_t w) +{ + if((uintptr_t)dest > USERLAND_MEMORY_LIMIT) return -EACCESS; + + _exrtab_push((void*)_umode_vma_fail); + for(size_t i = 0; i < w; i++) ((char*)dest)[i] = ((const char*)src)[i]; + _exrtab_pop(); + return 0; +} |