1 /* The kernel call implemented in this file:
2 * m_type: SYS_READBIOS
3 *
4 * The parameters for this kernel call are:
5 * m_lsys_krn_readbios.size number of bytes to copy
6 * m_lsys_krn_readbios.addr absolute address in BIOS area
7 * m_lsys_krn_readbios.buf buffer address in requesting process
8 */
9
10 #include "kernel/system.h"
11
12 /*===========================================================================*
13 * do_readbios *
14 *===========================================================================*/
do_readbios(struct proc * caller,message * m_ptr)15 int do_readbios(struct proc * caller, message * m_ptr)
16 {
17 struct vir_addr src, dst;
18 size_t len = m_ptr->m_lsys_krn_readbios.size;
19 vir_bytes limit;
20
21 src.offset = m_ptr->m_lsys_krn_readbios.addr;
22 dst.offset = m_ptr->m_lsys_krn_readbios.buf;
23 src.proc_nr_e = NONE;
24 dst.proc_nr_e = m_ptr->m_source;
25
26 limit = src.offset + len - 1;
27
28 #define VINRANGE(v, a, b) ((a) <= (v) && (v) <= (b))
29 #define SUBRANGE(a,b,c,d) (VINRANGE((a), (c), (d)) && VINRANGE((b),(c),(d)))
30 #define USERRANGE(a, b) SUBRANGE(src.offset, limit, (a), (b))
31
32 if(!USERRANGE(BIOS_MEM_BEGIN, BIOS_MEM_END) &&
33 !USERRANGE(BASE_MEM_TOP, UPPER_MEM_END))
34 return EPERM;
35
36 return virtual_copy_vmcheck(caller, &src, &dst, m_ptr->m_lsys_krn_readbios.size);
37 }
38