minix/drivers/memory/memory.c
2005-04-22 13:25:17 +00:00

300 lines
9 KiB
C

/* This file contains the device dependent part of the drivers for the
* following special files:
* /dev/ram - RAM disk
* /dev/mem - absolute memory
* /dev/kmem - kernel virtual memory
* /dev/null - null device (data sink)
* /dev/boot - boot FS loaded from boot image
*
* Changes:
* Apr 09, 2005 added support for boot FS (Jorrit N. Herder)
* Sep 03, 2004 secured code with ENABLE_USERPRIV (Jorrit N. Herder)
* Jul 26, 2004 moved RAM driver to user-space (Jorrit N. Herder)
* Apr 20, 1992 device dependent/independent split (Kees J. Bot)
*/
#include "../drivers.h"
#include "../libdriver/driver.h"
#include <sys/ioc_memory.h>
#if (CHIP == INTEL) && ENABLE_USERBIOS
#include <ibm/int86.h>
#endif
#define NR_DEVS 6 /* number of RAM-type devices */
PRIVATE struct device m_geom[NR_DEVS]; /* base and size of each RAM disk */
PRIVATE int m_device; /* current device */
PRIVATE struct kenviron kenv; /* need protected_mode */
PRIVATE struct psinfo psinfo = { NR_TASKS, NR_PROCS, 0, 0, 0 };
#define RANDOM_BUFFER_SIZE (1024*32)
PRIVATE char random_state[RANDOM_BUFFER_SIZE];
FORWARD _PROTOTYPE( struct device *m_prepare, (int device) );
FORWARD _PROTOTYPE( int m_transfer, (int proc_nr, int opcode, off_t position,
iovec_t *iov, unsigned nr_req) );
FORWARD _PROTOTYPE( int m_do_open, (struct driver *dp, message *m_ptr) );
FORWARD _PROTOTYPE( void m_init, (void) );
FORWARD _PROTOTYPE( int m_ioctl, (struct driver *dp, message *m_ptr) );
FORWARD _PROTOTYPE( void m_geometry, (struct partition *entry) );
FORWARD _PROTOTYPE( char *m_name, (void) );
/* Entry points to this driver. */
PRIVATE struct driver m_dtab = {
m_name, /* current device's name */
m_do_open, /* open or mount */
do_nop, /* nothing on a close */
m_ioctl, /* specify ram disk geometry */
m_prepare, /* prepare for I/O on a given minor device */
m_transfer, /* do the I/O */
nop_cleanup, /* no need to clean up */
m_geometry, /* memory device "geometry" */
nop_stop, /* no need to clean up on shutdown */
nop_alarm, /* ignore leftover alarms */
};
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC void main(void)
{
m_init();
driver_task(&m_dtab);
}
/*===========================================================================*
* m_name *
*===========================================================================*/
PRIVATE char *m_name()
{
/* Return a name for the current device. */
static char name[] = "memory";
return name;
}
/*===========================================================================*
* m_prepare *
*===========================================================================*/
PRIVATE struct device *m_prepare(device)
int device;
{
/* Prepare for I/O on a device: check if the minor device number is ok. */
if (device < 0 || device >= NR_DEVS) return(NIL_DEV);
m_device = device;
return(&m_geom[device]);
}
/*===========================================================================*
* m_transfer *
*===========================================================================*/
PRIVATE int m_transfer(proc_nr, opcode, position, iov, nr_req)
int proc_nr; /* process doing the request */
int opcode; /* DEV_GATHER or DEV_SCATTER */
off_t position; /* offset on device to read or write */
iovec_t *iov; /* pointer to read or write request vector */
unsigned nr_req; /* length of request vector */
{
/* Read or write /dev/null, /dev/mem, /dev/kmem, /dev/ram, /dev/boot,
* /dev/random, or /dev/urandom
*/
int device;
phys_bytes mem_phys, user_phys;
unsigned count;
vir_bytes user_vir;
struct device *dv;
unsigned long dv_size;
/* Get minor device number and check for /dev/null. */
device = m_device;
dv = &m_geom[device];
dv_size = cv64ul(dv->dv_size);
while (nr_req > 0) {
count = iov->iov_size;
user_vir = iov->iov_addr;
switch (device) {
case NULL_DEV:
if (opcode == DEV_GATHER) return(OK); /* always at EOF */
break;
case RANDOM_DEV:
return OK;
break;
default:
/* /dev/mem, /dev/kmem, /dev/ram, /dev/boot: check for EOF */
if (position >= dv_size) return(OK);
if (position + count > dv_size) count = dv_size - position;
mem_phys = cv64ul(dv->dv_base) + position;
/* Copy the data. */
if (opcode == DEV_GATHER) {
sys_copy(ABS, D, mem_phys, proc_nr, D, user_vir, count);
} else {
sys_copy(proc_nr, D, user_vir, ABS, D, mem_phys, count);
}
}
/* Book the number of bytes transferred. */
position += count;
iov->iov_addr += count;
if ((iov->iov_size -= count) == 0) { iov++; nr_req--; }
}
return(OK);
}
/*============================================================================*
* m_do_open *
*============================================================================*/
PRIVATE int m_do_open(dp, m_ptr)
struct driver *dp;
message *m_ptr;
{
/* Check device number on open. Give I/O privileges to a process opening
* /dev/mem or /dev/kmem. This is needed for systems with memory mapped I/O.
*/
if (m_prepare(m_ptr->DEVICE) == NIL_DEV) return(ENXIO);
#if (CHIP == INTEL) && ENABLE_USERPRIV && ENABLE_USERIOPL
if (m_device == MEM_DEV || m_device == KMEM_DEV) {
sys_enable_iop(m_ptr->PROC_NR);
printf("MEMORY: sys_enable_iop for proc nr %d.\n", m_ptr->PROC_NR);
}
#endif
return(OK);
}
/*===========================================================================*
* m_init *
*===========================================================================*/
PRIVATE void m_init()
{
/* Initialize this task. */
extern int end;
int s;
/* Print welcome message. */
printf("MEMORY: user-level memory (RAM) driver is alive");
/* Get kernel environment (protected_mode and addresses). */
if (OK != (s=sys_getkenviron(&kenv))) {
server_panic("MEM","Couldn't get kernel environment.",s);
}
m_geom[KMEM_DEV].dv_base = cvul64(kenv.kmem_base);
m_geom[KMEM_DEV].dv_size = cvul64(kenv.kmem_size);
m_geom[BOOT_DEV].dv_base = cvul64(kenv.bootfs_base);
m_geom[BOOT_DEV].dv_size = cvul64(kenv.bootfs_size);
/* dv_base isn't used for the random device */
m_geom[RANDOM_DEV].dv_base = cvul64(NULL);
m_geom[RANDOM_DEV].dv_size = cvul64(RANDOM_BUFFER_SIZE);
psinfo.proc = kenv.proc_addr;
#if (CHIP == INTEL)
if (!kenv.protected) {
m_geom[MEM_DEV].dv_size = cvul64(0x100000); /* 1M for 8086 systems */
} else {
#if _WORD_SIZE == 2
m_geom[MEM_DEV].dv_size = cvul64(0x1000000); /* 16M for 286 systems */
#else
m_geom[MEM_DEV].dv_size = cvul64(0xFFFFFFFF); /* 4G-1 for 386 systems */
#endif
}
#else /* !(CHIP == INTEL) */
#if (CHIP == M68000)
m_geom[MEM_DEV].dv_size = cvul64(MEM_BYTES);
#else /* !(CHIP == M68000) */
#error /* memory limit not set up */
#endif /* !(CHIP == M68000) */
#endif /* !(CHIP == INTEL) */
}
/*===========================================================================*
* m_ioctl *
*===========================================================================*/
PRIVATE int m_ioctl(dp, m_ptr)
struct driver *dp;
message *m_ptr; /* pointer to read or write message */
{
/* Set parameters for the RAM disk. */
struct device *dv;
if ((dv = m_prepare(m_ptr->DEVICE)) == NIL_DEV) return(ENXIO);
switch (m_ptr->REQUEST) {
case MIOCRAMSIZE: {
/* FS wants to create a new RAM disk with the given size. */
unsigned long bytesize;
phys_bytes base;
int s;
if (m_ptr->PROC_NR != FS_PROC_NR) return(EPERM);
/* Try to allocate a piece of kernel memory for the RAM disk. */
bytesize = m_ptr->POSITION;
if (OK != (s = sys_kmalloc(bytesize, &base)))
server_panic("MEM","Couldn't allocate kernel memory", s);
dv->dv_base = cvul64(base);
dv->dv_size = cvul64(bytesize);
break;
}
/* Perhaps it is cleaner to move all code relating to psinfo to the info
* server??? (Note that psinfo is global; psinfo.proc is set in m_init.)
* This requires changes to ioctl as well.
*/
case MIOCSPSINFO: {
/* MM or FS set the address of their process table. */
phys_bytes psinfo_phys;
if (m_ptr->PROC_NR == MM_PROC_NR) {
psinfo.mproc = (vir_bytes) m_ptr->ADDRESS;
} else
if (m_ptr->PROC_NR == FS_PROC_NR) {
psinfo.fproc = (vir_bytes) m_ptr->ADDRESS;
} else {
return(EPERM);
}
break;
}
case MIOCGPSINFO: {
/* The ps program wants the process table addresses. */
if (sys_datacopy(SELF, (vir_bytes) &psinfo,
m_ptr->PROC_NR, (vir_bytes) m_ptr->ADDRESS,
sizeof(psinfo)) != OK) return(EFAULT);
break;
}
default:
return(do_diocntl(&m_dtab, m_ptr));
}
return(OK);
}
/*============================================================================*
* m_geometry *
*============================================================================*/
PRIVATE void m_geometry(entry)
struct partition *entry;
{
/* Memory devices don't have a geometry, but the outside world insists. */
entry->cylinders = div64u(m_geom[m_device].dv_size, SECTOR_SIZE) / (64 * 32);
entry->heads = 64;
entry->sectors = 32;
}