minix/drivers/memory/memory.c

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/* 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)
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* /dev/boot - boot device loaded from boot image
* /dev/random - random number generator
* /dev/zero - null byte stream generator
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*
* Changes:
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* Apr 29, 2005 added null byte generator (Jorrit N. Herder)
* Apr 27, 2005 added random device handling (Jorrit N. Herder)
* Apr 09, 2005 added support for boot device (Jorrit N. Herder)
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* 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>
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#define NR_DEVS 7 /* number of minor devices */
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PRIVATE struct device m_geom[NR_DEVS]; /* base and size of each device */
PRIVATE int m_seg[NR_DEVS]; /* segment index of each device */
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PRIVATE int m_device; /* current device */
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PRIVATE struct kinfo kinfo; /* need kernel info */
PRIVATE struct machine machine; /* need machine info */
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PRIVATE struct psinfo psinfo = { NR_TASKS, NR_PROCS, 0, 0, 0 };
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 */
};
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/* Buffer for the /dev/zero null byte feed. */
#define ZERO_BUF_SIZE 1024
PRIVATE char zero[ZERO_BUF_SIZE];
/* Buffer for the /dev/random number generator. */
#define RANDOM_BUF_SIZE 1024
PRIVATE char random[RANDOM_BUF_SIZE];
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/*===========================================================================*
* 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 */
{
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/* Read or write /dev/null, /dev/mem, /dev/kmem, /dev/ram, or /dev/boot. */
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int device;
phys_bytes mem_phys, user_phys;
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int seg;
unsigned count, left, chunk;
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vir_bytes user_vir;
struct device *dv;
unsigned long dv_size;
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int s;
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/* 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) {
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/* How much to transfer and where to / from. */
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count = iov->iov_size;
user_vir = iov->iov_addr;
switch (device) {
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/* No copying; ignore request. */
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case NULL_DEV:
if (opcode == DEV_GATHER) return(OK); /* always at EOF */
break;
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/* Virtual copying. For boot device. */
case RAM_DEV:
case KMEM_DEV:
case BOOT_DEV:
if (position >= dv_size) return(OK); /* check for EOF */
if (position + count > dv_size) count = dv_size - position;
seg = m_seg[device];
if (opcode == DEV_GATHER) { /* copy actual data */
sys_vircopy(SELF,seg,position, proc_nr,D,user_vir, count);
} else {
sys_vircopy(proc_nr,D,user_vir, SELF,seg,position, count);
}
break;
/* Physical copying. Only used to access entire memory. */
case MEM_DEV:
if (position >= dv_size) return(OK); /* check for EOF */
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if (position + count > dv_size) count = dv_size - position;
mem_phys = cv64ul(dv->dv_base) + position;
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if (opcode == DEV_GATHER) { /* copy data */
sys_physcopy(NONE, PHYS_SEG, mem_phys,
proc_nr, D, user_vir, count);
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} else {
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sys_physcopy(proc_nr, D, user_vir,
NONE, PHYS_SEG, mem_phys, count);
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}
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break;
/* Random number generator. Character instead of block device. */
case RANDOM_DEV:
printf("MEMORY: please note /dev/random is NOT yet random!\n");
left = count;
while (left > 0) {
chunk = (left > RANDOM_BUF_SIZE) ? RANDOM_BUF_SIZE : left;
if (opcode == DEV_GATHER) {
sys_vircopy(SELF, D, (vir_bytes) random,
proc_nr, D, user_vir, chunk);
} else if (opcode == DEV_SCATTER) {
sys_vircopy(proc_nr, D, user_vir,
SELF, D, (vir_bytes) random, chunk);
}
left -= chunk;
}
break;
/* Null byte stream generator. */
case ZERO_DEV:
if (opcode == DEV_GATHER) {
left = count;
while (left > 0) {
chunk = (left > ZERO_BUF_SIZE) ? ZERO_BUF_SIZE : left;
if (OK != (s=sys_vircopy(SELF, D, (vir_bytes) zero,
proc_nr, D, user_vir, chunk)))
printf("MEMORY: sys_vircopy failed: %d\n", s);
left -= chunk;
}
}
break;
/* Unknown (illegal) minor device. */
default:
return(EINVAL);
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}
/* Book the number of bytes transferred. */
position += count;
iov->iov_addr += count;
if ((iov->iov_size -= count) == 0) { iov++; nr_req--; }
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}
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
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* /dev/mem or /dev/kmem. This may be needed in case of memory mapped I/O.
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*/
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()
{
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/* Initialize this task. All minor devices are initialized one by one. */
int i,s;
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/* Print welcome message. */
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printf("MEMORY: user-level memory (RAM, etc.) driver is alive\n");
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/* Get kernel info for memory addresses of kernel and boot device. */
if (OK != (s=sys_getkinfo(&kinfo))) {
server_panic("MEM","Couldn't get kernel information.",s);
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}
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/* Install remote segment for /dev/kmem memory. */
m_geom[KMEM_DEV].dv_base = cvul64(kinfo.kmem_base);
m_geom[KMEM_DEV].dv_size = cvul64(kinfo.kmem_size);
if (OK != (s=sys_segctl(&m_seg[KMEM_DEV], (u16_t *) &s, (vir_bytes *) &s,
kinfo.kmem_base, kinfo.kmem_size))) {
server_panic("MEM","Couldn't install remote segment.",s);
}
/* Install remote segment for /dev/boot memory, if enabled. */
m_geom[BOOT_DEV].dv_base = cvul64(kinfo.bootdev_base);
m_geom[BOOT_DEV].dv_size = cvul64(kinfo.bootdev_size);
if (kinfo.bootdev_base > 0) {
if (OK != (s=sys_segctl(&m_seg[BOOT_DEV], (u16_t *) &s, (vir_bytes *) &s,
kinfo.bootdev_base, kinfo.bootdev_size))) {
server_panic("MEM","Couldn't install remote segment.",s);
}
}
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psinfo.proc = kinfo.proc_addr;
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/* Initialize /dev/random and /dev/zero. */
for (i=0; i<ZERO_BUF_SIZE; i++) {
zero[i] = '\0';
}
for (i=0; i<RANDOM_BUF_SIZE; i++) {
random[i] = 'a' + i % 256;
}
/* Set up memory ranges for /dev/mem. */
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#if (CHIP == INTEL)
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if (OK != (s=sys_getmachine(&machine))) {
server_panic("MEM","Couldn't get machine information.",s);
}
if (! machine.protected) {
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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. */
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unsigned long ramdev_size;
phys_bytes ramdev_base;
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int s;
if (m_ptr->PROC_NR != FS_PROC_NR) return(EPERM);
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/* Try to allocate a piece of memory for the RAM disk. */
ramdev_size = m_ptr->POSITION;
if (OK != (s=sys_kmalloc(ramdev_size, &ramdev_base)))
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server_panic("MEM","Couldn't allocate kernel memory", s);
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dv->dv_base = cvul64(ramdev_base);
dv->dv_size = cvul64(ramdev_size);
if (OK != (s=sys_segctl(&m_seg[RAM_DEV], (u16_t *) &s, (vir_bytes *) &s,
ramdev_base, ramdev_size))) {
server_panic("MEM","Couldn't install remote segment.",s);
}
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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;
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if (m_ptr->PROC_NR == PM_PROC_NR) {
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psinfo.mproc = (vir_bytes) m_ptr->ADDRESS;
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} else if (m_ptr->PROC_NR == FS_PROC_NR) {
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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;
}