Hello,
As part of my debian-installer project[1] I have been working on
initrd support for GNU Mach. The new boot script command
$(devname=ramdisk-create) causes the contents of the module to be
copied into newly allocated memory which is made available to user
space through the device ${devname}.
The current version of my d-i images use this as the root filesystem,
with grub loading an ext2 filesystem image from the boot CD. Which is
not that good considering that the required free space on / will
likely vary from installation to installation. So a better solution
will be needed in the long run (union a tmpfs over / early on?)
There were also concerns raised on #hurd that this is not quite
hurdish and that its scope should be as limited as possible (read-only
gzipped data to be handled by userspace), or that modifying Mach for
this purpose is misguided and should be avoided (for instance by
embedding the initrd in a dedicated section of an elf module). Since
this is only needed for debian-installer, I beleive it could be kept
as a Debian patch until a more satifying solution is implemented.
My goal is to get a basic installer working as soon as possible, so
I'm going to move on to the other parts of my project for now unless
some critical problem with the attached patch shows up. However I
intend to return to this as soon as possible and I would appreciate if
we could discuss it in the meantime.
Thanks,
--
Jérémie Koenig <j...@jk.fr.eu.org>
http://jk.fr.eu.org/
[1] http://www.bddebian.com:8888/~hurd-web/user/jkoenig/
Index: gnumach/Makefrag.am
===================================================================
--- gnumach.orig/Makefrag.am 2009-11-28 17:42:50.000000000 +0100
+++ gnumach/Makefrag.am 2010-06-11 01:18:48.000000000 +0200
@@ -275,6 +275,8 @@
device/net_io.c \
device/net_io.h \
device/param.h \
+ device/ramdisk.c \
+ device/ramdisk.h \
device/subrs.c \
device/tty.h
EXTRA_DIST += \
Index: gnumach/i386/i386at/conf.c
===================================================================
--- gnumach.orig/i386/i386at/conf.c 2010-06-11 01:18:48.000000000 +0200
+++ gnumach/i386/i386at/conf.c 2010-06-11 01:18:48.000000000 +0200
@@ -29,6 +29,7 @@
#include <mach/machine/vm_types.h>
#include <device/conf.h>
+#include <device/ramdisk.h>
extern int timeopen(), timeclose();
extern vm_offset_t timemmap();
@@ -127,6 +128,8 @@
nodev, nulldev, nulldev, 0,
nodev },
+ RAMDISK_DEV_OPS,
+
#ifdef MACH_KMSG
{ kmsgname, kmsgopen, kmsgclose, kmsgread,
nodev, kmsggetstat, nodev, nomap,
Index: gnumach/kern/boot_script.c
===================================================================
--- gnumach.orig/kern/boot_script.c 2009-11-28 17:42:50.000000000 +0100
+++ gnumach/kern/boot_script.c 2010-06-11 01:18:48.000000000 +0200
@@ -88,12 +88,20 @@
return boot_script_prompt_task_resume (cmd);
}
+/* Create an initial ramdisk */
+static int
+ramdisk_create (struct cmd *cmd, int *val)
+{
+ return boot_script_ramdisk_create (cmd, (char **) val);
+}
+
/* List of builtin symbols. */
static struct sym builtin_symbols[] =
{
{ "task-create", VAL_FUNC, (int) create_task, VAL_TASK, 0 },
{ "task-resume", VAL_FUNC, (int) resume_task, VAL_NONE, 1 },
{ "prompt-task-resume", VAL_FUNC, (int) prompt_resume_task, VAL_NONE, 1 },
+ { "ramdisk-create", VAL_FUNC, (int) ramdisk_create, VAL_STR, 0 },
};
#define NUM_BUILTIN (sizeof (builtin_symbols) / sizeof (builtin_symbols[0]))
Index: gnumach/kern/bootstrap.c
===================================================================
--- gnumach.orig/kern/bootstrap.c 2009-11-28 17:42:50.000000000 +0100
+++ gnumach/kern/bootstrap.c 2010-06-11 01:18:48.000000000 +0200
@@ -48,6 +48,7 @@
#include <vm/vm_kern.h>
#include <vm/vm_user.h>
#include <device/device_port.h>
+#include <device/ramdisk.h>
#if MACH_KDB
#include <machine/db_machdep.h>
@@ -128,7 +129,7 @@
}
else
{
- int i, losers, maxlen;
+ int i, losers;
/* Initialize boot script variables. We leak these send rights. */
losers = boot_script_set_variable
@@ -219,23 +220,19 @@
}
#endif
- maxlen = 0;
for (i = 0; i < boot_info.mods_count; ++i)
{
int err;
char *line = (char*)phystokv(bmods[i].string);
- int len = strlen (line) + 1;
- if (len > maxlen)
- maxlen = len;
- printf ("\rmodule %d: %*s", i, -maxlen, line);
+ printf ("module %d: %s\n", i, line);
err = boot_script_parse_line (&bmods[i], line);
if (err)
{
- printf ("\n\tERROR: %s", boot_script_error_string (err));
+ printf ("\tERROR: %s\n", boot_script_error_string (err));
++losers;
}
}
- printf ("\r%d multiboot modules %*s", i, -maxlen, "");
+ printf ("%d multiboot modules\n", i);
if (losers)
panic ("%d of %d boot script commands could not be parsed",
losers, boot_info.mods_count);
@@ -776,6 +773,23 @@
}
int
+boot_script_ramdisk_create (struct cmd *cmd, char **name)
+{
+ struct multiboot_module *mod = cmd->hook;
+ vm_size_t size = mod->mod_end - mod->mod_start;
+ kern_return_t rc;
+ int no;
+
+ rc = ramdisk_create (size, (void *) phystokv (mod->mod_start), &no);
+ if (rc != KERN_SUCCESS)
+ return BOOT_SCRIPT_MACH_ERROR;
+
+ *name = boot_script_malloc (RAMDISK_NAMESZ);
+ sprintf(*name, RAMDISK_NAME "%d", no);
+ return 0;
+}
+
+int
boot_script_task_create (struct cmd *cmd)
{
kern_return_t rc = task_create(TASK_NULL, FALSE, &cmd->task);
Index: gnumach/device/ramdisk.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ gnumach/device/ramdisk.c 2010-06-11 10:33:37.000000000 +0200
@@ -0,0 +1,138 @@
+//#include <vm/pmap.h>
+#include <mach/vm_param.h>
+#include <machine/vm_param.h>
+#include <mach/machine/multiboot.h>
+#include <string.h>
+#include <vm/vm_kern.h>
+#include <kern/printf.h>
+#include <device/device_types.h>
+#include <device/ds_routines.h>
+#include <device/conf.h>
+#include <device/ramdisk.h>
+
+static struct ramdisk {
+ void *data;
+ vm_size_t size;
+} ramdisk[RAMDISK_MAX];
+
+static int ramdisk_num = 0;
+
+/* Initial ramdisks are created from the boot scripts */
+int ramdisk_create(vm_size_t size, const void *initdata, int *out_no)
+{
+ struct ramdisk *rd = &ramdisk[ramdisk_num];
+ int err;
+
+ if(ramdisk_num >= RAMDISK_MAX)
+ return -1;
+
+ /* allocate the memory */
+ rd->size = round_page(size);
+ err = kmem_alloc(kernel_map, (vm_offset_t *) &rd->data, rd->size);
+ if(err != KERN_SUCCESS)
+ return err;
+
+ /* initialize */
+ if(initdata)
+ memcpy(rd->data, initdata, rd->size);
+ else
+ memset(rd->data, 0, rd->size);
+
+ /* report */
+ if(out_no) *out_no = ramdisk_num;
+ printf("%s%d: %lu bytes @%p\n", RAMDISK_NAME, ramdisk_num,
+ (unsigned long) rd->size, rd->data);
+
+ ramdisk_num++;
+ return KERN_SUCCESS;
+}
+
+/* On d_open() we just check whether the ramdisk exists */
+int ramdisk_open(int dev, int mode, io_req_t ior)
+{
+ return (dev < ramdisk_num) ? D_SUCCESS : D_NO_SUCH_DEVICE;
+}
+
+/* d_getstat() is used to query the device characteristics */
+int ramdisk_getstat(int dev, dev_flavor_t flavor, dev_status_t status,
+ mach_msg_type_number_t *status_count)
+{
+ switch(flavor) {
+ case DEV_GET_SIZE:
+ status[DEV_GET_SIZE_DEVICE_SIZE] = ramdisk[dev].size;
+ status[DEV_GET_SIZE_RECORD_SIZE] = RAMDISK_BLOCKSZ;
+ *status_count = DEV_GET_SIZE_COUNT;
+ return D_SUCCESS;
+
+ case DEV_GET_RECORDS:
+ status[DEV_GET_RECORDS_DEVICE_RECORDS]
+ = ramdisk[dev].size / RAMDISK_BLOCKSZ;
+ status[DEV_GET_RECORDS_RECORD_SIZE] = RAMDISK_BLOCKSZ;
+ *status_count = DEV_GET_RECORDS_COUNT;
+ return D_SUCCESS;
+ }
+ return D_INVALID_OPERATION;
+}
+
+/* TODO: implement freeramdisk with setstat() ? */
+
+/* check the given io request and compute a pointer to the ramdisk data and the
+ * amount to be handled */
+static int ramdisk_ioreq(int dev, io_req_t ior, void **data, int *amt)
+{
+ vm_offset_t ofs = ior->io_recnum * RAMDISK_BLOCKSZ;
+ if(ofs >= ramdisk[dev].size)
+ return D_INVALID_RECNUM;
+
+ *data = (char*) ramdisk[dev].data + ofs;
+ *amt = ior->io_count;
+ if(ofs + *amt > ramdisk[dev].size)
+ *amt = ramdisk[dev].size - ofs;
+
+ return KERN_SUCCESS;
+}
+
+int ramdisk_read(int dev, io_req_t ior)
+{
+ void *data;
+ int amt, err;
+
+ err = ramdisk_ioreq(dev, ior, &data, &amt);
+ if(err != KERN_SUCCESS)
+ return err;
+
+ err = device_read_alloc (ior, ior->io_count);
+ if (err != KERN_SUCCESS)
+ return err;
+
+ memcpy(ior->io_data, data, amt);
+ ior->io_residual = ior->io_count - amt;
+
+ return D_SUCCESS;
+}
+
+int ramdisk_write(int dev, io_req_t ior)
+{
+ void *data;
+ int amt, err;
+
+ err = ramdisk_ioreq(dev, ior, &data, &amt);
+ if(err != KERN_SUCCESS)
+ return err;
+
+ memcpy(data, ior->io_data, amt);
+ ior->io_residual = ior->io_count - amt;
+
+ return D_SUCCESS;
+}
+
+vm_offset_t ramdisk_mmap(int dev, vm_offset_t off, vm_prot_t prot)
+{
+ if(dev >= ramdisk_num)
+ return -1;
+ if(off >= ramdisk[dev].size)
+ return -1;
+
+ return pmap_phys_to_frame(kvtophys((vm_offset_t) ramdisk[dev].data + off));
+}
+
Index: gnumach/device/ramdisk.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ gnumach/device/ramdisk.h 2010-06-11 01:18:48.000000000 +0200
@@ -0,0 +1,47 @@
+#ifndef _KERN_RAMDISK_H_
+#define _KERN_RAMDISK_H_
+
+#include <vm/pmap.h>
+#include <device/io_req.h>
+#include <device/conf.h>
+
+/* Maximum number of ramdisk devices */
+#define RAMDISK_MAX 4
+
+/* The block size used (userspace requires 512) */
+#define RAMDISK_BLOCKSZ 512
+
+/* Name associated to the ramdisk major */
+#define RAMDISK_NAME "rd"
+#define RAMDISK_NAMESZ (sizeof RAMDISK_NAME + sizeof (int) * 3 + 1)
+
+/* Create a new ramdisk of the given size. On success, if out_no and/or out_ptr
+ * are not NULL, the device number and pointer to the ramdisk's data are stored
+ * there. Returns D_SUCCESS or D_NO_MEMORY. */
+int ramdisk_create(vm_size_t size, const void *initdata, int *out_no);
+
+/* Device operations */
+int ramdisk_open(int, int, io_req_t);
+int ramdisk_getstat(int, dev_flavor_t, dev_status_t, mach_msg_type_number_t *);
+int ramdisk_read(int, io_req_t);
+//int ramdisk_write(int, io_req_t);
+vm_offset_t ramdisk_mmap(int, vm_offset_t, vm_prot_t);
+
+/* dev_ops initializer to be used from <machine>/conf.c */
+#define RAMDISK_DEV_OPS { \
+ .d_name = RAMDISK_NAME, \
+ .d_open = ramdisk_open, \
+ .d_close = nulldev, \
+ .d_read = ramdisk_read, \
+ .d_write = nodev /*ramdisk_write*/, \
+ .d_getstat = ramdisk_getstat, \
+ .d_setstat = nodev, \
+ .d_mmap = ramdisk_mmap, \
+ .d_async_in = nodev, \
+ .d_reset = nulldev, \
+ .d_port_death = nulldev, \
+ .d_subdev = 0, \
+ .d_dev_info = nodev, \
+ }
+
+#endif
