[patch 1/5] Remove existing hw_random implementation

[Deepak Saxena <dsaxena@plexity.net>]

[-- Attachment #1: rng/remove_current_rng.patch --]
[-- Type: text/plain, Size: 16432 bytes --]

Remove existing hw_random implementation so that it can be
replaced with a generic cross-architecture RNG codebase.

Signed-off-by: Deepak Saxena <dsaxena@plexity.net>


Index: linux-2.6-rng/drivers/char/Kconfig
===================================================================
--- linux-2.6-rng.orig/drivers/char/Kconfig
+++ linux-2.6-rng/drivers/char/Kconfig
@@ -644,21 +644,6 @@ config NWFLASH
 
 	  If you're not sure, say N.
 
-config HW_RANDOM
-	tristate "Intel/AMD/VIA HW Random Number Generator support"
-	depends on (X86 || IA64) && PCI
-	---help---
-	  This driver provides kernel-side support for the Random Number
-	  Generator hardware found on Intel i8xx-based motherboards,
-	  AMD 76x-based motherboards, and Via Nehemiah CPUs.
-
-	  Provides a character driver, used to read() entropy data.
-
-	  To compile this driver as a module, choose M here: the
-	  module will be called hw_random.
-
-	  If unsure, say N.
-
 config NVRAM
 	tristate "/dev/nvram support"
 	depends on ATARI || X86 || X86_64 || ARM || GENERIC_NVRAM
Index: linux-2.6-rng/drivers/char/Makefile
===================================================================
--- linux-2.6-rng.orig/drivers/char/Makefile
+++ linux-2.6-rng/drivers/char/Makefile
@@ -73,7 +73,6 @@ endif
 obj-$(CONFIG_TOSHIBA) += toshiba.o
 obj-$(CONFIG_I8K) += i8k.o
 obj-$(CONFIG_DS1620) += ds1620.o
-obj-$(CONFIG_HW_RANDOM) += hw_random.o
 obj-$(CONFIG_FTAPE) += ftape/
 obj-$(CONFIG_COBALT_LCD) += lcd.o
 obj-$(CONFIG_PPDEV) += ppdev.o
Index: linux-2.6-rng/drivers/char/hw_random.c
===================================================================
--- linux-2.6-rng.orig/drivers/char/hw_random.c
+++ /dev/null
@@ -1,627 +0,0 @@
-/*
- 	Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
-	(c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
- 
- 	derived from
- 
-        Hardware driver for the AMD 768 Random Number Generator (RNG)
-        (c) Copyright 2001 Red Hat Inc <alan@redhat.com>
-
- 	derived from
- 
-	Hardware driver for Intel i810 Random Number Generator (RNG)
-	Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
-	Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
-
-	Please read Documentation/hw_random.txt for details on use.
-
-	----------------------------------------------------------
-	This software may be used and distributed according to the terms
-        of the GNU General Public License, incorporated herein by reference.
-
- */
-
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/fs.h>
-#include <linux/init.h>
-#include <linux/pci.h>
-#include <linux/interrupt.h>
-#include <linux/spinlock.h>
-#include <linux/random.h>
-#include <linux/miscdevice.h>
-#include <linux/smp_lock.h>
-#include <linux/mm.h>
-#include <linux/delay.h>
-
-#ifdef __i386__
-#include <asm/msr.h>
-#include <asm/cpufeature.h>
-#endif
-
-#include <asm/io.h>
-#include <asm/uaccess.h>
-
-
-/*
- * core module and version information
- */
-#define RNG_VERSION "1.0.0"
-#define RNG_MODULE_NAME "hw_random"
-#define RNG_DRIVER_NAME   RNG_MODULE_NAME " hardware driver " RNG_VERSION
-#define PFX RNG_MODULE_NAME ": "
-
-
-/*
- * debugging macros
- */
-
-/* pr_debug() collapses to a no-op if DEBUG is not defined */
-#define DPRINTK(fmt, args...) pr_debug(PFX "%s: " fmt, __FUNCTION__ , ## args)
-
-
-#undef RNG_NDEBUG        /* define to enable lightweight runtime checks */
-#ifdef RNG_NDEBUG
-#define assert(expr)							\
-		if(!(expr)) {						\
-		printk(KERN_DEBUG PFX "Assertion failed! %s,%s,%s,"	\
-		"line=%d\n", #expr, __FILE__, __FUNCTION__, __LINE__);	\
-		}
-#else
-#define assert(expr)
-#endif
-
-#define RNG_MISCDEV_MINOR		183 /* official */
-
-static int rng_dev_open (struct inode *inode, struct file *filp);
-static ssize_t rng_dev_read (struct file *filp, char __user *buf, size_t size,
-				loff_t * offp);
-
-static int __init intel_init (struct pci_dev *dev);
-static void intel_cleanup(void);
-static unsigned int intel_data_present (void);
-static u32 intel_data_read (void);
-
-static int __init amd_init (struct pci_dev *dev);
-static void amd_cleanup(void);
-static unsigned int amd_data_present (void);
-static u32 amd_data_read (void);
-
-#ifdef __i386__
-static int __init via_init(struct pci_dev *dev);
-static void via_cleanup(void);
-static unsigned int via_data_present (void);
-static u32 via_data_read (void);
-#endif
-
-struct rng_operations {
-	int (*init) (struct pci_dev *dev);
-	void (*cleanup) (void);
-	unsigned int (*data_present) (void);
-	u32 (*data_read) (void);
-	unsigned int n_bytes; /* number of bytes per ->data_read */
-};
-static struct rng_operations *rng_ops;
-
-static struct file_operations rng_chrdev_ops = {
-	.owner		= THIS_MODULE,
-	.open		= rng_dev_open,
-	.read		= rng_dev_read,
-};
-
-
-static struct miscdevice rng_miscdev = {
-	RNG_MISCDEV_MINOR,
-	RNG_MODULE_NAME,
-	&rng_chrdev_ops,
-};
-
-enum {
-	rng_hw_none,
-	rng_hw_intel,
-	rng_hw_amd,
-	rng_hw_via,
-};
-
-static struct rng_operations rng_vendor_ops[] = {
-	/* rng_hw_none */
-	{ },
-
-	/* rng_hw_intel */
-	{ intel_init, intel_cleanup, intel_data_present,
-	  intel_data_read, 1 },
-
-	/* rng_hw_amd */
-	{ amd_init, amd_cleanup, amd_data_present, amd_data_read, 4 },
-
-#ifdef __i386__
-	/* rng_hw_via */
-	{ via_init, via_cleanup, via_data_present, via_data_read, 1 },
-#endif
-};
-
-/*
- * Data for PCI driver interface
- *
- * This data only exists for exporting the supported
- * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
- * register a pci_driver, because someone else might one day
- * want to register another driver on the same PCI id.
- */
-static struct pci_device_id rng_pci_tbl[] = {
-	{ 0x1022, 0x7443, PCI_ANY_ID, PCI_ANY_ID, 0, 0, rng_hw_amd },
-	{ 0x1022, 0x746b, PCI_ANY_ID, PCI_ANY_ID, 0, 0, rng_hw_amd },
-
-	{ 0x8086, 0x2418, PCI_ANY_ID, PCI_ANY_ID, 0, 0, rng_hw_intel },
-	{ 0x8086, 0x2428, PCI_ANY_ID, PCI_ANY_ID, 0, 0, rng_hw_intel },
-	{ 0x8086, 0x2448, PCI_ANY_ID, PCI_ANY_ID, 0, 0, rng_hw_intel },
-	{ 0x8086, 0x244e, PCI_ANY_ID, PCI_ANY_ID, 0, 0, rng_hw_intel },
-	{ 0x8086, 0x245e, PCI_ANY_ID, PCI_ANY_ID, 0, 0, rng_hw_intel },
-
-	{ 0, },	/* terminate list */
-};
-MODULE_DEVICE_TABLE (pci, rng_pci_tbl);
-
-
-/***********************************************************************
- *
- * Intel RNG operations
- *
- */
-
-/*
- * RNG registers (offsets from rng_mem)
- */
-#define INTEL_RNG_HW_STATUS			0
-#define         INTEL_RNG_PRESENT		0x40
-#define         INTEL_RNG_ENABLED		0x01
-#define INTEL_RNG_STATUS			1
-#define         INTEL_RNG_DATA_PRESENT		0x01
-#define INTEL_RNG_DATA				2
-
-/*
- * Magic address at which Intel PCI bridges locate the RNG
- */
-#define INTEL_RNG_ADDR				0xFFBC015F
-#define INTEL_RNG_ADDR_LEN			3
-
-/* token to our ioremap'd RNG register area */
-static void __iomem *rng_mem;
-
-static inline u8 intel_hwstatus (void)
-{
-	assert (rng_mem != NULL);
-	return readb (rng_mem + INTEL_RNG_HW_STATUS);
-}
-
-static inline u8 intel_hwstatus_set (u8 hw_status)
-{
-	assert (rng_mem != NULL);
-	writeb (hw_status, rng_mem + INTEL_RNG_HW_STATUS);
-	return intel_hwstatus ();
-}
-
-static unsigned int intel_data_present(void)
-{
-	assert (rng_mem != NULL);
-
-	return (readb (rng_mem + INTEL_RNG_STATUS) & INTEL_RNG_DATA_PRESENT) ?
-		1 : 0;
-}
-
-static u32 intel_data_read(void)
-{
-	assert (rng_mem != NULL);
-
-	return readb (rng_mem + INTEL_RNG_DATA);
-}
-
-static int __init intel_init (struct pci_dev *dev)
-{
-	int rc;
-	u8 hw_status;
-
-	DPRINTK ("ENTER\n");
-
-	rng_mem = ioremap (INTEL_RNG_ADDR, INTEL_RNG_ADDR_LEN);
-	if (rng_mem == NULL) {
-		printk (KERN_ERR PFX "cannot ioremap RNG Memory\n");
-		rc = -EBUSY;
-		goto err_out;
-	}
-
-	/* Check for Intel 82802 */
-	hw_status = intel_hwstatus ();
-	if ((hw_status & INTEL_RNG_PRESENT) == 0) {
-		printk (KERN_ERR PFX "RNG not detected\n");
-		rc = -ENODEV;
-		goto err_out_free_map;
-	}
-
-	/* turn RNG h/w on, if it's off */
-	if ((hw_status & INTEL_RNG_ENABLED) == 0)
-		hw_status = intel_hwstatus_set (hw_status | INTEL_RNG_ENABLED);
-	if ((hw_status & INTEL_RNG_ENABLED) == 0) {
-		printk (KERN_ERR PFX "cannot enable RNG, aborting\n");
-		rc = -EIO;
-		goto err_out_free_map;
-	}
-
-	DPRINTK ("EXIT, returning 0\n");
-	return 0;
-
-err_out_free_map:
-	iounmap (rng_mem);
-	rng_mem = NULL;
-err_out:
-	DPRINTK ("EXIT, returning %d\n", rc);
-	return rc;
-}
-
-static void intel_cleanup(void)
-{
-	u8 hw_status;
-
-	hw_status = intel_hwstatus ();
-	if (hw_status & INTEL_RNG_ENABLED)
-		intel_hwstatus_set (hw_status & ~INTEL_RNG_ENABLED);
-	else
-		printk(KERN_WARNING PFX "unusual: RNG already disabled\n");
-	iounmap(rng_mem);
-	rng_mem = NULL;
-}
-
-/***********************************************************************
- *
- * AMD RNG operations
- *
- */
-
-static u32 pmbase;			/* PMxx I/O base */
-static struct pci_dev *amd_dev;
-
-static unsigned int amd_data_present (void)
-{
-      	return inl(pmbase + 0xF4) & 1;
-}
-
-
-static u32 amd_data_read (void)
-{
-	return inl(pmbase + 0xF0);
-}
-
-static int __init amd_init (struct pci_dev *dev)
-{
-	int rc;
-	u8 rnen;
-
-	DPRINTK ("ENTER\n");
-
-	pci_read_config_dword(dev, 0x58, &pmbase);
-
-	pmbase &= 0x0000FF00;
-
-	if (pmbase == 0)
-	{
-		printk (KERN_ERR PFX "power management base not set\n");
-		rc = -EIO;
-		goto err_out;
-	}
-
-	pci_read_config_byte(dev, 0x40, &rnen);
-	rnen |= (1 << 7);	/* RNG on */
-	pci_write_config_byte(dev, 0x40, rnen);
-
-	pci_read_config_byte(dev, 0x41, &rnen);
-	rnen |= (1 << 7);	/* PMIO enable */
-	pci_write_config_byte(dev, 0x41, rnen);
-
-	pr_info( PFX "AMD768 system management I/O registers at 0x%X.\n",
-			pmbase);
-
-	amd_dev = dev;
-
-	DPRINTK ("EXIT, returning 0\n");
-	return 0;
-
-err_out:
-	DPRINTK ("EXIT, returning %d\n", rc);
-	return rc;
-}
-
-static void amd_cleanup(void)
-{
-	u8 rnen;
-
-	pci_read_config_byte(amd_dev, 0x40, &rnen);
-	rnen &= ~(1 << 7);	/* RNG off */
-	pci_write_config_byte(amd_dev, 0x40, rnen);
-
-	/* FIXME: twiddle pmio, also? */
-}
-
-#ifdef __i386__
-/***********************************************************************
- *
- * VIA RNG operations
- *
- */
-
-enum {
-	VIA_STRFILT_CNT_SHIFT	= 16,
-	VIA_STRFILT_FAIL	= (1 << 15),
-	VIA_STRFILT_ENABLE	= (1 << 14),
-	VIA_RAWBITS_ENABLE	= (1 << 13),
-	VIA_RNG_ENABLE		= (1 << 6),
-	VIA_XSTORE_CNT_MASK	= 0x0F,
-
-	VIA_RNG_CHUNK_8		= 0x00,	/* 64 rand bits, 64 stored bits */
-	VIA_RNG_CHUNK_4		= 0x01,	/* 32 rand bits, 32 stored bits */
-	VIA_RNG_CHUNK_4_MASK	= 0xFFFFFFFF,
-	VIA_RNG_CHUNK_2		= 0x02,	/* 16 rand bits, 32 stored bits */
-	VIA_RNG_CHUNK_2_MASK	= 0xFFFF,
-	VIA_RNG_CHUNK_1		= 0x03,	/* 8 rand bits, 32 stored bits */
-	VIA_RNG_CHUNK_1_MASK	= 0xFF,
-};
-
-static u32 via_rng_datum;
-
-/*
- * Investigate using the 'rep' prefix to obtain 32 bits of random data
- * in one insn.  The upside is potentially better performance.  The
- * downside is that the instruction becomes no longer atomic.  Due to
- * this, just like familiar issues with /dev/random itself, the worst
- * case of a 'rep xstore' could potentially pause a cpu for an
- * unreasonably long time.  In practice, this condition would likely
- * only occur when the hardware is failing.  (or so we hope :))
- *
- * Another possible performance boost may come from simply buffering
- * until we have 4 bytes, thus returning a u32 at a time,
- * instead of the current u8-at-a-time.
- */
-
-static inline u32 xstore(u32 *addr, u32 edx_in)
-{
-	u32 eax_out;
-
-	asm(".byte 0x0F,0xA7,0xC0 /* xstore %%edi (addr=%0) */"
-		:"=m"(*addr), "=a"(eax_out)
-		:"D"(addr), "d"(edx_in));
-
-	return eax_out;
-}
-
-static unsigned int via_data_present(void)
-{
-	u32 bytes_out;
-
-	/* We choose the recommended 1-byte-per-instruction RNG rate,
-	 * for greater randomness at the expense of speed.  Larger
-	 * values 2, 4, or 8 bytes-per-instruction yield greater
-	 * speed at lesser randomness.
-	 *
-	 * If you change this to another VIA_CHUNK_n, you must also
-	 * change the ->n_bytes values in rng_vendor_ops[] tables.
-	 * VIA_CHUNK_8 requires further code changes.
-	 *
-	 * A copy of MSR_VIA_RNG is placed in eax_out when xstore
-	 * completes.
-	 */
-	via_rng_datum = 0; /* paranoia, not really necessary */
-	bytes_out = xstore(&via_rng_datum, VIA_RNG_CHUNK_1) & VIA_XSTORE_CNT_MASK;
-	if (bytes_out == 0)
-		return 0;
-
-	return 1;
-}
-
-static u32 via_data_read(void)
-{
-	return via_rng_datum;
-}
-
-static int __init via_init(struct pci_dev *dev)
-{
-	u32 lo, hi, old_lo;
-
-	/* Control the RNG via MSR.  Tread lightly and pay very close
-	 * close attention to values written, as the reserved fields
-	 * are documented to be "undefined and unpredictable"; but it
-	 * does not say to write them as zero, so I make a guess that
-	 * we restore the values we find in the register.
-	 */
-	rdmsr(MSR_VIA_RNG, lo, hi);
-
-	old_lo = lo;
-	lo &= ~(0x7f << VIA_STRFILT_CNT_SHIFT);
-	lo &= ~VIA_XSTORE_CNT_MASK;
-	lo &= ~(VIA_STRFILT_ENABLE | VIA_STRFILT_FAIL | VIA_RAWBITS_ENABLE);
-	lo |= VIA_RNG_ENABLE;
-
-	if (lo != old_lo)
-		wrmsr(MSR_VIA_RNG, lo, hi);
-
-	/* perhaps-unnecessary sanity check; remove after testing if
-	   unneeded */
-	rdmsr(MSR_VIA_RNG, lo, hi);
-	if ((lo & VIA_RNG_ENABLE) == 0) {
-		printk(KERN_ERR PFX "cannot enable VIA C3 RNG, aborting\n");
-		return -ENODEV;
-	}
-
-	return 0;
-}
-
-static void via_cleanup(void)
-{
-	/* do nothing */
-}
-#endif
-
-
-/***********************************************************************
- *
- * /dev/hwrandom character device handling (major 10, minor 183)
- *
- */
-
-static int rng_dev_open (struct inode *inode, struct file *filp)
-{
-	/* enforce read-only access to this chrdev */
-	if ((filp->f_mode & FMODE_READ) == 0)
-		return -EINVAL;
-	if (filp->f_mode & FMODE_WRITE)
-		return -EINVAL;
-
-	return 0;
-}
-
-
-static ssize_t rng_dev_read (struct file *filp, char __user *buf, size_t size,
-				loff_t * offp)
-{
-	static DEFINE_SPINLOCK(rng_lock);
-	unsigned int have_data;
-	u32 data = 0;
-	ssize_t ret = 0;
-
-	while (size) {
-		spin_lock(&rng_lock);
-
-		have_data = 0;
-		if (rng_ops->data_present()) {
-			data = rng_ops->data_read();
-			have_data = rng_ops->n_bytes;
-		}
-
-		spin_unlock (&rng_lock);
-
-		while (have_data && size) {
-			if (put_user((u8)data, buf++)) {
-				ret = ret ? : -EFAULT;
-				break;
-			}
-			size--;
-			ret++;
-			have_data--;
-			data>>=8;
-		}
-
-		if (filp->f_flags & O_NONBLOCK)
-			return ret ? : -EAGAIN;
-
-		if(need_resched())
-			schedule_timeout_interruptible(1);
-		else
-			udelay(200);	/* FIXME: We could poll for 250uS ?? */
-
-		if (signal_pending (current))
-			return ret ? : -ERESTARTSYS;
-	}
-	return ret;
-}
-
-
-
-/*
- * rng_init_one - look for and attempt to init a single RNG
- */
-static int __init rng_init_one (struct pci_dev *dev)
-{
-	int rc;
-
-	DPRINTK ("ENTER\n");
-
-	assert(rng_ops != NULL);
-
-	rc = rng_ops->init(dev);
-	if (rc)
-		goto err_out;
-
-	rc = misc_register (&rng_miscdev);
-	if (rc) {
-		printk (KERN_ERR PFX "misc device register failed\n");
-		goto err_out_cleanup_hw;
-	}
-
-	DPRINTK ("EXIT, returning 0\n");
-	return 0;
-
-err_out_cleanup_hw:
-	rng_ops->cleanup();
-err_out:
-	DPRINTK ("EXIT, returning %d\n", rc);
-	return rc;
-}
-
-
-
-MODULE_AUTHOR("The Linux Kernel team");
-MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver");
-MODULE_LICENSE("GPL");
-
-
-/*
- * rng_init - initialize RNG module
- */
-static int __init rng_init (void)
-{
-	int rc;
-	struct pci_dev *pdev = NULL;
-	const struct pci_device_id *ent;
-
-	DPRINTK ("ENTER\n");
-
-	/* Probe for Intel, AMD RNGs */
-	for_each_pci_dev(pdev) {
-		ent = pci_match_id(rng_pci_tbl, pdev);
-		if (ent) {
-			rng_ops = &rng_vendor_ops[ent->driver_data];
-			goto match;
-		}
-	}
-
-#ifdef __i386__
-	/* Probe for VIA RNG */
-	if (cpu_has_xstore) {
-		rng_ops = &rng_vendor_ops[rng_hw_via];
-		pdev = NULL;
-		goto match;
-	}
-#endif
-
-	DPRINTK ("EXIT, returning -ENODEV\n");
-	return -ENODEV;
-
-match:
-	rc = rng_init_one (pdev);
-	if (rc)
-		return rc;
-
-	pr_info( RNG_DRIVER_NAME " loaded\n");
-
-	DPRINTK ("EXIT, returning 0\n");
-	return 0;
-}
-
-
-/*
- * rng_init - shutdown RNG module
- */
-static void __exit rng_cleanup (void)
-{
-	DPRINTK ("ENTER\n");
-
-	misc_deregister (&rng_miscdev);
-
-	if (rng_ops->cleanup)
-		rng_ops->cleanup();
-
-	DPRINTK ("EXIT\n");
-}
-
-
-module_init (rng_init);
-module_exit (rng_cleanup);

--
Deepak Saxena - dsaxena@plexity.net - http://www.plexity.net

Even a stopped clock gives the right time twice a day.