[patch 1/5] Remove existing hw_random implementation

From: dsaxena
Date: Wed Oct 19 2005 - 04:18:09 EST

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

Signed-off-by: Deepak Saxena <dsaxena@xxxxxxxxxxx>

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@xxxxxxxxxx>
-
- derived from
-
- Hardware driver for the AMD 768 Random Number Generator (RNG)
- (c) Copyright 2001 Red Hat Inc <alan@xxxxxxxxxx>
-
- derived from
-
- Hardware driver for Intel i810 Random Number Generator (RNG)
- Copyright 2000,2001 Jeff Garzik <jgarzik@xxxxxxxxx>
- Copyright 2000,2001 Philipp Rumpf <prumpf@xxxxxxxxxxxxxxxx>
-
- 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@xxxxxxxxxxx - http://www.plexity.net

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