Use stop_machine_run in the Intel RNG driver
Replace call_smp_function with stop_machine_run in the Intel RNG driver. CPU A has done read_lock(&lock) CPU B has done write_lock_irq(&lock) and is waiting for A to release the lock. A third CPU calls call_smp_function and issues the IPI. CPU A takes CPU C's IPI. CPU B is waiting with interrupts disabled and does not see the IPI. CPU C is stuck waiting for CPU B to respond to the IPI. Deadlock. The solution is to use stop_machine_run instead of call_smp_function (call_smp_function should not be called in situations where the CPUs may be suspended). [haruo.tomita@toshiba.co.jp: fix a typo in mod_init()] [haruo.tomita@toshiba.co.jp: fix memory leak] Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Jan Beulich <jbeulich@novell.com> Cc: "Tomita, Haruo" <haruo.tomita@toshiba.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Prarit Bhargava
Linus Torvalds
parent
616883df78
commit
ee527cd3a2
2 changed files with 129 additions and 102 deletions
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@ -24,10 +24,11 @@
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/pci.h>
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#include <linux/hw_random.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/stop_machine.h>
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#include <asm/io.h>
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@ -217,30 +218,117 @@ static struct hwrng intel_rng = {
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.data_read = intel_rng_data_read,
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};
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struct intel_rng_hw {
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struct pci_dev *dev;
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void __iomem *mem;
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u8 bios_cntl_off;
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u8 bios_cntl_val;
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u8 fwh_dec_en1_off;
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u8 fwh_dec_en1_val;
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};
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#ifdef CONFIG_SMP
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static char __initdata waitflag;
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static void __init intel_init_wait(void *unused)
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static int __init intel_rng_hw_init(void *_intel_rng_hw)
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{
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while (waitflag)
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cpu_relax();
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struct intel_rng_hw *intel_rng_hw = _intel_rng_hw;
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u8 mfc, dvc;
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/* interrupts disabled in stop_machine_run call */
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if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK))
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pci_write_config_byte(intel_rng_hw->dev,
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intel_rng_hw->fwh_dec_en1_off,
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intel_rng_hw->fwh_dec_en1_val |
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FWH_F8_EN_MASK);
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if (!(intel_rng_hw->bios_cntl_val & BIOS_CNTL_WRITE_ENABLE_MASK))
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pci_write_config_byte(intel_rng_hw->dev,
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intel_rng_hw->bios_cntl_off,
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intel_rng_hw->bios_cntl_val |
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BIOS_CNTL_WRITE_ENABLE_MASK);
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writeb(INTEL_FWH_RESET_CMD, intel_rng_hw->mem);
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writeb(INTEL_FWH_READ_ID_CMD, intel_rng_hw->mem);
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mfc = readb(intel_rng_hw->mem + INTEL_FWH_MANUFACTURER_CODE_ADDRESS);
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dvc = readb(intel_rng_hw->mem + INTEL_FWH_DEVICE_CODE_ADDRESS);
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writeb(INTEL_FWH_RESET_CMD, intel_rng_hw->mem);
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if (!(intel_rng_hw->bios_cntl_val &
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(BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK)))
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pci_write_config_byte(intel_rng_hw->dev,
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intel_rng_hw->bios_cntl_off,
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intel_rng_hw->bios_cntl_val);
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if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK))
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pci_write_config_byte(intel_rng_hw->dev,
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intel_rng_hw->fwh_dec_en1_off,
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intel_rng_hw->fwh_dec_en1_val);
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if (mfc != INTEL_FWH_MANUFACTURER_CODE ||
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(dvc != INTEL_FWH_DEVICE_CODE_8M &&
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dvc != INTEL_FWH_DEVICE_CODE_4M)) {
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printk(KERN_ERR PFX "FWH not detected\n");
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return -ENODEV;
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}
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return 0;
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}
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#endif
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static int __init intel_init_hw_struct(struct intel_rng_hw *intel_rng_hw,
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struct pci_dev *dev)
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{
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intel_rng_hw->bios_cntl_val = 0xff;
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intel_rng_hw->fwh_dec_en1_val = 0xff;
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intel_rng_hw->dev = dev;
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/* Check for Intel 82802 */
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if (dev->device < 0x2640) {
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intel_rng_hw->fwh_dec_en1_off = FWH_DEC_EN1_REG_OLD;
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intel_rng_hw->bios_cntl_off = BIOS_CNTL_REG_OLD;
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} else {
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intel_rng_hw->fwh_dec_en1_off = FWH_DEC_EN1_REG_NEW;
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intel_rng_hw->bios_cntl_off = BIOS_CNTL_REG_NEW;
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}
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pci_read_config_byte(dev, intel_rng_hw->fwh_dec_en1_off,
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&intel_rng_hw->fwh_dec_en1_val);
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pci_read_config_byte(dev, intel_rng_hw->bios_cntl_off,
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&intel_rng_hw->bios_cntl_val);
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if ((intel_rng_hw->bios_cntl_val &
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(BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK))
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== BIOS_CNTL_LOCK_ENABLE_MASK) {
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static __initdata /*const*/ char warning[] =
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KERN_WARNING PFX "Firmware space is locked read-only. "
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KERN_WARNING PFX "If you can't or\n don't want to "
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KERN_WARNING PFX "disable this in firmware setup, and "
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KERN_WARNING PFX "if\n you are certain that your "
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KERN_WARNING PFX "system has a functional\n RNG, try"
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KERN_WARNING PFX "using the 'no_fwh_detect' option.\n";
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if (no_fwh_detect)
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return -ENODEV;
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printk(warning);
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return -EBUSY;
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}
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intel_rng_hw->mem = ioremap_nocache(INTEL_FWH_ADDR, INTEL_FWH_ADDR_LEN);
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if (intel_rng_hw->mem == NULL)
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return -EBUSY;
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return 0;
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}
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static int __init mod_init(void)
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{
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int err = -ENODEV;
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unsigned i;
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int i;
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struct pci_dev *dev = NULL;
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void __iomem *mem;
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unsigned long flags;
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u8 bios_cntl_off, fwh_dec_en1_off;
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u8 bios_cntl_val = 0xff, fwh_dec_en1_val = 0xff;
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u8 hw_status, mfc, dvc;
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void __iomem *mem = mem;
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u8 hw_status;
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struct intel_rng_hw *intel_rng_hw;
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for (i = 0; !dev && pci_tbl[i].vendor; ++i)
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dev = pci_get_device(pci_tbl[i].vendor, pci_tbl[i].device, NULL);
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dev = pci_get_device(pci_tbl[i].vendor, pci_tbl[i].device,
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NULL);
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if (!dev)
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goto out; /* Device not found. */
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@ -250,39 +338,18 @@ static int __init mod_init(void)
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goto fwh_done;
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}
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/* Check for Intel 82802 */
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if (dev->device < 0x2640) {
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fwh_dec_en1_off = FWH_DEC_EN1_REG_OLD;
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bios_cntl_off = BIOS_CNTL_REG_OLD;
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} else {
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fwh_dec_en1_off = FWH_DEC_EN1_REG_NEW;
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bios_cntl_off = BIOS_CNTL_REG_NEW;
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}
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pci_read_config_byte(dev, fwh_dec_en1_off, &fwh_dec_en1_val);
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pci_read_config_byte(dev, bios_cntl_off, &bios_cntl_val);
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if ((bios_cntl_val &
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(BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK))
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== BIOS_CNTL_LOCK_ENABLE_MASK) {
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static __initdata /*const*/ char warning[] =
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KERN_WARNING PFX "Firmware space is locked read-only. If you can't or\n"
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KERN_WARNING PFX "don't want to disable this in firmware setup, and if\n"
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KERN_WARNING PFX "you are certain that your system has a functional\n"
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KERN_WARNING PFX "RNG, try using the 'no_fwh_detect' option.\n";
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intel_rng_hw = kmalloc(sizeof(*intel_rng_hw), GFP_KERNEL);
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if (!intel_rng_hw) {
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pci_dev_put(dev);
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if (no_fwh_detect)
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goto fwh_done;
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printk(warning);
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err = -EBUSY;
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goto out;
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}
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mem = ioremap_nocache(INTEL_FWH_ADDR, INTEL_FWH_ADDR_LEN);
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if (mem == NULL) {
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err = intel_init_hw_struct(intel_rng_hw, dev);
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if (err) {
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pci_dev_put(dev);
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err = -EBUSY;
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kfree(intel_rng_hw);
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if (err == -ENODEV)
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goto fwh_done;
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goto out;
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}
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@ -290,59 +357,18 @@ static int __init mod_init(void)
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* Since the BIOS code/data is going to disappear from its normal
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* location with the Read ID command, all activity on the system
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* must be stopped until the state is back to normal.
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*
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* Use stop_machine_run because IPIs can be blocked by disabling
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* interrupts.
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*/
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#ifdef CONFIG_SMP
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set_mb(waitflag, 1);
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if (smp_call_function(intel_init_wait, NULL, 1, 0) != 0) {
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set_mb(waitflag, 0);
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pci_dev_put(dev);
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printk(KERN_ERR PFX "cannot run on all processors\n");
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err = -EAGAIN;
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goto err_unmap;
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}
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#endif
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local_irq_save(flags);
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if (!(fwh_dec_en1_val & FWH_F8_EN_MASK))
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pci_write_config_byte(dev,
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fwh_dec_en1_off,
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fwh_dec_en1_val | FWH_F8_EN_MASK);
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if (!(bios_cntl_val & BIOS_CNTL_WRITE_ENABLE_MASK))
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pci_write_config_byte(dev,
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bios_cntl_off,
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bios_cntl_val | BIOS_CNTL_WRITE_ENABLE_MASK);
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writeb(INTEL_FWH_RESET_CMD, mem);
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writeb(INTEL_FWH_READ_ID_CMD, mem);
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mfc = readb(mem + INTEL_FWH_MANUFACTURER_CODE_ADDRESS);
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dvc = readb(mem + INTEL_FWH_DEVICE_CODE_ADDRESS);
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writeb(INTEL_FWH_RESET_CMD, mem);
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if (!(bios_cntl_val &
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(BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK)))
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pci_write_config_byte(dev, bios_cntl_off, bios_cntl_val);
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if (!(fwh_dec_en1_val & FWH_F8_EN_MASK))
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pci_write_config_byte(dev, fwh_dec_en1_off, fwh_dec_en1_val);
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local_irq_restore(flags);
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#ifdef CONFIG_SMP
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/* Tell other CPUs to resume. */
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set_mb(waitflag, 0);
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#endif
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iounmap(mem);
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err = stop_machine_run(intel_rng_hw_init, intel_rng_hw, NR_CPUS);
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pci_dev_put(dev);
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if (mfc != INTEL_FWH_MANUFACTURER_CODE ||
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(dvc != INTEL_FWH_DEVICE_CODE_8M &&
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dvc != INTEL_FWH_DEVICE_CODE_4M)) {
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printk(KERN_ERR PFX "FWH not detected\n");
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err = -ENODEV;
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iounmap(intel_rng_hw->mem);
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kfree(intel_rng_hw);
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if (err)
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goto out;
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}
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fwh_done:
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err = -ENOMEM;
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mem = ioremap(INTEL_RNG_ADDR, INTEL_RNG_ADDR_LEN);
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if (!mem)
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@ -352,22 +378,21 @@ static int __init mod_init(void)
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/* Check for Random Number Generator */
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err = -ENODEV;
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hw_status = hwstatus_get(mem);
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if ((hw_status & INTEL_RNG_PRESENT) == 0)
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goto err_unmap;
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if ((hw_status & INTEL_RNG_PRESENT) == 0) {
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iounmap(mem);
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goto out;
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}
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printk(KERN_INFO "Intel 82802 RNG detected\n");
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err = hwrng_register(&intel_rng);
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if (err) {
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printk(KERN_ERR PFX "RNG registering failed (%d)\n",
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err);
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goto err_unmap;
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iounmap(mem);
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}
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out:
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return err;
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err_unmap:
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iounmap(mem);
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goto out;
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}
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static void __exit mod_exit(void)
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@ -1,11 +1,12 @@
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/* Copyright 2005 Rusty Russell rusty@rustcorp.com.au IBM Corporation.
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* GPL v2 and any later version.
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*/
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#include <linux/stop_machine.h>
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#include <linux/kthread.h>
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#include <linux/sched.h>
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#include <linux/cpu.h>
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#include <linux/err.h>
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#include <linux/kthread.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/stop_machine.h>
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#include <linux/syscalls.h>
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#include <asm/atomic.h>
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#include <asm/semaphore.h>
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@ -208,3 +209,4 @@ int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu)
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return ret;
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}
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EXPORT_SYMBOL_GPL(stop_machine_run);
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