linux/drivers/edac/i82875p_edac.c
Jarkko Lavinen 09a81269c7 i82875p_edac: fix module remove
Fix module removal bugs of i82875p_edac.  Also i82975x_edac code seems to
have the same module removal bugs as in i82875p_edac.

The problems were:

1. In module removal i82875p_remove_one() is never called.

   Variable i82875p_registered is newer changed from 1, which
   guarantees i82875p_remove_one() is not called (and even if it were
   called, it would be called in wrong order).

   As a result, the edac_mc workque is not stopped and keeps probing.
   If kernel debugging options are not enabled, user may not notice
   anything going wrong.

   if debugging options are enabled and I do "rmmod i82875p_edac", I
   get:

      edac debug: edac_pci_workq_function() checking
      BUG: unable to handle kernel paging request at f882d16f
      ...
      call trace:
       [<f8834df3>] ? edac_mc_workq_function+0x55/0x7e [edac_core]
       [<c0233974>] ? run_workqueue+0xd7/0x1a5
       [<c023392f>] ? run_workqueue+0x92/0x1a5
       [<f8834d9e>] ? edac_mc_workq_function+0x0/0x7e [edac_core]
       [<c0233af9>] ? worker_thread+0xb7/0xc3
       [<c0236a7b>] ? autoremove_wake_function+0x0/0x33
       [<c0233a42>] ? worker_thread+0x0/0xc3
       [<c0236809>] ? kthread+0x3b/0x61
       [<c02367ce>] ? kthread+0x0/0x61
       [<c0204587>] ? kernel_thread_helper+0x7/0x10

   Fix for this is to get rid of needles variable i82875p_registered
   altogether and run i82875p_remove_one() *before*
   pci_unregister_driver().

2. edac_mc_del_mc() uses mci after freeing mci

   edac_mc_del_mc() calls calls edac_remove_sysfs_mci_device().  The
   kobject refcount of mci drops to 0 and mci is freed.  After this
   mci is accessed via debug print and i82875p_remove_one() still
   uses mci->pvt and tries to free mci again with edac_mc_free().

   The fix for this is add kobject_get(&mci->edac_mci_kobj) after
   edac_mc_alloc(). Then the mci is still available after returning
   from edac_mc_del_mc() with refcount 1, and mci->pvt is still
   available. When i82875p_remove_one() finally calls edac_mc_free(),
   this will cause kobject_put() and mci is released properly.

Signed-off-by: Jarkko Lavinen <jlavi@iki.fi>
Cc: Doug Thompson <norsk5@yahoo.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-01 19:55:25 -08:00

600 lines
15 KiB
C

/*
* Intel D82875P Memory Controller kernel module
* (C) 2003 Linux Networx (http://lnxi.com)
* This file may be distributed under the terms of the
* GNU General Public License.
*
* Written by Thayne Harbaugh
* Contributors:
* Wang Zhenyu at intel.com
*
* $Id: edac_i82875p.c,v 1.5.2.11 2005/10/05 00:43:44 dsp_llnl Exp $
*
* Note: E7210 appears same as D82875P - zhenyu.z.wang at intel.com
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/pci_ids.h>
#include <linux/slab.h>
#include <linux/edac.h>
#include "edac_core.h"
#define I82875P_REVISION " Ver: 2.0.2 " __DATE__
#define EDAC_MOD_STR "i82875p_edac"
#define i82875p_printk(level, fmt, arg...) \
edac_printk(level, "i82875p", fmt, ##arg)
#define i82875p_mc_printk(mci, level, fmt, arg...) \
edac_mc_chipset_printk(mci, level, "i82875p", fmt, ##arg)
#ifndef PCI_DEVICE_ID_INTEL_82875_0
#define PCI_DEVICE_ID_INTEL_82875_0 0x2578
#endif /* PCI_DEVICE_ID_INTEL_82875_0 */
#ifndef PCI_DEVICE_ID_INTEL_82875_6
#define PCI_DEVICE_ID_INTEL_82875_6 0x257e
#endif /* PCI_DEVICE_ID_INTEL_82875_6 */
/* four csrows in dual channel, eight in single channel */
#define I82875P_NR_CSROWS(nr_chans) (8/(nr_chans))
/* Intel 82875p register addresses - device 0 function 0 - DRAM Controller */
#define I82875P_EAP 0x58 /* Error Address Pointer (32b)
*
* 31:12 block address
* 11:0 reserved
*/
#define I82875P_DERRSYN 0x5c /* DRAM Error Syndrome (8b)
*
* 7:0 DRAM ECC Syndrome
*/
#define I82875P_DES 0x5d /* DRAM Error Status (8b)
*
* 7:1 reserved
* 0 Error channel 0/1
*/
#define I82875P_ERRSTS 0xc8 /* Error Status Register (16b)
*
* 15:10 reserved
* 9 non-DRAM lock error (ndlock)
* 8 Sftwr Generated SMI
* 7 ECC UE
* 6 reserved
* 5 MCH detects unimplemented cycle
* 4 AGP access outside GA
* 3 Invalid AGP access
* 2 Invalid GA translation table
* 1 Unsupported AGP command
* 0 ECC CE
*/
#define I82875P_ERRCMD 0xca /* Error Command (16b)
*
* 15:10 reserved
* 9 SERR on non-DRAM lock
* 8 SERR on ECC UE
* 7 SERR on ECC CE
* 6 target abort on high exception
* 5 detect unimplemented cyc
* 4 AGP access outside of GA
* 3 SERR on invalid AGP access
* 2 invalid translation table
* 1 SERR on unsupported AGP command
* 0 reserved
*/
/* Intel 82875p register addresses - device 6 function 0 - DRAM Controller */
#define I82875P_PCICMD6 0x04 /* PCI Command Register (16b)
*
* 15:10 reserved
* 9 fast back-to-back - ro 0
* 8 SERR enable - ro 0
* 7 addr/data stepping - ro 0
* 6 parity err enable - ro 0
* 5 VGA palette snoop - ro 0
* 4 mem wr & invalidate - ro 0
* 3 special cycle - ro 0
* 2 bus master - ro 0
* 1 mem access dev6 - 0(dis),1(en)
* 0 IO access dev3 - 0(dis),1(en)
*/
#define I82875P_BAR6 0x10 /* Mem Delays Base ADDR Reg (32b)
*
* 31:12 mem base addr [31:12]
* 11:4 address mask - ro 0
* 3 prefetchable - ro 0(non),1(pre)
* 2:1 mem type - ro 0
* 0 mem space - ro 0
*/
/* Intel 82875p MMIO register space - device 0 function 0 - MMR space */
#define I82875P_DRB_SHIFT 26 /* 64MiB grain */
#define I82875P_DRB 0x00 /* DRAM Row Boundary (8b x 8)
*
* 7 reserved
* 6:0 64MiB row boundary addr
*/
#define I82875P_DRA 0x10 /* DRAM Row Attribute (4b x 8)
*
* 7 reserved
* 6:4 row attr row 1
* 3 reserved
* 2:0 row attr row 0
*
* 000 = 4KiB
* 001 = 8KiB
* 010 = 16KiB
* 011 = 32KiB
*/
#define I82875P_DRC 0x68 /* DRAM Controller Mode (32b)
*
* 31:30 reserved
* 29 init complete
* 28:23 reserved
* 22:21 nr chan 00=1,01=2
* 20 reserved
* 19:18 Data Integ Mode 00=none,01=ecc
* 17:11 reserved
* 10:8 refresh mode
* 7 reserved
* 6:4 mode select
* 3:2 reserved
* 1:0 DRAM type 01=DDR
*/
enum i82875p_chips {
I82875P = 0,
};
struct i82875p_pvt {
struct pci_dev *ovrfl_pdev;
void __iomem *ovrfl_window;
};
struct i82875p_dev_info {
const char *ctl_name;
};
struct i82875p_error_info {
u16 errsts;
u32 eap;
u8 des;
u8 derrsyn;
u16 errsts2;
};
static const struct i82875p_dev_info i82875p_devs[] = {
[I82875P] = {
.ctl_name = "i82875p"},
};
static struct pci_dev *mci_pdev; /* init dev: in case that AGP code has
* already registered driver
*/
static struct edac_pci_ctl_info *i82875p_pci;
static void i82875p_get_error_info(struct mem_ctl_info *mci,
struct i82875p_error_info *info)
{
struct pci_dev *pdev;
pdev = to_pci_dev(mci->dev);
/*
* This is a mess because there is no atomic way to read all the
* registers at once and the registers can transition from CE being
* overwritten by UE.
*/
pci_read_config_word(pdev, I82875P_ERRSTS, &info->errsts);
if (!(info->errsts & 0x0081))
return;
pci_read_config_dword(pdev, I82875P_EAP, &info->eap);
pci_read_config_byte(pdev, I82875P_DES, &info->des);
pci_read_config_byte(pdev, I82875P_DERRSYN, &info->derrsyn);
pci_read_config_word(pdev, I82875P_ERRSTS, &info->errsts2);
/*
* If the error is the same then we can for both reads then
* the first set of reads is valid. If there is a change then
* there is a CE no info and the second set of reads is valid
* and should be UE info.
*/
if ((info->errsts ^ info->errsts2) & 0x0081) {
pci_read_config_dword(pdev, I82875P_EAP, &info->eap);
pci_read_config_byte(pdev, I82875P_DES, &info->des);
pci_read_config_byte(pdev, I82875P_DERRSYN, &info->derrsyn);
}
pci_write_bits16(pdev, I82875P_ERRSTS, 0x0081, 0x0081);
}
static int i82875p_process_error_info(struct mem_ctl_info *mci,
struct i82875p_error_info *info,
int handle_errors)
{
int row, multi_chan;
multi_chan = mci->csrows[0].nr_channels - 1;
if (!(info->errsts & 0x0081))
return 0;
if (!handle_errors)
return 1;
if ((info->errsts ^ info->errsts2) & 0x0081) {
edac_mc_handle_ce_no_info(mci, "UE overwrote CE");
info->errsts = info->errsts2;
}
info->eap >>= PAGE_SHIFT;
row = edac_mc_find_csrow_by_page(mci, info->eap);
if (info->errsts & 0x0080)
edac_mc_handle_ue(mci, info->eap, 0, row, "i82875p UE");
else
edac_mc_handle_ce(mci, info->eap, 0, info->derrsyn, row,
multi_chan ? (info->des & 0x1) : 0,
"i82875p CE");
return 1;
}
static void i82875p_check(struct mem_ctl_info *mci)
{
struct i82875p_error_info info;
debugf1("MC%d: %s()\n", mci->mc_idx, __func__);
i82875p_get_error_info(mci, &info);
i82875p_process_error_info(mci, &info, 1);
}
/* Return 0 on success or 1 on failure. */
static int i82875p_setup_overfl_dev(struct pci_dev *pdev,
struct pci_dev **ovrfl_pdev,
void __iomem **ovrfl_window)
{
struct pci_dev *dev;
void __iomem *window;
int err;
*ovrfl_pdev = NULL;
*ovrfl_window = NULL;
dev = pci_get_device(PCI_VEND_DEV(INTEL, 82875_6), NULL);
if (dev == NULL) {
/* Intel tells BIOS developers to hide device 6 which
* configures the overflow device access containing
* the DRBs - this is where we expose device 6.
* http://www.x86-secret.com/articles/tweak/pat/patsecrets-2.htm
*/
pci_write_bits8(pdev, 0xf4, 0x2, 0x2);
dev = pci_scan_single_device(pdev->bus, PCI_DEVFN(6, 0));
if (dev == NULL)
return 1;
err = pci_bus_add_device(dev);
if (err) {
i82875p_printk(KERN_ERR,
"%s(): pci_bus_add_device() Failed\n",
__func__);
}
pci_bus_assign_resources(dev->bus);
}
*ovrfl_pdev = dev;
if (pci_enable_device(dev)) {
i82875p_printk(KERN_ERR, "%s(): Failed to enable overflow "
"device\n", __func__);
return 1;
}
if (pci_request_regions(dev, pci_name(dev))) {
#ifdef CORRECT_BIOS
goto fail0;
#endif
}
/* cache is irrelevant for PCI bus reads/writes */
window = ioremap_nocache(pci_resource_start(dev, 0),
pci_resource_len(dev, 0));
if (window == NULL) {
i82875p_printk(KERN_ERR, "%s(): Failed to ioremap bar6\n",
__func__);
goto fail1;
}
*ovrfl_window = window;
return 0;
fail1:
pci_release_regions(dev);
#ifdef CORRECT_BIOS
fail0:
pci_disable_device(dev);
#endif
/* NOTE: the ovrfl proc entry and pci_dev are intentionally left */
return 1;
}
/* Return 1 if dual channel mode is active. Else return 0. */
static inline int dual_channel_active(u32 drc)
{
return (drc >> 21) & 0x1;
}
static void i82875p_init_csrows(struct mem_ctl_info *mci,
struct pci_dev *pdev,
void __iomem * ovrfl_window, u32 drc)
{
struct csrow_info *csrow;
unsigned long last_cumul_size;
u8 value;
u32 drc_ddim; /* DRAM Data Integrity Mode 0=none,2=edac */
u32 cumul_size;
int index;
drc_ddim = (drc >> 18) & 0x1;
last_cumul_size = 0;
/* The dram row boundary (DRB) reg values are boundary address
* for each DRAM row with a granularity of 32 or 64MB (single/dual
* channel operation). DRB regs are cumulative; therefore DRB7 will
* contain the total memory contained in all eight rows.
*/
for (index = 0; index < mci->nr_csrows; index++) {
csrow = &mci->csrows[index];
value = readb(ovrfl_window + I82875P_DRB + index);
cumul_size = value << (I82875P_DRB_SHIFT - PAGE_SHIFT);
debugf3("%s(): (%d) cumul_size 0x%x\n", __func__, index,
cumul_size);
if (cumul_size == last_cumul_size)
continue; /* not populated */
csrow->first_page = last_cumul_size;
csrow->last_page = cumul_size - 1;
csrow->nr_pages = cumul_size - last_cumul_size;
last_cumul_size = cumul_size;
csrow->grain = 1 << 12; /* I82875P_EAP has 4KiB reolution */
csrow->mtype = MEM_DDR;
csrow->dtype = DEV_UNKNOWN;
csrow->edac_mode = drc_ddim ? EDAC_SECDED : EDAC_NONE;
}
}
static int i82875p_probe1(struct pci_dev *pdev, int dev_idx)
{
int rc = -ENODEV;
struct mem_ctl_info *mci;
struct i82875p_pvt *pvt;
struct pci_dev *ovrfl_pdev;
void __iomem *ovrfl_window;
u32 drc;
u32 nr_chans;
struct i82875p_error_info discard;
debugf0("%s()\n", __func__);
ovrfl_pdev = pci_get_device(PCI_VEND_DEV(INTEL, 82875_6), NULL);
if (i82875p_setup_overfl_dev(pdev, &ovrfl_pdev, &ovrfl_window))
return -ENODEV;
drc = readl(ovrfl_window + I82875P_DRC);
nr_chans = dual_channel_active(drc) + 1;
mci = edac_mc_alloc(sizeof(*pvt), I82875P_NR_CSROWS(nr_chans),
nr_chans, 0);
if (!mci) {
rc = -ENOMEM;
goto fail0;
}
/* Keeps mci available after edac_mc_del_mc() till edac_mc_free() */
kobject_get(&mci->edac_mci_kobj);
debugf3("%s(): init mci\n", __func__);
mci->dev = &pdev->dev;
mci->mtype_cap = MEM_FLAG_DDR;
mci->edac_ctl_cap = EDAC_FLAG_NONE | EDAC_FLAG_SECDED;
mci->edac_cap = EDAC_FLAG_UNKNOWN;
mci->mod_name = EDAC_MOD_STR;
mci->mod_ver = I82875P_REVISION;
mci->ctl_name = i82875p_devs[dev_idx].ctl_name;
mci->dev_name = pci_name(pdev);
mci->edac_check = i82875p_check;
mci->ctl_page_to_phys = NULL;
debugf3("%s(): init pvt\n", __func__);
pvt = (struct i82875p_pvt *)mci->pvt_info;
pvt->ovrfl_pdev = ovrfl_pdev;
pvt->ovrfl_window = ovrfl_window;
i82875p_init_csrows(mci, pdev, ovrfl_window, drc);
i82875p_get_error_info(mci, &discard); /* clear counters */
/* Here we assume that we will never see multiple instances of this
* type of memory controller. The ID is therefore hardcoded to 0.
*/
if (edac_mc_add_mc(mci)) {
debugf3("%s(): failed edac_mc_add_mc()\n", __func__);
goto fail1;
}
/* allocating generic PCI control info */
i82875p_pci = edac_pci_create_generic_ctl(&pdev->dev, EDAC_MOD_STR);
if (!i82875p_pci) {
printk(KERN_WARNING
"%s(): Unable to create PCI control\n",
__func__);
printk(KERN_WARNING
"%s(): PCI error report via EDAC not setup\n",
__func__);
}
/* get this far and it's successful */
debugf3("%s(): success\n", __func__);
return 0;
fail1:
kobject_put(&mci->edac_mci_kobj);
edac_mc_free(mci);
fail0:
iounmap(ovrfl_window);
pci_release_regions(ovrfl_pdev);
pci_disable_device(ovrfl_pdev);
/* NOTE: the ovrfl proc entry and pci_dev are intentionally left */
return rc;
}
/* returns count (>= 0), or negative on error */
static int __devinit i82875p_init_one(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
int rc;
debugf0("%s()\n", __func__);
i82875p_printk(KERN_INFO, "i82875p init one\n");
if (pci_enable_device(pdev) < 0)
return -EIO;
rc = i82875p_probe1(pdev, ent->driver_data);
if (mci_pdev == NULL)
mci_pdev = pci_dev_get(pdev);
return rc;
}
static void __devexit i82875p_remove_one(struct pci_dev *pdev)
{
struct mem_ctl_info *mci;
struct i82875p_pvt *pvt = NULL;
debugf0("%s()\n", __func__);
if (i82875p_pci)
edac_pci_release_generic_ctl(i82875p_pci);
if ((mci = edac_mc_del_mc(&pdev->dev)) == NULL)
return;
pvt = (struct i82875p_pvt *)mci->pvt_info;
if (pvt->ovrfl_window)
iounmap(pvt->ovrfl_window);
if (pvt->ovrfl_pdev) {
#ifdef CORRECT_BIOS
pci_release_regions(pvt->ovrfl_pdev);
#endif /*CORRECT_BIOS */
pci_disable_device(pvt->ovrfl_pdev);
pci_dev_put(pvt->ovrfl_pdev);
}
edac_mc_free(mci);
}
static const struct pci_device_id i82875p_pci_tbl[] __devinitdata = {
{
PCI_VEND_DEV(INTEL, 82875_0), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
I82875P},
{
0,
} /* 0 terminated list. */
};
MODULE_DEVICE_TABLE(pci, i82875p_pci_tbl);
static struct pci_driver i82875p_driver = {
.name = EDAC_MOD_STR,
.probe = i82875p_init_one,
.remove = __devexit_p(i82875p_remove_one),
.id_table = i82875p_pci_tbl,
};
static int __init i82875p_init(void)
{
int pci_rc;
debugf3("%s()\n", __func__);
/* Ensure that the OPSTATE is set correctly for POLL or NMI */
opstate_init();
pci_rc = pci_register_driver(&i82875p_driver);
if (pci_rc < 0)
goto fail0;
if (mci_pdev == NULL) {
mci_pdev = pci_get_device(PCI_VENDOR_ID_INTEL,
PCI_DEVICE_ID_INTEL_82875_0, NULL);
if (!mci_pdev) {
debugf0("875p pci_get_device fail\n");
pci_rc = -ENODEV;
goto fail1;
}
pci_rc = i82875p_init_one(mci_pdev, i82875p_pci_tbl);
if (pci_rc < 0) {
debugf0("875p init fail\n");
pci_rc = -ENODEV;
goto fail1;
}
}
return 0;
fail1:
pci_unregister_driver(&i82875p_driver);
fail0:
if (mci_pdev != NULL)
pci_dev_put(mci_pdev);
return pci_rc;
}
static void __exit i82875p_exit(void)
{
debugf3("%s()\n", __func__);
i82875p_remove_one(mci_pdev);
pci_dev_put(mci_pdev);
pci_unregister_driver(&i82875p_driver);
}
module_init(i82875p_init);
module_exit(i82875p_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Linux Networx (http://lnxi.com) Thayne Harbaugh");
MODULE_DESCRIPTION("MC support for Intel 82875 memory hub controllers");
module_param(edac_op_state, int, 0444);
MODULE_PARM_DESC(edac_op_state, "EDAC Error Reporting state: 0=Poll,1=NMI");