[tip:x86/early-printk] x86/earlyprintk: Add a force option for pciserial device
Commit-ID: d2266bbfa9e3e32e3b642965088ca461bd24a94f
Gitweb: https://git.kernel.org/tip/d2266bbfa9e3e32e3b642965088ca461bd24a94f
Author: Feng Tang
AuthorDate: Wed, 3 Oct 2018 00:49:21 +0800
Committer: Borislav Petkov
CommitDate: Tue, 2 Oct 2018 21:02:47 +0200
x86/earlyprintk: Add a force option for pciserial device
The "pciserial" earlyprintk variant helps much on many modern x86
platforms, but unfortunately there are still some platforms with PCI
UART devices which have the wrong PCI class code. In that case, the
current class code check does not allow for them to be used for logging.
Add a sub-option "force" which overrides the class code check and thus
the use of such device can be enforced.
[ bp: massage formulations. ]
Suggested-by: Borislav Petkov
Signed-off-by: Feng Tang
Signed-off-by: Borislav Petkov
Cc: "H. Peter Anvin"
Cc: "Stuart R . Anderson"
Cc: Bjorn Helgaas
Cc: David Rientjes
Cc: Feng Tang
Cc: Frederic Weisbecker
Cc: Greg Kroah-Hartman
Cc: H Peter Anvin
Cc: Ingo Molnar
Cc: Jiri Kosina
Cc: Jonathan Corbet
Cc: Kai-Heng Feng
Cc: Kate Stewart
Cc: Konrad Rzeszutek Wilk
Cc: Peter Zijlstra
Cc: Philippe Ombredanne
Cc: Thomas Gleixner
Cc: Thymo van Beers
Cc: a...@linux.intel.com
Cc: linux-...@vger.kernel.org
Link: http://lkml.kernel.org/r/20181002164921.25833-1-feng.t...@intel.com
---
Documentation/admin-guide/kernel-parameters.txt | 6 -
arch/x86/kernel/early_printk.c | 29 -
2 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 92eb1f42240d..34e6800dea0e 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1063,7 +1063,7 @@
earlyprintk=serial[,0x...[,baudrate]]
earlyprintk=ttySn[,baudrate]
earlyprintk=dbgp[debugController#]
- earlyprintk=pciserial,bus:device.function[,baudrate]
+
earlyprintk=pciserial[,force],bus:device.function[,baudrate]
earlyprintk=xdbc[xhciController#]
earlyprintk is useful when the kernel crashes before
@@ -1095,6 +1095,10 @@
The sclp output can only be used on s390.
+ The optional "force" to "pciserial" enables use of a
+ PCI device even when its classcode is not of the
+ UART class.
+
edac_report=[HW,EDAC] Control how to report EDAC event
Format: {"on" | "off" | "force"}
on: enable EDAC to report H/W event. May be overridden
diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index 5e801c8c8ce7..374a52fa5296 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -213,8 +213,9 @@ static unsigned int mem32_serial_in(unsigned long addr, int
offset)
* early_pci_serial_init()
*
* This function is invoked when the early_printk param starts with "pciserial"
- * The rest of the param should be ",B:D.F,baud" where B, D & F describe the
- * location of a PCI device that must be a UART device.
+ * The rest of the param should be "[force],B:D.F,baud", where B, D & F
describe
+ * the location of a PCI device that must be a UART device. "force" is optional
+ * and overrides the use of an UART device with a wrong PCI class code.
*/
static __init void early_pci_serial_init(char *s)
{
@@ -224,17 +225,23 @@ static __init void early_pci_serial_init(char *s)
u32 classcode, bar0;
u16 cmdreg;
char *e;
+ int force = 0;
-
- /*
-* First, part the param to get the BDF values
-*/
if (*s == ',')
++s;
if (*s == 0)
return;
+ /* Force the use of an UART device with wrong class code */
+ if (!strncmp(s, "force,", 6)) {
+ force = 1;
+ s += 6;
+ }
+
+ /*
+* Part the param to get the BDF values
+*/
bus = (u8)simple_strtoul(s, &e, 16);
s = e;
if (*s != ':')
@@ -253,7 +260,7 @@ static __init void early_pci_serial_init(char *s)
s++;
/*
-* Second, find the device from the BDF
+* Find the device from the BDF
*/
cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
@@ -264,8 +271,10 @@ static __init void early_pci_serial_init(char *s)
*/
if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
(classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
- (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */
- return;
+ (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */ {
[tip:x86/early-printk] x86/earlyprintk: Add a force option for pciserial device
Commit-ID: fa7948a6413c63128335aa871fade8df55ac61e2
Gitweb: https://git.kernel.org/tip/fa7948a6413c63128335aa871fade8df55ac61e2
Author: Feng Tang
AuthorDate: Wed, 3 Oct 2018 00:49:21 +0800
Committer: Borislav Petkov
CommitDate: Tue, 2 Oct 2018 20:40:27 +0200
x86/earlyprintk: Add a force option for pciserial device
The "pciserial" earlyprintk variant helps much on many modern x86
platforms, but unfortunately there are still some platforms with PCI
UART devices which have the wrong PCI class code. In that case, the
current class code check does not allow for them to be used for logging.
Add a sub-option "force" which overrides the class code check and thus
the use of such device can be enforced.
[ bp: massage formulations. ]
Suggested-by: Borislav Petkov
Signed-off-by: Feng Tang
Cc: "H. Peter Anvin"
Cc: "Stuart R . Anderson"
Cc: Bjorn Helgaas
Cc: David Rientjes
Cc: Feng Tang
Cc: Frederic Weisbecker
Cc: Greg Kroah-Hartman
Cc: H Peter Anvin
Cc: Ingo Molnar
Cc: Jiri Kosina
Cc: Jonathan Corbet
Cc: Kai-Heng Feng
Cc: Kate Stewart
Cc: Konrad Rzeszutek Wilk
Cc: Peter Zijlstra
Cc: Philippe Ombredanne
Cc: Thomas Gleixner
Cc: Thymo van Beers
Cc: a...@linux.intel.com
Cc: linux-...@vger.kernel.org
Link: http://lkml.kernel.org/r/20181002164921.25833-1-feng.t...@intel.com
---
Documentation/admin-guide/kernel-parameters.txt | 6 -
arch/x86/kernel/early_printk.c | 29 -
2 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 92eb1f42240d..34e6800dea0e 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1063,7 +1063,7 @@
earlyprintk=serial[,0x...[,baudrate]]
earlyprintk=ttySn[,baudrate]
earlyprintk=dbgp[debugController#]
- earlyprintk=pciserial,bus:device.function[,baudrate]
+
earlyprintk=pciserial[,force],bus:device.function[,baudrate]
earlyprintk=xdbc[xhciController#]
earlyprintk is useful when the kernel crashes before
@@ -1095,6 +1095,10 @@
The sclp output can only be used on s390.
+ The optional "force" to "pciserial" enables use of a
+ PCI device even when its classcode is not of the
+ UART class.
+
edac_report=[HW,EDAC] Control how to report EDAC event
Format: {"on" | "off" | "force"}
on: enable EDAC to report H/W event. May be overridden
diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index 5e801c8c8ce7..374a52fa5296 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -213,8 +213,9 @@ static unsigned int mem32_serial_in(unsigned long addr, int
offset)
* early_pci_serial_init()
*
* This function is invoked when the early_printk param starts with "pciserial"
- * The rest of the param should be ",B:D.F,baud" where B, D & F describe the
- * location of a PCI device that must be a UART device.
+ * The rest of the param should be "[force],B:D.F,baud", where B, D & F
describe
+ * the location of a PCI device that must be a UART device. "force" is optional
+ * and overrides the use of an UART device with a wrong PCI class code.
*/
static __init void early_pci_serial_init(char *s)
{
@@ -224,17 +225,23 @@ static __init void early_pci_serial_init(char *s)
u32 classcode, bar0;
u16 cmdreg;
char *e;
+ int force = 0;
-
- /*
-* First, part the param to get the BDF values
-*/
if (*s == ',')
++s;
if (*s == 0)
return;
+ /* Force the use of an UART device with wrong class code */
+ if (!strncmp(s, "force,", 6)) {
+ force = 1;
+ s += 6;
+ }
+
+ /*
+* Part the param to get the BDF values
+*/
bus = (u8)simple_strtoul(s, &e, 16);
s = e;
if (*s != ':')
@@ -253,7 +260,7 @@ static __init void early_pci_serial_init(char *s)
s++;
/*
-* Second, find the device from the BDF
+* Find the device from the BDF
*/
cmdreg = read_pci_config(bus, slot, func, PCI_COMMAND);
classcode = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
@@ -264,8 +271,10 @@ static __init void early_pci_serial_init(char *s)
*/
if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) &&
(classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) ||
- (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */
- return;
+ (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */ {
+ if (!force)
+
