dump_stack: implement arch-specific hardware description in task dumps

x86 and ia64 can acquire extra hardware identification information
from DMI and print it along with task dumps; however, the usage isn't
consistent.

* x86 show_regs() collects vendor, product and board strings and print
  them out with PID, comm and utsname.  Some of the information is
  printed again later in the same dump.

* warn_slowpath_common() explicitly accesses the DMI board and prints
  it out with "Hardware name:" label.  This applies to both x86 and
  ia64 but is irrelevant on all other archs.

* ia64 doesn't show DMI information on other non-WARN dumps.

This patch introduces arch-specific hardware description used by
dump_stack().  It can be set by calling dump_stack_set_arch_desc()
during boot and, if exists, printed out in a separate line with
"Hardware name:" label.

dmi_set_dump_stack_arch_desc() is added which sets arch-specific
description from DMI data.  It uses dmi_ids_string[] which is set from
dmi_present() used for DMI debug message.  It is superset of the
information x86 show_regs() is using.  The function is called from x86
and ia64 boot code right after dmi_scan_machine().

This makes the explicit DMI handling in warn_slowpath_common()
unnecessary.  Removed.

show_regs() isn't yet converted to use generic debug information
printing and this patch doesn't remove the duplicate DMI handling in
x86 show_regs().  The next patch will unify show_regs() handling and
remove the duplication.

An example WARN dump follows.

 WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #3
 Hardware name: empty empty/S3992, BIOS 080011  10/26/2007
  0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
  ffffffff8108f500 ffffffff82228240 0000000000000040 ffffffff8234a08e
  0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
 Call Trace:
  [<ffffffff81c614dc>] dump_stack+0x19/0x1b
  [<ffffffff8108f500>] warn_slowpath_common+0x70/0xa0
  [<ffffffff8108f54a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff8234a0c3>] init_workqueues+0x35/0x505
  ...

v2: Use the same string as the debug message from dmi_present() which
    also contains BIOS information.  Move hardware name into its own
    line as warn_slowpath_common() did.  This change was suggested by
    Bjorn Helgaas.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/dmi.h b/include/linux/dmi.h
index f156cca25ad0..b6eb7a05d58e 100644
--- a/include/linux/dmi.h
+++ b/include/linux/dmi.h
@@ -99,6 +99,7 @@ extern const char * dmi_get_system_info(int field);
 extern const struct dmi_device * dmi_find_device(int type, const char *name,
 	const struct dmi_device *from);
 extern void dmi_scan_machine(void);
+extern void dmi_set_dump_stack_arch_desc(void);
 extern bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp);
 extern int dmi_name_in_vendors(const char *str);
 extern int dmi_name_in_serial(const char *str);
@@ -114,6 +115,7 @@ static inline const char * dmi_get_system_info(int field) { return NULL; }
 static inline const struct dmi_device * dmi_find_device(int type, const char *name,
 	const struct dmi_device *from) { return NULL; }
 static inline void dmi_scan_machine(void) { return; }
+static inline void dmi_set_dump_stack_arch_desc(void) { }
 static inline bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp)
 {
 	if (yearp)
diff --git a/include/linux/printk.h b/include/linux/printk.h
index 7ce1f878cf6a..47827c0a034d 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -145,6 +145,7 @@ extern void wake_up_klogd(void);
 
 void log_buf_kexec_setup(void);
 void __init setup_log_buf(int early);
+void dump_stack_set_arch_desc(const char *fmt, ...);
 void dump_stack_print_info(const char *log_lvl);
 #else
 static inline __printf(1, 0)
@@ -184,6 +185,10 @@ static inline void setup_log_buf(int early)
 {
 }
 
+static inline void dump_stack_set_arch_desc(const char *fmt, ...)
+{
+}
+
 static inline void dump_stack_print_info(const char *log_lvl)
 {
 }