[PATCH] lockdep: stacktrace subsystem, s390 support

stacktrace interface for s390 as needed by lock validator.

[clg@fr.ibm.com: build fix]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 821a141..5b28da4 100644 (file)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -7,6 +7,10 @@ config MMU
        bool
        default y
 
+config STACKTRACE_SUPPORT
+       bool
+       default y
+
 config RWSEM_GENERIC_SPINLOCK
        bool
 

diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 9269b57..eabf00a 100644 (file)
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_COMPAT)          += compat_linux.o compat_signal.o \
 obj-$(CONFIG_BINFMT_ELF32)     += binfmt_elf32.o
 
 obj-$(CONFIG_VIRT_TIMER)       += vtime.o
+obj-$(CONFIG_STACKTRACE)       += stacktrace.o
 
 # Kexec part
 S390_KEXEC_OBJS := machine_kexec.o crash.o

diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
new file mode 100644 (file)
index 0000000..de83f38
--- /dev/null
+++ b/arch/s390/kernel/stacktrace.c
@@ -0,0 +1,90 @@
+/*
+ * arch/s390/kernel/stacktrace.c
+ *
+ * Stack trace management functions
+ *
+ *  Copyright (C) IBM Corp. 2006
+ *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/kallsyms.h>
+
+static inline unsigned long save_context_stack(struct stack_trace *trace,
+                                              unsigned int *skip,
+                                              unsigned long sp,
+                                              unsigned long low,
+                                              unsigned long high)
+{
+       struct stack_frame *sf;
+       struct pt_regs *regs;
+       unsigned long addr;
+
+       while(1) {
+               sp &= PSW_ADDR_INSN;
+               if (sp < low || sp > high)
+                       return sp;
+               sf = (struct stack_frame *)sp;
+               while(1) {
+                       addr = sf->gprs[8] & PSW_ADDR_INSN;
+                       if (!(*skip))
+                               trace->entries[trace->nr_entries++] = addr;
+                       else
+                               (*skip)--;
+                       if (trace->nr_entries >= trace->max_entries)
+                               return sp;
+                       low = sp;
+                       sp = sf->back_chain & PSW_ADDR_INSN;
+                       if (!sp)
+                               break;
+                       if (sp <= low || sp > high - sizeof(*sf))
+                               return sp;
+                       sf = (struct stack_frame *)sp;
+               }
+               /* Zero backchain detected, check for interrupt frame. */
+               sp = (unsigned long)(sf + 1);
+               if (sp <= low || sp > high - sizeof(*regs))
+                       return sp;
+               regs = (struct pt_regs *)sp;
+               addr = regs->psw.addr & PSW_ADDR_INSN;
+               if (!(*skip))
+                       trace->entries[trace->nr_entries++] = addr;
+               else
+                       (*skip)--;
+               if (trace->nr_entries >= trace->max_entries)
+                       return sp;
+               low = sp;
+               sp = regs->gprs[15];
+       }
+}
+
+void save_stack_trace(struct stack_trace *trace,
+                     struct task_struct *task, int all_contexts,
+                     unsigned int skip)
+{
+       register unsigned long sp asm ("15");
+       unsigned long orig_sp;
+
+       sp &= PSW_ADDR_INSN;
+       orig_sp = sp;
+
+       sp = save_context_stack(trace, &skip, sp,
+                               S390_lowcore.panic_stack - PAGE_SIZE,
+                               S390_lowcore.panic_stack);
+       if ((sp != orig_sp) && !all_contexts)
+               return;
+       sp = save_context_stack(trace, &skip, sp,
+                               S390_lowcore.async_stack - ASYNC_SIZE,
+                               S390_lowcore.async_stack);
+       if ((sp != orig_sp) && !all_contexts)
+               return;
+       if (task)
+               save_context_stack(trace, &skip, sp,
+                                  (unsigned long) task_stack_page(task),
+                                  (unsigned long) task_stack_page(task) + THREAD_SIZE);
+       else
+               save_context_stack(trace, &skip, sp, S390_lowcore.thread_info,
+                                  S390_lowcore.thread_info + THREAD_SIZE);
+       return;
+}