Changeset 819a768 in mainline for kernel/arch/sparc64/src/debug/stacktrace.c

Timestamp:

2010-05-21T22:34:33Z (14 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

0242621

Parents:

2ee907e

Message:

On sparc64, we have a problem with determining the end of the kernel stack
because the preemptible trap handler cannot easily terminate the stack trace by
writing -STACK_BIAS to %fp as that %fp is unfortunatelly an %sp of the previous
context (user or kernel).

Without sacrifying performance via the FLUSHW instruction, we simply have to
stop tracing when we see the stack frame with %sp created by the SAVE
instruction inside the preemptible trap handler.

File:

• kernel/arch/sparc64/src/debug/stacktrace.c (modified) (2 diffs)

kernel/arch/sparc64/src/debug/stacktrace.c

@@ -37 +37 @@
 #include <typedefs.h>
 
+#include <arch.h>
 #include <arch/stack.h>
+#include <arch/trap/trap_table.h>
+
+#if defined(SUN4V)
+#include <arch/sun4v/arch.h>
+#endif
 
 #define FRAME_OFFSET_FP_PREV    14
@@ -46 +52 @@
 bool kernel_frame_pointer_validate(uintptr_t fp)
 {
+        uintptr_t kstack;
+        
+#if defined(SUN4U)
+        kstack = read_from_ag_g6();
+#elif defined(SUN4V)
+        kstack = asi_u64_read(ASI_SCRATCHPAD, SCRATCHPAD_KSTACK);
+#endif
+
+        kstack += STACK_BIAS;
+        kstack -= PREEMPTIBLE_HANDLER_STACK_FRAME_SIZE;
+
+        if (THREAD && (fp == kstack))
+                return false;
         return fp != 0;
 }