Changeset 819a768 in mainline

Timestamp:

2010-05-21T22:34:33Z (15 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.

Location:

kernel/arch/sparc64

Files:

• include/trap/trap_table.h (modified) (2 diffs)
• src/debug/stacktrace.c (modified) (2 diffs)

kernel/arch/sparc64/include/trap/trap_table.h

@@ -42 +42 @@
 #define TRAP_TABLE_SIZE         (TRAP_TABLE_ENTRY_COUNT * TRAP_TABLE_ENTRY_SIZE)
 
+/*
+ * The following needs to be in sync with the definition of the istate
+ * structure. The one STACK_ITEM_SIZE is counted for space holding the 7th
+ * argument to syscall_handler (i.e. syscall number) and the other
+ * STACK_ITEM_SIZE is counted because of the required alignment.
+ */
+#define PREEMPTIBLE_HANDLER_STACK_FRAME_SIZE \
+    (STACK_WINDOW_SAVE_AREA_SIZE + STACK_ARG_SAVE_AREA_SIZE + \
+    (2 * STACK_ITEM_SIZE) + (12 * 8))
+#define SAVED_TSTATE    -(1 * 8)
+#define SAVED_TPC       -(2 * 8)
+#define SAVED_TNPC      -(3 * 8)        /* <-- istate_t begins here */
+#define SAVED_Y         -(4 * 8)
+#define SAVED_I0        -(5 * 8)
+#define SAVED_I1        -(6 * 8)
+#define SAVED_I2        -(7 * 8)
+#define SAVED_I3        -(8 * 8)
+#define SAVED_I4        -(9 * 8)
+#define SAVED_I5        -(10 * 8)
+#define SAVED_I6        -(11 * 8)
+#define SAVED_I7        -(12 * 8)
+
 #ifndef __ASM__
 
@@ -77 +99 @@
 .endm
 
-/*
- * The following needs to be in sync with the definition of the istate
- * structure. The one STACK_ITEM_SIZE is counted for space holding the 7th
- * argument to syscall_handler (i.e. syscall number) and the other
- * STACK_ITEM_SIZE is counted because of the required alignment.
- */
-#define PREEMPTIBLE_HANDLER_STACK_FRAME_SIZE    \
-    (STACK_WINDOW_SAVE_AREA_SIZE + STACK_ARG_SAVE_AREA_SIZE + \
-    (2 * STACK_ITEM_SIZE) + (12 * 8))
-#define SAVED_TSTATE    -(1 * 8)
-#define SAVED_TPC       -(2 * 8)
-#define SAVED_TNPC      -(3 * 8)        /* <-- istate_t begins here */
-#define SAVED_Y         -(4 * 8)
-#define SAVED_I0        -(5 * 8)
-#define SAVED_I1        -(6 * 8)
-#define SAVED_I2        -(7 * 8)
-#define SAVED_I3        -(8 * 8)
-#define SAVED_I4        -(9 * 8)
-#define SAVED_I5        -(10 * 8)
-#define SAVED_I6        -(11 * 8)
-#define SAVED_I7        -(12 * 8)
-
 .macro PREEMPTIBLE_HANDLER f
         sethi %hi(\f), %g1

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;
 }