Set up a frame pointer on interrupt entry, to improve backtraces of

[pintos-anon] / src / threads / interrupt.h

diff --git a/src/threads/interrupt.h b/src/threads/interrupt.h
index d54b7ef0893ff4caff7af5883d47b7c123fcd0d8..b805671e626d6891f1b43aa06de64674f15a91d6 100644 (file)
--- a/src/threads/interrupt.h
+++ b/src/threads/interrupt.h
@@ -19,7 +19,7 @@ enum intr_level intr_disable (void);
 /* Interrupt stack frame. */
 struct intr_frame
   {
-    /* Pushed by intr_entry in intr-stubs.S (see intr-stubs.pl).
+    /* Pushed by intr_entry in intr-stubs.S.
        These are the interrupted task's saved registers. */
     uint32_t edi;               /* Saved EDI. */
     uint32_t esi;               /* Saved ESI. */
@@ -29,16 +29,23 @@ struct intr_frame
     uint32_t edx;               /* Saved EDX. */
     uint32_t ecx;               /* Saved ECX. */
     uint32_t eax;               /* Saved EAX. */
+    uint16_t gs, :16;           /* Saved GS segment register. */
+    uint16_t fs, :16;           /* Saved FS segment register. */
     uint16_t es, :16;           /* Saved ES segment register. */
     uint16_t ds, :16;           /* Saved DS segment register. */
 
-    /* Pushed by intrXX_stub in intr-stubs.S (see intr-stubs.pl). */
+    /* Pushed by intrNN_stub in intr-stubs.S. */
     uint32_t vec_no;            /* Interrupt vector number. */
 
     /* Sometimes pushed by the CPU,
-       otherwise for consistency pushed as 0 by intrXX_stub. */
+       otherwise for consistency pushed as 0 by intrNN_stub.
+       The CPU puts it just under `eip', but we move it here. */
     uint32_t error_code;        /* Error code. */
 
+    /* Pushed by intrNN_stub in intr-stubs.S.
+       This frame pointer eases interpretation of backtraces. */
+    void *frame_pointer;        /* Saved EBP (frame pointer). */
+
     /* Pushed by the CPU.
        These are the interrupted task's saved registers. */
     void (*eip) (void);         /* Next instruction to execute. */