Date: Tue, 1 Oct 1996 16:16:36 -0400 From: Garrett Wollman <wollman@lcs.mit.edu> To: Julian Elischer <julian@whistle.com> Cc: current@FreeBSD.ORG Subject: Re: gdb port testing... gdb-4.16 to move into /usr/src soon... Message-ID: <9610012016.AA00447@halloran-eldar.lcs.mit.edu> In-Reply-To: <3251786E.59E2B600@whistle.com> References: <9610011420.AA04046@cssmuc.frt.dec.com> <3251786E.59E2B600@whistle.com>
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<<On Tue, 01 Oct 1996 13:00:46 -0700, Julian Elischer <julian@whistle.com> said:
> for me, looking at stack traces on the new one (using the dgb stubs)
> on a running kernel, were not as good on the new one as in the old one..
> I'll try to give examples soon.
I have hacked a bit on the code to make it properly decode special
frames when debugging the kernel. Patches follow, beware cut&paste
lossage...
-GAWollman
diff -u -r1.1 -r1.7
--- kvm-fbsd.c 1996/09/30 21:04:19 1.1
+++ kvm-fbsd.c 1996/10/01 20:13:15 1.7
@@ -40,6 +40,7 @@
#include <machine/vmparam.h>
#include <machine/pcb.h>
+#include <machine/frame.h>
static void kcore_files_info PARAMS ((struct target_ops *));
@@ -105,6 +106,92 @@
*/
#define kvread(addr, p) \
(target_read_memory ((CORE_ADDR)(addr), (char *)(p), sizeof(*(p))))
+
+
+/*
+ * The following is FreeBSD-specific hackery to decode special frames
+ * and elide the assembly-language stub. This could be made faster by
+ * defining a frame_type field in the machine-dependent frame information,
+ * but we don't think that's too important right now.
+ */
+enum frametype { tf_normal, tf_trap, tf_interrupt, tf_syscall };
+
+CORE_ADDR
+fbsd_kern_frame_saved_pc (fr)
+struct frame_info *fr;
+{
+ struct minimal_symbol *sym;
+ CORE_ADDR this_saved_pc;
+ enum frametype frametype;
+
+ this_saved_pc = read_memory_integer (fr->frame + 4, 4);
+ sym = lookup_minimal_symbol_by_pc (this_saved_pc);
+ frametype = tf_normal;
+ if (sym != NULL) {
+ if (strcmp (SYMBOL_NAME(sym), "calltrap") == 0)
+ frametype = tf_trap;
+ else if (strncmp (SYMBOL_NAME(sym), "Xresume", 7) == 0)
+ frametype = tf_interrupt;
+ else if (strcmp (SYMBOL_NAME(sym), "Xsyscall") == 0)
+ frametype = tf_syscall;
+ }
+
+ switch (frametype) {
+ case tf_normal:
+ return (this_saved_pc);
+
+#define oEIP offsetof(struct trapframe, tf_eip)
+
+ case tf_trap:
+ return (read_memory_integer (fr->frame + 8 + oEIP, 4));
+
+ case tf_interrupt:
+ return (read_memory_integer (fr->frame + 16 + oEIP, 4));
+
+ case tf_syscall:
+ return (read_memory_integer (fr->frame + 8 + oEIP, 4));
+#undef oEIP
+ }
+}
+
+CORE_ADDR
+fbsd_kern_frame_chain (fr)
+struct frame_info *fr;
+{
+ struct minimal_symbol *sym;
+ CORE_ADDR this_saved_pc;
+ enum frametype frametype;
+
+ this_saved_pc = read_memory_integer (fr->frame + 4, 4);
+ sym = lookup_minimal_symbol_by_pc (this_saved_pc);
+ frametype = tf_normal;
+ if (sym != NULL) {
+ if (strcmp (SYMBOL_NAME(sym), "calltrap") == 0)
+ frametype = tf_trap;
+ else if (strncmp (SYMBOL_NAME(sym), "Xresume", 7) == 0)
+ frametype = tf_interrupt;
+ else if (strcmp (SYMBOL_NAME(sym), "_Xsyscall") == 0)
+ frametype = tf_syscall;
+ }
+
+ switch (frametype) {
+ case tf_normal:
+ return (read_memory_integer (fr->frame, 4));
+
+#define oEBP offsetof(struct trapframe, tf_ebp)
+
+ case tf_trap:
+ return (read_memory_integer (fr->frame + 8 + oEBP, 4));
+
+ case tf_interrupt:
+ return (read_memory_integer (fr->frame + 16 + oEBP, 4));
+
+ case tf_syscall:
+ return (read_memory_integer (fr->frame + 8 + oEBP, 4));
+#undef oEBP
+ }
+}
+
static CORE_ADDR
ksym_lookup (name)
diff -u -r1.1 -r1.2
--- tm-fbsd.h 1996/09/30 21:04:48 1.1
+++ tm-fbsd.h 1996/10/01 18:54:36 1.2
@@ -35,4 +35,30 @@
#define IN_SOLIB_CALL_TRAMPOLINE(pc, name) STREQ (name, "_DYNAMIC")
+/* FRAME_CHAIN takes a frame's nominal address and produces the frame's
+ chain-pointer.
+ In the case of the i386, the frame's nominal address
+ is the address of a 4-byte word containing the calling frame's address. */
+
+extern CORE_ADDR fbsd_kern_frame_chain (struct frame_info *);
+#undef FRAME_CHAIN
+#define FRAME_CHAIN(thisframe) \
+ (kernel_debugging ? fbsd_kern_frame_chain(thisframe) : \
+ ((thisframe)->signal_handler_caller \
+ ? (thisframe)->frame \
+ : (!inside_entry_file ((thisframe)->pc) \
+ ? read_memory_integer ((thisframe)->frame, 4) \
+ : 0)))
+
+/* Saved Pc. Get it from sigcontext if within sigtramp. */
+
+extern CORE_ADDR fbsd_kern_frame_saved_pc (struct frame_info *);
+#undef FRAME_SAVED_PC
+#define FRAME_SAVED_PC(FRAME) \
+ (kernel_debugging ? fbsd_kern_frame_saved_pc(FRAME) : \
+ (((FRAME)->signal_handler_caller \
+ ? sigtramp_saved_pc (FRAME) \
+ : read_memory_integer ((FRAME)->frame + 4, 4)) \
+ ))
+
#endif /* TM_FBSD_H */
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