Unwind across trap frames. This adds most of the meat. The sniffer

just needs to be taught about all the other entry points and the
unwinder needs to be taught about the frame variation between them.

MFC after: 1 week

1 files changed, 86 insertions, 6 deletions

diff --git a/gnu/usr.bin/gdb/kgdb/trgt_i386.c b/gnu/usr.bin/gdb/kgdb/trgt_i386.c
index eb58df3..0522e24 100644
--- a/gnu/usr.bin/gdb/kgdb/trgt_i386.c
+++ b/gnu/usr.bin/gdb/kgdb/trgt_i386.c
@@ -29,6 +29,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <machine/pcb.h>
+#include <machine/frame.h>
 #include <err.h>
 #include <kvm.h>
 #include <string.h>
@@ -39,6 +40,7 @@ __FBSDID("$FreeBSD$");
 #include <inferior.h>
 #include <regcache.h>
 #include <frame-unwind.h>
+#include <i386-tdep.h>
 
 #include "kgdb.h"
 
@@ -55,12 +57,12 @@ kgdb_trgt_fetch_registers(int regno __unused)
 		warnx("kvm_read: %s", kvm_geterr(kvm));
 		memset(&pcb, 0, sizeof(pcb));
 	}
-	supply_register(3, (char *)&pcb.pcb_ebx);
-	supply_register(4, (char *)&pcb.pcb_esp);
-	supply_register(5, (char *)&pcb.pcb_ebp);
-	supply_register(6, (char *)&pcb.pcb_esi);
-	supply_register(7, (char *)&pcb.pcb_edi);
-	supply_register(8, (char *)&pcb.pcb_eip);
+	supply_register(I386_EBX_REGNUM, (char *)&pcb.pcb_ebx);
+	supply_register(I386_ESP_REGNUM, (char *)&pcb.pcb_esp);
+	supply_register(I386_EBP_REGNUM, (char *)&pcb.pcb_ebp);
+	supply_register(I386_ESI_REGNUM, (char *)&pcb.pcb_esi);
+	supply_register(I386_EDI_REGNUM, (char *)&pcb.pcb_edi);
+	supply_register(I386_EIP_REGNUM, (char *)&pcb.pcb_eip);
 }
 
 void
@@ -69,10 +71,55 @@ kgdb_trgt_store_registers(int regno __unused)
 	fprintf_unfiltered(gdb_stderr, "XXX: %s\n", __func__);
 }
 
+struct kgdb_frame_cache {
+	CORE_ADDR	pc;
+	CORE_ADDR	sp;
+};
+
+static int kgdb_trgt_frame_offset[15] = {
+	offsetof(struct trapframe, tf_eax),
+	offsetof(struct trapframe, tf_ecx),
+	offsetof(struct trapframe, tf_edx),
+	offsetof(struct trapframe, tf_ebx),
+	offsetof(struct trapframe, tf_esp),
+	offsetof(struct trapframe, tf_ebp),
+	offsetof(struct trapframe, tf_esi),
+	offsetof(struct trapframe, tf_edi),
+	offsetof(struct trapframe, tf_eip),
+	offsetof(struct trapframe, tf_eflags),
+	offsetof(struct trapframe, tf_cs),
+	offsetof(struct trapframe, tf_ss),
+	offsetof(struct trapframe, tf_ds),
+	offsetof(struct trapframe, tf_es),
+	offsetof(struct trapframe, tf_fs)
+};
+
+static struct kgdb_frame_cache *
+kgdb_trgt_frame_cache(struct frame_info *next_frame, void **this_cache)
+{
+	char buf[MAX_REGISTER_SIZE];
+	struct kgdb_frame_cache *cache;
+
+	cache = *this_cache;
+	if (cache == NULL) {
+		cache = FRAME_OBSTACK_ZALLOC(struct kgdb_frame_cache);
+		*this_cache = cache;
+		cache->pc = frame_func_unwind(next_frame);
+		frame_unwind_register(next_frame, SP_REGNUM, buf);
+		cache->sp = extract_unsigned_integer(buf,
+		    register_size(current_gdbarch, SP_REGNUM));
+	}
+	return (cache);
+}
+
 static void
 kgdb_trgt_trapframe_this_id(struct frame_info *next_frame, void **this_cache,
     struct frame_id *this_id)
 {
+	struct kgdb_frame_cache *cache;
+
+	cache = kgdb_trgt_frame_cache(next_frame, this_cache);
+	*this_id = frame_id_build(cache->sp, cache->pc);
 }
 
 static void
@@ -80,6 +127,29 @@ kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
     void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
     CORE_ADDR *addrp, int *realnump, void *valuep)
 {
+	char dummy_valuep[MAX_REGISTER_SIZE];
+	struct kgdb_frame_cache *cache;
+	int ofs, regsz;
+
+	regsz = register_size(current_gdbarch, regnum);
+
+	if (valuep == NULL)
+		valuep = dummy_valuep;
+	memset(valuep, 0, regsz);
+	*optimizedp = 0;
+	*addrp = 0;
+	*lvalp = not_lval;
+	*realnump = -1;
+
+	ofs = (regnum >= I386_EAX_REGNUM && regnum <= I386_FS_REGNUM)
+	    ? kgdb_trgt_frame_offset[regnum] : -1;
+	if (ofs == -1)
+		return;
+
+	cache = kgdb_trgt_frame_cache(next_frame, this_cache);
+	*addrp = cache->sp + ofs;
+	*lvalp = lval_memory;
+	target_read_memory(*addrp, valuep, regsz);
 }
 
 static const struct frame_unwind kgdb_trgt_trapframe_unwind = {
@@ -91,6 +161,16 @@ static const struct frame_unwind kgdb_trgt_trapframe_unwind = {
 const struct frame_unwind *
 kgdb_trgt_trapframe_sniffer(struct frame_info *next_frame)
 {
+	char *pname;
+	CORE_ADDR pc;
 
+	pc = frame_pc_unwind(next_frame);
+	pname = NULL;
+	find_pc_partial_function(pc, &pname, NULL, NULL);
+	if (pname == NULL)
+		return (NULL);
+	if (strcmp(pname, "calltrap") == 0)
+		return (&kgdb_trgt_trapframe_unwind);
+	/* printf("%s: %llx =%s\n", __func__, pc, pname); */
         return (NULL);
 }