X86-64 kernel backtrace

default.nix

@@ -7,7 +7,7 @@
 , cpio
 , curl
 , gcc5
-, gdb
+, gdb-multitarget
 , git
 , gmp
 , gnugrep
@@ -47,7 +47,7 @@ let src-repo = fetchgit {
 	cpio
 	curl
 	gcc5
-	gdb
+	gdb-multitarget
 	git
 	gmp
 	gnugrep

hake/Config.hs.template

@@ -160,6 +160,10 @@ microbenchmarks = False
 trace :: Bool
 trace = False
 
+-- Include code for a runtime stacktrace
+stack_trace :: Bool
+stack_trace = True
+
 -- Enable QEMU networking. (ie. make network work in small memory)
 support_qemu_networking :: Bool
 support_qemu_networking  = False
@@ -368,6 +372,7 @@ defines :: [RuleToken]
 defines = [ Str ("-D" ++ d) | d <- [
              if microbenchmarks then "CONFIG_MICROBENCHMARKS" else "",
              if trace then "CONFIG_TRACE" else "",
+             if stack_trace then "CONFIG_KERNEL_STACK_TRACE" else "",
              if support_qemu_networking then "CONFIG_QEMU_NETWORK" else "",
              if trace_network_subsystem then "NETWORK_STACK_TRACE" else "",
              if trace_disable_lrpc then "TRACE_DISABLE_LRPC" else "",

hake/X86_32.hs

@@ -99,14 +99,16 @@ kernelCFlags = [ Str s | s <- [ "-fno-builtin",
                                 "-mno-sse4.2",
                                 "-mno-sse4",
                                 "-mno-sse4a",
-                                "-mno-3dnow" ]]
+                                "-mno-3dnow" ]
+                                ++ [ "-fno-omit-frame-pointer" | Config.stack_trace ]]
 
 kernelLdFlags = [ Str s | s <- [ "-Wl,-N",
                                  "-pie",
                                  "-fno-builtin",
                                  "-nostdlib",
                                  "-Wl,--fatal-warnings",
-                                 "-m32" ] ]
+                                 "-m32" ]
+                                 ++ [ "-rdynamic" | Config.stack_trace ] ]
 
 --
 -- Compilers

hake/X86_64.hs

@@ -99,14 +99,16 @@ kernelCFlags = [ Str s | s <- [ "-fno-builtin",
                                 "-mno-sse4.2",
                                 "-mno-sse4",
                                 "-mno-sse4a",
-                                "-mno-3dnow" ]]
+                                "-mno-3dnow" ]
+                                ++ [ "-fno-omit-frame-pointer" | Config.stack_trace ] ]
 
 kernelLdFlags = [ Str s | s <- [ "-Wl,-N",
                                 "-pie",
-                                 "-fno-builtin",
+                                "-fno-builtin",
                                 "-nostdlib",
                                 "-Wl,--fatal-warnings",
-                                "-m64" ] ]
+                                "-m64" ]
+                                ++ [ "-rdynamic" | Config.stack_trace ] ]
 
 
 ------------------------------------------------------------------------

kernel/Hakefile

@@ -12,18 +12,6 @@
 --
 --------------------------------------------------------------------------
 
---
--- Missing from this new Hakefile is the rule to build kernel debug
--- symbols, since this requires some thinking about naming
--- conventions.  Here is the rule we need:
---
---                Rule ( [ Str "OBJDUMP=objdump",
---                         In SrcTree "src" "/tools/gen-gdbscript.sh",
---                         In SrcTree "src" "/tools/debug.gdb.in",
---                         In BuildTree arch "../sbin/cpu",
---                         Str ">", Out arch "/debug.gdb"
---                        ] )
-
 let
   scheduler = case Config.scheduler of
       Config.RR   -> "schedule_rr.c"
@@ -49,6 +37,7 @@ let
                "useraccess.c",
                "coreboot.c",
                "systime.c" ]
+             ++ (if Config.stack_trace then ["qsort.c"] else [])
              ++ (if Config.microbenchmarks then ["microbenchmarks.c"] else [])
              ++ (if Config.oneshot_timer then ["timer.c"] else [])
   common_libs = [ "getopt", "mdb_kernel" ]

kernel/arch/x86/misc.c

@@ -53,7 +53,11 @@ wait_cycles(uint64_t duration)
  */
 void __stack_chk_fail(void); // Existence implied by (certainly configured) GCC.
 
+void dump_stack (void);
+
 void __stack_chk_fail (void)
 {
+    printf ("FATAL: stack smashed.\n");
+    dump_stack ();
     panic("finally reached __stack_chk_fail()");
 }