[PATCH 2/7] Linux kernel generic support

[Sergio Durigan Junior <sergiodj@redhat.com>]

This is, along with the gdbarch changes, the main patch of this series.
It implements the generic converter between GDB's internal signals and
Linux kernel generic ones, and also the converter for the other way
around (i.e., converting from Linux kernel generic signal to GDB's
internal representation).

It defines the full enum containing all Linux kernel generic signals (as
defined in <include/uapi/asm-generic/signal.h>). Then, it defines
the generics linux_gdb_signal_{to,from}_target, and export them to some
-tdep files.  These functions will be used by other targets when they
want to re-define some non-generic signals of their own, but want to use
the rest of the generic signals as-is.

For the specific case of linux_gdb_signal_from_target, it is actually
the natural extension of a previous MIPS-only implementation, which can
be seen at:

<http://sourceware.org/ml/gdb-patches/2012-06/msg00048.html>

Now every target that uses the Linux kernel supports this function.

This patch also includes a comment about SIGSWI for ARM target, which
can be seen at:

<http://sourceware.org/ml/gdb-patches/2013-07/msg00595.html>

OK to apply?

2013-07-26  Sergio Durigan Junior  <sergiodj@redhat.com>

	* linux-tdep.c: Define enum with generic signal numbers.
	(linux_gdb_signal_from_target): New function.
	(linux_gdb_signal_to_target): Likewise.
	(linux_init_abi): Set gdbarch_gdb_signal_{to,from}_target
	methods to the functions above.
	* linux-tdep.h (linux_gdb_signal_from_target): New prototype.
	(linux_gdb_signal_to_target): Likewise.
---
 gdb/linux-tdep.c | 320 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/linux-tdep.h |   6 ++
 2 files changed, 326 insertions(+)

diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index bfb6404..fbdca46 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -36,6 +36,71 @@
 
 #include <ctype.h>
 
+/* This enum represents the signals' numbers on a generic architecture
+   running the Linux kernel.  The definition of "generic" comes from
+   the file <include/uapi/asm-generic/signal.h>, from the Linux kernel
+   tree, which is the "de facto" implementation of signal numbers to
+   be used by new architecture ports.
+
+   For those architectures which have differences between the generic
+   standard (e.g., Alpha), we define the different signals (and *only*
+   those) in the specific target-dependent file (e.g.,
+   alpha-linux-tdep.c, for Alpha).  Please refer to the architecture's
+   tdep file for more information.
+
+   ARM deserves a special mention here.  On the file
+   <arch/arm/include/uapi/asm/signal.h>, it defines only one different
+   (and ARM-only) signal, which is SIGSWI, with the same number as
+   SIGRTMIN.  This signal is used only for a very specific target,
+   called ArthurOS (from RISCOS).  Therefore, we do not handle it on
+   the ARM-tdep file, and we can safely use the generic signal handler
+   here for ARM targets.
+
+   As stated above, this enum is derived from
+   <include/uapi/asm-generic/signal.h>, from the Linux kernel
+   tree.  */
+
+enum
+  {
+    LINUX_SIGHUP = 1,
+    LINUX_SIGINT = 2,
+    LINUX_SIGQUIT = 3,
+    LINUX_SIGILL = 4,
+    LINUX_SIGTRAP = 5,
+    LINUX_SIGABRT = 6,
+    LINUX_SIGIOT = 6,
+    LINUX_SIGBUS = 7,
+    LINUX_SIGFPE = 8,
+    LINUX_SIGKILL = 9,
+    LINUX_SIGUSR1 = 10,
+    LINUX_SIGSEGV = 11,
+    LINUX_SIGUSR2 = 12,
+    LINUX_SIGPIPE = 13,
+    LINUX_SIGALRM = 14,
+    LINUX_SIGTERM = 15,
+    LINUX_SIGSTKFLT = 16,
+    LINUX_SIGCHLD = 17,
+    LINUX_SIGCONT = 18,
+    LINUX_SIGSTOP = 19,
+    LINUX_SIGTSTP = 20,
+    LINUX_SIGTTIN = 21,
+    LINUX_SIGTTOU = 22,
+    LINUX_SIGURG = 23,
+    LINUX_SIGXCPU = 24,
+    LINUX_SIGXFSZ = 25,
+    LINUX_SIGVTALRM = 26,
+    LINUX_SIGPROF = 27,
+    LINUX_SIGWINCH = 28,
+    LINUX_SIGIO = 29,
+    LINUX_SIGPOLL = LINUX_SIGIO,
+    LINUX_SIGPWR = 30,
+    LINUX_SIGSYS = 31,
+    LINUX_SIGUNUSED = 31,
+
+    LINUX_SIGRTMIN = 32,
+    LINUX_SIGRTMAX = 64,
+  };
+
 static struct gdbarch_data *linux_gdbarch_data_handle;
 
 struct linux_gdbarch_data
@@ -1447,6 +1512,257 @@ linux_make_corefile_notes_1 (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 				      linux_collect_thread_registers);
 }
 
+/* Implementation of `gdbarch_gdb_signal_from_target', as defined in
+   gdbarch.h.  This function is not static because it is exported to
+   other -tdep files.  */
+
+enum gdb_signal
+linux_gdb_signal_from_target (struct gdbarch *gdbarch, int signal)
+{
+  switch (signal)
+    {
+    case 0:
+      return GDB_SIGNAL_0;
+
+    case LINUX_SIGHUP:
+      return GDB_SIGNAL_HUP;
+
+    case LINUX_SIGINT:
+      return GDB_SIGNAL_INT;
+
+    case LINUX_SIGQUIT:
+      return GDB_SIGNAL_QUIT;
+
+    case LINUX_SIGILL:
+      return GDB_SIGNAL_ILL;
+
+    case LINUX_SIGTRAP:
+      return GDB_SIGNAL_TRAP;
+
+    case LINUX_SIGABRT:
+      return GDB_SIGNAL_ABRT;
+
+    case LINUX_SIGBUS:
+      return GDB_SIGNAL_BUS;
+
+    case LINUX_SIGFPE:
+      return GDB_SIGNAL_FPE;
+
+    case LINUX_SIGKILL:
+      return GDB_SIGNAL_KILL;
+
+    case LINUX_SIGUSR1:
+      return GDB_SIGNAL_USR1;
+
+    case LINUX_SIGSEGV:
+      return GDB_SIGNAL_SEGV;
+
+    case LINUX_SIGUSR2:
+      return GDB_SIGNAL_USR2;
+
+    case LINUX_SIGPIPE:
+      return GDB_SIGNAL_PIPE;
+
+    case LINUX_SIGALRM:
+      return GDB_SIGNAL_ALRM;
+
+    case LINUX_SIGTERM:
+      return GDB_SIGNAL_TERM;
+
+    case LINUX_SIGCHLD:
+      return GDB_SIGNAL_CHLD;
+
+    case LINUX_SIGCONT:
+      return GDB_SIGNAL_CONT;
+
+    case LINUX_SIGSTOP:
+      return GDB_SIGNAL_STOP;
+
+    case LINUX_SIGTSTP:
+      return GDB_SIGNAL_TSTP;
+
+    case LINUX_SIGTTIN:
+      return GDB_SIGNAL_TTIN;
+
+    case LINUX_SIGTTOU:
+      return GDB_SIGNAL_TTOU;
+
+    case LINUX_SIGURG:
+      return GDB_SIGNAL_URG;
+
+    case LINUX_SIGXCPU:
+      return GDB_SIGNAL_XCPU;
+
+    case LINUX_SIGXFSZ:
+      return GDB_SIGNAL_XFSZ;
+
+    case LINUX_SIGVTALRM:
+      return GDB_SIGNAL_VTALRM;
+
+    case LINUX_SIGPROF:
+      return GDB_SIGNAL_PROF;
+
+    case LINUX_SIGWINCH:
+      return GDB_SIGNAL_WINCH;
+
+    /* No way to differentiate between SIGIO and SIGPOLL.
+       Therefore, we just handle the first one.  */
+    case LINUX_SIGIO:
+      return GDB_SIGNAL_IO;
+
+    case LINUX_SIGPWR:
+      return GDB_SIGNAL_PWR;
+
+    case LINUX_SIGSYS:
+      return GDB_SIGNAL_SYS;
+
+    /* SIGRTMIN and SIGRTMAX are not continuous in <gdb/signals.def>,
+       therefore we have to handle them here.  */
+    case LINUX_SIGRTMIN:
+      return GDB_SIGNAL_REALTIME_32;
+
+    case LINUX_SIGRTMAX:
+      return GDB_SIGNAL_REALTIME_64;
+    }
+
+  if (signal >= LINUX_SIGRTMIN + 1 && signal <= LINUX_SIGRTMAX - 1)
+    {
+      int offset = signal - LINUX_SIGRTMIN + 1;
+
+      return (enum gdb_signal) ((int) GDB_SIGNAL_REALTIME_33 + offset);
+    }
+
+  return GDB_SIGNAL_UNKNOWN;
+}
+
+/* Implementation of `gdbarch_gdb_signal_to_target', as defined in
+   gdbarch.h.  This function is not static because it is exported to
+   other -tdep files.  */
+
+int
+linux_gdb_signal_to_target (struct gdbarch *gdbarch,
+			    enum gdb_signal signal)
+{
+  switch (signal)
+    {
+    case GDB_SIGNAL_0:
+      return 0;
+
+    case GDB_SIGNAL_HUP:
+      return LINUX_SIGHUP;
+
+    case GDB_SIGNAL_INT:
+      return LINUX_SIGINT;
+
+    case GDB_SIGNAL_QUIT:
+      return LINUX_SIGQUIT;
+
+    case GDB_SIGNAL_ILL:
+      return LINUX_SIGILL;
+
+    case GDB_SIGNAL_TRAP:
+      return LINUX_SIGTRAP;
+
+    case GDB_SIGNAL_ABRT:
+      return LINUX_SIGABRT;
+
+    case GDB_SIGNAL_FPE:
+      return LINUX_SIGFPE;
+
+    case GDB_SIGNAL_KILL:
+      return LINUX_SIGKILL;
+
+    case GDB_SIGNAL_BUS:
+      return LINUX_SIGBUS;
+
+    case GDB_SIGNAL_SEGV:
+      return LINUX_SIGSEGV;
+
+    case GDB_SIGNAL_SYS:
+      return LINUX_SIGSYS;
+
+    case GDB_SIGNAL_PIPE:
+      return LINUX_SIGPIPE;
+
+    case GDB_SIGNAL_ALRM:
+      return LINUX_SIGALRM;
+
+    case GDB_SIGNAL_TERM:
+      return LINUX_SIGTERM;
+
+    case GDB_SIGNAL_URG:
+      return LINUX_SIGURG;
+
+    case GDB_SIGNAL_STOP:
+      return LINUX_SIGSTOP;
+
+    case GDB_SIGNAL_TSTP:
+      return LINUX_SIGTSTP;
+
+    case GDB_SIGNAL_CONT:
+      return LINUX_SIGCONT;
+
+    case GDB_SIGNAL_CHLD:
+      return LINUX_SIGCHLD;
+
+    case GDB_SIGNAL_TTIN:
+      return LINUX_SIGTTIN;
+
+    case GDB_SIGNAL_TTOU:
+      return LINUX_SIGTTOU;
+
+    case GDB_SIGNAL_IO:
+      return LINUX_SIGIO;
+
+    case GDB_SIGNAL_XCPU:
+      return LINUX_SIGXCPU;
+
+    case GDB_SIGNAL_XFSZ:
+      return LINUX_SIGXFSZ;
+
+    case GDB_SIGNAL_VTALRM:
+      return LINUX_SIGVTALRM;
+
+    case GDB_SIGNAL_PROF:
+      return LINUX_SIGPROF;
+
+    case GDB_SIGNAL_WINCH:
+      return LINUX_SIGWINCH;
+
+    case GDB_SIGNAL_USR1:
+      return LINUX_SIGUSR1;
+
+    case GDB_SIGNAL_USR2:
+      return LINUX_SIGUSR2;
+
+    case GDB_SIGNAL_PWR:
+      return LINUX_SIGPWR;
+
+    case GDB_SIGNAL_POLL:
+      return LINUX_SIGPOLL;
+
+    /* GDB_SIGNAL_REALTIME_32 is not continuous in <gdb/signals.def>,
+       therefore we have to handle it here.  */
+    case GDB_SIGNAL_REALTIME_32:
+      return LINUX_SIGRTMIN;
+
+    /* Same comment applies to _64.  */
+    case GDB_SIGNAL_REALTIME_64:
+      return LINUX_SIGRTMAX;
+    }
+
+  /* GDB_SIGNAL_REALTIME_33 to _64 are continuous.  */
+  if (signal >= GDB_SIGNAL_REALTIME_33
+      && signal <= GDB_SIGNAL_REALTIME_63)
+    {
+      int offset = signal - GDB_SIGNAL_REALTIME_33;
+
+      return LINUX_SIGRTMIN + 1 + offset;
+    }
+
+  return -1;
+}
+
 /* To be called from the various GDB_OSABI_LINUX handlers for the
    various GNU/Linux architectures and machine types.  */
 
@@ -1460,6 +1776,10 @@ linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   set_gdbarch_make_corefile_notes (gdbarch, linux_make_corefile_notes_1);
   set_gdbarch_has_shared_address_space (gdbarch,
 					linux_has_shared_address_space);
+  set_gdbarch_gdb_signal_from_target (gdbarch,
+				      linux_gdb_signal_from_target);
+  set_gdbarch_gdb_signal_to_target (gdbarch,
+				    linux_gdb_signal_to_target);
 }
 
 /* Provide a prototype to silence -Wmissing-prototypes.  */
diff --git a/gdb/linux-tdep.h b/gdb/linux-tdep.h
index 380507e..5841f29 100644
--- a/gdb/linux-tdep.h
+++ b/gdb/linux-tdep.h
@@ -34,6 +34,12 @@ char *linux_make_corefile_notes (struct gdbarch *, bfd *, int *,
 
 struct type *linux_get_siginfo_type (struct gdbarch *);
 
+extern enum gdb_signal linux_gdb_signal_from_target (struct gdbarch *gdbarch,
+						     int signal);
+
+extern int linux_gdb_signal_to_target (struct gdbarch *gdbarch,
+				       enum gdb_signal signal);
+
 extern void linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch);
 
 #endif /* linux-tdep.h */
-- 
1.7.11.7