Jumbo-commit to enhance 32 bit application support on 64 bit kernels.

This is good enough to be able to run a RELENG_4 gdb binary against
a RELENG_4 application, along with various other tools (eg: 4.x gcore).
We use this at work.

ia32_reg.[ch]: handle the 32 bit register file format, used by ptrace,
	procfs and core dumps.
procfs_*regs.c: vary the format of proc/XXX/*regs depending on the client
	and target application.
procfs_map.c: Don't print a 64 bit value to 32 bit consumers, or their
	sscanf fails.  They expect an unsigned long.
imgact_elf.c: produce a valid 32 bit coredump for 32 bit apps.
sys_process.c: handle 32 bit consumers debugging 32 bit targets.  Note
	that 64 bit consumers can still debug 32 bit targets.

IA64 has got stubs for ia32_reg.c.

Known limitations: a 5.x/6.x gdb uses get/setcontext(), which isn't
implemented in the 32/64 wrapper yet.  We also make a tiny patch to
gdb pacify it over conflicting formats of ld-elf.so.1.

Approved by:	re

1 files changed, 46 insertions, 3 deletions

diff --git a/sys/fs/procfs/procfs_fpregs.c b/sys/fs/procfs/procfs_fpregs.c
index 93356ce..cb9797b 100644
--- a/sys/fs/procfs/procfs_fpregs.c
+++ b/sys/fs/procfs/procfs_fpregs.c
@@ -37,6 +37,8 @@
  * $FreeBSD$
  */
 
+#include "opt_compat.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/lock.h>
@@ -50,11 +52,42 @@
 #include <fs/pseudofs/pseudofs.h>
 #include <fs/procfs/procfs.h>
 
+#ifdef COMPAT_IA32
+#include <sys/procfs.h>
+#include <machine/fpu.h>
+#include <compat/ia32/ia32_reg.h>
+
+extern struct sysentvec ia32_freebsd_sysvec;
+/*
+ * PROC(write, fpregs, td2, &r) becomes
+ * proc_write_fpregs(td2, &r)   or
+ * proc_write_fpregs32(td2, &r32)
+ *
+ * UIOMOVE_FROMBUF(r, uio) becomes
+ * uiomove_frombuf(&r, sizeof(r), uio)  or
+ * uiomove_frombuf(&r32, sizeof(r32), uio)
+ */
+#define	PROC(d, w, t, r)	wrap32 ? \
+	proc_ ## d ## _ ## w ## 32(t, r ## 32) : \
+	proc_ ## d ## _ ## w(t, r)
+#define	UIOMOVE_FROMBUF(k, u)	wrap32 ? \
+	uiomove_frombuf(& k ## 32, sizeof(k ## 32), u) : \
+	uiomove_frombuf(& k, sizeof(k), u)
+#else
+#define	PROC(d, w, t, r)	proc_ ## d ## _ ## w(t, r)
+#define	UIOMOVE_FROMBUF(k, u)	uiomove_frombuf(& k, sizeof(k), u)
+#endif
+
 int
 procfs_doprocfpregs(PFS_FILL_ARGS)
 {
 	int error;
 	struct fpreg r;
+	struct thread *td2;
+#ifdef COMPAT_IA32
+	struct fpreg32 r32;
+	int wrap32 = 0;
+#endif
 
 	PROC_LOCK(p);
 	KASSERT(p->p_lock > 0, ("proc not held"));
@@ -64,10 +97,20 @@ procfs_doprocfpregs(PFS_FILL_ARGS)
 	}
 
 	/* XXXKSE: */
-	error = proc_read_fpregs(FIRST_THREAD_IN_PROC(p), &r);
+	td2 = FIRST_THREAD_IN_PROC(p);
+#ifdef COMPAT_IA32
+	if (td->td_proc->p_sysent == &ia32_freebsd_sysvec) {
+		if (td2->td_proc->p_sysent != &ia32_freebsd_sysvec) {
+			PROC_UNLOCK(p);
+			return (EINVAL);
+		}
+		wrap32 = 1;
+	}
+#endif
+	error = PROC(read, fpregs, td2, &r);
 	if (error == 0) {
 		PROC_UNLOCK(p);
-		error = uiomove_frombuf(&r, sizeof(r), uio);
+		error = UIOMOVE_FROMBUF(r, uio);
 		PROC_LOCK(p);
 	}
 	if (error == 0 && uio->uio_rw == UIO_WRITE) {
@@ -75,7 +118,7 @@ procfs_doprocfpregs(PFS_FILL_ARGS)
 			error = EBUSY;
 		else
 			/* XXXKSE: */
-			error = proc_write_fpregs(FIRST_THREAD_IN_PROC(p), &r);
+			error = PROC(write, fpregs, td2, &r);
 	}
 	PROC_UNLOCK(p);