Add PT_GETREGSET

This adds the PT_GETREGSET and PT_SETREGSET ptrace types. These can be
used to access all the registers from a specified core dump note type.
The NT_PRSTATUS and NT_FPREGSET notes are initially supported. Other
machine-dependant types are expected to be added in the future.

The ptrace addr points to a struct iovec pointing at memory to hold the
registers along with its length. On success the length in the iovec is
updated to tell userspace the actual length the kernel wrote or, if the
base address is NULL, the length the kernel would have written.

Because the data field is an int the arguments are backwards when
compared to the Linux PTRACE_GETREGSET call.

Reviewed by:	kib
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D19831

1 files changed, 5 insertions, 0 deletions

diff --git a/sys/amd64/amd64/elf_machdep.c b/sys/amd64/amd64/elf_machdep.c
index 192a73e0a7df..1237eadcd239 100644
--- a/sys/amd64/amd64/elf_machdep.c
+++ b/sys/amd64/amd64/elf_machdep.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/imgact.h>
 #include <sys/linker.h>
 #include <sys/proc.h>
+#include <sys/reg.h>
 #include <sys/sysent.h>
 #include <sys/imgact_elf.h>
 #include <sys/syscall.h>
@@ -95,6 +96,8 @@ struct sysentvec elf64_freebsd_sysvec_la48 = {
 	.sv_onexec_old	= exec_onexec_old,
 	.sv_onexit	= exit_onexit,
 	.sv_set_fork_retval = x86_set_fork_retval,
+	.sv_regset_begin = SET_BEGIN(__elfN(regset)),
+	.sv_regset_end  = SET_LIMIT(__elfN(regset)),
 };
 
 struct sysentvec elf64_freebsd_sysvec_la57 = {
@@ -137,6 +140,8 @@ struct sysentvec elf64_freebsd_sysvec_la57 = {
 	.sv_onexec_old	= exec_onexec_old,
 	.sv_onexit	= exit_onexit,
 	.sv_set_fork_retval=  x86_set_fork_retval,
+	.sv_regset_begin = SET_BEGIN(__elfN(regset)),
+	.sv_regset_end  = SET_LIMIT(__elfN(regset)),
 };
 
 static void