This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
PATCH: Add x32 arch_prctl support
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Date: Thu, 17 May 2012 03:35:38 -0700
- Subject: PATCH: Add x32 arch_prctl support
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Hi,
X32 kernel interface stores 64-bit value for ARCH_GET_FS and ARCH_GET_GS.
But user interface of ARCH_GET_FS and ARCH_GET_GS in arch_prctl and ptrace
only expects 32-bit value. This patch adds x32 arch_prctl.c and
ptrace.c to allocate a temporary 64-bit value for system call and copy
the lower 32-bit to user. Tested on Linux/x32. OK to install?
Thanks.
H.J.
---
* sysdeps/unix/sysv/linux/x86_64/x32/Makefile (sysdep_routines):
Add arch_prctl.
* sysdeps/unix/sysv/linux/x86_64/x32/arch_prctl.c: New file.
* sysdeps/unix/sysv/linux/x86_64/x32/ptrace.c: Likewise.
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/Makefile b/sysdeps/unix/sysv/linux/x86_64/x32/Makefile
index 5f77df7..aa78238 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/Makefile
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/Makefile
@@ -1,3 +1,7 @@
+ifeq ($(subdir),misc)
+sysdep_routines += arch_prctl
+endif
+
ifeq ($(subdir),posix)
sysdep_routines += getcpu sched_getcpu-static
endif
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/arch_prctl.c b/sysdeps/unix/sysv/linux/x86_64/x32/arch_prctl.c
new file mode 100644
index 0000000..8aa0ebf
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/arch_prctl.c
@@ -0,0 +1,64 @@
+/* arch_prctl call for Linux/x32.
+ Copyright (C) 2012 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <sys/prctl.h>
+#include <sys/syscall.h>
+#include <sysdep.h>
+
+/* Since x32 arch_prctl stores 32bit base address of segment register %fs
+ and %gs as unsigned 64bit value via ARCH_GET_FS and ARCH_GET_GS, we
+ use a local unsigned 64bit variable to hold the base address and copy
+ it to ADDR after arch_prctl return. */
+
+int
+__arch_prctl (int code, unsigned long *addr)
+{
+ int res;
+ unsigned long long base_addr;
+ unsigned long *addr_saved;
+
+ switch (code)
+ {
+ case ARCH_GET_FS:
+ case ARCH_GET_GS:
+ addr_saved = addr;
+ addr = (unsigned long *) &base_addr;
+ break;
+
+ default:
+ break;
+ }
+
+ res = INLINE_SYSCALL (arch_prctl, 2, code, addr);
+ if (res == 0)
+ switch (code)
+ {
+ case ARCH_GET_FS:
+ case ARCH_GET_GS:
+ *addr_saved = (unsigned long) base_addr;
+ break;
+
+ default:
+ break;
+ }
+
+ return res;
+}
+
+weak_alias (__arch_prctl, arch_prctl);
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/ptrace.c b/sysdeps/unix/sysv/linux/x86_64/x32/ptrace.c
new file mode 100644
index 0000000..09bdac9
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/ptrace.c
@@ -0,0 +1,98 @@
+/* ptrace call for Linux/x32.
+ Copyright (C) 2012 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <sys/types.h>
+#define ptrace __redirect_ptrace
+#include <sys/ptrace.h>
+#undef ptrace
+#include <sys/syscall.h>
+#include <sysdep.h>
+
+#ifndef PTRACE_ARCH_PRCTL
+#define PTRACE_ARCH_PRCTL 30
+#endif
+
+/* Since x32 ptrace stores 32bit base address of segment register %fs
+ and %gs as unsigned 64bit value via ARCH_GET_FS and ARCH_GET_GS with
+ PTRACE_ARCH_PRCTL, we use a local unsigned 64bit variable to hold
+ the base address and copy it to ADDR after ptrace return. */
+
+long
+ptrace (enum __ptrace_request request, pid_t pid, void *addr, void *data)
+{
+ long res, ret;
+ unsigned long long base_addr;
+ unsigned long *addr_saved;
+
+ switch ((int) request)
+ {
+ case PTRACE_PEEKTEXT:
+ case PTRACE_PEEKDATA:
+ case PTRACE_PEEKUSER:
+ /* Pass the address of return data to kernel. */
+ data = &ret;
+ break;
+
+ case PTRACE_ARCH_PRCTL:
+ switch ((int) data)
+ {
+ case ARCH_GET_FS:
+ case ARCH_GET_GS:
+ addr_saved = (unsigned long *) addr;
+ addr = &base_addr;
+ break;
+
+ default:
+ break;
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ res = INLINE_SYSCALL (ptrace, 4, request, pid, addr, data);
+ if (res >= 0)
+ switch ((int) request)
+ {
+ case PTRACE_PEEKTEXT:
+ case PTRACE_PEEKDATA:
+ case PTRACE_PEEKUSER:
+ __set_errno (0);
+ return ret;
+
+ case PTRACE_ARCH_PRCTL:
+ switch ((int) data)
+ {
+ case ARCH_GET_FS:
+ case ARCH_GET_GS:
+ *addr_saved = (unsigned long) base_addr;
+ break;
+
+ default:
+ break;
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ return res;
+}