[PATCH 1/3] lib: fwts_ioport: add helper functions to do port I/O

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

When testing on a Xen Dom0 I discovered that restricted port I/O causes
a segfault.  This patch adds a thin layer of abstraction onto the
port read/write operations to catch segfaults and to return FWTS_ERROR.

Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 src/lib/include/fwts.h        |   1 +
 src/lib/include/fwts_ioport.h |  32 ++++++++++
 src/lib/src/Makefile.am       |   1 +
 src/lib/src/fwts_ioport.c     | 136 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 170 insertions(+)
 create mode 100644 src/lib/include/fwts_ioport.h
 create mode 100644 src/lib/src/fwts_ioport.c

diff --git a/src/lib/include/fwts.h b/src/lib/include/fwts.h
index 414252d..cbf9dd9 100644
--- a/src/lib/include/fwts.h
+++ b/src/lib/include/fwts.h
@@ -78,5 +78,6 @@
 #include "fwts_battery.h"
 #include "fwts_button.h"
 #include "fwts_json.h"
+#include "fwts_ioport.h"
 
 #endif
diff --git a/src/lib/include/fwts_ioport.h b/src/lib/include/fwts_ioport.h
new file mode 100644
index 0000000..183fb4a
--- /dev/null
+++ b/src/lib/include/fwts_ioport.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2013 Canonical
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+#ifndef __FWTS_IO_PORT_H__
+#define __FWTS_IO_PORT_H__
+
+#include <stdint.h>
+
+int fwts_inb(uint32_t port, uint8_t *value);
+int fwts_inw(uint32_t port, uint16_t *value);
+int fwts_inl(uint32_t port, uint32_t *value);
+
+int fwts_outb(uint32_t port, uint8_t value);
+int fwts_outw(uint32_t port, uint16_t value);
+int fwts_outl(uint32_t port, uint32_t value);
+
+#endif
diff --git a/src/lib/src/Makefile.am b/src/lib/src/Makefile.am
index a91d9ab..6a44641 100644
--- a/src/lib/src/Makefile.am
+++ b/src/lib/src/Makefile.am
@@ -44,6 +44,7 @@ libfwts_la_SOURCES = 		\
 	fwts_hwinfo.c 		\
 	fwts_iasl.c 		\
 	fwts_interactive.c 	\
+	fwts_ioport.c		\
 	fwts_keymap.c 		\
 	fwts_klog.c 		\
 	fwts_list.c 		\
diff --git a/src/lib/src/fwts_ioport.c b/src/lib/src/fwts_ioport.c
new file mode 100644
index 0000000..bc6243e
--- /dev/null
+++ b/src/lib/src/fwts_ioport.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2013 Canonical
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include <sys/io.h>
+#include <stdint.h>
+#include <signal.h>
+#include <setjmp.h>
+
+#include "fwts.h"
+
+static jmp_buf jmpbuf;
+
+/*
+ *  If we hit a SIGSEGV then the port read
+ *  failed and we longjmp back and return
+ *  FWTS_ERROR
+ */
+static void segv_handler(int dummy)
+{
+	FWTS_UNUSED(dummy);
+
+	signal(SIGSEGV, SIG_DFL);
+	longjmp(jmpbuf, 1);
+}
+
+/*
+ *  fwts_inb()
+ *	8 bit port read, handle access errors
+ */
+int fwts_inb(uint32_t port, uint8_t *value)
+{
+	if (setjmp(jmpbuf) != 0)
+		return FWTS_ERROR;
+
+	signal(SIGSEGV, segv_handler);
+	*value = inb(port);
+	signal(SIGSEGV, SIG_DFL);
+
+	return FWTS_OK;
+}
+
+/*
+ *  fwts_inw()
+ *	16 bit port read, handle access errors
+ */
+int fwts_inw(uint32_t port, uint16_t *value)
+{
+	if (setjmp(jmpbuf) != 0)
+		return FWTS_ERROR;
+
+	signal(SIGSEGV, segv_handler);
+	*value = inw(port);
+	signal(SIGSEGV, SIG_DFL);
+
+	return FWTS_OK;
+}
+
+/*
+ *  fwts_inl()
+ *	32 bit port read, handle access errors
+ */
+int fwts_inl(uint32_t port, uint32_t *value)
+{
+	if (setjmp(jmpbuf) != 0)
+		return FWTS_ERROR;
+
+	signal(SIGSEGV, segv_handler);
+	*value = inl(port);
+	signal(SIGSEGV, SIG_DFL);
+
+	return FWTS_OK;
+}
+
+/*
+ *  fwts_outb()
+ *	8 bit port write, handle access errors
+ */
+int fwts_outb(uint32_t port, uint8_t value)
+{
+	if (setjmp(jmpbuf) != 0)
+		return FWTS_ERROR;
+
+	signal(SIGSEGV, segv_handler);
+	outb(port, value);
+	signal(SIGSEGV, SIG_DFL);
+
+	return FWTS_OK;
+}
+
+/*
+ *  fwts_outw()
+ *	16 bit port write, handle access errors
+ */
+int fwts_outw(uint32_t port, uint16_t value)
+{
+	if (setjmp(jmpbuf) != 0)
+		return FWTS_ERROR;
+
+	signal(SIGSEGV, segv_handler);
+	outw(port, value);
+	signal(SIGSEGV, SIG_DFL);
+
+	return FWTS_OK;
+}
+
+/*
+ *  fwts_outl()
+ *	32 bit port write, handle access errors
+ */
+int fwts_outl(uint32_t port, uint32_t value)
+{
+	if (setjmp(jmpbuf) != 0)
+		return FWTS_ERROR;
+
+	signal(SIGSEGV, segv_handler);
+	outw(port, value);
+	signal(SIGSEGV, SIG_DFL);
+
+	return FWTS_OK;
+}
-- 
1.8.0