From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 drivers/pci/syscall.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 drivers/pci/syscall.c

(limited to 'drivers/pci/syscall.c')

diff --git a/drivers/pci/syscall.c b/drivers/pci/syscall.c
new file mode 100644
index 000000000..b91c4da68
--- /dev/null
+++ b/drivers/pci/syscall.c
@@ -0,0 +1,136 @@
+/*
+ *	pci_syscall.c
+ *
+ * For architectures where we want to allow direct access
+ * to the PCI config stuff - it would probably be preferable
+ * on PCs too, but there people just do it by hand with the
+ * magic northbridge registers..
+ */
+
+#include <linux/errno.h>
+#include <linux/pci.h>
+#include <linux/syscalls.h>
+#include <asm/uaccess.h>
+#include "pci.h"
+
+SYSCALL_DEFINE5(pciconfig_read, unsigned long, bus, unsigned long, dfn,
+		unsigned long, off, unsigned long, len, void __user *, buf)
+{
+	struct pci_dev *dev;
+	u8 byte;
+	u16 word;
+	u32 dword;
+	long err;
+	long cfg_ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	err = -ENODEV;
+	dev = pci_get_bus_and_slot(bus, dfn);
+	if (!dev)
+		goto error;
+
+	switch (len) {
+	case 1:
+		cfg_ret = pci_user_read_config_byte(dev, off, &byte);
+		break;
+	case 2:
+		cfg_ret = pci_user_read_config_word(dev, off, &word);
+		break;
+	case 4:
+		cfg_ret = pci_user_read_config_dword(dev, off, &dword);
+		break;
+	default:
+		err = -EINVAL;
+		goto error;
+	}
+
+	err = -EIO;
+	if (cfg_ret != PCIBIOS_SUCCESSFUL)
+		goto error;
+
+	switch (len) {
+	case 1:
+		err = put_user(byte, (unsigned char __user *)buf);
+		break;
+	case 2:
+		err = put_user(word, (unsigned short __user *)buf);
+		break;
+	case 4:
+		err = put_user(dword, (unsigned int __user *)buf);
+		break;
+	}
+	pci_dev_put(dev);
+	return err;
+
+error:
+	/* ??? XFree86 doesn't even check the return value.  They
+	   just look for 0xffffffff in the output, since that's what
+	   they get instead of a machine check on x86.  */
+	switch (len) {
+	case 1:
+		put_user(-1, (unsigned char __user *)buf);
+		break;
+	case 2:
+		put_user(-1, (unsigned short __user *)buf);
+		break;
+	case 4:
+		put_user(-1, (unsigned int __user *)buf);
+		break;
+	}
+	pci_dev_put(dev);
+	return err;
+}
+
+SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn,
+		unsigned long, off, unsigned long, len, void __user *, buf)
+{
+	struct pci_dev *dev;
+	u8 byte;
+	u16 word;
+	u32 dword;
+	int err = 0;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	dev = pci_get_bus_and_slot(bus, dfn);
+	if (!dev)
+		return -ENODEV;
+
+	switch (len) {
+	case 1:
+		err = get_user(byte, (u8 __user *)buf);
+		if (err)
+			break;
+		err = pci_user_write_config_byte(dev, off, byte);
+		if (err != PCIBIOS_SUCCESSFUL)
+			err = -EIO;
+		break;
+
+	case 2:
+		err = get_user(word, (u16 __user *)buf);
+		if (err)
+			break;
+		err = pci_user_write_config_word(dev, off, word);
+		if (err != PCIBIOS_SUCCESSFUL)
+			err = -EIO;
+		break;
+
+	case 4:
+		err = get_user(dword, (u32 __user *)buf);
+		if (err)
+			break;
+		err = pci_user_write_config_dword(dev, off, dword);
+		if (err != PCIBIOS_SUCCESSFUL)
+			err = -EIO;
+		break;
+
+	default:
+		err = -EINVAL;
+		break;
+	}
+	pci_dev_put(dev);
+	return err;
+}
-- 
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