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To:     Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>
Cc:     linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
        linuxppc-dev@lists.ozlabs.org
Message-Id: <2fe2b8e6395aeacfafcbde590a50922d4e632189.1545784679.git.fthain@telegraphics.com.au>
In-Reply-To: <cover.1545784679.git.fthain@telegraphics.com.au>
References: <cover.1545784679.git.fthain@telegraphics.com.au>
From:   Finn Thain <fthain@telegraphics.com.au>
Subject: [PATCH v8 24/25] powerpc: Adopt nvram module for PPC64
Date:   Wed, 26 Dec 2018 11:37:59 +1100
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Adopt nvram module to reduce code duplication. This means CONFIG_NVRAM
becomes available to CONFIG_PPC64 builds (until now it was only PPC32).

The IOC_NVRAM_GET_OFFSET ioctl as implemented on PPC64 validates the offset
returned by pmac_get_partition(). Add this test to the nvram module.

Note that the old PPC32 generic_nvram module lacked this test.
So when CONFIG_PPC32 && CONFIG_PPC_PMAC, the IOC_NVRAM_GET_OFFSET ioctl
would have returned 0 (always). But when CONFIG_PPC64 && CONFIG_PPC_PMAC,
the IOC_NVRAM_GET_OFFSET ioctl would have returned -1 (which is -EPERM)
when the requested partition was not found.

With this patch, the result is now -EINVAL on both PPC32 and PPC64 when
the requested PowerMac NVRAM partition is not found. This is a userspace-
visible change, in the non-existent partition case, which would be in
an error path for an IOC_NVRAM_GET_OFFSET ioctl syscall.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Laurent Vivier <lvivier@redhat.com>
Tested-by: Stan Johnson <userm57@yahoo.com>
---
BTW, the IOC_NVRAM_SYNC ioctl call returns -EINVAL on PPC64. This patch
retains this behaviour though it might be better to actually perform a sync.
Both PPC64 and PPC32 kernels implement ppc_md.nvram_sync() for Core99,
but on PPC64 the ioctl is unimplemented (unlike PPC32).

Changed since v7:
 - Drop pointless comment edit.
---
 arch/powerpc/Kconfig                     |   3 +-
 arch/powerpc/kernel/nvram_64.c           | 185 +++++------------------
 arch/powerpc/platforms/powermac/Makefile |   2 -
 arch/powerpc/platforms/powermac/setup.c  |   2 +-
 arch/powerpc/platforms/powermac/time.c   |   2 +-
 arch/powerpc/platforms/pseries/nvram.c   |   2 -
 drivers/char/nvram.c                     |   2 +
 7 files changed, 40 insertions(+), 158 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 5b859b7f6599..940de2d62fb5 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -271,10 +271,9 @@ config SYSVIPC_COMPAT
 	depends on COMPAT && SYSVIPC
 	default y
 
-# All PPC32s use generic nvram driver through ppc_md
 config HAVE_ARCH_NVRAM_OPS
 	bool
-	default y if PPC32
+	default y
 
 config SCHED_OMIT_FRAME_POINTER
 	bool
diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
index 22e9d281324d..6d0461c02e0f 100644
--- a/arch/powerpc/kernel/nvram_64.c
+++ b/arch/powerpc/kernel/nvram_64.c
@@ -7,12 +7,6 @@
  *      2 of the License, or (at your option) any later version.
  *
  * /dev/nvram driver for PPC64
- *
- * This perhaps should live in drivers/char
- *
- * TODO: Split the /dev/nvram part (that one can use
- *       drivers/char/generic_nvram.c) from the arch & partition
- *       parsing code.
  */
 
 #include <linux/types.h>
@@ -716,136 +710,6 @@ static void oops_to_nvram(struct kmsg_dumper *dumper,
 	spin_unlock_irqrestore(&lock, flags);
 }
 
-static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
-{
-	if (ppc_md.nvram_size == NULL)
-		return -ENODEV;
-	return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE,
-					ppc_md.nvram_size());
-}
-
-
-static ssize_t dev_nvram_read(struct file *file, char __user *buf,
-			  size_t count, loff_t *ppos)
-{
-	ssize_t ret;
-	char *tmp = NULL;
-	ssize_t size;
-
-	if (!ppc_md.nvram_size) {
-		ret = -ENODEV;
-		goto out;
-	}
-
-	size = ppc_md.nvram_size();
-	if (size < 0) {
-		ret = size;
-		goto out;
-	}
-
-	if (*ppos >= size) {
-		ret = 0;
-		goto out;
-	}
-
-	count = min_t(size_t, count, size - *ppos);
-	count = min(count, PAGE_SIZE);
-
-	tmp = kmalloc(count, GFP_KERNEL);
-	if (!tmp) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	ret = ppc_md.nvram_read(tmp, count, ppos);
-	if (ret <= 0)
-		goto out;
-
-	if (copy_to_user(buf, tmp, ret))
-		ret = -EFAULT;
-
-out:
-	kfree(tmp);
-	return ret;
-
-}
-
-static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
-			  size_t count, loff_t *ppos)
-{
-	ssize_t ret;
-	char *tmp = NULL;
-	ssize_t size;
-
-	ret = -ENODEV;
-	if (!ppc_md.nvram_size)
-		goto out;
-
-	ret = 0;
-	size = ppc_md.nvram_size();
-	if (*ppos >= size || size < 0)
-		goto out;
-
-	count = min_t(size_t, count, size - *ppos);
-	count = min(count, PAGE_SIZE);
-
-	tmp = memdup_user(buf, count);
-	if (IS_ERR(tmp)) {
-		ret = PTR_ERR(tmp);
-		goto out;
-	}
-
-	ret = ppc_md.nvram_write(tmp, count, ppos);
-
-	kfree(tmp);
-out:
-	return ret;
-}
-
-static long dev_nvram_ioctl(struct file *file, unsigned int cmd,
-			    unsigned long arg)
-{
-	switch(cmd) {
-#ifdef CONFIG_PPC_PMAC
-	case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
-		printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
-	case IOC_NVRAM_GET_OFFSET: {
-		int part, offset;
-
-		if (!machine_is(powermac))
-			return -EINVAL;
-		if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
-			return -EFAULT;
-		if (part < pmac_nvram_OF || part > pmac_nvram_NR)
-			return -EINVAL;
-		offset = pmac_get_partition(part);
-		if (offset < 0)
-			return offset;
-		if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
-			return -EFAULT;
-		return 0;
-	}
-#endif /* CONFIG_PPC_PMAC */
-	default:
-		return -EINVAL;
-	}
-}
-
-static const struct file_operations nvram_fops = {
-	.owner		= THIS_MODULE,
-	.llseek		= dev_nvram_llseek,
-	.read		= dev_nvram_read,
-	.write		= dev_nvram_write,
-	.unlocked_ioctl	= dev_nvram_ioctl,
-};
-
-static struct miscdevice nvram_dev = {
-	NVRAM_MINOR,
-	"nvram",
-	&nvram_fops
-};
-
-
 #ifdef DEBUG_NVRAM
 static void __init nvram_print_partitions(char * label)
 {
@@ -993,6 +857,8 @@ loff_t __init nvram_create_partition(const char *name, int sig,
 	long size = 0;
 	int rc;
 
+	BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
+
 	/* Convert sizes from bytes to blocks */
 	req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
 	min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
@@ -1194,21 +1060,40 @@ int __init nvram_scan_partitions(void)
 	return err;
 }
 
-static int __init nvram_init(void)
+#if IS_ENABLED(CONFIG_NVRAM)
+
+static ssize_t ppc_nvram_read(char *buf, size_t count, loff_t *index)
 {
-	int rc;
-	
-	BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
+	if (ppc_md.nvram_read)
+		return ppc_md.nvram_read(buf, count, index);
+	return -EINVAL;
+}
 
-	if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
-		return  -ENODEV;
+static ssize_t ppc_nvram_write(char *buf, size_t count, loff_t *index)
+{
+	if (ppc_md.nvram_write)
+		return ppc_md.nvram_write(buf, count, index);
+	return -EINVAL;
+}
 
-  	rc = misc_register(&nvram_dev);
-	if (rc != 0) {
-		printk(KERN_ERR "nvram_init: failed to register device\n");
-		return rc;
-	}
-  	
-  	return rc;
+static ssize_t ppc_nvram_get_size(void)
+{
+	if (ppc_md.nvram_size)
+		return ppc_md.nvram_size();
+	return -ENODEV;
+}
+
+static long ppc_nvram_sync(void)
+{
+	return -EINVAL;
 }
-device_initcall(nvram_init);
+
+const struct nvram_ops arch_nvram_ops = {
+	.read           = ppc_nvram_read,
+	.write          = ppc_nvram_write,
+	.get_size       = ppc_nvram_get_size,
+	.sync           = ppc_nvram_sync,
+};
+EXPORT_SYMBOL(arch_nvram_ops);
+
+#endif /* CONFIG_NVRAM */
diff --git a/arch/powerpc/platforms/powermac/Makefile b/arch/powerpc/platforms/powermac/Makefile
index 923bfb340433..20ebf35d7913 100644
--- a/arch/powerpc/platforms/powermac/Makefile
+++ b/arch/powerpc/platforms/powermac/Makefile
@@ -15,7 +15,5 @@ obj-$(CONFIG_PMAC_BACKLIGHT)	+= backlight.o
 # need this to be a bool.  Cheat here and pretend CONFIG_NVRAM=m is really
 # CONFIG_NVRAM=y
 obj-$(CONFIG_NVRAM:m=y)		+= nvram.o
-# ppc64 pmac doesn't define CONFIG_NVRAM but needs nvram stuff
-obj-$(CONFIG_PPC64)		+= nvram.o
 obj-$(CONFIG_PPC32)		+= bootx_init.o
 obj-$(CONFIG_SMP)		+= smp.o
diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index ce340ae4ee38..dc56ae23118a 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/arch/powerpc/platforms/powermac/setup.c
@@ -316,7 +316,7 @@ static void __init pmac_setup_arch(void)
 	find_via_pmu();
 	smu_init();
 
-#if IS_ENABLED(CONFIG_NVRAM) || defined(CONFIG_PPC64)
+#if IS_ENABLED(CONFIG_NVRAM)
 	pmac_nvram_init();
 #endif
 #ifdef CONFIG_PPC32
diff --git a/arch/powerpc/platforms/powermac/time.c b/arch/powerpc/platforms/powermac/time.c
index f157e3d071f2..b36ddee17c87 100644
--- a/arch/powerpc/platforms/powermac/time.c
+++ b/arch/powerpc/platforms/powermac/time.c
@@ -68,7 +68,7 @@
 long __init pmac_time_init(void)
 {
 	s32 delta = 0;
-#ifdef CONFIG_NVRAM
+#if defined(CONFIG_NVRAM) && defined(CONFIG_PPC32)
 	int dst;
 	
 	delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16;
diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
index 69cedc1b3b8a..1136a38ff039 100644
--- a/arch/powerpc/platforms/pseries/nvram.c
+++ b/arch/powerpc/platforms/pseries/nvram.c
@@ -7,8 +7,6 @@
  *      2 of the License, or (at your option) any later version.
  *
  * /dev/nvram driver for PPC64
- *
- * This perhaps should live in drivers/char
  */
 
 
diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
index 8339885e8e9b..8cbfed86ec8d 100644
--- a/drivers/char/nvram.c
+++ b/drivers/char/nvram.c
@@ -334,6 +334,8 @@ static long nvram_misc_ioctl(struct file *file, unsigned int cmd,
 			if (part < pmac_nvram_OF || part > pmac_nvram_NR)
 				return -EINVAL;
 			offset = pmac_get_partition(part);
+			if (offset < 0)
+				return -EINVAL;
 			if (copy_to_user((void __user *)arg,
 					 &offset, sizeof(offset)) != 0)
 				return -EFAULT;
-- 
2.19.2