[RFC 21/24] powerpc: Adopt nvram module for PPC64

Finn Thain
2015-05-31T01:17:50Z

[-- Attachment #1: ppc64-adopt-drivers-char-nvram --]
[-- Type: text/plain, Size: 9694 bytes --]

Adopt nvram module to reduce code duplication.

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 -ENOENT 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>

---

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).

---
arch/powerpc/Kconfig | 3
arch/powerpc/kernel/nvram_64.c | 203 ++++---------------------------
arch/powerpc/platforms/powermac/Makefile | 5
arch/powerpc/platforms/powermac/nvram.c | 2
arch/powerpc/platforms/powermac/setup.c | 2
drivers/char/nvram.c | 2
6 files changed, 38 insertions(+), 179 deletions(-)

Index: linux/arch/powerpc/Kconfig
===================================================================
--- linux.orig/arch/powerpc/Kconfig 2015-05-31 11:01:22.000000000 +1000
+++ linux/arch/powerpc/Kconfig 2015-05-31 11:01:24.000000000 +1000
@@ -177,10 +177,9 @@ 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
Index: linux/arch/powerpc/kernel/nvram_64.c
===================================================================
--- linux.orig/arch/powerpc/kernel/nvram_64.c 2015-05-31 11:00:59.000000000 +1000
+++ linux/arch/powerpc/kernel/nvram_64.c 2015-05-31 11:01:25.000000000 +1000
@@ -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/module.h>
@@ -731,153 +725,6 @@ static void oops_to_nvram(struct kmsg_du
spin_unlock_irqrestore(&lock, flags);
}

-static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
-{
- int size;
-
- if (ppc_md.nvram_size == NULL)
- return -ENODEV;
- size = ppc_md.nvram_size();
-
- switch (origin) {
- case 1:
- offset += file->f_pos;
- break;
- case 2:
- offset += size;
- break;
- }
- if (offset < 0)
- return -EINVAL;
- file->f_pos = offset;
- return file->f_pos;
-}
-
-
-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);
-
- ret = -ENOMEM;
- tmp = kmalloc(count, GFP_KERNEL);
- if (!tmp)
- goto out;
-
- ret = -EFAULT;
- if (copy_from_user(tmp, buf, count))
- goto out;
-
- ret = ppc_md.nvram_write(tmp, count, ppos);
-
-out:
- kfree(tmp);
- 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;
- }
-}
-
-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)
@@ -1026,6 +873,8 @@ loff_t __init nvram_create_partition(con
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;
@@ -1226,29 +1075,41 @@ 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 void __exit nvram_cleanup(void)
+static long ppc_nvram_sync(void)
{
- misc_deregister( &nvram_dev );
+ return -EINVAL;
}

-module_init(nvram_init);
-module_exit(nvram_cleanup);
-MODULE_LICENSE("GPL");
+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 */
Index: linux/arch/powerpc/platforms/powermac/Makefile
===================================================================
--- linux.orig/arch/powerpc/platforms/powermac/Makefile 2015-05-31 11:00:59.000000000 +1000
+++ linux/arch/powerpc/platforms/powermac/Makefile 2015-05-31 11:01:25.000000000 +1000
@@ -9,11 +9,6 @@ obj-y += pic.o setup.o time.o feature
sleep.o low_i2c.o cache.o pfunc_core.o \
pfunc_base.o udbg_scc.o udbg_adb.o
obj-$(CONFIG_PMAC_BACKLIGHT) += backlight.o
-# CONFIG_NVRAM is an arch. independent tristate symbol, for pmac32 we really
-# need this to be a bool. Cheat here and pretend CONFIG_NVRAM=m is really
-# CONFIG_NVRAM=y
obj-$(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
Index: linux/arch/powerpc/platforms/powermac/setup.c
===================================================================
--- linux.orig/arch/powerpc/platforms/powermac/setup.c 2015-05-31 11:01:22.000000000 +1000
+++ linux/arch/powerpc/platforms/powermac/setup.c 2015-05-31 11:01:25.000000000 +1000
@@ -321,7 +321,7 @@ 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

Index: linux/drivers/char/nvram.c
===================================================================
--- linux.orig/drivers/char/nvram.c 2015-05-31 11:01:21.000000000 +1000
+++ linux/drivers/char/nvram.c 2015-05-31 11:01:25.000000000 +1000
@@ -342,6 +342,8 @@ static long nvram_misc_ioctl(struct file
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;
Index: linux/arch/powerpc/platforms/powermac/nvram.c
===================================================================
--- linux.orig/arch/powerpc/platforms/powermac/nvram.c 2015-05-31 11:01:15.000000000 +1000
+++ linux/arch/powerpc/platforms/powermac/nvram.c 2015-05-31 11:01:25.000000000 +1000
@@ -629,6 +629,8 @@ bail:

int pmac_get_partition(int partition)
{
+ if (nvram_partitions[partition] < 0)
+ return -ENOENT;
return nvram_partitions[partition];
}