[PATCH v9 22/22] powerpc: Adopt nvram module for PPC64

Finn Thain
2019-01-15T04:23:13Z

Adopt nvram module to reduce code duplication. This means CONFIG_NVRAM
becomes available to PPC64 builds. Previously it was only available to
PPC32 builds because it depended on CONFIG_GENERIC_NVRAM.

The IOC_NVRAM_GET_OFFSET ioctl as implemented on PPC64 validates the
offset returned by pmac_get_partition(). Do the same in 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.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
BTW, the IOC_NVRAM_SYNC ioctl call returns an error on PPC64. This patch
retains this behaviour though it might be better to actually perform a sync
since both PPC64 and PPC32 do implement ppc_md.nvram_sync() for Core99.

Changed since v8:
- Dropped the arch_nvram_ops struct in favour of equivalent ppc_md
method calls. Regardless of the actual implementation, the presence of
this functionality is indicated by CONFIG_HAVE_ARCH_NVRAM_OPS=y.

Changed since v7:
- Dropped pointless comment edit.
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/kernel/nvram_64.c | 158 +----------------------
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 | 4 +
7 files changed, 9 insertions(+), 163 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index f62e6a3f9c4e..621912365508 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -178,7 +178,7 @@ config PPC
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
- select HAVE_ARCH_NVRAM_OPS if PPC32
+ select HAVE_ARCH_NVRAM_OPS
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_CBPF_JIT if !PPC64
diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
index 38b03a330cd2..244d2462e781 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>
@@ -714,137 +708,6 @@ 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");
- /* fall through */
- 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)
{
@@ -992,6 +855,8 @@ 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;
@@ -1192,22 +1057,3 @@ int __init nvram_scan_partitions(void)
kfree(header);
return err;
}
-
-static int __init nvram_init(void)
-{
- int rc;
-
- BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
-
- if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
- return -ENODEV;
-
- rc = misc_register(&nvram_dev);
- if (rc != 0) {
- printk(KERN_ERR "nvram_init: failed to register device\n");
- return rc;
- }
-
- return rc;
-}
-device_initcall(nvram_init);
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 b47f49cf9c4d..b7efcf336589 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 944f05fddacd..eff1e3f1b3a2 100644
--- a/drivers/char/nvram.c
+++ b/drivers/char/nvram.c
@@ -302,6 +302,8 @@ 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;
@@ -309,6 +311,7 @@ static long nvram_misc_ioctl(struct file *file, unsigned int cmd,
}
#endif
break;
+#ifdef CONFIG_PPC32
case IOC_NVRAM_SYNC:
if (ppc_md.nvram_sync != NULL) {
mutex_lock(&nvram_mutex);
@@ -317,6 +320,7 @@ static long nvram_misc_ioctl(struct file *file, unsigned int cmd,
}
ret = 0;
break;
+#endif
#elif defined(CONFIG_X86) || defined(CONFIG_M68K)
case NVRAM_INIT:
/* initialize NVRAM contents and checksum */
--
2.19.2