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powerpc: Adopt nvram module for PPC64

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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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Finn Thain
2019-01-15 15:18:56 +11:00
committed by Greg Kroah-Hartman
parent 537f3286ad
commit 20e07af71f
7 changed files with 9 additions and 163 deletions
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4
drivers/char/nvram.c
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@@ -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 */