Re: [PATCH] powerpc/pkeys: Fix reading of ibm,processor-storage-keys property
From: Ram Pai
Date: Thu Sep 20 2018 - 12:12:03 EST
On Thu, Sep 20, 2018 at 01:38:58AM -0300, Thiago Jung Bauermann wrote:
> scan_pkey_feature() uses of_property_read_u32_array() to read the
> ibm,processor-storage-keys property and calls be32_to_cpu() on the
> value it gets. The problem is that of_property_read_u32_array() already
> returns the value converted to the CPU byte order.
> The value of pkeys_total ends up more or less sane because there's a min()
> call in pkey_initialize() which reduces pkeys_total to 32. So in practice
> the kernel ignores the fact that the hypervisor reserved one key for
> itself (the device tree advertises 31 keys in my test VM).
> This is wrong, but the effect in practice is that when a process tries to
> allocate the 32nd key, it gets an -EINVAL error instead of -ENOSPC which
> would indicate that there aren't any keys available
Thanks for the fix.
Reviewed-by: Ram Pai <linuxram@xxxxxxxxxx>
> Fixes: cf43d3b26452 ("powerpc: Enable pkey subsystem")
> Signed-off-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx>
> arch/powerpc/mm/pkeys.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
> index 333b1f80c435..b271b283c785 100644
> --- a/arch/powerpc/mm/pkeys.c
> +++ b/arch/powerpc/mm/pkeys.c
> @@ -45,7 +45,7 @@ static void scan_pkey_feature(void)
> * Since any pkey can be used for data or execute, we will just treat
> * all keys as equal and track them as one entity.
> - pkeys_total = be32_to_cpu(vals);
> + pkeys_total = vals;
> pkeys_devtree_defined = true;