Please don't chain swap_bytes32 with le_to_cpu32 as it's a less readable equivalent of be_to_cpu32
On Thu, 31 Oct 2019, 11:38 Javier Martinez Canillas, <javi...@redhat.com> wrote: > From: Masahiro Matsuya <mmats...@redhat.com> > > The netmask configured in firmware is not respected on ppc64 (big endian). > When 255.255.252.0 is set as netmask in firmware, the following is the > value of bootpath string in grub_ieee1275_parse_bootpath(). > > /vdevice/l-lan@30000002 > :speed=auto,duplex=auto,192.168.88.10,,192.168.89.113,192.168.88.1,5,5,255.255.252.0,512 > > The netmask in this bootpath is no problem, since it's a value specified > in firmware. But, The value of 'subnet_mask.ipv4' was set with 0xfffffc00, > and __builtin_ctz (~grub_le_to_cpu32 (subnet_mask.ipv4)) returned 16 (not > 22). > As a result, 16 was used for netmask wrongly. > > 1111 1111 1111 1111 1111 1100 0000 0000 # subnet_mask.ipv4 (=0xfffffc00) > 0000 0000 1111 1100 1111 1111 1111 1111 # grub_le_to_cpu32 > (subnet_mask.ipv4) > 1111 1111 0000 0011 0000 0000 0000 0000 # ~grub_le_to_cpu32 > (subnet_mask.ipv4) > > And, the count of zero with __builtin_ctz can be 16. > This patch changes it as below. > > 1111 1111 1111 1111 1111 1100 0000 0000 # subnet_mask.ipv4 (=0xfffffc00) > 0000 0000 1111 1100 1111 1111 1111 1111 # grub_le_to_cpu32 > (subnet_mask.ipv4) > 1111 1111 1111 1111 1111 1100 0000 0000 # > grub_swap_bytes32(grub_le_to_cpu32 (subnet_mask.ipv4)) > 0000 0000 0000 0000 0000 0011 1111 1111 # > ~grub_swap_bytes32(grub_le_to_cpu32 (subnet_mask.ipv4)) > > The count of zero with __builtin_clz can be 22. (clz counts the number of > one bits preceding the most significant zero bit) > > Signed-off-by: Masahiro Matsuya <mmats...@redhat.com> > Signed-off-by: Javier Martinez Canillas <javi...@redhat.com> > --- > > grub-core/net/drivers/ieee1275/ofnet.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git grub-core/net/drivers/ieee1275/ofnet.c > grub-core/net/drivers/ieee1275/ofnet.c > index ac4e62a95c9..3860b6f78d8 100644 > --- grub-core/net/drivers/ieee1275/ofnet.c > +++ grub-core/net/drivers/ieee1275/ofnet.c > @@ -220,8 +220,7 @@ grub_ieee1275_parse_bootpath (const char *devpath, > char *bootpath, > flags); > inter->vlantag = vlantag; > grub_net_add_ipv4_local (inter, > - __builtin_ctz (~grub_le_to_cpu32 > (subnet_mask.ipv4))); > - > + __builtin_clz > (~grub_swap_bytes32(grub_le_to_cpu32 (subnet_mask.ipv4)))); > } > > if (gateway_addr.ipv4 != 0) > -- > 2.21.0 > > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > https://lists.gnu.org/mailman/listinfo/grub-devel >
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