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From: | diegodo |
Subject: | Re: Fix incorrect subnet mask for ppc64 |
Date: | Wed, 14 Mar 2018 15:07:49 -0300 |
User-agent: | Roundcube Webmail/1.0.1 |
On 2018-03-14 15:05, diegodo wrote:
On 2018-03-13 12:09, diegodo wrote:From: Masahiro Matsuya <address@hidden>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/address@hidden: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) --- grub-core/net/drivers/ieee1275/ofnet.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/grub-core/net/drivers/ieee1275/ofnet.c b/grub-core/net/drivers/ieee1275/ofnet.c index 002446be1..3df75357a 100644 --- a/grub-core/net/drivers/ieee1275/ofnet.c +++ b/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 (~ (subnet_mask.ipv4)))); } if (gateway_addr.ipv4 != 0)Sorry, this patch contains error in parenthesis. I'll send again with this fixed. _______________________________________________ Bug-grub mailing list address@hidden https://lists.gnu.org/mailman/listinfo/bug-grub
From: Masahiro Matsuya <address@hidden>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/address@hidden: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)
--- grub-core/net/drivers/ieee1275/ofnet.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)diff --git a/grub-core/net/drivers/ieee1275/ofnet.c b/grub-core/net/drivers/ieee1275/ofnet.c
index 002446be1..3df75357a 100644 --- a/grub-core/net/drivers/ieee1275/ofnet.c +++ b/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 (~ (subnet_mask.ipv4))); } if (gateway_addr.ipv4 != 0) -- 2.13.5
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