Re: [PATCH net] powerpc: use big endian to hash len and proto in csum_ipv6_magic
From: LEROY Christophe <hidden>
Date: 2018-09-08 16:33:32
Also in:
netdev
Xin Long [off-list ref] a =C3=A9crit=C2=A0:
quoted hunk ↗ jump to hunk
The function csum_ipv6_magic doesn't convert len and proto to big endian before doing ipv6 csum hash, which is not consistent with RFC and other arches. Jianlin found it when ICMPv6 packets from other hosts were dropped in the powerpc64 system. This patch is to fix it by using instruction 'lwbrx' to do this conversion in powerpc32/64 csum_ipv6_magic. Fixes: e9c4943a107b ("powerpc: Implement csum_ipv6_magic in assembly") Reported-by: Jianlin Shi <redacted> Signed-off-by: Xin Long <lucien.xin@gmail.com> --- arch/powerpc/lib/checksum_32.S | 4 ++++ arch/powerpc/lib/checksum_64.S | 4 ++++ 2 files changed, 8 insertions(+)diff --git a/arch/powerpc/lib/checksum_32.S b/arch/powerpc/lib/checksum_3=
2.S
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index aa22406..7d3446e 100644--- a/arch/powerpc/lib/checksum_32.S +++ b/arch/powerpc/lib/checksum_32.S@@ -325,6 +325,10 @@ _GLOBAL(csum_ipv6_magic) adde r0, r0, r9 lwz r11, 12(r4) adde r0, r0, r10 + STWX_BE r5, 0, r1 + lwz r5, 0(r1) + STWX_BE r6, 0, r1 + lwz r6, 0(r1)
PPC32 doesn't support little endian, so nothing to do here.
quoted hunk ↗ jump to hunk
add r5, r5, r6 /* assumption: len + proto doesn't carry */ adde r0, r0, r11 adde r0, r0, r5diff --git a/arch/powerpc/lib/checksum_64.S b/arch/powerpc/lib/checksum_6=
4.S
quoted hunk ↗ jump to hunk
index 886ed94..302e732 100644--- a/arch/powerpc/lib/checksum_64.S +++ b/arch/powerpc/lib/checksum_64.S@@ -439,6 +439,10 @@ EXPORT_SYMBOL(csum_partial_copy_generic) _GLOBAL(csum_ipv6_magic) ld r8, 0(r3) ld r9, 8(r3) + STWX_BE r5, 0, r1 + lwz r5, 0(r1) + STWX_BE r6, 0, r1 + lwz r6, 0(r1) add r5, r5, r6
This is overkill. For LE it should be enough to rotate r5 by 8 bits=20=20 after=20the sum. Best place to do it would be after ld r11 I think. Christophe
addc r0, r8, r9 ld r10, 0(r4) -- 2.1.0