linux/arch/parisc
Guenter Roeck 0568b6f0d8 parisc: Strip upper 32 bit of sum in csum_ipv6_magic for 64-bit builds
IPv6 checksum tests with unaligned addresses on 64-bit builds result
in unexpected failures.

Expected expected == csum_result, but
    expected == 46591 (0xb5ff)
    csum_result == 46381 (0xb52d)
with alignment offset 1

Oddly enough, the problem disappeared after adding test code into
the beginning of csum_ipv6_magic().

As it turns out, the 'sum' parameter of csum_ipv6_magic() is declared as
__wsum, which is a 32-bit variable. However, it is treated as 64-bit
variable in the 64-bit assembler code. Tests showed that the upper 32 bit
of the register used to pass the variable are _not_ cleared when entering
the function. This can result in checksum calculation errors.

Clearing the upper 32 bit of 'sum' as first operation in the assembler
code fixes the problem.

Acked-by: Helge Deller <deller@gmx.de>
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Helge Deller <deller@gmx.de>
2024-02-27 22:51:45 +01:00
..
boot parisc: Allow building uncompressed Linux kernel 2023-10-30 14:54:40 +01:00
configs staging: qlge: Retire the driver 2023-10-21 11:52:54 +02:00
include parisc: Strip upper 32 bit of sum in csum_ipv6_magic for 64-bit builds 2024-02-27 22:51:45 +01:00
kernel parisc/unaligned: Rewrite 64-bit inline assembly of emulate_ldd() 2024-02-27 22:51:44 +01:00
lib parisc: ucmpdi2: Fix no previous prototype for '__ucmpdi2' warning 2023-08-10 18:34:05 +02:00
math-emu parisc: avoid c23 'nullptr' idenitifier 2024-02-27 22:51:44 +01:00
mm parisc: Fix random data corruption from exception handler 2024-01-30 17:18:58 +01:00
net parisc: Add eBPF JIT compiler glue code and Makefile 2023-08-22 10:24:47 +02:00
video arch/parisc: Detect primary video device from device instance 2024-01-12 12:38:37 +01:00
defpalo.conf
install.sh kbuild: factor out the common installation code into scripts/install.sh 2022-05-11 21:45:53 +09:00
Kbuild parisc: Wire up eBPF JIT compiler 2023-08-22 10:24:47 +02:00
Kconfig parisc: Fix random data corruption from exception handler 2024-01-30 17:18:58 +01:00
Kconfig.debug parisc: Use page table locks only if DEBUG_KERNEL is enabled 2023-08-20 20:23:46 +02:00
Makefile kbuild: use 4-space indentation when followed by conditionals 2024-02-15 06:05:44 +09:00