Re: [tip:x86/core 1/1] arch/x86/um/../lib/csum-partial_64.c:98:12: error: implicit declaration of function 'load_unaligned_zeropad'
From: Noah Goldstein <hidden>
Date: 2021-11-25 02:20:22
Also in:
lkml, oe-kbuild-all
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Eric Dumazet <edumazet@google.com> On Thu, Nov 18, 2021 at 8:57 AM Eric Dumazet [off-list ref] wrote:
Unless fixups can be handled, the signature of the function needs to be different. In UM, we would need to provide a number of bytes that can be read.
We can make this a bit less ugly of course.
diff --git a/arch/x86/lib/csum-partial_64.c b/arch/x86/lib/csum-partial_64.c
index 5ec35626945b6db2f7f41c6d46d5e422810eac46..7a3c4e7e05c4b21566e1ee3813a071509a9d54ff100644
--- a/arch/x86/lib/csum-partial_64.c
+++ b/arch/x86/lib/csum-partial_64.c@@ -21,6 +21,25 @@ static inline unsigned short from32to16(unsigned a) return b; } + +static inline unsigned long load_partial_long(const void *buff, int len) +{ +#ifndef CONFIG_DCACHE_WORD_ACCESS + union { + unsigned long ulval; + u8 bytes[sizeof(long)]; + } v; + + v.ulval = 0; + memcpy(v.bytes, buff, len); + return v.ulval; +#else + unsigned int shift = (sizeof(long) - len) * BITS_PER_BYTE; + + return (load_unaligned_zeropad(buff) << shift) >> shift; +#endif +} + /* * Do a checksum on an arbitrary memory area. * Returns a 32bit checksum.
@@ -91,11 +110,9 @@ __wsum csum_partial(const void *buff, int len, __wsum sum) : "memory"); buff += 8; } - if (len & 7) { - unsigned int shift = (8 - (len & 7)) * 8; - unsigned long trail; - - trail = (load_unaligned_zeropad(buff) << shift) >> shift; + len &= 7; + if (len) { + unsigned long trail = load_partial_long(buff, len); asm("addq %[trail],%[res]\n\t" "adcq $0,%[res]"
Hi, I'm not sure if this is intentional or not, but I noticed that the output of 'csum_partial' is different after this patch. I figured that the checksum algorithm is fixed so just wanted mention it incase its a bug. If not sorry for the spam. Example on x86_64: Buff: [ 87, b3, 92, b7, 8b, 53, 96, db, cd, 0f, 7e, 7e ] len : 11 sum : 0 csum_partial new : 2480936615 csum_partial HEAD: 2472089390 _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um