Re: [tip:x86/core 1/1] arch/x86/um/../lib/csum-partial_64.c:98:12: error: implicit declaration of function 'load_unaligned_zeropad'

Eric Dumazet
2021-11-18T17:03:00Z

On Thu, Nov 18, 2021 at 8:57 AM Eric Dumazet <edumazet@google.com> 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..7a3c4e7e05c4b21566e1ee3813a071509a9d54ff
100644
--- 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]"