pcala64.c

#include <stdio.h>
#include <stdlib.h>

int
main (int argc, char *argv[])
{
	long target;
	long dest;
	long pc;
	long delta;
	long pcala_hi20;
	long pcala_lo12;
	long pcala64_lo20;
	long pcala64_hi12;

	dest = strtoul (argv[1], NULL, 16);
	pc = strtoul (argv[2], NULL, 16);

	delta = dest - (pc & ~0xfffUL);
	delta = delta + ((delta & 0x800UL) << 1);
	delta = delta + ((delta & 0x80000000UL) << 1);
	delta = delta - ((delta & 0x800UL) << 21);

	pcala_hi20 = (delta >> 12) & 0xfffffUL;
	pcala_lo12 = delta & 0xfffUL;
	pcala64_lo20 = (delta >> 32) & 0xfffffUL;
	pcala64_hi12 = (delta >> 52) & 0xfffUL;

	printf ("R_LARCH_PCALA_HI20   = 0x%lx\n", pcala_hi20);
	printf ("R_LARCH_PCALA_LO12   = 0x%lx\n", pcala_lo12);
	printf ("R_LARCH_PCALA64_LO20 = 0x%lx\n", pcala64_lo20);
	printf ("R_LARCH_PCALA64_HI12 = 0x%lx\n", pcala64_hi12);

	target = (pc & ~0xfffUL) + ((pcala_hi20 << 44) >> 32) +
	         ((pcala64_hi12 << 52) | (pcala64_lo20 << 32) | (((pcala_lo12 << 52) >> 52) & 0xffffffffUL));
	if (target != dest) {
		printf ("%0lx != %0lx\n", dest, target);
		return -1;
	}

	return 0;
}

Yes. The instruction's free encoding bit-field can be used to maintain the relationship before relocation. But this is no longer compatible with what it used to be.