parisc: Document rules regarding checksum of HPMC handler (41dbee81) · Commits · 戴 / test

arch/parisc/kernel/traps.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -837,6 +837,17 @@ void __init initialize_ivt(const void *iva)
		if (pdc_instr(&instr) == PDC_OK)
		ivap[0] = instr;

		/*
		* Rules for the checksum of the HPMC handler:
		* 1. The IVA does not point to PDC/PDH space (ie: the OS has installed
		* its own IVA).
		* 2. The word at IVA + 32 is nonzero.
		* 3. If Length (IVA + 60) is not zero, then Length (IVA + 60) and
		* Address (IVA + 56) are word-aligned.
		* 4. The checksum of the 8 words starting at IVA + 32 plus the sum of
		* the Length/4 words starting at Address is zero.
		*/

		/* Compute Checksum for HPMC handler */
		length = os_hpmc_size;
		ivap[7] = length;