unsigned long leon_swprobe()

in mm/leon_mm.c [36:181]

• 128 lines of code
• 35 McCabe index (conditional complexity)

unsigned long leon_swprobe(unsigned long vaddr, unsigned long *paddr)
{

	unsigned int ctxtbl;
	unsigned int pgd, pmd, ped;
	unsigned int ptr;
	unsigned int lvl, pte, paddrbase;
	unsigned int ctx;
	unsigned int paddr_calc;

	paddrbase = 0;

	if (srmmu_swprobe_trace)
		printk(KERN_INFO "swprobe: trace on\n");

	ctxtbl = leon_get_ctable_ptr();
	if (!(ctxtbl)) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO "swprobe: leon_get_ctable_ptr returned 0=>0\n");
		return 0;
	}
	if (!_pfn_valid(PFN(ctxtbl))) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO
			       "swprobe: !_pfn_valid(%x)=>0\n",
			       PFN(ctxtbl));
		return 0;
	}

	ctx = srmmu_get_context();
	if (srmmu_swprobe_trace)
		printk(KERN_INFO "swprobe:  --- ctx (%x) ---\n", ctx);

	pgd = LEON_BYPASS_LOAD_PA(ctxtbl + (ctx * 4));

	if (((pgd & SRMMU_ET_MASK) == SRMMU_ET_PTE)) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO "swprobe: pgd is entry level 3\n");
		lvl = 3;
		pte = pgd;
		paddrbase = pgd & _SRMMU_PTE_PMASK_LEON;
		goto ready;
	}
	if (((pgd & SRMMU_ET_MASK) != SRMMU_ET_PTD)) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO "swprobe: pgd is invalid => 0\n");
		return 0;
	}

	if (srmmu_swprobe_trace)
		printk(KERN_INFO "swprobe:  --- pgd (%x) ---\n", pgd);

	ptr = (pgd & SRMMU_PTD_PMASK) << 4;
	ptr += ((((vaddr) >> LEON_PGD_SH) & LEON_PGD_M) * 4);
	if (!_pfn_valid(PFN(ptr)))
		return 0;

	pmd = LEON_BYPASS_LOAD_PA(ptr);
	if (((pmd & SRMMU_ET_MASK) == SRMMU_ET_PTE)) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO "swprobe: pmd is entry level 2\n");
		lvl = 2;
		pte = pmd;
		paddrbase = pmd & _SRMMU_PTE_PMASK_LEON;
		goto ready;
	}
	if (((pmd & SRMMU_ET_MASK) != SRMMU_ET_PTD)) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO "swprobe: pmd is invalid => 0\n");
		return 0;
	}

	if (srmmu_swprobe_trace)
		printk(KERN_INFO "swprobe:  --- pmd (%x) ---\n", pmd);

	ptr = (pmd & SRMMU_PTD_PMASK) << 4;
	ptr += (((vaddr >> LEON_PMD_SH) & LEON_PMD_M) * 4);
	if (!_pfn_valid(PFN(ptr))) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO "swprobe: !_pfn_valid(%x)=>0\n",
			       PFN(ptr));
		return 0;
	}

	ped = LEON_BYPASS_LOAD_PA(ptr);

	if (((ped & SRMMU_ET_MASK) == SRMMU_ET_PTE)) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO "swprobe: ped is entry level 1\n");
		lvl = 1;
		pte = ped;
		paddrbase = ped & _SRMMU_PTE_PMASK_LEON;
		goto ready;
	}
	if (((ped & SRMMU_ET_MASK) != SRMMU_ET_PTD)) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO "swprobe: ped is invalid => 0\n");
		return 0;
	}

	if (srmmu_swprobe_trace)
		printk(KERN_INFO "swprobe:  --- ped (%x) ---\n", ped);

	ptr = (ped & SRMMU_PTD_PMASK) << 4;
	ptr += (((vaddr >> LEON_PTE_SH) & LEON_PTE_M) * 4);
	if (!_pfn_valid(PFN(ptr)))
		return 0;

	ptr = LEON_BYPASS_LOAD_PA(ptr);
	if (((ptr & SRMMU_ET_MASK) == SRMMU_ET_PTE)) {
		if (srmmu_swprobe_trace)
			printk(KERN_INFO "swprobe: ptr is entry level 0\n");
		lvl = 0;
		pte = ptr;
		paddrbase = ptr & _SRMMU_PTE_PMASK_LEON;
		goto ready;
	}
	if (srmmu_swprobe_trace)
		printk(KERN_INFO "swprobe: ptr is invalid => 0\n");
	return 0;

ready:
	switch (lvl) {
	case 0:
		paddr_calc =
		    (vaddr & ~(-1 << LEON_PTE_SH)) | ((pte & ~0xff) << 4);
		break;
	case 1:
		paddr_calc =
		    (vaddr & ~(-1 << LEON_PMD_SH)) | ((pte & ~0xff) << 4);
		break;
	case 2:
		paddr_calc =
		    (vaddr & ~(-1 << LEON_PGD_SH)) | ((pte & ~0xff) << 4);
		break;
	default:
	case 3:
		paddr_calc = vaddr;
		break;
	}
	if (srmmu_swprobe_trace)
		printk(KERN_INFO "swprobe: padde %x\n", paddr_calc);
	if (paddr)
		*paddr = paddr_calc;
	return pte;
}