tmp = read_aux_reg(ARC_REG_MMU_BCR);
mmu->ver = (tmp >> 24);
- if (mmu->ver <= 2) {
- mmu2 = (struct bcr_mmu_1_2 *)&tmp;
- mmu->pg_sz_k = TO_KB(0x2000);
- mmu->sets = 1 << mmu2->sets;
- mmu->ways = 1 << mmu2->ways;
- mmu->u_dtlb = mmu2->u_dtlb;
- mmu->u_itlb = mmu2->u_itlb;
- } else if (mmu->ver == 3) {
- mmu3 = (struct bcr_mmu_3 *)&tmp;
- mmu->pg_sz_k = 1 << (mmu3->pg_sz - 1);
- mmu->sets = 1 << mmu3->sets;
- mmu->ways = 1 << mmu3->ways;
- mmu->u_dtlb = mmu3->u_dtlb;
- mmu->u_itlb = mmu3->u_itlb;
- mmu->sasid = mmu3->sasid;
+ if (is_isa_arcompact()) {
+ if (mmu->ver <= 2) {
+ mmu2 = (struct bcr_mmu_1_2 *)&tmp;
+ mmu->pg_sz_k = TO_KB(0x2000);
+ mmu->sets = 1 << mmu2->sets;
+ mmu->ways = 1 << mmu2->ways;
+ mmu->u_dtlb = mmu2->u_dtlb;
+ mmu->u_itlb = mmu2->u_itlb;
+ } else {
+ mmu3 = (struct bcr_mmu_3 *)&tmp;
+ mmu->pg_sz_k = 1 << (mmu3->pg_sz - 1);
+ mmu->sets = 1 << mmu3->sets;
+ mmu->ways = 1 << mmu3->ways;
+ mmu->u_dtlb = mmu3->u_dtlb;
+ mmu->u_itlb = mmu3->u_itlb;
+ mmu->sasid = mmu3->sasid;
+ }
} else {
mmu4 = (struct bcr_mmu_4 *)&tmp;
mmu->pg_sz_k = 1 << (mmu4->sz0 - 1);
void arc_mmu_init(void)
{
- char str[256];
struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
+ char str[256];
+ int compat = 0;
pr_info("%s", arc_mmu_mumbojumbo(0, str, sizeof(str)));
*/
BUILD_BUG_ON(!IS_ALIGNED(STACK_TOP, PMD_SIZE));
- /* For efficiency sake, kernel is compile time built for a MMU ver
- * This must match the hardware it is running on.
- * Linux built for MMU V2, if run on MMU V1 will break down because V1
- * hardware doesn't understand cmds such as WriteNI, or IVUTLB
- * On the other hand, Linux built for V1 if run on MMU V2 will do
- * un-needed workarounds to prevent memcpy thrashing.
- * Similarly MMU V3 has new features which won't work on older MMU
+ /*
+ * Ensure that MMU features assumed by kernel exist in hardware.
+ * For older ARC700 cpus, it has to be exact match, since the MMU
+ * revisions were not backwards compatible (MMUv3 TLB layout changed
+ * so even if kernel for v2 didn't use any new cmds of v3, it would
+ * still not work.
+ * For HS cpus, MMUv4 was baseline and v5 is backwards compatible
+ * (will run older software).
*/
- if (mmu->ver != CONFIG_ARC_MMU_VER) {
+ if (is_isa_arcompact() && mmu->ver == CONFIG_ARC_MMU_VER)
+ compat = 1;
+ else if (is_isa_arcv2() && mmu->ver >= CONFIG_ARC_MMU_VER)
+ compat = 1;
+
+ if (!compat) {
panic("MMU ver %d doesn't match kernel built for %d...\n",
mmu->ver, CONFIG_ARC_MMU_VER);
}
struct pt_regs *regs)
{
struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
- unsigned int pd0[mmu->ways];
unsigned long flags;
- int set;
+ int set, n_ways = mmu->ways;
+
+ n_ways = min(n_ways, 4);
+ BUG_ON(mmu->ways > 4);
local_irq_save(flags);
for (set = 0; set < mmu->sets; set++) {
int is_valid, way;
+ unsigned int pd0[4];
/* read out all the ways of current set */
- for (way = 0, is_valid = 0; way < mmu->ways; way++) {
+ for (way = 0, is_valid = 0; way < n_ways; way++) {
write_aux_reg(ARC_REG_TLBINDEX,
SET_WAY_TO_IDX(mmu, set, way));
write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead);
continue;
/* Scan the set for duplicate ways: needs a nested loop */
- for (way = 0; way < mmu->ways - 1; way++) {
+ for (way = 0; way < n_ways - 1; way++) {
int n;
if (!pd0[way])
continue;
- for (n = way + 1; n < mmu->ways; n++) {
+ for (n = way + 1; n < n_ways; n++) {
if (pd0[way] != pd0[n])
continue;