1 files changed, 379 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/cplb-mpu/cplbmgr.c b/arch/blackfin/kernel/cplb-mpu/cplbmgr.c
new file mode 100644
index 000000000..b56bd8514
--- /dev/null
+++ b/arch/blackfin/kernel/cplb-mpu/cplbmgr.c
@@ -0,0 +1,379 @@
+/*
+ * Blackfin CPLB exception handling for when MPU in on
+ *
+ * Copyright 2008-2009 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/mm.h>
+
+#include <asm/blackfin.h>
+#include <asm/cacheflush.h>
+#include <asm/cplb.h>
+#include <asm/cplbinit.h>
+#include <asm/mmu_context.h>
+
+/*
+ * WARNING
+ *
+ * This file is compiled with certain -ffixed-reg options.  We have to
+ * make sure not to call any functions here that could clobber these
+ * registers.
+ */
+
+int page_mask_nelts;
+int page_mask_order;
+unsigned long *current_rwx_mask[NR_CPUS];
+
+int nr_dcplb_miss[NR_CPUS], nr_icplb_miss[NR_CPUS];
+int nr_icplb_supv_miss[NR_CPUS], nr_dcplb_prot[NR_CPUS];
+int nr_cplb_flush[NR_CPUS];
+
+#ifdef CONFIG_EXCPT_IRQ_SYSC_L1
+#define MGR_ATTR __attribute__((l1_text))
+#else
+#define MGR_ATTR
+#endif
+
+/*
+ * Given the contents of the status register, return the index of the
+ * CPLB that caused the fault.
+ */
+static inline int faulting_cplb_index(int status)
+{
+	int signbits = __builtin_bfin_norm_fr1x32(status & 0xFFFF);
+	return 30 - signbits;
+}
+
+/*
+ * Given the contents of the status register and the DCPLB_DATA contents,
+ * return true if a write access should be permitted.
+ */
+static inline int write_permitted(int status, unsigned long data)
+{
+	if (status & FAULT_USERSUPV)
+		return !!(data & CPLB_SUPV_WR);
+	else
+		return !!(data & CPLB_USER_WR);
+}
+
+/* Counters to implement round-robin replacement.  */
+static int icplb_rr_index[NR_CPUS], dcplb_rr_index[NR_CPUS];
+
+/*
+ * Find an ICPLB entry to be evicted and return its index.
+ */
+MGR_ATTR static int evict_one_icplb(unsigned int cpu)
+{
+	int i;
+	for (i = first_switched_icplb; i < MAX_CPLBS; i++)
+		if ((icplb_tbl[cpu][i].data & CPLB_VALID) == 0)
+			return i;
+	i = first_switched_icplb + icplb_rr_index[cpu];
+	if (i >= MAX_CPLBS) {
+		i -= MAX_CPLBS - first_switched_icplb;
+		icplb_rr_index[cpu] -= MAX_CPLBS - first_switched_icplb;
+	}
+	icplb_rr_index[cpu]++;
+	return i;
+}
+
+MGR_ATTR static int evict_one_dcplb(unsigned int cpu)
+{
+	int i;
+	for (i = first_switched_dcplb; i < MAX_CPLBS; i++)
+		if ((dcplb_tbl[cpu][i].data & CPLB_VALID) == 0)
+			return i;
+	i = first_switched_dcplb + dcplb_rr_index[cpu];
+	if (i >= MAX_CPLBS) {
+		i -= MAX_CPLBS - first_switched_dcplb;
+		dcplb_rr_index[cpu] -= MAX_CPLBS - first_switched_dcplb;
+	}
+	dcplb_rr_index[cpu]++;
+	return i;
+}
+
+MGR_ATTR static noinline int dcplb_miss(unsigned int cpu)
+{
+	unsigned long addr = bfin_read_DCPLB_FAULT_ADDR();
+	int status = bfin_read_DCPLB_STATUS();
+	unsigned long *mask;
+	int idx;
+	unsigned long d_data;
+
+	nr_dcplb_miss[cpu]++;
+
+	d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
+#ifdef CONFIG_BFIN_EXTMEM_DCACHEABLE
+	if (bfin_addr_dcacheable(addr)) {
+		d_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
+# ifdef CONFIG_BFIN_EXTMEM_WRITETHROUGH
+		d_data |= CPLB_L1_AOW | CPLB_WT;
+# endif
+	}
+#endif
+
+	if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
+		addr = L2_START;
+		d_data = L2_DMEMORY;
+	} else if (addr >= physical_mem_end) {
+		if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
+#if defined(CONFIG_ROMFS_ON_MTD) && defined(CONFIG_MTD_ROM)
+			mask = current_rwx_mask[cpu];
+			if (mask) {
+				int page = (addr - (ASYNC_BANK0_BASE - _ramend)) >> PAGE_SHIFT;
+				int idx = page >> 5;
+				int bit = 1 << (page & 31);
+
+				if (mask[idx] & bit)
+					d_data |= CPLB_USER_RD;
+			}
+#endif
+		} else if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
+		    && (status & (FAULT_RW | FAULT_USERSUPV)) == FAULT_USERSUPV) {
+			addr &= ~(1 * 1024 * 1024 - 1);
+			d_data &= ~PAGE_SIZE_4KB;
+			d_data |= PAGE_SIZE_1MB;
+		} else
+			return CPLB_PROT_VIOL;
+	} else if (addr >= _ramend) {
+		d_data |= CPLB_USER_RD | CPLB_USER_WR;
+		if (reserved_mem_dcache_on)
+			d_data |= CPLB_L1_CHBL;
+	} else {
+		mask = current_rwx_mask[cpu];
+		if (mask) {
+			int page = addr >> PAGE_SHIFT;
+			int idx = page >> 5;
+			int bit = 1 << (page & 31);
+
+			if (mask[idx] & bit)
+				d_data |= CPLB_USER_RD;
+
+			mask += page_mask_nelts;
+			if (mask[idx] & bit)
+				d_data |= CPLB_USER_WR;
+		}
+	}
+	idx = evict_one_dcplb(cpu);
+
+	addr &= PAGE_MASK;
+	dcplb_tbl[cpu][idx].addr = addr;
+	dcplb_tbl[cpu][idx].data = d_data;
+
+	_disable_dcplb();
+	bfin_write32(DCPLB_DATA0 + idx * 4, d_data);
+	bfin_write32(DCPLB_ADDR0 + idx * 4, addr);
+	_enable_dcplb();
+
+	return 0;
+}
+
+MGR_ATTR static noinline int icplb_miss(unsigned int cpu)
+{
+	unsigned long addr = bfin_read_ICPLB_FAULT_ADDR();
+	int status = bfin_read_ICPLB_STATUS();
+	int idx;
+	unsigned long i_data;
+
+	nr_icplb_miss[cpu]++;
+
+	/* If inside the uncached DMA region, fault.  */
+	if (addr >= _ramend - DMA_UNCACHED_REGION && addr < _ramend)
+		return CPLB_PROT_VIOL;
+
+	if (status & FAULT_USERSUPV)
+		nr_icplb_supv_miss[cpu]++;
+
+	/*
+	 * First, try to find a CPLB that matches this address.  If we
+	 * find one, then the fact that we're in the miss handler means
+	 * that the instruction crosses a page boundary.
+	 */
+	for (idx = first_switched_icplb; idx < MAX_CPLBS; idx++) {
+		if (icplb_tbl[cpu][idx].data & CPLB_VALID) {
+			unsigned long this_addr = icplb_tbl[cpu][idx].addr;
+			if (this_addr <= addr && this_addr + PAGE_SIZE > addr) {
+				addr += PAGE_SIZE;
+				break;
+			}
+		}
+	}
+
+	i_data = CPLB_VALID | CPLB_PORTPRIO | PAGE_SIZE_4KB;
+
+#ifdef CONFIG_BFIN_EXTMEM_ICACHEABLE
+	/*
+	 * Normal RAM, and possibly the reserved memory area, are
+	 * cacheable.
+	 */
+	if (addr < _ramend ||
+	    (addr < physical_mem_end && reserved_mem_icache_on))
+		i_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
+#endif
+
+	if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
+		addr = L2_START;
+		i_data = L2_IMEMORY;
+	} else if (addr >= physical_mem_end) {
+		if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE) {
+			if (!(status & FAULT_USERSUPV)) {
+				unsigned long *mask = current_rwx_mask[cpu];
+
+				if (mask) {
+					int page = (addr - (ASYNC_BANK0_BASE - _ramend)) >> PAGE_SHIFT;
+					int idx = page >> 5;
+					int bit = 1 << (page & 31);
+
+					mask += 2 * page_mask_nelts;
+					if (mask[idx] & bit)
+						i_data |= CPLB_USER_RD;
+				}
+			}
+		} else if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
+		    && (status & FAULT_USERSUPV)) {
+			addr &= ~(1 * 1024 * 1024 - 1);
+			i_data &= ~PAGE_SIZE_4KB;
+			i_data |= PAGE_SIZE_1MB;
+		} else
+		    return CPLB_PROT_VIOL;
+	} else if (addr >= _ramend) {
+		i_data |= CPLB_USER_RD;
+		if (reserved_mem_icache_on)
+			i_data |= CPLB_L1_CHBL;
+	} else {
+		/*
+		 * Two cases to distinguish - a supervisor access must
+		 * necessarily be for a module page; we grant it
+		 * unconditionally (could do better here in the future).
+		 * Otherwise, check the x bitmap of the current process.
+		 */
+		if (!(status & FAULT_USERSUPV)) {
+			unsigned long *mask = current_rwx_mask[cpu];
+
+			if (mask) {
+				int page = addr >> PAGE_SHIFT;
+				int idx = page >> 5;
+				int bit = 1 << (page & 31);
+
+				mask += 2 * page_mask_nelts;
+				if (mask[idx] & bit)
+					i_data |= CPLB_USER_RD;
+			}
+		}
+	}
+	idx = evict_one_icplb(cpu);
+	addr &= PAGE_MASK;
+	icplb_tbl[cpu][idx].addr = addr;
+	icplb_tbl[cpu][idx].data = i_data;
+
+	_disable_icplb();
+	bfin_write32(ICPLB_DATA0 + idx * 4, i_data);
+	bfin_write32(ICPLB_ADDR0 + idx * 4, addr);
+	_enable_icplb();
+
+	return 0;
+}
+
+MGR_ATTR static noinline int dcplb_protection_fault(unsigned int cpu)
+{
+	int status = bfin_read_DCPLB_STATUS();
+
+	nr_dcplb_prot[cpu]++;
+
+	if (status & FAULT_RW) {
+		int idx = faulting_cplb_index(status);
+		unsigned long data = dcplb_tbl[cpu][idx].data;
+		if (!(data & CPLB_WT) && !(data & CPLB_DIRTY) &&
+		    write_permitted(status, data)) {
+			data |= CPLB_DIRTY;
+			dcplb_tbl[cpu][idx].data = data;
+			bfin_write32(DCPLB_DATA0 + idx * 4, data);
+			return 0;
+		}
+	}
+	return CPLB_PROT_VIOL;
+}
+
+MGR_ATTR int cplb_hdr(int seqstat, struct pt_regs *regs)
+{
+	int cause = seqstat & 0x3f;
+	unsigned int cpu = raw_smp_processor_id();
+	switch (cause) {
+	case 0x23:
+		return dcplb_protection_fault(cpu);
+	case 0x2C:
+		return icplb_miss(cpu);
+	case 0x26:
+		return dcplb_miss(cpu);
+	default:
+		return 1;
+	}
+}
+
+void flush_switched_cplbs(unsigned int cpu)
+{
+	int i;
+	unsigned long flags;
+
+	nr_cplb_flush[cpu]++;
+
+	flags = hard_local_irq_save();
+	_disable_icplb();
+	for (i = first_switched_icplb; i < MAX_CPLBS; i++) {
+		icplb_tbl[cpu][i].data = 0;
+		bfin_write32(ICPLB_DATA0 + i * 4, 0);
+	}
+	_enable_icplb();
+
+	_disable_dcplb();
+	for (i = first_switched_dcplb; i < MAX_CPLBS; i++) {
+		dcplb_tbl[cpu][i].data = 0;
+		bfin_write32(DCPLB_DATA0 + i * 4, 0);
+	}
+	_enable_dcplb();
+	hard_local_irq_restore(flags);
+
+}
+
+void set_mask_dcplbs(unsigned long *masks, unsigned int cpu)
+{
+	int i;
+	unsigned long addr = (unsigned long)masks;
+	unsigned long d_data;
+	unsigned long flags;
+
+	if (!masks) {
+		current_rwx_mask[cpu] = masks;
+		return;
+	}
+
+	flags = hard_local_irq_save();
+	current_rwx_mask[cpu] = masks;
+
+	if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
+		addr = L2_START;
+		d_data = L2_DMEMORY;
+	} else {
+		d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
+#ifdef CONFIG_BFIN_EXTMEM_DCACHEABLE
+		d_data |= CPLB_L1_CHBL;
+# ifdef CONFIG_BFIN_EXTMEM_WRITETHROUGH
+		d_data |= CPLB_L1_AOW | CPLB_WT;
+# endif
+#endif
+	}
+
+	_disable_dcplb();
+	for (i = first_mask_dcplb; i < first_switched_dcplb; i++) {
+		dcplb_tbl[cpu][i].addr = addr;
+		dcplb_tbl[cpu][i].data = d_data;
+		bfin_write32(DCPLB_DATA0 + i * 4, d_data);
+		bfin_write32(DCPLB_ADDR0 + i * 4, addr);
+		addr += PAGE_SIZE;
+	}
+	_enable_dcplb();
+	hard_local_irq_restore(flags);
+}