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/*
* 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];
/*
* 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.
*/
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;
}
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;
}
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
&& (status & FAULT_USERSUPV)) {
addr &= ~0x3fffff;
d_data &= ~PAGE_SIZE_4KB;
d_data |= PAGE_SIZE_4MB;
} 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;
} 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;
}
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 >= 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;
} 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;
}
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;
}
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]++;
local_irq_save_hw(flags);
_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();
local_irq_restore_hw(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;
}
local_irq_save_hw(flags);
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();
local_irq_restore_hw(flags);
}
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