@@ -237,14 +237,6 @@ enum {
UXE = (1 << 7),
};
-/* check if tlb available */
-enum {
- TLBRET_INVALID = -3,
- TLBRET_NOMATCH = -2,
- TLBRET_BADADDR = -1,
- TLBRET_MATCH = 0
-};
-
typedef struct OpenRISCTLBEntry {
uint32_t mr;
uint32_t tr;
@@ -29,148 +29,78 @@
#endif
#ifndef CONFIG_USER_ONLY
-static inline int get_phys_nommu(hwaddr *physical, int *prot,
- target_ulong address)
+static inline void get_phys_nommu(hwaddr *phys_addr, int *prot,
+ target_ulong address)
{
- *physical = address;
+ *phys_addr = address;
*prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
- return TLBRET_MATCH;
}
-static int get_phys_code(OpenRISCCPU *cpu, hwaddr *physical, int *prot,
- target_ulong address, int rw, bool supervisor)
+static int get_phys_mmu(OpenRISCCPU *cpu, hwaddr *phys_addr, int *prot,
+ target_ulong addr, int need, bool super)
{
- int vpn = address >> TARGET_PAGE_BITS;
- int idx = vpn & TLB_MASK;
- int right = 0;
- uint32_t mr = cpu->env.tlb.itlb[idx].mr;
- uint32_t tr = cpu->env.tlb.itlb[idx].tr;
-
- if ((mr >> TARGET_PAGE_BITS) != vpn) {
- return TLBRET_NOMATCH;
- }
- if (!(mr & 1)) {
- return TLBRET_INVALID;
- }
- if (supervisor) {
- if (tr & SXE) {
- right |= PAGE_EXEC;
- }
- } else {
- if (tr & UXE) {
- right |= PAGE_EXEC;
+ int idx = (addr >> TARGET_PAGE_BITS) & TLB_MASK;
+ uint32_t imr = cpu->env.tlb.itlb[idx].mr;
+ uint32_t itr = cpu->env.tlb.itlb[idx].tr;
+ uint32_t dmr = cpu->env.tlb.dtlb[idx].mr;
+ uint32_t dtr = cpu->env.tlb.dtlb[idx].tr;
+ int right, match, valid;
+
+ /* If the ITLB and DTLB indexes map to the same page, we want to
+ load all permissions all at once. If the destination pages do
+ not match, zap the one we don't need. */
+ if (unlikely((itr ^ dtr) & TARGET_PAGE_MASK)) {
+ if (need & PAGE_EXEC) {
+ dmr = dtr = 0;
+ } else {
+ imr = itr = 0;
}
}
- if ((rw & 2) && ((right & PAGE_EXEC) == 0)) {
- return TLBRET_BADADDR;
- }
- *physical = (tr & TARGET_PAGE_MASK) | (address & ~TARGET_PAGE_MASK);
- *prot = right;
- return TLBRET_MATCH;
-}
+ /* Check if either of the entries matches the source address. */
+ match = (imr ^ addr) & TARGET_PAGE_MASK ? 0 : PAGE_EXEC;
+ match |= (dmr ^ addr) & TARGET_PAGE_MASK ? 0 : PAGE_READ | PAGE_WRITE;
-static int get_phys_data(OpenRISCCPU *cpu, hwaddr *physical, int *prot,
- target_ulong address, int rw, bool supervisor)
-{
- int vpn = address >> TARGET_PAGE_BITS;
- int idx = vpn & TLB_MASK;
- int right = 0;
- uint32_t mr = cpu->env.tlb.dtlb[idx].mr;
- uint32_t tr = cpu->env.tlb.dtlb[idx].tr;
+ /* Check if either of the entries is valid. */
+ valid = imr & 1 ? PAGE_EXEC : 0;
+ valid |= dmr & 1 ? PAGE_READ | PAGE_WRITE : 0;
+ valid &= match;
- if ((mr >> TARGET_PAGE_BITS) != vpn) {
- return TLBRET_NOMATCH;
- }
- if (!(mr & 1)) {
- return TLBRET_INVALID;
- }
- if (supervisor) {
- if (tr & SRE) {
- right |= PAGE_READ;
- }
- if (tr & SWE) {
- right |= PAGE_WRITE;
- }
- } else {
- if (tr & URE) {
- right |= PAGE_READ;
- }
- if (tr & UWE) {
- right |= PAGE_WRITE;
- }
- }
-
- if (!(rw & 1) && ((right & PAGE_READ) == 0)) {
- return TLBRET_BADADDR;
- }
- if ((rw & 1) && ((right & PAGE_WRITE) == 0)) {
- return TLBRET_BADADDR;
- }
+ /* Collect the permissions from the entries. */
+ right = itr & (super ? SXE : UXE) ? PAGE_EXEC : 0;
+ right |= dtr & (super ? SRE : URE) ? PAGE_READ : 0;
+ right |= dtr & (super ? SWE : UWE) ? PAGE_WRITE : 0;
+ right &= valid;
- *physical = (tr & TARGET_PAGE_MASK) | (address & ~TARGET_PAGE_MASK);
+ /* Note that above we validated that itr and dtr match on page.
+ So oring them together changes nothing without having to
+ check which one we needed. We also want to store to these
+ variables even on failure, as it avoids compiler warnings. */
+ *phys_addr = ((itr | dtr) & TARGET_PAGE_MASK) | (addr & ~TARGET_PAGE_MASK);
*prot = right;
- return TLBRET_MATCH;
-}
-static int get_phys_addr(OpenRISCCPU *cpu, hwaddr *physical,
- int *prot, target_ulong address, int rw)
-{
- bool supervisor = (cpu->env.sr & SR_SM) != 0;
- int ret;
+ qemu_log_mask(CPU_LOG_MMU,
+ "MMU lookup: need %d match %d valid %d right %d -> %s\n",
+ need, match, valid, right, (need & right) ? "OK" : "FAIL");
- /* Assume nommu results for a moment. */
- ret = get_phys_nommu(physical, prot, address);
+ /* Check the collective permissions are present. */
+ if (likely(need & right)) {
+ return 0; /* success! */
+ }
- /* Overwrite with TLB lookup if enabled. */
- if (rw == MMU_INST_FETCH) {
- if (cpu->env.sr & SR_IME) {
- ret = get_phys_code(cpu, physical, prot, address, rw, supervisor);
- }
+ /* Determine what kind of failure we have. */
+ if (need & valid) {
+ return need & PAGE_EXEC ? EXCP_IPF : EXCP_DPF;
} else {
- if (cpu->env.sr & SR_DME) {
- ret = get_phys_data(cpu, physical, prot, address, rw, supervisor);
- }
+ return need & PAGE_EXEC ? EXCP_ITLBMISS : EXCP_DTLBMISS;
}
-
- return ret;
}
#endif
-static void cpu_openrisc_raise_mmu_exception(OpenRISCCPU *cpu,
- target_ulong address,
- int rw, int tlb_error)
+static void raise_mmu_exception(OpenRISCCPU *cpu, target_ulong address,
+ int exception)
{
CPUState *cs = CPU(cpu);
- int exception = 0;
-
- switch (tlb_error) {
- default:
- if (rw == 2) {
- exception = EXCP_IPF;
- } else {
- exception = EXCP_DPF;
- }
- break;
-#ifndef CONFIG_USER_ONLY
- case TLBRET_BADADDR:
- if (rw == 2) {
- exception = EXCP_IPF;
- } else {
- exception = EXCP_DPF;
- }
- break;
- case TLBRET_INVALID:
- case TLBRET_NOMATCH:
- /* No TLB match for a mapped address */
- if (rw == 2) {
- exception = EXCP_ITLBMISS;
- } else {
- exception = EXCP_DTLBMISS;
- }
- break;
-#endif
- }
cs->exception_index = exception;
cpu->env.eear = address;
@@ -182,7 +112,7 @@ int openrisc_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int size,
{
#ifdef CONFIG_USER_ONLY
OpenRISCCPU *cpu = OPENRISC_CPU(cs);
- cpu_openrisc_raise_mmu_exception(cpu, address, rw, 0);
+ raise_mmu_exception(cpu, address, EXCP_DPF);
return 1;
#else
g_assert_not_reached();
@@ -193,27 +123,32 @@ int openrisc_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int size,
hwaddr openrisc_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
{
OpenRISCCPU *cpu = OPENRISC_CPU(cs);
+ int prot, excp, sr = cpu->env.sr;
hwaddr phys_addr;
- int prot;
- int miss;
- /* Check memory for any kind of address, since during debug the
- gdb can ask for anything, check data tlb for address */
- miss = get_phys_addr(cpu, &phys_addr, &prot, addr, 0);
+ switch (sr & (SR_DME | SR_IME)) {
+ case SR_DME | SR_IME:
+ /* The mmu is definitely enabled. */
+ excp = get_phys_mmu(cpu, &phys_addr, &prot, addr,
+ PROT_EXEC | PROT_READ | PROT_WRITE,
+ (sr & SR_SM) != 0);
+ return excp ? -1 : phys_addr;
- /* Check instruction tlb */
- if (miss) {
- miss = get_phys_addr(cpu, &phys_addr, &prot, addr, MMU_INST_FETCH);
- }
-
- /* Last, fall back to a plain address */
- if (miss) {
- miss = get_phys_nommu(&phys_addr, &prot, addr);
- }
+ default:
+ /* The mmu is partially enabled, and we don't really have
+ a "real" access type. Begin by trying the mmu, but if
+ that fails try again without. */
+ excp = get_phys_mmu(cpu, &phys_addr, &prot, addr,
+ PROT_EXEC | PROT_READ | PROT_WRITE,
+ (sr & SR_SM) != 0);
+ if (!excp) {
+ return phys_addr;
+ }
+ /* fallthru */
- if (miss) {
- return -1;
- } else {
+ case 0:
+ /* The mmu is definitely disabled; lookups never fail. */
+ get_phys_nommu(&phys_addr, &prot, addr);
return phys_addr;
}
}
@@ -222,37 +157,28 @@ void tlb_fill(CPUState *cs, target_ulong addr, int size,
MMUAccessType access_type, int mmu_idx, uintptr_t retaddr)
{
OpenRISCCPU *cpu = OPENRISC_CPU(cs);
- int ret, prot = 0;
- hwaddr physical = 0;
+ int prot, excp;
+ hwaddr phys_addr;
if (mmu_idx == MMU_NOMMU_IDX) {
- ret = get_phys_nommu(&physical, &prot, addr);
+ /* The mmu is disabled; lookups never fail. */
+ get_phys_nommu(&phys_addr, &prot, addr);
+ excp = 0;
} else {
bool super = mmu_idx == MMU_SUPERVISOR_IDX;
- if (access_type == MMU_INST_FETCH) {
- ret = get_phys_code(cpu, &physical, &prot, addr, 2, super);
- } else {
- ret = get_phys_data(cpu, &physical, &prot, addr,
- access_type == MMU_DATA_STORE, super);
- }
+ int need = (access_type == MMU_INST_FETCH ? PROT_EXEC
+ : access_type == MMU_DATA_STORE ? PROT_WRITE
+ : PROT_READ);
+ excp = get_phys_mmu(cpu, &phys_addr, &prot, addr, need, super);
}
- if (ret == TLBRET_MATCH) {
- tlb_set_page(cs, addr & TARGET_PAGE_MASK,
- physical & TARGET_PAGE_MASK, prot,
- mmu_idx, TARGET_PAGE_SIZE);
- } else if (ret < 0) {
- int rw;
- if (access_type == MMU_INST_FETCH) {
- rw = 2;
- } else if (access_type == MMU_DATA_STORE) {
- rw = 1;
- } else {
- rw = 0;
- }
- cpu_openrisc_raise_mmu_exception(cpu, addr, rw, ret);
- /* Raise Exception. */
+ if (unlikely(excp)) {
+ raise_mmu_exception(cpu, addr, excp);
cpu_loop_exit_restore(cs, retaddr);
}
+
+ tlb_set_page(cs, addr & TARGET_PAGE_MASK,
+ phys_addr & TARGET_PAGE_MASK, prot,
+ mmu_idx, TARGET_PAGE_SIZE);
}
#endif