+#ifndef _RISCV_MMU_H
+#define _RISCV_MMU_H
+
#include "decode.h"
#include "trap.h"
#include "icsim.h"
+#include "common.h"
+#include "processor.h"
class processor_t;
+typedef reg_t pte_t;
+
+const reg_t LEVELS = 4;
+const reg_t PGSHIFT = 12;
+const reg_t PGSIZE = 1 << PGSHIFT;
+const reg_t PTIDXBITS = PGSHIFT - (sizeof(pte_t) == 8 ? 3 : 2);
+const reg_t PPN_BITS = 8*sizeof(reg_t) - PGSHIFT;
+
+#define PTE_T 0x001 // Entry is a page Table descriptor
+#define PTE_E 0x002 // Entry is a page table Entry
+#define PTE_R 0x004 // Referenced
+#define PTE_D 0x008 // Dirty
+#define PTE_UX 0x010 // User eXecute permission
+#define PTE_UW 0x020 // User Read permission
+#define PTE_UR 0x040 // User Write permission
+#define PTE_SX 0x080 // Supervisor eXecute permission
+#define PTE_SW 0x100 // Supervisor Read permission
+#define PTE_SR 0x200 // Supervisor Write permission
+#define PTE_PERM (PTE_SR | PTE_SW | PTE_SX | PTE_UR | PTE_UW | PTE_UX)
+#define PTE_PERM_SHIFT 4
+#define PTE_PPN_SHIFT 12
+
class mmu_t
{
public:
- mmu_t(char* _mem, size_t _memsz)
- : mem(_mem), memsz(_memsz), badvaddr(0),
- icsim(NULL), dcsim(NULL), itlbsim(NULL), dtlbsim(NULL)
- {
- }
-
- void set_icsim(icsim_t* _icsim) { icsim = _icsim; }
- void set_dcsim(icsim_t* _dcsim) { dcsim = _dcsim; }
- void set_itlbsim(icsim_t* _itlbsim) { itlbsim = _itlbsim; }
- void set_dtlbsim(icsim_t* _dtlbsim) { dtlbsim = _dtlbsim; }
+ mmu_t(char* _mem, size_t _memsz);
+ ~mmu_t();
#ifdef RISCV_ENABLE_ICSIM
# define dcsim_tick(dcsim, dtlbsim, addr, size, st) \
do { if(dcsim) (dcsim)->tick(addr, size, st); \
if(dtlbsim) (dtlbsim)->tick(addr, sizeof(reg_t), false); } while(0)
#else
- # define dcsim_tick(dcsim, addr, size)
+ # define dcsim_tick(dcsim, dtlbsim, addr, size, st)
#endif
#define load_func(type) \
type##_t load_##type(reg_t addr) { \
- check_align_and_bounds(addr, sizeof(type##_t), false, false); \
- dcsim_tick(dcsim, dtlbsim, addr, sizeof(type##_t), false); \
- return *(type##_t*)(mem+addr); \
+ if(unlikely(addr % sizeof(type##_t))) \
+ { \
+ badvaddr = addr; \
+ throw trap_load_address_misaligned; \
+ } \
+ void* paddr = translate(addr, false, false); \
+ dcsim_tick(dcsim, dtlbsim, paddr-mem, sizeof(type##_t), false); \
+ return *(type##_t*)paddr; \
}
#define store_func(type) \
void store_##type(reg_t addr, type##_t val) { \
- check_align_and_bounds(addr, sizeof(type##_t), true, false); \
- dcsim_tick(dcsim, dtlbsim, addr, sizeof(type##_t), true); \
- *(type##_t*)(mem+addr) = val; \
+ if(unlikely(addr % sizeof(type##_t))) \
+ { \
+ badvaddr = addr; \
+ throw trap_store_address_misaligned; \
+ } \
+ void* paddr = translate(addr, true, false); \
+ dcsim_tick(dcsim, dtlbsim, paddr-mem, sizeof(type##_t), true); \
+ *(type##_t*)paddr = val; \
}
- insn_t load_insn(reg_t addr, bool rvc)
+ insn_t __attribute__((always_inline)) load_insn(reg_t addr, bool rvc,
+ insn_func_t* func)
{
+ insn_t insn;
+
#ifdef RISCV_ENABLE_RVC
- check_align_and_bounds(addr, rvc ? 2 : 4, false, true);
- uint16_t lo = *(uint16_t*)(mem+addr);
- uint16_t hi = *(uint16_t*)(mem+addr+2);
+ if(addr % 4 == 2 && rvc) // fetch across word boundary
+ {
+ void* addr_lo = translate(addr, false, true);
+ insn.bits = *(uint16_t*)addr_lo;
- insn_t insn;
- insn.bits = lo | ((uint32_t)hi << 16);
+ *func = processor_t::dispatch_table
+ [insn.bits % processor_t::DISPATCH_TABLE_SIZE];
+
+ if(!INSN_IS_RVC(insn.bits))
+ {
+ void* addr_hi = translate(addr+2, false, true);
+ insn.bits |= (uint32_t)*(uint16_t*)addr_hi << 16;
+ }
+ }
+ else
+ #endif
+ {
+ reg_t idx = (addr/sizeof(insn_t)) % ICACHE_ENTRIES;
+ insn_t data = icache_data[idx];
+ *func = icache_func[idx];
+ if(likely(icache_tag[idx] == addr))
+ return data;
+
+ // the processor guarantees alignment based upon rvc mode
+ void* paddr = translate(addr, false, true);
+ insn = *(insn_t*)paddr;
+
+ icache_tag[idx] = addr;
+ icache_data[idx] = insn;
+ icache_func[idx] = *func = processor_t::dispatch_table
+ [insn.bits % processor_t::DISPATCH_TABLE_SIZE];
+ }
#ifdef RISCV_ENABLE_ICSIM
if(icsim)
- icsim->tick(addr, insn_length(insn), false);
+ icsim->tick(addr, insn_length(insn.bits), false);
if(itlbsim)
itlbsim->tick(addr, sizeof(reg_t), false);
#endif
return insn;
- #else
- check_align_and_bounds(addr, 4, false, true);
- return *(insn_t*)(mem+addr);
- #endif
}
load_func(uint8)
store_func(uint64)
reg_t get_badvaddr() { return badvaddr; }
+ reg_t get_ptbr() { return ptbr; }
+
+ void set_supervisor(bool sup) { supervisor = sup; }
+ void set_vm_enabled(bool en) { vm_enabled = en; }
+ void set_ptbr(reg_t addr) { ptbr = addr & ~(PGSIZE-1); flush_tlb(); }
+
+ void set_icsim(icsim_t* _icsim) { icsim = _icsim; }
+ void set_dcsim(icsim_t* _dcsim) { dcsim = _dcsim; }
+ void set_itlbsim(icsim_t* _itlbsim) { itlbsim = _itlbsim; }
+ void set_dtlbsim(icsim_t* _dtlbsim) { dtlbsim = _dtlbsim; }
+
+ void flush_tlb();
+ void flush_icache();
private:
char* mem;
size_t memsz;
reg_t badvaddr;
+ reg_t ptbr;
+ bool supervisor;
+ bool vm_enabled;
+
+ static const reg_t TLB_ENTRIES = 256;
+ long tlb_data[TLB_ENTRIES];
+ reg_t tlb_insn_tag[TLB_ENTRIES];
+ reg_t tlb_load_tag[TLB_ENTRIES];
+ reg_t tlb_store_tag[TLB_ENTRIES];
+
+ static const reg_t ICACHE_ENTRIES = 256;
+ insn_t icache_data[ICACHE_ENTRIES];
+ insn_func_t icache_func[ICACHE_ENTRIES];
+ reg_t icache_tag[ICACHE_ENTRIES];
+
icsim_t* icsim;
icsim_t* dcsim;
icsim_t* itlbsim;
icsim_t* dtlbsim;
- void check_align(reg_t addr, int size, bool store, bool fetch)
- {
- if(addr & (size-1))
- {
- badvaddr = addr;
- if(fetch)
- throw trap_instruction_address_misaligned;
- if(store)
- throw trap_store_address_misaligned;
- throw trap_load_address_misaligned;
- }
- }
+ void* refill(reg_t addr, bool store, bool fetch);
+ pte_t walk(reg_t addr);
- void check_bounds(reg_t addr, int size, bool store, bool fetch)
+ void* translate(reg_t addr, bool store, bool fetch)
{
- if(addr >= memsz || addr + size > memsz)
- {
- badvaddr = addr;
- if(fetch)
- throw trap_instruction_access_fault;
- throw store ? trap_store_access_fault : trap_load_access_fault;
- }
- }
+ reg_t idx = (addr >> PGSHIFT) % TLB_ENTRIES;
- void check_align_and_bounds(reg_t addr, int size, bool store, bool fetch)
- {
- check_align(addr, size, store, fetch);
- check_bounds(addr, size, store, fetch);
+ reg_t* tlb_tag = fetch ? tlb_insn_tag : store ? tlb_store_tag :tlb_load_tag;
+ reg_t expected_tag = addr & ~(PGSIZE-1);
+ if(likely(tlb_tag[idx] == expected_tag))
+ return (void*)(((long)addr & (PGSIZE-1)) | tlb_data[idx]);
+
+ return refill(addr, store, fetch);
}
friend class processor_t;
};
+
+#endif
projects / riscv-isa-sim.git / blobdiff