diff options
Diffstat (limited to 'machine')
-rw-r--r-- | machine/mtrap.c | 22 | ||||
-rw-r--r-- | machine/unprivileged_memory.h | 11 |
2 files changed, 26 insertions, 7 deletions
diff --git a/machine/mtrap.c b/machine/mtrap.c index e48d3d5..42006b8 100644 --- a/machine/mtrap.c +++ b/machine/mtrap.c @@ -194,14 +194,30 @@ void pmp_trap(uintptr_t* regs, uintptr_t mcause, uintptr_t mepc) redirect_trap(mepc, read_csr(mstatus), read_csr(mbadaddr)); } -static void machine_page_fault(uintptr_t* regs, uintptr_t dummy, uintptr_t mepc) +static void machine_page_fault(uintptr_t* regs, uintptr_t mcause, uintptr_t mepc) { // MPRV=1 iff this trap occurred while emulating an instruction on behalf // of a lower privilege level. In that case, a2=epc and a3=mstatus. + // a1 holds MPRV if emulating a load or store, or MPRV | MXR if loading + // an instruction from memory. In the latter case, we should report an + // instruction fault instead of a load fault. if (read_csr(mstatus) & MSTATUS_MPRV) { + if (regs[11] == (MSTATUS_MPRV | MSTATUS_MXR)) { + if (mcause == CAUSE_LOAD_PAGE_FAULT) + write_csr(mcause, CAUSE_FETCH_PAGE_FAULT); + else if (mcause == CAUSE_LOAD_ACCESS) + write_csr(mcause, CAUSE_FETCH_ACCESS); + else + goto fail; + } else if (regs[11] != MSTATUS_MPRV) { + goto fail; + } + return redirect_trap(regs[12], regs[13], read_csr(mbadaddr)); } - bad_trap(regs, dummy, mepc); + +fail: + bad_trap(regs, mcause, mepc); } void trap_from_machine_mode(uintptr_t* regs, uintptr_t dummy, uintptr_t mepc) @@ -215,7 +231,7 @@ void trap_from_machine_mode(uintptr_t* regs, uintptr_t dummy, uintptr_t mepc) case CAUSE_FETCH_ACCESS: case CAUSE_LOAD_ACCESS: case CAUSE_STORE_ACCESS: - return machine_page_fault(regs, dummy, mepc); + return machine_page_fault(regs, mcause, mepc); default: bad_trap(regs, dummy, mepc); } diff --git a/machine/unprivileged_memory.h b/machine/unprivileged_memory.h index a904fd6..fb70baa 100644 --- a/machine/unprivileged_memory.h +++ b/machine/unprivileged_memory.h @@ -10,6 +10,7 @@ #define DECLARE_UNPRIVILEGED_LOAD_FUNCTION(type, insn) \ static inline type load_##type(const type* addr, uintptr_t mepc) \ { \ + register uintptr_t __mstatus_adjust asm ("a1") = MSTATUS_MPRV; \ register uintptr_t __mepc asm ("a2") = mepc; \ register uintptr_t __mstatus asm ("a3"); \ type val; \ @@ -17,20 +18,21 @@ #insn " %1, %2\n" \ "csrw mstatus, %0" \ : "+&r" (__mstatus), "=&r" (val) \ - : "m" (*addr), "r" (MSTATUS_MPRV), "r" (__mepc)); \ + : "m" (*addr), "r" (__mstatus_adjust), "r" (__mepc)); \ return val; \ } #define DECLARE_UNPRIVILEGED_STORE_FUNCTION(type, insn) \ static inline void store_##type(type* addr, type val, uintptr_t mepc) \ { \ + register uintptr_t __mstatus_adjust asm ("a1") = MSTATUS_MPRV; \ register uintptr_t __mepc asm ("a2") = mepc; \ register uintptr_t __mstatus asm ("a3"); \ asm volatile ("csrrs %0, mstatus, %3\n" \ #insn " %1, %2\n" \ "csrw mstatus, %0" \ : "+&r" (__mstatus) \ - : "r" (val), "m" (*addr), "r" (MSTATUS_MPRV), \ + : "r" (val), "m" (*addr), "r" (__mstatus_adjust), \ "r" (__mepc)); \ } @@ -66,6 +68,7 @@ static inline void store_uint64_t(uint64_t* addr, uint64_t val, uintptr_t mepc) static uintptr_t __attribute__((always_inline)) get_insn(uintptr_t mepc, uintptr_t* mstatus) { + register uintptr_t __mstatus_adjust asm ("a1") = MSTATUS_MPRV | MSTATUS_MXR; register uintptr_t __mepc asm ("a2") = mepc; register uintptr_t __mstatus asm ("a3"); uintptr_t val; @@ -74,7 +77,7 @@ static uintptr_t __attribute__((always_inline)) get_insn(uintptr_t mepc, uintptr STR(LWU) " %[insn], (%[addr])\n" "csrw mstatus, %[mstatus]" : [mstatus] "+&r" (__mstatus), [insn] "=&r" (val) - : [mprv] "r" (MSTATUS_MPRV | MSTATUS_MXR), [addr] "r" (__mepc)); + : [mprv] "r" (__mstatus_adjust), [addr] "r" (__mepc)); #else uintptr_t rvc_mask = 3, tmp; asm ("csrrs %[mstatus], mstatus, %[mprv]\n" @@ -95,7 +98,7 @@ static uintptr_t __attribute__((always_inline)) get_insn(uintptr_t mepc, uintptr "add %[insn], %[insn], %[tmp]\n" "2: csrw mstatus, %[mstatus]" : [mstatus] "+&r" (__mstatus), [insn] "=&r" (val), [tmp] "=&r" (tmp) - : [mprv] "r" (MSTATUS_MPRV | MSTATUS_MXR), [addr] "r" (__mepc), + : [mprv] "r" (__mstatus_adjust), [addr] "r" (__mepc), [rvc_mask] "r" (rvc_mask), [xlen_minus_16] "i" (__riscv_xlen - 16)); #endif *mstatus = __mstatus; |