| /* | |
| * qemu user cpu loop | |
| * | |
| * Copyright (c) 2003-2008 Fabrice Bellard | |
| * | |
| * This program is free software; you can redistribute it and/or modify | |
| * it under the terms of the GNU General Public License as published by | |
| * the Free Software Foundation; either version 2 of the License, or | |
| * (at your option) any later version. | |
| * | |
| * This program is distributed in the hope that it will be useful, | |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| * GNU General Public License for more details. | |
| * | |
| * You should have received a copy of the GNU General Public License | |
| * along with this program; if not, see <http://www.gnu.org/licenses/>. | |
| */ | |
| #include "qemu/osdep.h" | |
| #include "qemu.h" | |
| #include "user-internals.h" | |
| #include "elf.h" | |
| #include "cpu_loop-common.h" | |
| #include "signal-common.h" | |
| #include "semihosting/common-semi.h" | |
| #include "target/arm/syndrome.h" | |
| #define get_user_code_u32(x, gaddr, env) \ | |
| ({ abi_long __r = get_user_u32((x), (gaddr)); \ | |
| if (!__r && bswap_code(arm_sctlr_b(env))) { \ | |
| (x) = bswap32(x); \ | |
| } \ | |
| __r; \ | |
| }) | |
| #define get_user_code_u16(x, gaddr, env) \ | |
| ({ abi_long __r = get_user_u16((x), (gaddr)); \ | |
| if (!__r && bswap_code(arm_sctlr_b(env))) { \ | |
| (x) = bswap16(x); \ | |
| } \ | |
| __r; \ | |
| }) | |
| #define get_user_data_u32(x, gaddr, env) \ | |
| ({ abi_long __r = get_user_u32((x), (gaddr)); \ | |
| if (!__r && arm_cpu_bswap_data(env)) { \ | |
| (x) = bswap32(x); \ | |
| } \ | |
| __r; \ | |
| }) | |
| #define get_user_data_u16(x, gaddr, env) \ | |
| ({ abi_long __r = get_user_u16((x), (gaddr)); \ | |
| if (!__r && arm_cpu_bswap_data(env)) { \ | |
| (x) = bswap16(x); \ | |
| } \ | |
| __r; \ | |
| }) | |
| #define put_user_data_u32(x, gaddr, env) \ | |
| ({ typeof(x) __x = (x); \ | |
| if (arm_cpu_bswap_data(env)) { \ | |
| __x = bswap32(__x); \ | |
| } \ | |
| put_user_u32(__x, (gaddr)); \ | |
| }) | |
| #define put_user_data_u16(x, gaddr, env) \ | |
| ({ typeof(x) __x = (x); \ | |
| if (arm_cpu_bswap_data(env)) { \ | |
| __x = bswap16(__x); \ | |
| } \ | |
| put_user_u16(__x, (gaddr)); \ | |
| }) | |
| /* | |
| * Similar to code in accel/tcg/user-exec.c, but outside the execution loop. | |
| * Must be called with mmap_lock. | |
| * We get the PC of the entry address - which is as good as anything, | |
| * on a real kernel what you get depends on which mode it uses. | |
| */ | |
| static void *atomic_mmu_lookup(CPUArchState *env, uint32_t addr, int size) | |
| { | |
| int need_flags = PAGE_READ | PAGE_WRITE_ORG | PAGE_VALID; | |
| int page_flags; | |
| /* Enforce guest required alignment. */ | |
| if (unlikely(addr & (size - 1))) { | |
| force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr); | |
| return NULL; | |
| } | |
| page_flags = page_get_flags(addr); | |
| if (unlikely((page_flags & need_flags) != need_flags)) { | |
| force_sig_fault(TARGET_SIGSEGV, | |
| page_flags & PAGE_VALID ? | |
| TARGET_SEGV_ACCERR : TARGET_SEGV_MAPERR, addr); | |
| return NULL; | |
| } | |
| return g2h(env_cpu(env), addr); | |
| } | |
| /* | |
| * See the Linux kernel's Documentation/arm/kernel_user_helpers.rst | |
| * Input: | |
| * r0 = oldval | |
| * r1 = newval | |
| * r2 = pointer to target value | |
| * | |
| * Output: | |
| * r0 = 0 if *ptr was changed, non-0 if no exchange happened | |
| * C set if *ptr was changed, clear if no exchange happened | |
| */ | |
| static void arm_kernel_cmpxchg32_helper(CPUARMState *env) | |
| { | |
| uint32_t oldval, newval, val, addr, cpsr, *host_addr; | |
| /* Swap if host != guest endianness, for the host cmpxchg below */ | |
| oldval = tswap32(env->regs[0]); | |
| newval = tswap32(env->regs[1]); | |
| addr = env->regs[2]; | |
| mmap_lock(); | |
| host_addr = atomic_mmu_lookup(env, addr, 4); | |
| if (!host_addr) { | |
| mmap_unlock(); | |
| return; | |
| } | |
| val = qatomic_cmpxchg__nocheck(host_addr, oldval, newval); | |
| mmap_unlock(); | |
| cpsr = (val == oldval) * CPSR_C; | |
| cpsr_write(env, cpsr, CPSR_C, CPSRWriteByInstr); | |
| env->regs[0] = cpsr ? 0 : -1; | |
| } | |
| /* | |
| * See the Linux kernel's Documentation/arm/kernel_user_helpers.rst | |
| * Input: | |
| * r0 = pointer to oldval | |
| * r1 = pointer to newval | |
| * r2 = pointer to target value | |
| * | |
| * Output: | |
| * r0 = 0 if *ptr was changed, non-0 if no exchange happened | |
| * C set if *ptr was changed, clear if no exchange happened | |
| * | |
| * Note segv's in kernel helpers are a bit tricky, we can set the | |
| * data address sensibly but the PC address is just the entry point. | |
| */ | |
| static void arm_kernel_cmpxchg64_helper(CPUARMState *env) | |
| { | |
| uint64_t oldval, newval, val; | |
| uint32_t addr, cpsr; | |
| uint64_t *host_addr; | |
| addr = env->regs[0]; | |
| if (get_user_u64(oldval, addr)) { | |
| goto segv; | |
| } | |
| addr = env->regs[1]; | |
| if (get_user_u64(newval, addr)) { | |
| goto segv; | |
| } | |
| mmap_lock(); | |
| addr = env->regs[2]; | |
| host_addr = atomic_mmu_lookup(env, addr, 8); | |
| if (!host_addr) { | |
| mmap_unlock(); | |
| return; | |
| } | |
| /* Swap if host != guest endianness, for the host cmpxchg below */ | |
| oldval = tswap64(oldval); | |
| newval = tswap64(newval); | |
| #ifdef CONFIG_ATOMIC64 | |
| val = qatomic_cmpxchg__nocheck(host_addr, oldval, newval); | |
| cpsr = (val == oldval) * CPSR_C; | |
| #else | |
| /* | |
| * This only works between threads, not between processes, but since | |
| * the host has no 64-bit cmpxchg, it is the best that we can do. | |
| */ | |
| start_exclusive(); | |
| val = *host_addr; | |
| if (val == oldval) { | |
| *host_addr = newval; | |
| cpsr = CPSR_C; | |
| } else { | |
| cpsr = 0; | |
| } | |
| end_exclusive(); | |
| #endif | |
| mmap_unlock(); | |
| cpsr_write(env, cpsr, CPSR_C, CPSRWriteByInstr); | |
| env->regs[0] = cpsr ? 0 : -1; | |
| return; | |
| segv: | |
| force_sig_fault(TARGET_SIGSEGV, | |
| page_get_flags(addr) & PAGE_VALID ? | |
| TARGET_SEGV_ACCERR : TARGET_SEGV_MAPERR, addr); | |
| } | |
| /* Handle a jump to the kernel code page. */ | |
| static int | |
| do_kernel_trap(CPUARMState *env) | |
| { | |
| uint32_t addr; | |
| switch (env->regs[15]) { | |
| case 0xffff0fa0: /* __kernel_memory_barrier */ | |
| smp_mb(); | |
| break; | |
| case 0xffff0fc0: /* __kernel_cmpxchg */ | |
| arm_kernel_cmpxchg32_helper(env); | |
| break; | |
| case 0xffff0fe0: /* __kernel_get_tls */ | |
| env->regs[0] = cpu_get_tls(env); | |
| break; | |
| case 0xffff0f60: /* __kernel_cmpxchg64 */ | |
| arm_kernel_cmpxchg64_helper(env); | |
| break; | |
| default: | |
| return 1; | |
| } | |
| /* Jump back to the caller. */ | |
| addr = env->regs[14]; | |
| if (addr & 1) { | |
| env->thumb = true; | |
| addr &= ~1; | |
| } | |
| env->regs[15] = addr; | |
| return 0; | |
| } | |
| static bool insn_is_linux_bkpt(uint32_t opcode, bool is_thumb) | |
| { | |
| /* | |
| * Return true if this insn is one of the three magic UDF insns | |
| * which the kernel treats as breakpoint insns. | |
| */ | |
| if (!is_thumb) { | |
| return (opcode & 0x0fffffff) == 0x07f001f0; | |
| } else { | |
| /* | |
| * Note that we get the two halves of the 32-bit T32 insn | |
| * in the opposite order to the value the kernel uses in | |
| * its undef_hook struct. | |
| */ | |
| return ((opcode & 0xffff) == 0xde01) || (opcode == 0xa000f7f0); | |
| } | |
| } | |
| static bool emulate_arm_fpa11(CPUARMState *env, uint32_t opcode) | |
| { | |
| TaskState *ts = env_cpu(env)->opaque; | |
| int rc = EmulateAll(opcode, &ts->fpa, env); | |
| int raise, enabled; | |
| if (rc == 0) { | |
| /* Illegal instruction */ | |
| return false; | |
| } | |
| if (rc > 0) { | |
| /* Everything ok. */ | |
| env->regs[15] += 4; | |
| return true; | |
| } | |
| /* FP exception */ | |
| rc = -rc; | |
| raise = 0; | |
| /* Translate softfloat flags to FPSR flags */ | |
| if (rc & float_flag_invalid) { | |
| raise |= BIT_IOC; | |
| } | |
| if (rc & float_flag_divbyzero) { | |
| raise |= BIT_DZC; | |
| } | |
| if (rc & float_flag_overflow) { | |
| raise |= BIT_OFC; | |
| } | |
| if (rc & float_flag_underflow) { | |
| raise |= BIT_UFC; | |
| } | |
| if (rc & float_flag_inexact) { | |
| raise |= BIT_IXC; | |
| } | |
| /* Accumulate unenabled exceptions */ | |
| enabled = ts->fpa.fpsr >> 16; | |
| ts->fpa.fpsr |= raise & ~enabled; | |
| if (raise & enabled) { | |
| /* | |
| * The kernel's nwfpe emulator does not pass a real si_code. | |
| * It merely uses send_sig(SIGFPE, current, 1), which results in | |
| * __send_signal() filling out SI_KERNEL with pid and uid 0 (under | |
| * the "SEND_SIG_PRIV" case). That's what our force_sig() does. | |
| */ | |
| force_sig(TARGET_SIGFPE); | |
| } else { | |
| env->regs[15] += 4; | |
| } | |
| return true; | |
| } | |
| void cpu_loop(CPUARMState *env) | |
| { | |
| CPUState *cs = env_cpu(env); | |
| int trapnr, si_signo, si_code; | |
| unsigned int n, insn; | |
| abi_ulong ret; | |
| for(;;) { | |
| cpu_exec_start(cs); | |
| trapnr = cpu_exec(cs); | |
| cpu_exec_end(cs); | |
| process_queued_cpu_work(cs); | |
| switch(trapnr) { | |
| case EXCP_UDEF: | |
| case EXCP_NOCP: | |
| case EXCP_INVSTATE: | |
| { | |
| uint32_t opcode; | |
| /* we handle the FPU emulation here, as Linux */ | |
| /* we get the opcode */ | |
| /* FIXME - what to do if get_user() fails? */ | |
| get_user_code_u32(opcode, env->regs[15], env); | |
| /* | |
| * The Linux kernel treats some UDF patterns specially | |
| * to use as breakpoints (instead of the architectural | |
| * bkpt insn). These should trigger a SIGTRAP rather | |
| * than SIGILL. | |
| */ | |
| if (insn_is_linux_bkpt(opcode, env->thumb)) { | |
| goto excp_debug; | |
| } | |
| if (!env->thumb && emulate_arm_fpa11(env, opcode)) { | |
| break; | |
| } | |
| force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPN, | |
| env->regs[15]); | |
| } | |
| break; | |
| case EXCP_SWI: | |
| { | |
| env->eabi = true; | |
| /* system call */ | |
| if (env->thumb) { | |
| /* Thumb is always EABI style with syscall number in r7 */ | |
| n = env->regs[7]; | |
| } else { | |
| /* | |
| * Equivalent of kernel CONFIG_OABI_COMPAT: read the | |
| * Arm SVC insn to extract the immediate, which is the | |
| * syscall number in OABI. | |
| */ | |
| /* FIXME - what to do if get_user() fails? */ | |
| get_user_code_u32(insn, env->regs[15] - 4, env); | |
| n = insn & 0xffffff; | |
| if (n == 0) { | |
| /* zero immediate: EABI, syscall number in r7 */ | |
| n = env->regs[7]; | |
| } else { | |
| /* | |
| * This XOR matches the kernel code: an immediate | |
| * in the valid range (0x900000 .. 0x9fffff) is | |
| * converted into the correct EABI-style syscall | |
| * number; invalid immediates end up as values | |
| * > 0xfffff and are handled below as out-of-range. | |
| */ | |
| n ^= ARM_SYSCALL_BASE; | |
| env->eabi = false; | |
| } | |
| } | |
| if (n > ARM_NR_BASE) { | |
| switch (n) { | |
| case ARM_NR_cacheflush: | |
| /* nop */ | |
| break; | |
| case ARM_NR_set_tls: | |
| cpu_set_tls(env, env->regs[0]); | |
| env->regs[0] = 0; | |
| break; | |
| case ARM_NR_breakpoint: | |
| env->regs[15] -= env->thumb ? 2 : 4; | |
| goto excp_debug; | |
| case ARM_NR_get_tls: | |
| env->regs[0] = cpu_get_tls(env); | |
| break; | |
| default: | |
| if (n < 0xf0800) { | |
| /* | |
| * Syscalls 0xf0000..0xf07ff (or 0x9f0000.. | |
| * 0x9f07ff in OABI numbering) are defined | |
| * to return -ENOSYS rather than raising | |
| * SIGILL. Note that we have already | |
| * removed the 0x900000 prefix. | |
| */ | |
| qemu_log_mask(LOG_UNIMP, | |
| "qemu: Unsupported ARM syscall: 0x%x\n", | |
| n); | |
| env->regs[0] = -TARGET_ENOSYS; | |
| } else { | |
| /* | |
| * Otherwise SIGILL. This includes any SWI with | |
| * immediate not originally 0x9fxxxx, because | |
| * of the earlier XOR. | |
| * Like the real kernel, we report the addr of the | |
| * SWI in the siginfo si_addr but leave the PC | |
| * pointing at the insn after the SWI. | |
| */ | |
| abi_ulong faultaddr = env->regs[15]; | |
| faultaddr -= env->thumb ? 2 : 4; | |
| force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLTRP, | |
| faultaddr); | |
| } | |
| break; | |
| } | |
| } else { | |
| ret = do_syscall(env, | |
| n, | |
| env->regs[0], | |
| env->regs[1], | |
| env->regs[2], | |
| env->regs[3], | |
| env->regs[4], | |
| env->regs[5], | |
| 0, 0); | |
| if (ret == -QEMU_ERESTARTSYS) { | |
| env->regs[15] -= env->thumb ? 2 : 4; | |
| } else if (ret != -QEMU_ESIGRETURN) { | |
| env->regs[0] = ret; | |
| } | |
| } | |
| } | |
| break; | |
| case EXCP_SEMIHOST: | |
| do_common_semihosting(cs); | |
| env->regs[15] += env->thumb ? 2 : 4; | |
| break; | |
| case EXCP_INTERRUPT: | |
| /* just indicate that signals should be handled asap */ | |
| break; | |
| case EXCP_PREFETCH_ABORT: | |
| case EXCP_DATA_ABORT: | |
| /* For user-only we don't set TTBCR_EAE, so look at the FSR. */ | |
| switch (env->exception.fsr & 0x1f) { | |
| case 0x1: /* Alignment */ | |
| si_signo = TARGET_SIGBUS; | |
| si_code = TARGET_BUS_ADRALN; | |
| break; | |
| case 0x3: /* Access flag fault, level 1 */ | |
| case 0x6: /* Access flag fault, level 2 */ | |
| case 0x9: /* Domain fault, level 1 */ | |
| case 0xb: /* Domain fault, level 2 */ | |
| case 0xd: /* Permission fault, level 1 */ | |
| case 0xf: /* Permission fault, level 2 */ | |
| si_signo = TARGET_SIGSEGV; | |
| si_code = TARGET_SEGV_ACCERR; | |
| break; | |
| case 0x5: /* Translation fault, level 1 */ | |
| case 0x7: /* Translation fault, level 2 */ | |
| si_signo = TARGET_SIGSEGV; | |
| si_code = TARGET_SEGV_MAPERR; | |
| break; | |
| default: | |
| g_assert_not_reached(); | |
| } | |
| force_sig_fault(si_signo, si_code, env->exception.vaddress); | |
| break; | |
| case EXCP_DEBUG: | |
| case EXCP_BKPT: | |
| excp_debug: | |
| force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->regs[15]); | |
| break; | |
| case EXCP_KERNEL_TRAP: | |
| if (do_kernel_trap(env)) | |
| goto error; | |
| break; | |
| case EXCP_YIELD: | |
| /* nothing to do here for user-mode, just resume guest code */ | |
| break; | |
| case EXCP_ATOMIC: | |
| cpu_exec_step_atomic(cs); | |
| break; | |
| default: | |
| error: | |
| EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n", trapnr); | |
| abort(); | |
| } | |
| process_pending_signals(env); | |
| } | |
| } | |
| void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs) | |
| { | |
| CPUState *cpu = env_cpu(env); | |
| TaskState *ts = cpu->opaque; | |
| struct image_info *info = ts->info; | |
| int i; | |
| cpsr_write(env, regs->uregs[16], CPSR_USER | CPSR_EXEC, | |
| CPSRWriteByInstr); | |
| for(i = 0; i < 16; i++) { | |
| env->regs[i] = regs->uregs[i]; | |
| } | |
| #if TARGET_BIG_ENDIAN | |
| /* Enable BE8. */ | |
| if (EF_ARM_EABI_VERSION(info->elf_flags) >= EF_ARM_EABI_VER4 | |
| && (info->elf_flags & EF_ARM_BE8)) { | |
| env->uncached_cpsr |= CPSR_E; | |
| env->cp15.sctlr_el[1] |= SCTLR_E0E; | |
| } else { | |
| env->cp15.sctlr_el[1] |= SCTLR_B; | |
| } | |
| arm_rebuild_hflags(env); | |
| #endif | |
| ts->stack_base = info->start_stack; | |
| ts->heap_base = info->brk; | |
| /* This will be filled in on the first SYS_HEAPINFO call. */ | |
| ts->heap_limit = 0; | |
| } |