diff options
Diffstat (limited to 'linux-user/main.c')
| -rw-r--r-- | linux-user/main.c | 89 |
1 files changed, 88 insertions, 1 deletions
diff --git a/linux-user/main.c b/linux-user/main.c index 89a51d76cd..25cb4ddf36 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -456,6 +456,83 @@ void cpu_loop(CPUX86State *env) #ifdef TARGET_ARM +/* + * See the Linux kernel's Documentation/arm/kernel_user_helpers.txt + * 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; + target_siginfo_t info; + + /* Based on the 32 bit code in do_kernel_trap */ + + /* XXX: This only works between threads, not between processes. + It's probably possible to implement this with native host + operations. However things like ldrex/strex are much harder so + there's not much point trying. */ + start_exclusive(); + cpsr = cpsr_read(env); + addr = env->regs[2]; + + if (get_user_u64(oldval, env->regs[0])) { + env->cp15.c6_data = env->regs[0]; + goto segv; + }; + + if (get_user_u64(newval, env->regs[1])) { + env->cp15.c6_data = env->regs[1]; + goto segv; + }; + + if (get_user_u64(val, addr)) { + env->cp15.c6_data = addr; + goto segv; + } + + if (val == oldval) { + val = newval; + + if (put_user_u64(val, addr)) { + env->cp15.c6_data = addr; + goto segv; + }; + + env->regs[0] = 0; + cpsr |= CPSR_C; + } else { + env->regs[0] = -1; + cpsr &= ~CPSR_C; + } + cpsr_write(env, cpsr, CPSR_C); + end_exclusive(); + return; + +segv: + end_exclusive(); + /* 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. */ + info.si_signo = SIGSEGV; + info.si_errno = 0; + /* XXX: check env->error_code */ + info.si_code = TARGET_SEGV_MAPERR; + info._sifields._sigfault._addr = env->cp15.c6_data; + queue_signal(env, info.si_signo, &info); + + end_exclusive(); +} + /* Handle a jump to the kernel code page. */ static int do_kernel_trap(CPUARMState *env) @@ -495,6 +572,10 @@ do_kernel_trap(CPUARMState *env) case 0xffff0fe0: /* __kernel_get_tls */ env->regs[0] = env->cp15.c13_tls2; break; + case 0xffff0f60: /* __kernel_cmpxchg64 */ + arm_kernel_cmpxchg64_helper(env); + break; + default: return 1; } @@ -752,7 +833,6 @@ void cpu_loop(CPUARMState *env) goto do_segv; case EXCP_DATA_ABORT: addr = env->cp15.c6_data; - goto do_segv; do_segv: { info.si_signo = SIGSEGV; @@ -3180,6 +3260,13 @@ int main(int argc, char **argv, char **envp) } qemu_log("Reserved 0x%lx bytes of guest address space\n", reserved_va); } + + if (reserved_va || have_guest_base) { + if (!guest_validate_base(guest_base)) { + fprintf(stderr, "Guest base/Reserved VA rejected by guest code\n"); + exit(1); + } + } #endif /* CONFIG_USE_GUEST_BASE */ /* |