On 4/21/20 9:44 AM, Edgar E. Iglesias wrote:
> On Mon, Apr 20, 2020 at 10:22:05PM +0100, Peter Maydell wrote:
>> The kernel has different handling for syscalls with invalid
>> numbers that are in the "arm-specific" range 0x9f0000 and up:
>> * 0x9f0000..0x9f07ff return -ENOSYS if not implemented
>> * other out of range syscalls cause a SIGILL
>> (see the kernel's arch/arm/kernel/traps.c:arm_syscall())
>>
>> Implement this distinction. (Note that our code doesn't look
>> quite like the kernel's, because we have removed the
>> 0x900000 prefix by this point, whereas the kernel retains
>> it in arm_syscall().)
>>
>> Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
>> ---
>> linux-user/arm/cpu_loop.c | 30 ++++++++++++++++++++++++++----
>> 1 file changed, 26 insertions(+), 4 deletions(-)
>>
>> diff --git a/linux-user/arm/cpu_loop.c b/linux-user/arm/cpu_loop.c
>> index 025887d6b86..f042108b0be 100644
>> --- a/linux-user/arm/cpu_loop.c
>> +++ b/linux-user/arm/cpu_loop.c
>> @@ -332,10 +332,32 @@ void cpu_loop(CPUARMState *env)
>> env->regs[0] = cpu_get_tls(env);
>> break;
>> default:
>> - qemu_log_mask(LOG_UNIMP,
>> - "qemu: Unsupported ARM syscall:
>> 0x%x\n",
>> - n);
>> - env->regs[0] = -TARGET_ENOSYS;
>> + 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 */
>> + info.si_signo = TARGET_SIGILL;
>> + info.si_errno = 0;
>> + info.si_code = TARGET_ILL_ILLTRP;
>> + info._sifields._sigfault._addr =
>> env->regs[15];
>> + if (env->thumb) {
>> + info._sifields._sigfault._addr -= 2;
>> + } else {
>> + info._sifields._sigfault._addr -= 2;
>> + }
>
>
> Am I missing some detail or are both branches of the if-else doing the
> same thing?
Oops good catch. R-b stands using '-= 4' on 2nd line.
>
> Cheers,
> Edgar
>
>
>
>> + queue_signal(env, info.si_signo,
>> + QEMU_SI_FAULT, &info);
>> + }
>> break;
>> }
>> } else {
>> --
>> 2.20.1
>>
>>
>
