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?
Cheers,
Edgar
> + queue_signal(env, info.si_signo,
> + QEMU_SI_FAULT, &info);
> + }
> break;
> }
> } else {
> --
> 2.20.1
>
>
