On 03.04.2014 21:56, Richard Henderson wrote:
> Since the kernel doesn't pass any info on the reason for the fault,
> disassemble the instruction to detect a store.
>
> Signed-off-by: Richard Henderson <r...@twiddle.net>
> ---
> user-exec.c | 29 +++++++++++++++++++++++------
> 1 file changed, 23 insertions(+), 6 deletions(-)
>
> diff --git a/user-exec.c b/user-exec.c
> index bc58056..52f76c9 100644
> --- a/user-exec.c
> +++ b/user-exec.c
> @@ -465,16 +465,33 @@ int cpu_signal_handler(int host_signum, void *pinfo,
>
> #elif defined(__aarch64__)
>
> -int cpu_signal_handler(int host_signum, void *pinfo,
> - void *puc)
> +int cpu_signal_handler(int host_signum, void *pinfo, void *puc)
> {
> siginfo_t *info = pinfo;
> struct ucontext *uc = puc;
> - uint64_t pc;
> - int is_write = 0; /* XXX how to determine? */
> + uintptr_t pc = uc->uc_mcontext.pc;
> + uint32_t insn = *(uint32_t *)pc;
> + bool is_write;
>
> - pc = uc->uc_mcontext.pc;
> - return handle_cpu_signal(pc, (uint64_t)info->si_addr,
> + /* XXX: need kernel patch to get write flag faster. */
> + /* XXX: several of these could be combined. */
> + is_write = ( (insn & 0xbfff0000) == 0x0c000000 /* C3.3.1 */
> + || (insn & 0xbfe00000) == 0x0c800000 /* C3.3.2 */
> + || (insn & 0xbfdf0000) == 0x0d000000 /* C3.3.3 */
> + || (insn & 0xbfc00000) == 0x0d800000 /* C3.3.4 */
> + || (insn & 0x3f400000) == 0x08000000 /* C3.3.6 */
> + || (insn & 0x3bc00000) == 0x28400000 /* C3.3.7 */
I think the Load (L) bit should be 0 here so
== 0x28000000
> + || (insn & 0x3be00c00) == 0x38000400 /* C3.3.8 */
With V=1, an opc of 0b10 is also a write, I think. It's the 128bit FP/SIMD STR.
> + || (insn & 0x3be00c00) == 0x38000c00 /* C3.3.9 */
Same here.
> + || (insn & 0x3be00c00) == 0x38200800 /* C3.3.10 */
Same.
> + || (insn & 0x3be00c00) == 0x38000800 /* C3.3.11 */
> + || (insn & 0x3be00c00) == 0x38000000 /* C3.3.12 */
Same.
> + || (insn & 0x3bc00000) == 0x39000000 /* C3.3.13 */
Same.
> + || (insn & 0x3bc00000) == 0x29000000 /* C3.3.14 */
> + || (insn & 0x3bc00000) == 0x28800000 /* C3.3.15 */
> + || (insn & 0x3bc00000) == 0x29800000); /* C3.3.16 */
> +
> + return handle_cpu_signal(pc, (uintptr_t)info->si_addr,
> is_write, &uc->uc_sigmask, puc);
> }
>
>
Thanks,
Claudio
