Re: [Qemu-devel] [PATCH v3 06/24] target-ppc: Enable writes to user-privileged PMU registers

[Alexey Kardashevskiy]

On 05/27/2014 08:37 PM, Alexey Kardashevskiy wrote:
> This adds spr_write_ureg() helper and uses it for UPMCx and MMCR0 SPRs.
> 
> Signed-off-by: Alexey Kardashevskiy <address@hidden>
> ---
>  target-ppc/translate_init.c | 25 +++++++++++++++----------
>  1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> index 88acf70..595fd3f 100644
> --- a/target-ppc/translate_init.c
> +++ b/target-ppc/translate_init.c
> @@ -175,6 +175,11 @@ static void spr_read_ureg (void *opaque, int gprn, int 
> sprn)
>      gen_load_spr(cpu_gpr[gprn], sprn + 0x10);
>  }
>  
> +static void spr_write_ureg(void *opaque, int gprn, int sprn)
> +{
> +    gen_store_spr(sprn + 0x10, cpu_gpr[gprn]);
> +}


Here I need assistance. I defined spr_write_ureg() similar to
spr_read_ureg() and tried using it for UMMCR2. And QEMU crashes on
segfault. May be spr_read_ureg() is broken too, it is not called in my
example. Does this xxx_ureg() do something fundamentally wrong with TCG?



 Info: performing kexec reboot

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x3fff93deeee0 (LWP 10648)]
0x000000001053153c in tcg_constant_folding (s=0x10c2a000 <tcg_ctx>,
tcg_opc_ptr=0x10c312e6 <tcg_ctx+29414>, args=0x10c3
19f8 <tcg_ctx+31224>, tcg_op_defs=0x10761730 <tcg_op_defs>) at
/home/alexey/p/qemu/tcg/optimize.c:550
550                 if (temps[args[i]].state == TCG_TEMP_COPY) {
Missing separate debuginfos, use: debuginfo-install
glusterfs-api-3.4.0-8.fc19.ppc64 glusterfs-libs-3.4.0-8.fc19.ppc64
gnutls-3.1.17-2.fc19.ppc64 keyutils-libs-1.5.6-1.fc19.ppc64
libgcc-4.8.2-1.fc19.ppc64 libgcrypt-1.5.3-2.fc19.ppc64 libi
bverbs-1.1.7-3.fc19.ppc64 libiscsi-1.7.0-5.fc19.ppc64
libpng-1.5.13-2.fc19.ppc64 librdmacm-1.0.17-1.fc19.ppc64 libusbx-
1.0.16-3.fc19.ppc64 systemd-libs-204-17.fc19.ppc64 usbredir-0.6-2.fc19.ppc64
(gdb) bt
#0  0x000000001053153c in tcg_constant_folding (s=0x10c2a000 <tcg_ctx>,
tcg_opc_ptr=0x10c312e6 <tcg_ctx+29414>, args=0x10c319f8 <tcg_ctx+31224>,
tcg_op_defs=0x10761730 <tcg_op_defs>) at /home/alexey/p/qemu/tcg/optimize.c:550
#1  0x0000000010534a68 in tcg_optimize (s=0x10c2a000 <tcg_ctx>,
tcg_opc_ptr=0x10c312e6 <tcg_ctx+29414>, args=0x10c317a0 <tcg_ctx+30624>,
tcg_op_defs=0x10761730 <tcg_op_defs>) at
/home/alexey/p/qemu/tcg/optimize.c:1294
#2  0x00000000105439e4 in tcg_gen_code_common (s=0x10c2a000 <tcg_ctx>,
gen_code_buf=0x3fffb1145010, search_pc=0xffffffffffffffff) at
/home/alexey/p/qemu/tcg/tcg.c:2536
#3  0x0000000010544138 in tcg_gen_code (s=0x10c2a000 <tcg_ctx>,
gen_code_buf=0x3fffb1145010) at /home/alexey/p/qemu/tcg/tcg.c:2659
#4  0x00000000105456d4 in cpu_ppc_gen_code (env=0x10ee23a0,
tb=0x3fff9af9bc78, gen_code_size_ptr=0x3fff93dee078) at
/home/alexey/p/qemu/translate-all.c:179
#5  0x000000001054704c in tb_gen_code (cpu=0x10ed9f70,
pc=0xc000000000028790, cs_base=0x0, flags=0x1, cflags=0x0) at
/home/alexey/p/qemu/translate-all.c:966
#6  0x0000000010328dc8 in tb_find_slow (env=0x10ee23a0,
pc=0xc000000000028790, cs_base=0x0, flags=0x1) at
/home/alexey/p/qemu/cpu-exec.c:157
#7  0x00000000103290bc in tb_find_fast (env=0x10ee23a0) at
/home/alexey/p/qemu/cpu-exec.c:185
#8  0x000000001032964c in cpu_ppc_exec (env=0x10ee23a0) at
/home/alexey/p/qemu/cpu-exec.c:609
#9  0x000000001032d684 in tcg_cpu_exec (env=0x10ee23a0) at
/home/alexey/p/qemu/cpus.c:1271
#10 0x000000001032d814 in tcg_exec_all () at /home/alexey/p/qemu/cpus.c:1303
#11 0x000000001032c7bc in qemu_tcg_cpu_thread_fn (arg=0x10ed9f70) at
/home/alexey/p/qemu/cpus.c:952
#12 0x00000080bcd0c29c in start_thread (arg=0x3fff93deeee0) at
pthread_create.c:310
#13 0x00000080bcb1ddb0 in .__clone () at
../sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S:111
(gdb)





> +
>  /* SPR common to all non-embedded PowerPC */
>  /* DECR */
>  #if !defined(CONFIG_USER_ONLY)
> @@ -7379,28 +7384,28 @@ static void gen_spr_book3s_pmu(CPUPPCState *env)
>                   &spr_read_generic, SPR_NOACCESS,
>                   0x00000000);
>      spr_register(env, SPR_POWER_UMMCR0, "UMMCR0",
> -                 &spr_read_ureg, SPR_NOACCESS,
> -                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, &spr_write_ureg,
> +                 &spr_read_ureg, &spr_write_ureg,
>                   0x00000000);
>      spr_register(env, SPR_POWER_UMMCR1, "UMMCR1",
>                   &spr_read_ureg, SPR_NOACCESS,
>                   &spr_read_ureg, SPR_NOACCESS,
>                   0x00000000);
>      spr_register(env, SPR_POWER_UPMC1, "UPMC1",
> -                 &spr_read_ureg, SPR_NOACCESS,
> -                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, &spr_write_ureg,
> +                 &spr_read_ureg, &spr_write_ureg,
>                   0x00000000);
>      spr_register(env, SPR_POWER_UPMC2, "UPMC2",
> -                 &spr_read_ureg, SPR_NOACCESS,
> -                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, &spr_write_ureg,
> +                 &spr_read_ureg, &spr_write_ureg,
>                   0x00000000);
>      spr_register(env, SPR_POWER_UPMC3, "UPMC3",
> -                 &spr_read_ureg, SPR_NOACCESS,
> -                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, &spr_write_ureg,
> +                 &spr_read_ureg, &spr_write_ureg,
>                   0x00000000);
>      spr_register(env, SPR_POWER_UPMC4, "UPMC4",
> -                 &spr_read_ureg, SPR_NOACCESS,
> -                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, &spr_write_ureg,
> +                 &spr_read_ureg, &spr_write_ureg,
>                   0x00000000);
>      spr_register(env, SPR_POWER_USIAR, "USIAR",
>                   &spr_read_ureg, SPR_NOACCESS,
> 


-- 
Alexey