On 2/2/25 13:46, Richard Henderson wrote:
On 1/31/25 13:44, Artyom Tarasenko wrote:
fake access to
PCR Performance Control Register
and
PIC Performance Instrumentation Counter.
Ignore writes in privileged mode, and return 0 on reads.
This allows booting Tribblix, MilaX and v9os under Niagara target.
Signed-off-by: Artyom Tarasenko <atar4q...@gmail.com>
---
target/sparc/insns.decode | 7 ++++++-
target/sparc/translate.c | 20 ++++++++++++++++++++
2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/target/sparc/insns.decode b/target/sparc/insns.decode
index 989c20b44a..504147563c 100644
--- a/target/sparc/insns.decode
+++ b/target/sparc/insns.decode
@@ -96,7 +96,10 @@ CALL 01 i:s30
RDTICK 10 rd:5 101000 00100 0 0000000000000
RDPC 10 rd:5 101000 00101 0 0000000000000
RDFPRS 10 rd:5 101000 00110 0 0000000000000
- RDASR17 10 rd:5 101000 10001 0 0000000000000
+ {
+ RDASR17 10 rd:5 101000 10001 0 0000000000000
+ RDPIC 10 rd:5 101000 10001 0 0000000000000
+ }
RDGSR 10 rd:5 101000 10011 0 0000000000000
RDSOFTINT 10 rd:5 101000 10110 0 0000000000000
RDTICK_CMPR 10 rd:5 101000 10111 0 0000000000000
@@ -114,6 +117,8 @@ CALL 01 i:s30
WRCCR 10 00010 110000 ..... . ............. @n_r_ri
WRASI 10 00011 110000 ..... . ............. @n_r_ri
WRFPRS 10 00110 110000 ..... . ............. @n_r_ri
+ WRPCR 10 10000 110000 01000 0 0000000000000
+ WRPIC 10 10001 110000 01000 0 0000000000000
{
WRGSR 10 10011 110000 ..... . ............. @n_r_ri
WRPOWERDOWN 10 10011 110000 ..... . ............. @n_r_ri
diff --git a/target/sparc/translate.c b/target/sparc/translate.c
index 7e5c7351cb..285c9b0a59 100644
--- a/target/sparc/translate.c
+++ b/target/sparc/translate.c
@@ -2882,6 +2882,15 @@ static TCGv do_rd_leon3_config(DisasContext *dc, TCGv
dst)
TRANS(RDASR17, ASR17, do_rd_special, true, a->rd, do_rd_leon3_config)
+static TCGv do_rdpic(DisasContext *dc, TCGv dst)
+{
+ tcg_gen_movi_tl(dst, 0UL);
+ return dst;
+}
return tcg_constant_tl(0);
+
+TRANS(RDPIC, HYPV, do_rd_special, true, a->rd, do_rdpic)
Surely reads are not allowed in user mode.
You might as well implement RDPCR as well, which *is* privileged.
Since PCR=0, then RDPCR is allowed.
It might be worthwhile to implement PCR, or at least PCR.PRIV.
r~
r~
