[PULL v2 25/27] target/sparc: fake UltraSPARC T1 PCR and PIC registers

[Richard Henderson <richard.henderson@linaro.org>]

From: Artyom Tarasenko <atar4qemu@gmail.com>

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 <atar4qemu@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250209211248.50383-1-atar4qemu@gmail.com>
---
 target/sparc/translate.c  | 19 +++++++++++++++++++
 target/sparc/insns.decode |  7 ++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/target/sparc/translate.c b/target/sparc/translate.c
index 7e5c7351cb..bfe63649db 100644
--- a/target/sparc/translate.c
+++ b/target/sparc/translate.c
@@ -2882,6 +2882,14 @@ 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)
+{
+    return tcg_constant_tl(0);
+}
+
+TRANS(RDPIC, HYPV, do_rd_special, supervisor(dc), a->rd, do_rdpic)
+
+
 static TCGv do_rdccr(DisasContext *dc, TCGv dst)
 {
     gen_helper_rdccr(dst, tcg_env);
@@ -3315,6 +3323,17 @@ static void do_wrfprs(DisasContext *dc, TCGv src)
 
 TRANS(WRFPRS, 64, do_wr_special, a, true, do_wrfprs)
 
+static bool do_priv_nop(DisasContext *dc, bool priv)
+{
+    if (!priv) {
+        return raise_priv(dc);
+    }
+    return advance_pc(dc);
+}
+
+TRANS(WRPCR, HYPV, do_priv_nop, supervisor(dc))
+TRANS(WRPIC, HYPV, do_priv_nop, supervisor(dc))
+
 static void do_wrgsr(DisasContext *dc, TCGv src)
 {
     gen_trap_ifnofpu(dc);
diff --git a/target/sparc/insns.decode b/target/sparc/insns.decode
index cfcdf6690e..9e39d23273 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
-- 
2.43.0