diff mbox series

Hexagon (target/hexagon) Add overrides for cache/sync/barrier instructions

Message ID 20230410202402.2856852-1-tsimpson@quicinc.com (mailing list archive)
State New, archived
Headers show
Series Hexagon (target/hexagon) Add overrides for cache/sync/barrier instructions | expand

Commit Message

Taylor Simpson April 10, 2023, 8:24 p.m. UTC
Most of these are not modelled in QEMU, so save the overhead of
calling a helper.

The only exception is dczeroa.  It assigns to hex_dczero_addr, which
is handled during packet commit.

Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
---
 target/hexagon/gen_tcg.h | 24 ++++++++++++++++++++++++
 target/hexagon/macros.h  | 18 ++++--------------
 2 files changed, 28 insertions(+), 14 deletions(-)

Comments

Richard Henderson April 11, 2023, 1:29 a.m. UTC | #1
On 4/10/23 13:24, Taylor Simpson wrote:
> Most of these are not modelled in QEMU, so save the overhead of
> calling a helper.
> 
> The only exception is dczeroa.  It assigns to hex_dczero_addr, which
> is handled during packet commit.
> 
> Signed-off-by: Taylor Simpson<tsimpson@quicinc.com>
> ---
>   target/hexagon/gen_tcg.h | 24 ++++++++++++++++++++++++
>   target/hexagon/macros.h  | 18 ++++--------------
>   2 files changed, 28 insertions(+), 14 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Something to look at in the future: I believe quite a lot of these variables like 
dczero_addr are not "real" architectural state, in that they do not persist beyond the 
lifetime of the packet.  There are others, e.g. pkt_has_store_s1.

These variables could be moved to DisasContext and allocated on demand.  Even recently 
this was tedious, because of TCG temporary lifetime issues, but no longer.

Just a thought.


r~
Taylor Simpson April 11, 2023, 2:29 a.m. UTC | #2
> -----Original Message-----
> From: Richard Henderson <richard.henderson@linaro.org>
> Sent: Monday, April 10, 2023 8:30 PM
> To: Taylor Simpson <tsimpson@quicinc.com>; qemu-devel@nongnu.org
> Cc: philmd@linaro.org; ale@rev.ng; anjo@rev.ng; Brian Cain
> <bcain@quicinc.com>; Matheus Bernardino (QUIC)
> <quic_mathbern@quicinc.com>
> Subject: Re: [PATCH] Hexagon (target/hexagon) Add overrides for
> cache/sync/barrier instructions
> 
> On 4/10/23 13:24, Taylor Simpson wrote:
> > Most of these are not modelled in QEMU, so save the overhead of
> > calling a helper.
> >
> > The only exception is dczeroa.  It assigns to hex_dczero_addr, which
> > is handled during packet commit.
> >
> > Signed-off-by: Taylor Simpson<tsimpson@quicinc.com>
> > ---
> >   target/hexagon/gen_tcg.h | 24 ++++++++++++++++++++++++
> >   target/hexagon/macros.h  | 18 ++++--------------
> >   2 files changed, 28 insertions(+), 14 deletions(-)
> 
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> 
> Something to look at in the future: I believe quite a lot of these variables like
> dczero_addr are not "real" architectural state, in that they do not persist
> beyond the lifetime of the packet.  There are others, e.g. pkt_has_store_s1.

That's correct.

> These variables could be moved to DisasContext and allocated on demand.
> Even recently this was tedious, because of TCG temporary lifetime issues,
> but no longer.

I'll work on this.  The obvious advantage is to allow the TCG optimizer more opportunity to fold copies and propagate constants.

Any other advantage?

Thanks,
Taylor
Richard Henderson April 12, 2023, 6:41 a.m. UTC | #3
On 4/11/23 04:29, Taylor Simpson wrote:
>> These variables could be moved to DisasContext and allocated on demand.
>> Even recently this was tedious, because of TCG temporary lifetime issues,
>> but no longer.
> 
> I'll work on this.  The obvious advantage is to allow the TCG optimizer more opportunity to fold copies and propagate constants.
> 
> Any other advantage?

Once the packet is complete, the value is discarded, rather than written back to env.


r~
diff mbox series

Patch

diff --git a/target/hexagon/gen_tcg.h b/target/hexagon/gen_tcg.h
index bcf0cf466a..ca41ca1e41 100644
--- a/target/hexagon/gen_tcg.h
+++ b/target/hexagon/gen_tcg.h
@@ -487,6 +487,19 @@ 
 #define fGEN_TCG_S2_storerinew_pcr(SHORTCODE) \
     fGEN_TCG_STORE_pcr(2, fSTORE(1, 4, EA, NtN))
 
+/* dczeroa clears the 32 byte cache line at the address given */
+#define fGEN_TCG_Y2_dczeroa(SHORTCODE) SHORTCODE
+
+/* In linux-user mode, these are not modelled, suppress compiler warning */
+#define fGEN_TCG_Y2_dcinva(SHORTCODE) \
+    do { RsV = RsV; } while (0)
+#define fGEN_TCG_Y2_dccleaninva(SHORTCODE) \
+    do { RsV = RsV; } while (0)
+#define fGEN_TCG_Y2_dccleana(SHORTCODE) \
+    do { RsV = RsV; } while (0)
+#define fGEN_TCG_Y2_icinva(SHORTCODE) \
+    do { RsV = RsV; } while (0)
+
 /*
  * dealloc_return
  * Assembler mapped to
@@ -1187,6 +1200,17 @@ 
     do { \
         RsV = RsV; \
     } while (0)
+#define fGEN_TCG_Y2_isync(SHORTCODE) \
+    do { } while (0)
+#define fGEN_TCG_Y2_barrier(SHORTCODE) \
+    do { } while (0)
+#define fGEN_TCG_Y2_syncht(SHORTCODE) \
+    do { } while (0)
+#define fGEN_TCG_Y2_dcfetchbo(SHORTCODE) \
+    do { \
+        RsV = RsV; \
+        uiV = uiV; \
+    } while (0)
 
 #define fGEN_TCG_J2_trap0(SHORTCODE) \
     do { \
diff --git a/target/hexagon/macros.h b/target/hexagon/macros.h
index 482a9c787f..d878688d96 100644
--- a/target/hexagon/macros.h
+++ b/target/hexagon/macros.h
@@ -688,20 +688,10 @@  static inline TCGv gen_read_ireg(TCGv result, TCGv val, int shift)
                    reg_field_info[FIELD].offset)
 #define fGET_FIELD(VAL, FIELD)
 #define fSET_FIELD(VAL, FIELD, NEWVAL)
-#define fBARRIER()
-#define fSYNCH()
-#define fISYNC()
-#define fDCFETCH(REG) \
-    do { (void)REG; } while (0) /* Nothing to do in qemu */
-#define fICINVA(REG) \
-    do { (void)REG; } while (0) /* Nothing to do in qemu */
-#define fL2FETCH(ADDR, HEIGHT, WIDTH, STRIDE, FLAGS)
-#define fDCCLEANA(REG) \
-    do { (void)REG; } while (0) /* Nothing to do in qemu */
-#define fDCCLEANINVA(REG) \
-    do { (void)REG; } while (0) /* Nothing to do in qemu */
-
-#define fDCZEROA(REG) do { env->dczero_addr = (REG); } while (0)
+
+#ifdef QEMU_GENERATE
+#define fDCZEROA(REG) tcg_gen_mov_tl(hex_dczero_addr, (REG))
+#endif
 
 #define fBRANCH_SPECULATE_STALL(DOTNEWVAL, JUMP_COND, SPEC_DIR, HINTBITNUM, \
                                 STRBITNUM) /* Nothing */