On 06/12/2022 23.22, Richard Henderson wrote:
On 12/6/22 13:29, Ilya Leoshkevich wrote:
On Thu, Dec 01, 2022 at 10:51:49PM -0800, Richard Henderson wrote:
This reverts 829e1376d940 ("tcg/s390: Introduce TCG_REG_TB"), and
several follow-up patches. The primary motivation is to reduce the
less-tested code paths, pre-z10. Secondarily, this allows the
unconditional use of TCG_TARGET_HAS_direct_jump, which might be more
important for performance than any slight increase in code size.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
tcg/s390x/tcg-target.h | 2 +-
tcg/s390x/tcg-target.c.inc | 176 +++++--------------------------------
2 files changed, 23 insertions(+), 155 deletions(-)
Reviewed-by: Ilya Leoshkevich <i...@linux.ibm.com>
I have a few questions/ideas for the future below.
diff --git a/tcg/s390x/tcg-target.h b/tcg/s390x/tcg-target.h
index 22d70d431b..645f522058 100644
--- a/tcg/s390x/tcg-target.h
+++ b/tcg/s390x/tcg-target.h
@@ -103,7 +103,7 @@ extern uint64_t s390_facilities[3];
#define TCG_TARGET_HAS_mulsh_i32 0
#define TCG_TARGET_HAS_extrl_i64_i32 0
#define TCG_TARGET_HAS_extrh_i64_i32 0
-#define TCG_TARGET_HAS_direct_jump HAVE_FACILITY(GEN_INST_EXT)
+#define TCG_TARGET_HAS_direct_jump 1
This change doesn't seem to affect that, but what is the minimum
supported s390x qemu host? z900?
Possibly z990, if I'm reading the gcc processor_flags_table[] correctly;
long-displacement-facility is definitely a minimum.
We probably should revisit what the minimum for TCG should be, assert those
features at startup, and drop the corresponding runtime tests.
If we consider the official IBM support statement:
https://www.ibm.com/support/pages/system/files/inline-files/IBM%20Mainframe%20Life%20Cycle%20History%20V2.10%20-%20Sept%2013%202022_1.pdf
... that would mean that the z10 and all older machines are not supported
anymore.
Thomas
