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From: Helge Deller <deller@kernel.org>
To: qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@gmail.com>
Cc: "Helge Deller" <deller@gmx.de>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Philippe Mathieu-Daudé" <philmd@oss.qualcomm.com>
Subject: [PULL 1/4] target/hppa: Work-around for Fast TLB insert instruction on HP-UX 9
Date: Sun,  5 Jul 2026 17:47:45 +0200	[thread overview]
Message-ID: <20260705154749.7368-2-deller@kernel.org> (raw)
In-Reply-To: <20260705154749.7368-1-deller@kernel.org>

From: Helge Deller <deller@gmx.de>

The HP-UX 9 kernel uses two TLB insert instructions (0x05315440 and
0x05385400), which seem to be wrongly encoded fast TLB instructions, but
similiar to the non-fast instructions idtlba r17,(r9) and
idtlbp r24,(r9).

It's not clear, if those undocumented instructions were used by mistake,
or intentionally. Either way, this patch allows qemu to handle those
instructions, so that a HP-UX 9 boot-CD can now boot somewhat further (but
still crashes due to other reasons afterwards).

Signed-off-by: Helge Deller <deller@gmx.de>
Suggested-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/hppa/insns.decode | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/target/hppa/insns.decode b/target/hppa/insns.decode
index 13c6a55bf2..f700fe472e 100644
--- a/target/hppa/insns.decode
+++ b/target/hppa/insns.decode
@@ -164,6 +164,8 @@ ixtlbx          000001 b:5 r:5 ... 000000 addr:1 0 00000        \
 
 # pcxl and pcxl2 Fast TLB Insert instructions
 ixtlbxf         000001 00000 r:5 00 0 data:1 01000 addr:1 0 00000
+# workaround for non-standard encoding as used in HP-UX 9
+ixtlbxf         000001 01001 r:5 01 0 data:1 01000 addr:1 0 00000
 
 # pa2.0 tlb insert idtlbt and iitlbt instructions
 ixtlbt          000001 r2:5 r1:5 000 data:1 100000 0 00000    # idtlbt
-- 
2.54.0



  reply	other threads:[~2026-07-05 15:49 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-05 15:47 [PULL 0/4] Hppa fixes for v11.1 patches Helge Deller
2026-07-05 15:47 ` Helge Deller [this message]
2026-07-05 15:47 ` [PULL 2/4] target/hppa: Delay MMU update until TLB protection bits were set Helge Deller
2026-07-05 15:47 ` [PULL 3/4] hw/misc/lasi: derive IRR from pending and unmasked requests Helge Deller

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