Re: [PATCH] kvx: fix kvx_reassemble_bundle index 8 out of bounds

[Paul Iannetta <piannetta@kalrayinc.com>]

On Thu, Sep 07, 2023 at 10:16:28PM +0930, Alan Modra wrote:
> On Thu, Aug 24, 2023 at 11:26:49AM +0200, Paul Iannetta wrote:
> > > > 	* kvx-dis.c (print_insn_kvx): Change the loop condition so that
> > > > 	  wordcount is always less than KVXMAXBUNDLEWORDS.
> 
> Hi Paul,
> Does the following patch look good to you, and can you please craft a
> testcase that exercises a maximum size bundle?
> 
> While the patch already committed for pr30793 prevents the asan error,
> there is a problem: Now the last element of bundle_words never gets
> written.  That's very likely wrong, or KVXMAXBUNDLEWORDS is too big.
> So this patch rearranges things a little to support writing of all of
> bundle_words and does the parallel bit checking only when filling
> bundle_words.  In the normal case, kvx_reassemble_bundle will see
> bundle_words[word_count-1] with the parallel bit clear and all other
> words having it set.  In the error case where all words in
> bundle_words have the parallel bit set, kvx_reassemble_bundle will be
> passed a wordcount of KVXMAXBUNDLEWORDS + 1.  I've also made
> kvx_reassemble_bundle return true for success rather than zero, and
> removed the unnecessary check for zero wordcount.

Hi Alan,

Thank you for catching this, your patch looks good to me.  Below is a
patch which adds a test case, you can merge it with yours if you want.

Thanks,
--
Paul
Kalray


commit 8dbb32052cb0e1e5ea1569e3fb708582f8158290
Author: Paul Iannetta <piannetta@kalrayinc.com>
Date:   Thu Sep 7 17:10:01 2023 +0200

    kvx: Add a testcase for bundles with KVXMAXBUNDLEWORDS syllables

    The previous fix (f1917fc) for pr30793 introduced a bug when dealing
    with bundles of with KVXMAXBUNDLEWORDS syllables.  This adds a test case
    to ensure that such bundle are correctly disassembled.

    gas/ChangeLog:

    2023-09-07  Paul Iannetta  <piannetta@kalrayinc.com>

            * testsuite/gas/kvx/fat-bundles.s: New test.
            * testsuite/gas/kvx/kv3-1-fat-bundles.d: New test.
            * testsuite/gas/kvx/kv3-2-fat-bundles.d: New test.

diff --git a/gas/testsuite/gas/kvx/fat-bundles.s b/gas/testsuite/gas/kvx/fat-bundles.s
new file mode 100644
index 00000000000..8119c6043de
--- /dev/null
+++ b/gas/testsuite/gas/kvx/fat-bundles.s
@@ -0,0 +1,13 @@
+# The bundles in this file all have 8 syllables.
+
+	addd $r0 = $r0, 123456789010	# 1 ALU + 2 Immediate Extensions
+	addd $r0 = $r0, 123456789010	# 1 ALU + 2 Immediate Extensions
+	addd $r1 = $r2, 1234		# 1 ALU + 1 Immediate Extension
+	;;
+	igoto $r0			# 1 BCU
+	xmt44d $a0a1a2a3 = $a0a1a2a3	# 1 TCA
+	addd $r0 = $r0, 1234		# 1 ALU + 1 Immediate Extension
+	addd $r0 = $r0, 12345678901	# 1 ALU + 1 Immediate Extension
+	fmuld $r1 = $r2, $r3		# 1 MAU
+	lwz $r0 = 0[$r0]		# 1 LSU
+	;;
diff --git a/gas/testsuite/gas/kvx/kv3-1-fat-bundles.d b/gas/testsuite/gas/kvx/kv3-1-fat-bundles.d
new file mode 100644
index 00000000000..1f80e0444fd
--- /dev/null
+++ b/gas/testsuite/gas/kvx/kv3-1-fat-bundles.d
@@ -0,0 +1,20 @@
+#as: -march=kv3-1
+#objdump: -d
+#source: fat-bundles.s
+.*\/fat-bundles.o:     file format elf64-kvx
+
+
+Disassembly of section .text:
+
+0000000000000000 <.text>:
+   0:	82 34 04 e1 80 84 00 e1                         	addd \$r1 = \$r2, 1234 \(0x4d2\)
+   8:	80 84 00 e1 01 00 00 80 46 a6 2f 8f             	addd \$r0 = \$r0, 123456789010 \(0x1cbe991a12\)
+  14:	00 00 00 88 46 a6 2f 97 00 00 00 10             	addd \$r0 = \$r0, 123456789010 \(0x1cbe991a12\);;
+
+  20:	00 00 d8 8f                                     	igoto \$r0
+  24:	00 00 0c 84                                     	xmt44d \$a0a1a2a3 = \$a0a1a2a3
+  28:	80 34 00 e1 40 0d 00 e1                         	addd \$r0 = \$r0, 1234 \(0x4d2\)
+  30:	c2 70 05 d8 00 00 00 b0                         	addd \$r0 = \$r0, 12345678901 \(0x2dfdc1c35\)
+  38:	01 00 00 80                                     	fmuld \$r1 = \$r2, \$r3
+  3c:	07 f7 b7 08                                     	lwz \$r0 = 0 \(0x0\)\[\$r0\];;
+
diff --git a/gas/testsuite/gas/kvx/kv3-2-fat-bundles.d b/gas/testsuite/gas/kvx/kv3-2-fat-bundles.d
new file mode 100644
index 00000000000..54717eb55b4
--- /dev/null
+++ b/gas/testsuite/gas/kvx/kv3-2-fat-bundles.d
@@ -0,0 +1,20 @@
+#as: -march=kv3-2
+#objdump: -d
+#source: fat-bundles.s
+.*\/fat-bundles.o:     file format elf64-kvx
+
+
+Disassembly of section .text:
+
+0000000000000000 <.text>:
+   0:	82 34 04 e2 80 84 00 e2                         	addd \$r1 = \$r2, 1234 \(0x4d2\)
+   8:	80 84 00 e2 01 00 00 80 46 a6 2f 8f             	addd \$r0 = \$r0, 123456789010 \(0x1cbe991a12\)
+  14:	00 00 00 88 46 a6 2f 97 00 00 00 10             	addd \$r0 = \$r0, 123456789010 \(0x1cbe991a12\);;
+
+  20:	00 00 d8 8f                                     	igoto \$r0
+  24:	00 10 05 87                                     	xcopyv.td \$a0a1a2a3 = \$a0a1a2a3
+  28:	80 34 00 e2 40 0d 00 e2                         	addd \$r0 = \$r0, 1234 \(0x4d2\)
+  30:	c2 70 05 d8 00 00 00 b0                         	addd \$r0 = \$r0, 12345678901 \(0x2dfdc1c35\)
+  38:	01 00 00 80                                     	fmuld \$r1 = \$r2, \$r3
+  3c:	07 f7 b7 08                                     	lwz \$r0 = 0 \(0x0\)\[\$r0\];;
+