powerel9
/
gdb
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
2 Commits
1 Branch
0 Tags
837 KiB
 
 
Tree: 260dcfb0e6
Branches Tags
${ item.name }
Create tag ${ searchTerm }
Create branch ${ searchTerm }
from '260dcfb0e6'
${ noResults }
gdb/SOURCES/gdb-rhbz1870031-p10-prefixe...

633 lines
22 KiB
Raw Blame History

From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
From: Keith Seitz <keiths@redhat.com>
Date: Thu, 6 May 2021 14:53:00 -0400
Subject: gdb-rhbz1870031-p10-prefixed-insn-2of3.patch
;; Backport "gdb-power10-single-step"
;; (Will Schmidt, RHBZ 1870031)
commit c8a379440e0f8bf94ed5730e823c9256e64bf37c
Author: Will Schmidt <will_schmidt@vnet.ibm.com>
Date: Mon Apr 12 14:11:02 2021 -0500
[PATCH] gdb-power10-single-step
Hi,
This is based on a patch originally written by Alan Modra.
Powerpc / Power10 ISA 3.1 adds prefixed instructions, which
are 8 bytes in length. This is in contrast to powerpc previously
always having 4 byte instruction length. This patch implements
changes to allow GDB to better detect prefixed instructions, and
handle single stepping across the 8 byte instructions.
Added #defines to help test for PNOP and prefix instructions.
Update ppc_displaced_step_copy_insn() to handle pnop and prefixed
instructions whem R=0 (non-pc-relative).
Updated ppc_displaced_step_fixup() to properly handle the offset
value matching the current instruction size
Updated the for-loop within ppc_deal_with_atomic_sequence() to
count instructions properly in case we have a mix of 4-byte and
8-byte instructions within the atomic_sequence_length.
Added testcase and harness to exercise pc-relative load/store
instructions with R=0.
2021-04-12 Will Schmidt <will_schmidt@vnet.ibm.com>
gdb/ChangeLog:
* rs6000-tdep.c: Add support for single-stepping of
prefixed instructions.
gdb/testsuite/ChangeLog:
* gdb.arch/powerpc-plxv-nonrel.s: Testcase using
non-relative plxv instructions.
* gdb.arch/powerpc-plxv-nonrel.exp: Testcase harness.
diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
--- a/gdb/rs6000-tdep.c
+++ b/gdb/rs6000-tdep.c
@@ -814,7 +814,7 @@ typedef BP_MANIPULATION_ENDIAN (little_breakpoint, big_breakpoint)
rs6000_breakpoint;
/* Instruction masks for displaced stepping. */
-#define BRANCH_MASK 0xfc000000
+#define OP_MASK 0xfc000000
#define BP_MASK 0xFC0007FE
#define B_INSN 0x48000000
#define BC_INSN 0x40000000
@@ -842,6 +842,11 @@ typedef BP_MANIPULATION_ENDIAN (little_breakpoint, big_breakpoint)
#define ADDPCIS_TARGET_REGISTER 0x03F00000
#define ADDPCIS_INSN_REGSHIFT 21
+#define PNOP_MASK 0xfff3ffff
+#define PNOP_INSN 0x07000000
+#define R_MASK 0x00100000
+#define R_ZERO 0x00000000
+
/* Check if insn is one of the Load And Reserve instructions used for atomic
sequences. */
#define IS_LOAD_AND_RESERVE_INSN(insn) ((insn & LOAD_AND_RESERVE_MASK) == LWARX_INSTRUCTION \
@@ -873,10 +878,38 @@ ppc_displaced_step_copy_insn (struct gdbarch *gdbarch,
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
int insn;
- read_memory (from, buf, len);
+ len = target_read (current_inferior()->top_target(), TARGET_OBJECT_MEMORY, NULL,
+ buf, from, len);
+ if ((ssize_t) len < PPC_INSN_SIZE)
+ memory_error (TARGET_XFER_E_IO, from);
insn = extract_signed_integer (buf, PPC_INSN_SIZE, byte_order);
+ /* Check for PNOP and for prefixed instructions with R=0. Those
+ instructions are safe to displace. Prefixed instructions with R=1
+ will read/write data to/from locations relative to the current PC.
+ We would not be able to fixup after an instruction has written data
+ into a displaced location, so decline to displace those instructions. */
+ if ((insn & OP_MASK) == 1 << 26)
+ {
+ if (((insn & PNOP_MASK) != PNOP_INSN)
+ && ((insn & R_MASK) != R_ZERO))
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "displaced: {ppc} Not displacing prefixed "
+ "instruction %08x at %s",
+ insn, paddress (gdbarch, from));
+ return NULL;
+ }
+ }
+ else
+ /* Non-prefixed instructions.. */
+ {
+ /* Set the instruction length to 4 to match the actual instruction
+ length. */
+ len = 4;
+ }
+
/* Assume all atomic sequences start with a Load and Reserve instruction. */
if (IS_LOAD_AND_RESERVE_INSN (insn))
{
@@ -917,11 +950,17 @@ ppc_displaced_step_fixup (struct gdbarch *gdbarch,
ppc_displaced_step_closure *closure = (ppc_displaced_step_closure *) closure_;
ULONGEST insn = extract_unsigned_integer (closure->buf.data (),
PPC_INSN_SIZE, byte_order);
- ULONGEST opcode = 0;
+ ULONGEST opcode;
/* Offset for non PC-relative instructions. */
- LONGEST offset = PPC_INSN_SIZE;
+ LONGEST offset;
- opcode = insn & BRANCH_MASK;
+ opcode = insn & OP_MASK;
+
+ /* Set offset to 8 if this is an 8-byte (prefixed) instruction. */
+ if ((opcode) == 1 << 26)
+ offset = 2 * PPC_INSN_SIZE;
+ else
+ offset = PPC_INSN_SIZE;
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
@@ -1058,13 +1097,16 @@ ppc_deal_with_atomic_sequence (struct regcache *regcache)
instructions. */
for (insn_count = 0; insn_count < atomic_sequence_length; ++insn_count)
{
- loc += PPC_INSN_SIZE;
+ if ((insn & OP_MASK) == 1 << 26)
+ loc += 2 * PPC_INSN_SIZE;
+ else
+ loc += PPC_INSN_SIZE;
insn = read_memory_integer (loc, PPC_INSN_SIZE, byte_order);
/* Assume that there is at most one conditional branch in the atomic
sequence. If a conditional branch is found, put a breakpoint in
its destination address. */
- if ((insn & BRANCH_MASK) == BC_INSN)
+ if ((insn & OP_MASK) == BC_INSN)
{
int immediate = ((insn & 0xfffc) ^ 0x8000) - 0x8000;
int absolute = insn & 2;
@@ -7095,7 +7137,7 @@ rs6000_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
set_gdbarch_displaced_step_location (gdbarch,
displaced_step_at_entry_point);
- set_gdbarch_max_insn_length (gdbarch, PPC_INSN_SIZE);
+ set_gdbarch_max_insn_length (gdbarch, 2 * PPC_INSN_SIZE);
/* Hook in ABI-specific overrides, if they have been registered. */
info.target_desc = tdesc;
diff --git a/gdb/testsuite/gdb.arch/powerpc-addpcis.exp b/gdb/testsuite/gdb.arch/powerpc-addpcis.exp
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/powerpc-addpcis.exp
@@ -0,0 +1,104 @@
+# Copyright 2021 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+# Test to confirm that gdb is properly single stepping over the
+# displaced addpcis instruction.
+# The addpcis instruction and its extended mnemonics lnia and subpcis
+# apply an immediate shifted value (X || 0x0000) to the current PC/NIA
+# value, and store that value into the instructions target register.
+# When the instruction is displaced, it needs special handling.
+
+# lnia Rx == addpcis Rx,0
+# subcis Rx,value == addpcis Rx,-value
+
+if { ![istarget powerpc*-*] } {
+ verbose "Skipping powerpc addpcis test."
+ return
+}
+
+set retval 0
+
+standard_testfile .s
+
+if { [prepare_for_testing "failed to prepare" $testfile "$srcfile" \
+ {debug quiet}] } {
+ return -1
+}
+
+if ![runto_main] then {
+ return
+}
+
+set check_pc [get_hexadecimal_valueof "\$pc" "default0"]
+set bp1 *$check_pc+4
+set bp2 *$check_pc+12
+set bp3 *$check_pc+16
+gdb_breakpoint $bp1
+gdb_breakpoint $bp2
+gdb_breakpoint $bp3
+
+gdb_test "stepi" "" "set r3 "
+set check_r3 [get_hexadecimal_valueof "\$r3" "default0"]
+gdb_test "stepi" "" "set r4"
+set check_r4 [get_hexadecimal_valueof "\$r4" "default0"]
+gdb_test "stepi" "" "set r5"
+set check_r5 [get_hexadecimal_valueof "\$r5" "default0"]
+gdb_test "stepi" "" "set r6"
+set check_r6 [get_hexadecimal_valueof "\$r6" "default0"]
+gdb_test "stepi" "" "set r7"
+set check_r7 [get_hexadecimal_valueof "\$r7" "default0"]
+gdb_test "stepi" "" "set r8"
+set check_r8 [get_hexadecimal_valueof "\$r8" "default0"]
+gdb_test "stepi" "" "set r9"
+set check_r9 [get_hexadecimal_valueof "\$r9" "default0"]
+
+# R6 will contain the reference value. All other
+# instructions in this test will be storing values
+# relative to what is stored in R6.
+
+# subpcis 3,+0x100 # /* set r3 */
+# subpcis 4,+0x10 # /* set r4 */
+# subpcis 5,+0x1 # /* set r5 */
+# lnia 6 # /* set r6 */
+# addpcis 7,+0x1 # /* set r7 */
+# addpcis 8,+0x10 # /* set r8 */
+# addpcis 9,+0x100 # /* set r9 */
+
+if [expr $check_r3 + 0x1000000 != $check_r6 - 0xc ] {
+ fail "unexpected value r3 + 0x1,000,000 != r6 + 0xc ; r3: $check_r3 r6: $check_r6 "
+}
+if [expr $check_r4 + 0x100000 != $check_r6 - 0x8 ] {
+ fail "unexpected value r4 + 0x100,000 != r6 - 0x8 ; r4: $check_r4 r6: $check_r6 "
+}
+if [expr $check_r5 + 0x10000 != $check_r6 - 0x4 ] {
+ fail "unexpected value r5 + 0x10,000 != r6 , r5: $check_r5 r6: $check_r6 "
+}
+if [expr $check_r6 != $check_r6] {
+ fail "unexpected value r6 != r6 , r6: $check_r6 r6: $check_r6 "
+}
+if [expr $check_r7 - 0x10000 != $check_r6 + 0x4] {
+ fail "unexpected value r7 - 0x10,000 != r6 + 0x4 , r7: $check_r7 r7: $check_r6 "
+}
+if [expr $check_r8 - 0x100000 != $check_r6 + 0x8 ] {
+ fail "unexpected value r8 - 0x100,000 != r6 , r8: $check_r8 r8: $check_r6 "
+}
+if [expr $check_r9 - 0x1000000 != $check_r6 + 0xc ] {
+ fail "unexpected value r9 - 0x1,000,000 != r6 + 0xc , r9: $check_r9 r6: $check_r6 "
+}
+
+gdb_test "info break"
+gdb_test "info register r3 r4 r5 r6 r7 r8 r9"
+gdb_test "disas main"
diff --git a/gdb/testsuite/gdb.arch/powerpc-addpcis.s b/gdb/testsuite/gdb.arch/powerpc-addpcis.s
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/powerpc-addpcis.s
@@ -0,0 +1,33 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2021 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+
+/* Test to confirm that gdb is properly single stepping over the
+ displaced addpcis instruction. */
+
+.global main
+.type main,function
+# addpcis: the sum of NIA + ( D || 0x0000) is placed in RT.
+main:
+ subpcis 3,+0x100 # /* set r3 */
+ subpcis 4,+0x10 # /* set r4 */
+ subpcis 5,+0x1 # /* set r5 */
+ lnia 6 # /* set r6 */
+ addpcis 7,+0x1 # /* set r7 */
+ addpcis 8,+0x10 # /* set r8 */
+ addpcis 9,+0x100 # /* set r9 */
+ blr
diff --git a/gdb/testsuite/gdb.arch/powerpc-lnia.exp b/gdb/testsuite/gdb.arch/powerpc-lnia.exp
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/powerpc-lnia.exp
@@ -0,0 +1,100 @@
+# Copyright 2021 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# Test to see if gdb is properly single stepping over the
+# displaced lnia instruction. This test checks that a series
+# of lnia instructions are loading ascending values as expected.
+
+# lnia is an extended mnemonic for the addpcis instruction, which
+# stores the $NIA plus an immediate value into a register.
+#
+# lnia Rx == addpcis Rx,0 == lnia Rx
+# subcis Rx,value == addpcis Rx,-value
+
+if { ![istarget powerpc*-*] } {
+ verbose "Skipping powerpc lnia test."
+ return
+}
+
+set retval 0
+
+standard_testfile .s
+
+if { [prepare_for_testing "failed to prepare" $testfile "$srcfile" \
+ {debug quiet}] } {
+ return -1
+}
+
+if ![runto_main] then {
+ return
+}
+
+set before_pc 0
+set check_pc [get_hexadecimal_valueof "\$pc" "default0"]
+
+# set some breakpoints on the instructions below main().
+set bp1 *$check_pc+4
+set bp2 *$check_pc+12
+set bp3 *$check_pc+16
+gdb_breakpoint $bp1
+gdb_breakpoint $bp2
+gdb_breakpoint $bp3
+
+# single-step through the lnia instructions, and retrieve the
+# register values as we proceed.
+gdb_test "stepi" "" "set r3"
+set check_r3 [get_hexadecimal_valueof "\$r3" "default0"]
+gdb_test "stepi" "" "set r4"
+set check_r4 [get_hexadecimal_valueof "\$r4" "default0"]
+gdb_test "stepi" "" "set r5"
+set check_r5 [get_hexadecimal_valueof "\$r5" "default0"]
+gdb_test "stepi" "" "set r6"
+set check_r6 [get_hexadecimal_valueof "\$r6" "default0"]
+gdb_test "stepi" "" "set r7"
+set check_r7 [get_hexadecimal_valueof "\$r7" "default0"]
+gdb_test "stepi" "" "set r8"
+set check_r8 [get_hexadecimal_valueof "\$r8" "default0"]
+gdb_test "stepi" "" "set r9"
+set check_r9 [get_hexadecimal_valueof "\$r9" "default0"]
+
+# Ensure that our register values are as expected.
+# Specifically that the values loaded by the lnia instruction
+# reflect the value of the PC as if the instruction was
+# not displaced.
+if [expr $check_r3 + 4 != $check_r4] {
+ fail "unexpected value r3+4 != r4 , r3: $check_r3 r4: $check_r4 "
+}
+if [expr $check_r4 + 4 != $check_r5] {
+ fail "unexpected value r4+4 != r5 , r4: $check_r4 r5: $check_r5 "
+}
+if [expr $check_r5 + 4 != $check_r6] {
+ fail "unexpected value r5+4 != r6 , r5: $check_r5 r6: $check_r6 "
+}
+if [expr $check_r6 + 4 != $check_r7] {
+ fail "unexpected value r6+4 != r7 , r6: $check_r6 r7: $check_r7 "
+}
+if [expr $check_r7 + 4 != $check_r8] {
+ fail "unexpected value r7+4 != r8 , r7: $check_r7 r8: $check_r8 "
+}
+if [expr $check_r8 + 4 != $check_r9] {
+ fail "unexpected value r8+4 != r9 , r8: $check_r8 r9: $check_r9 "
+}
+
+gdb_test "info break"
+gdb_test "info register r3 r4 r5 r6 r7 r8 r9"
+gdb_test "disas main"
+
+# Let the inferior store all vector registers in a buffer, then dump
+# the buffer and check it.
diff --git a/gdb/testsuite/gdb.arch/powerpc-lnia.s b/gdb/testsuite/gdb.arch/powerpc-lnia.s
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/powerpc-lnia.s
@@ -0,0 +1,32 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2021 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Test to confirm that gdb properly handles lnia instructions
+ that load the current PC into a target register when executed
+ from a displaced location. */
+
+.global main
+.type main,function
+main:
+ lnia 3 # /* set r3 */
+ lnia 4 # /* set r4 */
+ lnia 5 # /* set r5 */
+ lnia 6 # /* set r6 */
+ lnia 7 # /* set r7 */
+ lnia 8 # /* set r8 */
+ lnia 9 # /* set r9 */
+ blr
diff --git a/gdb/testsuite/gdb.arch/powerpc-plxv-nonrel.exp b/gdb/testsuite/gdb.arch/powerpc-plxv-nonrel.exp
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/powerpc-plxv-nonrel.exp
@@ -0,0 +1,130 @@
+# Copyright 2021 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# Test to see if gdb is properly single stepping over the
+# displaced plxv instruction.
+
+if { ![istarget powerpc*-*] } {
+ verbose "Skipping powerpc plxv test."
+ return
+}
+
+set retval 0
+
+standard_testfile .s
+
+if { [prepare_for_testing "failed to prepare" $testfile "$srcfile" \
+ {debug quiet}] } {
+ return -1
+}
+
+gdb_test "set radix 0b10000"
+gdb_test "set debug displaced"
+
+if ![runto_main] then {
+ return
+}
+
+gdb_test "set debug displaced on"
+
+# Proc to extract the uint128 hex value from the output of
+# a print vector statement.
+proc get_vector_hexadecimal_valueof { exp default {test ""} } {
+ set val "0x0000"
+ global gdb_prompt
+ if {$test == ""} {
+ set test "get vector_hexadecimal valueof \"${exp}\""
+ }
+ gdb_test_multiple "print $${exp}.uint128" $test {
+ -re -wrap "\\$\[0-9\]* = (0x\[0-9a-zA-Z\]+).*" {
+ set val $expect_out(1,string)
+ pass "$test"
+ }
+ -re -wrap ".*Illegal instruction.* $" {
+ fail "Illegal instruction on print."
+ set val 0xffff
+ }
+ }
+ return ${val}
+}
+
+# Proc to do a single-step, and ensure we gently handle
+# an illegal instruction situation.
+proc stepi_over_instruction { xyz } {
+ global gdb_prompt
+ gdb_test_multiple "stepi" "${xyz} " {
+ -re -wrap ".*Illegal instruction.*" {
+ fail "Illegal instruction on single step."
+ return
+ }
+ -re -wrap ".*" {
+ pass "stepi ${xyz}"
+ }
+ }
+}
+
+set check_pc [get_hexadecimal_valueof "\$pc" "default0"]
+
+# set some breakpoints on the instructions below main().
+gdb_test "disas /r main"
+set bp1 *$check_pc+4
+set bp2 *$check_pc+0d12
+set bp3 *$check_pc+0d20
+set bp4 *$check_pc+0d28
+gdb_breakpoint $bp1
+gdb_breakpoint $bp2
+gdb_breakpoint $bp3
+gdb_breakpoint $bp4
+
+# single-step through the plxv instructions, and retrieve the
+# register values as we proceed.
+
+stepi_over_instruction "stepi over NOP"
+stepi_over_instruction "stepi over lnia"
+stepi_over_instruction "stepi over addi"
+
+stepi_over_instruction "stepi over vs4 assignment"
+set check_vs4 [get_vector_hexadecimal_valueof "vs4" "default0"]
+
+stepi_over_instruction "stepi over vs5 assignment"
+set check_vs5 [get_vector_hexadecimal_valueof "vs5" "default0"]
+
+stepi_over_instruction "stepi over vs6 assignment"
+set check_vs6 [get_vector_hexadecimal_valueof "vs6" "default0"]
+
+stepi_over_instruction "stepi over vs7 assignment"
+set check_vs7 [get_vector_hexadecimal_valueof "vs7" "default0"]
+
+set vs4_expected 0xa5b5c5d5a4b4c4d4a3b3c3d3a2b2c2d2
+set vs5_expected 0xa7b7c7d7a6b6c6d6a5b5c5d5a4b4c4d4
+set vs6_expected 0xa9b9c9d9a8b8c8d8a7b7c7d7a6b6c6d6
+set vs7_expected 0xabbbcbdbaabacadaa9b9c9d9a8b8c8d8
+
+if [expr $check_vs4 != $vs4_expected] {
+ fail "unexpected value vs4; actual:$check_vs4 expected:$vs4_expected"
+}
+if [expr $check_vs5 != $vs5_expected ] {
+ fail "unexpected value vs5; actual:$check_vs5 expected:$vs5_expected"
+}
+if [expr $check_vs6 != $vs6_expected ] {
+ fail "unexpected value vs6; actual:$check_vs6 expected:$vs6_expected"
+}
+if [expr $check_vs7 != $vs7_expected ] {
+ fail "unexpected value vs7; actual:$check_vs7 expected:$vs7_expected"
+}
+
+gdb_test "info break"
+gdb_test "info register vs4 vs5 vs6 vs7 "
+gdb_test "disas main #2"
diff --git a/gdb/testsuite/gdb.arch/powerpc-plxv-nonrel.s b/gdb/testsuite/gdb.arch/powerpc-plxv-nonrel.s
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/powerpc-plxv-nonrel.s
@@ -0,0 +1,44 @@
+# Copyright 2021 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+# test to verify that the prefixed instructions that
+# load/store non-relative values work OK.
+
+.global main
+.type main,function
+main:
+ nop
+ lnia 4
+ addi 4,4,40
+ plxv 4,4(4),0
+ plxv 5,12(4),0
+ plxv 6,20(4),0
+ plxv 7,28(4),0
+check_here:
+ blr
+mydata:
+ .long 0xa1b1c1d1 # <<-
+ .long 0xa2b2c2d2 # <<- loaded into vs4
+ .long 0xa3b3c3d3 # <<- loaded into vs4
+ .long 0xa4b4c4d4 # <<- loaded into vs4, vs5
+ .long 0xa5b5c5d5 # <<- loaded into vs4, vs5
+ .long 0xa6b6c6d6 # <<- loaded into vs5, vs6
+ .long 0xa7b7c7d7 # <<- loaded into vs5, vs6
+ .long 0xa8b8c8d8 # <<- loaded into vs6, vs7
+ .long 0xa9b9c9d9 # <<- loaded into vs6, vs7
+ .long 0xaabacada # <<- loaded into vs7
+ .long 0xabbbcbdb # <<- loaded into vs7
+ .long 0xacbcccdc # <<-