147 lines
4.8 KiB
Diff
147 lines
4.8 KiB
Diff
From b40f43e9fd3e523c0c4b50b0dcd8ca743cb6b9a7 Mon Sep 17 00:00:00 2001
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From: Tom de Vries <tdevries@suse.de>
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Date: Fri, 17 Feb 2023 15:33:18 +0100
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Subject: [PATCH] [gdb/testsuite] Simplify gdb.arch/amd64-disp-step-avx.exp
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On SLE-11, with glibc 2.11.3, I run into:
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...
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(gdb) PASS: gdb.arch/amd64-disp-step-avx.exp: vex3: \
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var128 has expected value after
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continue^M
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Continuing.^M
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^M
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Program received signal SIGSEGV, Segmentation fault.^M
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0x0000000000400283 in _exit (status=0) at \
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../sysdeps/unix/sysv/linux/_exit.c:33^M
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33 ../sysdeps/unix/sysv/linux/_exit.c: No such file or directory.^M
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(gdb) FAIL: gdb.arch/amd64-disp-step-avx.exp: \
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continue until exit at amd64-disp-step-avx
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...
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This is not related to gdb, we get the same result by just running the exec.
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The problem is that the test-case:
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- calls glibc's _exit, and
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- uses -nostartfiles -static, putting the burden for any necessary
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initialization for calling glibc's _exit on the test-case itself.
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So, when we get to the second insn in _exit:
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...
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000000000040acb0 <_exit>:
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40acb0: 48 63 d7 movslq %edi,%rdx
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40acb3: 64 4c 8b 14 25 00 00 mov %fs:0x0,%r10
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...
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no glibc-related initialization is done, and we run into the segfault.
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Adding this (borrowed from __libc_start_main) in _start in the .S file is
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sufficient to fix it:
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...
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.rept 200
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nop
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+ call __pthread_initialize_minimal
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.endr
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...
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But that already doesn't compile with say glibc 2.31, and regardless I think
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this sort of fix is too fragile.
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We could of course fix this by simply not running to exit. But ideally we'd
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have an exec that doesn't segfault when you just run it.
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Alternatively, we could hand-code an _exit syscall and bypass glibc
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all together. But I'd rather fix this in a way that simplifies the test-case.
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Taking a step back, the -nostartfiles -static was added to address that the
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xmm registers were not zero at main (which AFAICT is a valid thing to happen).
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[ The change itself silently broke the test-case, needing further fixing by
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commit 40310f30a51 ("gdb: make gdb.arch/amd64-disp-step-avx.exp actually test
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displaced stepping"). ]
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Instead, simplify things by reverting to the original situation:
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- no -nostartfiles -static compilation flags,
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- no _start in the .S file,
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- use exit instead of _exit in the .S file,
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and fix the original problem by setting the xmm registers to zero rather than
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checking that they're zero.
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Now that we're no longer forcing -static, add nopie to the flags to prevent
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compilation failure with target board unix/-fPIE/-pie.
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Tested on x86_64-linux.
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PR testsuite/30132
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Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30132
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---
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gdb/testsuite/gdb.arch/amd64-disp-step-avx.S | 12 ++----------
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gdb/testsuite/gdb.arch/amd64-disp-step-avx.exp | 14 ++++----------
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2 files changed, 6 insertions(+), 20 deletions(-)
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diff --git a/gdb/testsuite/gdb.arch/amd64-disp-step-avx.S b/gdb/testsuite/gdb.arch/amd64-disp-step-avx.S
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index 924deef224f..b39ee9f6567 100644
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--- a/gdb/testsuite/gdb.arch/amd64-disp-step-avx.S
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+++ b/gdb/testsuite/gdb.arch/amd64-disp-step-avx.S
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@@ -19,15 +19,7 @@
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instructions. */
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.text
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-
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- .global _start,main
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-_start:
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- # The area at _start is used as the displaced stepping buffer. Put
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- # more than enough nop instructions so that the instructions under test
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- # below don't conflict with it.
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- .rept 200
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- nop
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- .endr
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+ .global main
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main:
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nop
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@@ -66,7 +58,7 @@ ro_var:
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done:
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mov $0,%rdi
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- call _exit
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+ call exit
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hlt
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/* RIP-relative data for VEX3 test above. */
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diff --git a/gdb/testsuite/gdb.arch/amd64-disp-step-avx.exp b/gdb/testsuite/gdb.arch/amd64-disp-step-avx.exp
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index a64c85bc0e9..e6bdc3c242f 100644
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--- a/gdb/testsuite/gdb.arch/amd64-disp-step-avx.exp
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+++ b/gdb/testsuite/gdb.arch/amd64-disp-step-avx.exp
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@@ -30,9 +30,7 @@ if { ![have_avx] } {
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standard_testfile .S
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-set options [list debug \
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- additional_flags=-static \
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- additional_flags=-nostartfiles]
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+set options [list debug nopie]
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if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} $options] } {
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return -1
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}
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@@ -111,14 +109,10 @@ proc disp_step_func { func } {
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# Test a VEX2-encoded RIP-relative instruction.
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with_test_prefix "vex2" {
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- # This test writes to the 'xmm0' register. As the test is
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- # statically linked, we know that the XMM registers should all
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- # have the default value of 0 at this point in time. We're about
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- # to run an AVX instruction that will modify $xmm0, but lets first
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- # confirm that all XMM registers are 0.
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+ # Initialize all XMM registers to 0.
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for {set i 0 } { $i < 16 } { incr i } {
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- gdb_test "p /x \$xmm${i}.uint128" " = 0x0" \
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- "xmm${i} has expected value before"
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+ gdb_test_no_output "set \$xmm${i}.uint128 = 0" \
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+ "xmm${i} set to zero"
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}
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disp_step_func "test_rip_vex2"
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base-commit: 8f25c476588b41f18ef7b026c81a6b415a809930
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--
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2.35.3
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