From: Xi Ruoyao <xry111@xry111.site>
To: mengqinggang <mengqinggang@loongson.cn>, libc-alpha@sourceware.org
Cc: adhemerval.zanella@linaro.org, xuchenghua@loongson.cn,
caiyinyu@loongson.cn, chenglulu@loongson.cn,
cailulu@loongson.cn, i.swmail@xen0n.name, maskray@google.com,
luweining@loongson.cn, wanglei@loongson.cn,
hejinyang@loongson.cn
Subject: Re: [PATCH v6] LoongArch: Add support for TLS Descriptors
Date: Tue, 07 May 2024 17:58:43 +0800 [thread overview]
Message-ID: <7ce5fe6ee84503a167a35ef41018e2c030581367.camel@xry111.site> (raw)
In-Reply-To: <4b187c66e201bd8e7217bf1094dadfe7a901d600.camel@xry111.site>
On Tue, 2024-05-07 at 17:21 +0800, Xi Ruoyao wrote:
> Unfortunately I'm getting a test failure:
>
> FAIL: elf/tst-gnu2-tls2
> original exit status 1
> open tst-gnu2-tls2mod0.so
> open tst-gnu2-tls2mod1.so
> open tst-gnu2-tls2mod2.so
> close tst-gnu2-tls2mod0.so
> close tst-gnu2-tls2mod1.so
> open tst-gnu2-tls2mod0.so
> open tst-gnu2-tls2mod1.so
> Didn't expect signal from child: got `Aborted'
>
> The problem is GCC 14.1 has LSX enabled by default (!) and for
> "tls_var1[1] = *p;" we get something like:
>
> 17c: 1a000004 pcalau12i $a0, 0
> 17c: R_LARCH_TLS_DESC_PC_HI20 .LANCHOR0
> 17c: R_LARCH_RELAX *ABS*
> 180: 02c00084 addi.d $a0, $a0, 0
> 180: R_LARCH_TLS_DESC_PC_LO12 .LANCHOR0
> 180: R_LARCH_RELAX *ABS*
> 184: 28c00081 ld.d $ra, $a0, 0
> 184: R_LARCH_TLS_DESC_LD .LANCHOR0
> 184: R_LARCH_RELAX *ABS*
> 188: 4c000021 jirl $ra, $ra, 0
> 188: R_LARCH_TLS_DESC_CALL .LANCHOR0
> 188: R_LARCH_RELAX *ABS*
>
> 000000000000018c <L0^A>:
> 18c: 2c004300 vld $vr0, $s1, 16
> 190: 2c000301 vld $vr1, $s1, 0
> 194: 0010888c add.d $t0, $a0, $tp
> 198: 38440881 vstx $vr1, $a0, $tp
> 19c: 2c404180 vst $vr0, $t0, 16
>
> Thus the tlsdesc call does not clobber vr0 and vr1, but storing into
> tls_var1[1] clobbers them.
>
> While I don't think GCC should enable LSX by default (I've complained at
> https://gcc.gnu.org/pipermail/gcc-patches/2024-May/650909.html),
> downstream may still build Glibc with LSX enabled (AFAIK AOSC
> deliberately enables LSX building packages for LoongArch). Maybe
> disable LSX for tst-gnu2-tls2mod{0,1,2}.c ?
This fixes the issue for me:
diff --git a/sysdeps/loongarch/Makefile b/sysdeps/loongarch/Makefile
index 86ede3534b..a4ee915eff 100644
--- a/sysdeps/loongarch/Makefile
+++ b/sysdeps/loongarch/Makefile
@@ -31,6 +31,13 @@ ifeq ($(subdir),elf)
sysdep-dl-routines += \
dl-get-cpu-features \
# sysdep-dl-routines
+
+# Disable the compiler from using LSX for TLS descriptor tests, or storing into
+# 16B TLS variable may clobber FP/vector registers and prevent us from checking
+# their contents.
+CFLAGS-tst-gnu2-tls2mod0.c += -mno-lsx
+CFLAGS-tst-gnu2-tls2mod1.c += -mno-lsx
+CFLAGS-tst-gnu2-tls2mod2.c += -mno-lsx
endif
# LoongArch's assembler also needs to know about PIC as it changes the
But I'm not sure if this is the best way.
--
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University
next prev parent reply other threads:[~2024-05-07 9:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 2:02 mengqinggang
2024-05-07 9:21 ` Xi Ruoyao
2024-05-07 9:58 ` Xi Ruoyao [this message]
2024-05-07 11:41 ` Xi Ruoyao
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