From: "H.J. Lu" <hjl.tools@gmail.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: libc-alpha@sourceware.org, Szabolcs Nagy <szabolcs.nagy@arm.com>,
Arjun Shankar <arjun@redhat.com>
Subject: Re: [PATCH v2 2/3] arm: Update _dl_tlsdesc_dynamic to preserve caller-saved registers (BZ 31372)
Date: Tue, 12 Mar 2024 09:35:41 -0700 [thread overview]
Message-ID: <CAMe9rOr+BGiNZjUNquDSubEOuUSg71S0iPcG9n8C9v4uV=ffCA@mail.gmail.com> (raw)
In-Reply-To: <20240312162120.1360522-3-adhemerval.zanella@linaro.org>
On Tue, Mar 12, 2024 at 9:21 AM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
> ARM _dl_tlsdesc_dynamic slow path has two issues:
>
> * The ip/r12 is defined by AAPCS as a scratch register, and gcc is
> used to save the stack pointer before on some function calls. So it
> should also be saved/restored as well. It fixes the tst-gnu2-tls2.
>
> * None of the possible VFP registers are saved/restored. ARM has the
> additional complexity to have different VFP bank sizes (depending of
> VFP support by the chip).
>
> The tst-gnu2-tls2 test is extended to check for VFP registers, although
> only for hardfp builds. Different than setcontext, _dl_tlsdesc_dynamic
> does not have HWCAP_ARM_IWMMXT (I don't have a way to properly test
> it and it is almost a decade since newer hardware was released).
>
> With this patch there is no need to mark tst-gnu2-tls2 as XFAIL.
>
> Checked on arm-linux-gnueabihf.
> ---
> config.h.in | 3 +
> elf/Makefile | 4 --
> elf/tst-gnu2-tls2.h | 4 ++
> elf/tst-gnu2-tls2mod0.c | 3 +-
> elf/tst-gnu2-tls2mod1.c | 3 +-
> elf/tst-gnu2-tls2mod2.c | 3 +-
> sysdeps/arm/configure | 32 +++++++++
> sysdeps/arm/configure.ac | 15 +++++
> sysdeps/arm/dl-tlsdesc.S | 70 +++++++++++++++++---
> sysdeps/arm/tst-gnu2-tls2.h | 128 ++++++++++++++++++++++++++++++++++++
> 10 files changed, 250 insertions(+), 15 deletions(-)
> create mode 100644 sysdeps/arm/tst-gnu2-tls2.h
>
> diff --git a/config.h.in b/config.h.in
> index 2f0669e19b..cf4212f5eb 100644
> --- a/config.h.in
> +++ b/config.h.in
> @@ -141,6 +141,9 @@
> /* LOONGARCH floating-point ABI for ld.so. */
> #undef LOONGARCH_ABI_FRLEN
>
> +/* Define whether ARM used hard-float and support VFPvX-D32. */
> +#undef HAVE_ARM_PCS_VFP_D32
> +
> /* Linux specific: minimum supported kernel version. */
> #undef __LINUX_KERNEL_VERSION
>
> diff --git a/elf/Makefile b/elf/Makefile
> index 520a270f0f..393a27ef2a 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -3059,10 +3059,6 @@ $(objpfx)tst-gnu2-tls2.out: \
> $(objpfx)tst-gnu2-tls2mod2.so
>
> ifeq (yes,$(have-mtls-dialect-gnu2))
> -# This test fails if dl_tlsdesc_dynamic doesn't preserve all caller-saved
> -# registers. See https://sourceware.org/bugzilla/show_bug.cgi?id=31372
> -test-xfail-tst-gnu2-tls2 = yes
> -
> CFLAGS-tst-tlsgap-mod0.c += -mtls-dialect=gnu2
> CFLAGS-tst-tlsgap-mod1.c += -mtls-dialect=gnu2
> CFLAGS-tst-tlsgap-mod2.c += -mtls-dialect=gnu2
> diff --git a/elf/tst-gnu2-tls2.h b/elf/tst-gnu2-tls2.h
> index 77964a57a3..1ade8151e2 100644
> --- a/elf/tst-gnu2-tls2.h
> +++ b/elf/tst-gnu2-tls2.h
> @@ -27,6 +27,10 @@ extern struct tls *apply_tls (struct tls *);
>
> /* An architecture can define them to verify that clobber caller-saved
> registers aren't changed by the implicit TLSDESC call. */
> +#ifndef INIT_TLSDESC_CALL
> +# define INIT_TLSDESC_CALL()
> +#endif
> +
> #ifndef BEFORE_TLSDESC_CALL
> # define BEFORE_TLSDESC_CALL()
> #endif
> diff --git a/elf/tst-gnu2-tls2mod0.c b/elf/tst-gnu2-tls2mod0.c
> index 45556a0e17..3fe3c14277 100644
> --- a/elf/tst-gnu2-tls2mod0.c
> +++ b/elf/tst-gnu2-tls2mod0.c
> @@ -16,13 +16,14 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> -#include "tst-gnu2-tls2.h"
> +#include <tst-gnu2-tls2.h>
>
> __thread struct tls tls_var0 __attribute__ ((visibility ("hidden")));
>
> struct tls *
> apply_tls (struct tls *p)
> {
> + INIT_TLSDESC_CALL ();
> BEFORE_TLSDESC_CALL ();
> tls_var0 = *p;
> struct tls *ret = &tls_var0;
> diff --git a/elf/tst-gnu2-tls2mod1.c b/elf/tst-gnu2-tls2mod1.c
> index e10b9dbc0a..e210538468 100644
> --- a/elf/tst-gnu2-tls2mod1.c
> +++ b/elf/tst-gnu2-tls2mod1.c
> @@ -16,13 +16,14 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> -#include "tst-gnu2-tls2.h"
> +#include <tst-gnu2-tls2.h>
>
> __thread struct tls tls_var1[100] __attribute__ ((visibility ("hidden")));
>
> struct tls *
> apply_tls (struct tls *p)
> {
> + INIT_TLSDESC_CALL ();
> BEFORE_TLSDESC_CALL ();
> tls_var1[1] = *p;
> struct tls *ret = &tls_var1[1];
> diff --git a/elf/tst-gnu2-tls2mod2.c b/elf/tst-gnu2-tls2mod2.c
> index 141af51e55..6d3031dc5f 100644
> --- a/elf/tst-gnu2-tls2mod2.c
> +++ b/elf/tst-gnu2-tls2mod2.c
> @@ -16,13 +16,14 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> -#include "tst-gnu2-tls2.h"
> +#include <tst-gnu2-tls2.h>
>
> __thread struct tls tls_var2 __attribute__ ((visibility ("hidden")));
>
> struct tls *
> apply_tls (struct tls *p)
> {
> + INIT_TLSDESC_CALL ();
> BEFORE_TLSDESC_CALL ();
> tls_var2 = *p;
> struct tls *ret = &tls_var2;
> diff --git a/sysdeps/arm/configure b/sysdeps/arm/configure
> index 35e2918922..4ef4d46cbd 100644
> --- a/sysdeps/arm/configure
> +++ b/sysdeps/arm/configure
> @@ -187,6 +187,38 @@ else
> default-abi = soft"
> fi
>
> +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether VFP supports 32 registers" >&5
> +printf %s "checking whether VFP supports 32 registers... " >&6; }
> +if test ${libc_cv_arm_pcs_vfp_d32+y}
> +then :
> + printf %s "(cached) " >&6
> +else $as_nop
> +
> +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> +/* end confdefs.h. */
> +
> +void foo (void)
> +{
> + asm volatile ("vldr d16,=17" : : : "d16");
> +}
> +
> +_ACEOF
> +if ac_fn_c_try_compile "$LINENO"
> +then :
> + libc_cv_arm_pcs_vfp_d32=yes
> +else $as_nop
> + libc_cv_arm_pcs_vfp_d32=no
> +fi
> +rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
> +fi
> +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_arm_pcs_vfp_d32" >&5
> +printf "%s\n" "$libc_cv_arm_pcs_vfp_d32" >&6; }
> +if test "$libc_cv_arm_pcs_vfp_d32" = yes ;
> +then
> + printf "%s\n" "#define HAVE_ARM_PCS_VFP_D32 1" >>confdefs.h
> +
> +fi
> +
> { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether PC-relative relocs in movw/movt work properly" >&5
> printf %s "checking whether PC-relative relocs in movw/movt work properly... " >&6; }
> if test ${libc_cv_arm_pcrel_movw+y}
> diff --git a/sysdeps/arm/configure.ac b/sysdeps/arm/configure.ac
> index 5172e30bbe..cd00ddc9d9 100644
> --- a/sysdeps/arm/configure.ac
> +++ b/sysdeps/arm/configure.ac
> @@ -21,6 +21,21 @@ else
> LIBC_CONFIG_VAR([default-abi], [soft])
> fi
>
> +AC_CACHE_CHECK([whether VFP supports 32 registers],
> + libc_cv_arm_pcs_vfp_d32, [
> +AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
> +void foo (void)
> +{
> + asm volatile ("vldr d16,=17" : : : "d16");
> +}
> +]])],
> + [libc_cv_arm_pcs_vfp_d32=yes],
> + [libc_cv_arm_pcs_vfp_d32=no])])
> +if test "$libc_cv_arm_pcs_vfp_d32" = yes ;
> +then
> + AC_DEFINE(HAVE_ARM_PCS_VFP_D32)
> +fi
> +
> AC_CACHE_CHECK([whether PC-relative relocs in movw/movt work properly],
> libc_cv_arm_pcrel_movw, [
> cat > conftest.s <<\EOF
> diff --git a/sysdeps/arm/dl-tlsdesc.S b/sysdeps/arm/dl-tlsdesc.S
> index 764c56e70f..ada106521d 100644
> --- a/sysdeps/arm/dl-tlsdesc.S
> +++ b/sysdeps/arm/dl-tlsdesc.S
> @@ -19,6 +19,7 @@
> #include <sysdep.h>
> #include <arm-features.h>
> #include <tls.h>
> +#include <rtld-global-offsets.h>
> #include "tlsdesc.h"
>
> .text
> @@ -83,14 +84,20 @@ _dl_tlsdesc_dynamic(struct tlsdesc *tdp)
> .align 2
> _dl_tlsdesc_dynamic:
> /* Our calling convention is to clobber r0, r1 and the processor
> - flags. All others that are modified must be saved */
> - eabi_save ({r2,r3,r4,lr})
> - push {r2,r3,r4,lr}
> - cfi_adjust_cfa_offset (16)
> + flags. All others that are modified must be saved. r5 is
> + used as the hwcap value to avoid reload after __tls_get_addr
> + call. If required we will save the vector register on the slow
> + path. */
> + eabi_save ({r2,r3,r4,r5,ip,lr})
> + push {r2,r3,r4,r5,ip,lr}
> + cfi_adjust_cfa_offset (24)
> cfi_rel_offset (r2,0)
> cfi_rel_offset (r3,4)
> cfi_rel_offset (r4,8)
> - cfi_rel_offset (lr,12)
> + cfi_rel_offset (r5,12)
> + cfi_rel_offset (ip,16)
> + cfi_rel_offset (lr,20)
> +
> ldr r1, [r0] /* td */
> GET_TLS (lr)
> mov r4, r0 /* r4 = tp */
> @@ -113,22 +120,69 @@ _dl_tlsdesc_dynamic:
> rsbne r0, r4, r3
> bne 2f
> 1: mov r0, r1
> +
> + /* Load the hwcap to check for vector support. */
> + ldr r2, 3f
> + ldr r1, .Lrtld_global_ro
> +0: add r2, pc, r2
> + ldr r2, [r2, r1]
> + ldr r5, [r2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
> +
> +#ifdef __SOFTFP__
> + tst r5, #HWCAP_ARM_VFP
> + beq .Lno_vfp
> +#endif
> +
> + /* Store the VFP registers. Don't use VFP instructions directly
> + because this code is used in non-VFP multilibs. */
> +#define VFP_STACK_REQ (32*8 + 8)
> + sub sp, sp, VFP_STACK_REQ
> + cfi_adjust_cfa_offset (VFP_STACK_REQ)
> + mov r3, sp
> + .inst 0xeca30b20 /* vstmia r3!, {d0-d15} */
> + tst r5, #HWCAP_ARM_VFPD32
> + beq 4f
> + .inst 0xece30b20 /* vstmia r3!, {d16-d31} */
> + /* Store the floating-point status register. */
> +4: .inst 0xeef12a10 /* vmrs r2, fpscr */
> + str r2, [r3]
> +.Lno_vfp:
> bl __tls_get_addr
> rsb r0, r4, r0
> +#ifdef __SOFTFP__
> + tst r5, #HWCAP_ARM_VFP
> + beq 2f
> +#endif
> + mov r3, sp
> + .inst 0xecb30b20 /* vldmia r3!, {d0-d15} */
> + tst r5, #HWCAP_ARM_VFPD32
> + beq 5f
> + .inst 0xecf30b20 /* vldmia r3!, {d16-d31} */
> + ldr r4, [r3]
> +5: .inst 0xeee14a10 /* vmsr fpscr, r4 */
> + add sp, sp, VFP_STACK_REQ
> + cfi_adjust_cfa_offset (-VFP_STACK_REQ)
> +
> 2:
> #if ((defined (__ARM_ARCH_4T__) && defined (__THUMB_INTERWORK__)) \
> || defined (ARM_ALWAYS_BX))
> - pop {r2,r3,r4, lr}
> - cfi_adjust_cfa_offset (-16)
> + pop {r2,r3,r4,r5,ip, lr}
> + cfi_adjust_cfa_offset (-20)
> cfi_restore (lr)
> + cfi_restore (ip)
> + cfi_restore (r5)
> cfi_restore (r4)
> cfi_restore (r3)
> cfi_restore (r2)
> bx lr
> #else
> - pop {r2,r3,r4, pc}
> + pop {r2,r3,r4,r5,ip, pc}
> #endif
> eabi_fnend
> cfi_endproc
> .size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
> +
> +3: .long _GLOBAL_OFFSET_TABLE_ - 0b - PC_OFS
> +.Lrtld_global_ro:
> + .long C_SYMBOL_NAME(_rtld_global_ro)(GOT)
> #endif /* SHARED */
> diff --git a/sysdeps/arm/tst-gnu2-tls2.h b/sysdeps/arm/tst-gnu2-tls2.h
> new file mode 100644
> index 0000000000..e413ac21fb
> --- /dev/null
> +++ b/sysdeps/arm/tst-gnu2-tls2.h
> @@ -0,0 +1,128 @@
> +/* Test TLSDESC relocation. ARM version.
> + Copyright (C) 2024 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library 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
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <config.h>
> +#include <sys/auxv.h>
> +#include <string.h>
> +#include <stdlib.h>
> +#include <endian.h>
> +
> +#ifndef __SOFTFP__
> +
> +# ifdef HAVE_ARM_PCS_VFP_D32
> +# define SAVE_VFP_D32 \
> + asm volatile ("vldr d16,=17" : : : "d16"); \
> + asm volatile ("vldr d17,=18" : : : "d17"); \
> + asm volatile ("vldr d18,=19" : : : "d18"); \
> + asm volatile ("vldr d19,=20" : : : "d19"); \
> + asm volatile ("vldr d20,=21" : : : "d20"); \
> + asm volatile ("vldr d21,=22" : : : "d21"); \
> + asm volatile ("vldr d22,=23" : : : "d22"); \
> + asm volatile ("vldr d23,=24" : : : "d23"); \
> + asm volatile ("vldr d24,=25" : : : "d24"); \
> + asm volatile ("vldr d25,=26" : : : "d25"); \
> + asm volatile ("vldr d26,=27" : : : "d26"); \
> + asm volatile ("vldr d27,=28" : : : "d27"); \
> + asm volatile ("vldr d28,=29" : : : "d28"); \
> + asm volatile ("vldr d29,=30" : : : "d29"); \
> + asm volatile ("vldr d30,=31" : : : "d30"); \
> + asm volatile ("vldr d31,=32" : : : "d31");
> +# else
> +# define SAVE_VFP_D32
> +# endif
> +
> +# define INIT_TLSDESC_CALL() \
> + unsigned long hwcap = getauxval (AT_HWCAP)
> +
> +/* Set each vector register to a value from 1 to 32 before the TLS access,
> + dump to memory after TLS access, and compare with the expected values. */
> +
> +# define BEFORE_TLSDESC_CALL() \
> + if (hwcap & HWCAP_ARM_VFP) \
> + { \
> + asm volatile ("vldr d0,=1" : : : "d0"); \
> + asm volatile ("vldr d1,=2" : : : "d1"); \
> + asm volatile ("vldr d2,=3" : : : "d1"); \
> + asm volatile ("vldr d3,=4" : : : "d3"); \
> + asm volatile ("vldr d4,=5" : : : "d4"); \
> + asm volatile ("vldr d5,=6" : : : "d5"); \
> + asm volatile ("vldr d6,=7" : : : "d6"); \
> + asm volatile ("vldr d7,=8" : : : "d7"); \
> + asm volatile ("vldr d8,=9" : : : "d8"); \
> + asm volatile ("vldr d9,=10" : : : "d9"); \
> + asm volatile ("vldr d10,=11" : : : "d10"); \
> + asm volatile ("vldr d11,=12" : : : "d11"); \
> + asm volatile ("vldr d12,=13" : : : "d12"); \
> + asm volatile ("vldr d13,=14" : : : "d13"); \
> + asm volatile ("vldr d14,=15" : : : "d14"); \
> + asm volatile ("vldr d15,=16" : : : "d15"); \
> + } \
> + if (hwcap & HWCAP_ARM_VFPD32) \
> + { \
> + SAVE_VFP_D32 \
> + }
> +
> +# define VFP_STACK_REQ (16*8)
> +# if __BYTE_ORDER == __BIG_ENDIAN
> +# define DISP 7
> +# else
> +# define DISP 0
> +# endif
> +
> +# ifdef HAVE_ARM_PCS_VFP_D32
> +# define CHECK_VFP_D32 \
> + char vfp[VFP_STACK_REQ]; \
> + asm volatile ("vstmia %0, {d16-d31}\n" \
> + : \
> + : "r" (vfp) \
> + : "memory"); \
> + \
> + char expected[VFP_STACK_REQ] = { 0 }; \
> + for (int i = 0; i < 16; ++i) \
> + expected[i * 8 + DISP] = i + 17; \
> + \
> + if (memcmp (vfp, expected, VFP_STACK_REQ) != 0) \
> + abort ();
> +# else
> +# define CHECK_VFP_D32
> +# endif
> +
> +# define AFTER_TLSDESC_CALL() \
> + if (hwcap & HWCAP_ARM_VFP) \
> + { \
> + char vfp[VFP_STACK_REQ]; \
> + asm volatile ("vstmia %0, {d0-d15}\n" \
> + : \
> + : "r" (vfp) \
> + : "memory"); \
> + \
> + char expected[VFP_STACK_REQ] = { 0 }; \
> + for (int i = 0; i < 16; ++i) \
> + expected[i * 8 + DISP] = i + 1; \
> + \
> + if (memcmp (vfp, expected, VFP_STACK_REQ) != 0) \
> + abort (); \
> + } \
> + if (hwcap & HWCAP_ARM_VFPD32) \
> + { \
> + CHECK_VFP_D32 \
> + }
> +
> +#endif /* __SOFTFP__ */
> +
> +#include_next <tst-gnu2-tls2.h>
> --
> 2.34.1
>
LGTM.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Thanks.
--
H.J.
next prev parent reply other threads:[~2024-03-12 16:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-12 16:21 [PATCH v2 0/3] Extending TLS testing and fixing TLS gnu2 for ARM Adhemerval Zanella
2024-03-12 16:21 ` [PATCH v2 1/3] Ignore undefined symbols for -mtls-dialect=gnu2 Adhemerval Zanella
2024-03-12 16:34 ` H.J. Lu
2024-03-12 16:21 ` [PATCH v2 2/3] arm: Update _dl_tlsdesc_dynamic to preserve caller-saved registers (BZ 31372) Adhemerval Zanella
2024-03-12 16:35 ` H.J. Lu [this message]
2024-03-12 16:21 ` [PATCH v2 3/3] elf: Enable TLS descriptor tests on aarch64 Adhemerval Zanella
2024-03-12 16:38 ` H.J. Lu
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