[v3,4/4] i386: Remove CET support bits

  1. Remove _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk.
2. Move CET offsets from x86 cpu-features-offsets.sym to x86-64
features-offsets.sym.
3. Rename x86 cet-control.h to x86-64 feature-control.h since it is only
for x86-64 and also used for PLT rewrite.
4. Add x86-64 ldsodefs.h to include feature-control.h.
5. Change TUNABLE_CALLBACK (set_plt_rewrite) to x86-64 only.
6. Move x86 dl-procruntime.c to x86-64.
---
 sysdeps/i386/dl-machine.h                     | 11 +--
 sysdeps/i386/dl-trampoline.S                  | 69 -------------------
 sysdeps/unix/sysv/linux/x86_64/dl-cet.h       |  2 +-
 sysdeps/x86/cpu-features-offsets.sym          |  2 -
 sysdeps/x86/cpu-features.c                    |  4 +-
 sysdeps/x86/ldsodefs.h                        |  1 -
 sysdeps/x86_64/Makefile                       |  2 +-
 sysdeps/{x86 => x86_64}/dl-procruntime.c      |  2 +-
 sysdeps/x86_64/dl-trampoline.S                |  1 +
 .../feature-control.h}                        |  8 +--
 sysdeps/x86_64/features-offsets.sym           |  6 ++
 sysdeps/x86_64/ldsodefs.h                     | 26 +++++++
 12 files changed, 45 insertions(+), 89 deletions(-)
 rename sysdeps/{x86 => x86_64}/dl-procruntime.c (97%)
 rename sysdeps/{x86/cet-control.h => x86_64/feature-control.h} (92%)
 create mode 100644 sysdeps/x86_64/features-offsets.sym
 create mode 100644 sysdeps/x86_64/ldsodefs.h
  

On 09/01/24 17:23, H.J. Lu wrote:
> 1. Remove _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk.
> 2. Move CET offsets from x86 cpu-features-offsets.sym to x86-64
> features-offsets.sym.
> 3. Rename x86 cet-control.h to x86-64 feature-control.h since it is only
> for x86-64 and also used for PLT rewrite.
> 4. Add x86-64 ldsodefs.h to include feature-control.h.
> 5. Change TUNABLE_CALLBACK (set_plt_rewrite) to x86-64 only.
> 6. Move x86 dl-procruntime.c to x86-64.

LGTM, thanks.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> ---
>  sysdeps/i386/dl-machine.h                     | 11 +--
>  sysdeps/i386/dl-trampoline.S                  | 69 -------------------
>  sysdeps/unix/sysv/linux/x86_64/dl-cet.h       |  2 +-
>  sysdeps/x86/cpu-features-offsets.sym          |  2 -
>  sysdeps/x86/cpu-features.c                    |  4 +-
>  sysdeps/x86/ldsodefs.h                        |  1 -
>  sysdeps/x86_64/Makefile                       |  2 +-
>  sysdeps/{x86 => x86_64}/dl-procruntime.c      |  2 +-
>  sysdeps/x86_64/dl-trampoline.S                |  1 +
>  .../feature-control.h}                        |  8 +--
>  sysdeps/x86_64/features-offsets.sym           |  6 ++
>  sysdeps/x86_64/ldsodefs.h                     | 26 +++++++
>  12 files changed, 45 insertions(+), 89 deletions(-)
>  rename sysdeps/{x86 => x86_64}/dl-procruntime.c (97%)
>  rename sysdeps/{x86/cet-control.h => x86_64/feature-control.h} (92%)
>  create mode 100644 sysdeps/x86_64/features-offsets.sym
>  create mode 100644 sysdeps/x86_64/ldsodefs.h
> 
> diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h
> index c69ae165ac..fc1ef96587 100644
> --- a/sysdeps/i386/dl-machine.h
> +++ b/sysdeps/i386/dl-machine.h
> @@ -65,9 +65,6 @@ elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
>    extern void _dl_runtime_profile (Elf32_Word) attribute_hidden;
>    extern void _dl_runtime_resolve_shstk (Elf32_Word) attribute_hidden;
>    extern void _dl_runtime_profile_shstk (Elf32_Word) attribute_hidden;
> -  /* Check if SHSTK is enabled by kernel.  */
> -  bool shstk_enabled
> -    = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
>  
>    if (l->l_info[DT_JMPREL] && lazy)
>      {
> @@ -95,9 +92,7 @@ elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
>  #ifdef SHARED
>        if (__glibc_unlikely (profile))
>  	{
> -	  got[2] = (shstk_enabled
> -		    ? (Elf32_Addr) &_dl_runtime_profile_shstk
> -		    : (Elf32_Addr) &_dl_runtime_profile);
> +	  got[2] = (Elf32_Addr) &_dl_runtime_profile;
>  
>  	  if (GLRO(dl_profile) != NULL
>  	      && _dl_name_match_p (GLRO(dl_profile), l))
> @@ -109,9 +104,7 @@ elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
>  #endif
>  	/* This function will get called to fix up the GOT entry indicated by
>  	   the offset on the stack, and then jump to the resolved address.  */
> -	got[2] = (shstk_enabled
> -		  ? (Elf32_Addr) &_dl_runtime_resolve_shstk
> -		  : (Elf32_Addr) &_dl_runtime_resolve);
> +	got[2] = (Elf32_Addr) &_dl_runtime_resolve;
>      }
>  
>    return lazy;
> diff --git a/sysdeps/i386/dl-trampoline.S b/sysdeps/i386/dl-trampoline.S
> index 2632020145..6c14d463b6 100644
> --- a/sysdeps/i386/dl-trampoline.S
> +++ b/sysdeps/i386/dl-trampoline.S
> @@ -44,76 +44,7 @@ _dl_runtime_resolve:
>  	cfi_endproc
>  	.size _dl_runtime_resolve, .-_dl_runtime_resolve
>  
> -# The SHSTK compatible version.
> -	.text
> -	.globl _dl_runtime_resolve_shstk
> -	.type _dl_runtime_resolve_shstk, @function
> -	cfi_startproc
> -	.align 16
> -_dl_runtime_resolve_shstk:
> -	cfi_adjust_cfa_offset (8)
> -	pushl %eax		# Preserve registers otherwise clobbered.
> -	cfi_adjust_cfa_offset (4)
> -	pushl %edx
> -	cfi_adjust_cfa_offset (4)
> -	movl 12(%esp), %edx	# Copy args pushed by PLT in register.  Note
> -	movl 8(%esp), %eax	# that `fixup' takes its parameters in regs.
> -	call _dl_fixup		# Call resolver.
> -	movl (%esp), %edx	# Get register content back.
> -	movl %eax, %ecx		# Store the function address.
> -	movl 4(%esp), %eax	# Get register content back.
> -	addl $16, %esp		# Adjust stack: PLT1 + PLT2 + %eax + %edx
> -	cfi_adjust_cfa_offset (-16)
> -	jmp *%ecx		# Jump to function address.
> -	cfi_endproc
> -	.size _dl_runtime_resolve_shstk, .-_dl_runtime_resolve_shstk
> -
>  #if !defined PROF && defined SHARED
> -# The SHSTK compatible version.
> -	.globl _dl_runtime_profile_shstk
> -	.type _dl_runtime_profile_shstk, @function
> -	cfi_startproc
> -	.align 16
> -_dl_runtime_profile_shstk:
> -	cfi_adjust_cfa_offset (8)
> -	pushl %esp
> -	cfi_adjust_cfa_offset (4)
> -	addl $8, (%esp)		# Account for the pushed PLT data
> -	pushl %ebp
> -	cfi_adjust_cfa_offset (4)
> -	pushl %eax		# Preserve registers otherwise clobbered.
> -	cfi_adjust_cfa_offset (4)
> -	pushl %ecx
> -	cfi_adjust_cfa_offset (4)
> -	pushl %edx
> -	cfi_adjust_cfa_offset (4)
> -	movl %esp, %ecx
> -	subl $8, %esp
> -	cfi_adjust_cfa_offset (8)
> -	movl $-1, 4(%esp)
> -	leal 4(%esp), %edx
> -	movl %edx, (%esp)
> -	pushl %ecx		# Address of the register structure
> -	cfi_adjust_cfa_offset (4)
> -	movl 40(%esp), %ecx	# Load return address
> -	movl 36(%esp), %edx	# Copy args pushed by PLT in register.  Note
> -	movl 32(%esp), %eax	# that `fixup' takes its parameters in regs.
> -	call _dl_profile_fixup	# Call resolver.
> -	cfi_adjust_cfa_offset (-8)
> -	movl (%esp), %edx
> -	testl %edx, %edx
> -	jns 1f
> -	movl 4(%esp), %edx	# Get register content back.
> -	movl %eax, %ecx		# Store the function address.
> -	movl 12(%esp), %eax	# Get register content back.
> -	# Adjust stack: PLT1 + PLT2 + %esp + %ebp + %eax + %ecx + %edx
> -	# + free.
> -	addl $32, %esp
> -	cfi_adjust_cfa_offset (-32)
> -	jmp *%ecx		# Jump to function address.
> -	cfi_endproc
> -	.size _dl_runtime_profile_shstk, .-_dl_runtime_profile_shstk
> -
>  	.globl _dl_runtime_profile
>  	.type _dl_runtime_profile, @function
>  	cfi_startproc
> diff --git a/sysdeps/unix/sysv/linux/x86_64/dl-cet.h b/sysdeps/unix/sysv/linux/x86_64/dl-cet.h
> index 94e9b9aa86..a00c7ee662 100644
> --- a/sysdeps/unix/sysv/linux/x86_64/dl-cet.h
> +++ b/sysdeps/unix/sysv/linux/x86_64/dl-cet.h
> @@ -17,7 +17,7 @@
>  
>  #include <sys/prctl.h>
>  #include <asm/prctl.h>
> -#include <cpu-features-offsets.h>
> +#include <features-offsets.h>
>  
>  static __always_inline int
>  dl_cet_disable_cet (unsigned int cet_feature)
> diff --git a/sysdeps/x86/cpu-features-offsets.sym b/sysdeps/x86/cpu-features-offsets.sym
> index 5429f60632..6a8fd29813 100644
> --- a/sysdeps/x86/cpu-features-offsets.sym
> +++ b/sysdeps/x86/cpu-features-offsets.sym
> @@ -2,6 +2,4 @@
>  
>  #include <ldsodefs.h>
>  
> -RTLD_GLOBAL_RO_DL_X86_CPU_FEATURES_OFFSET offsetof (struct rtld_global_ro, _dl_x86_cpu_features)
>  XSAVE_STATE_SIZE_OFFSET	offsetof (struct cpu_features, xsave_state_size)
> -RTLD_GLOBAL_DL_X86_FEATURE_1_OFFSET offsetof (struct rtld_global, _dl_x86_feature_1)
> diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
> index 9ca307f521..46bdaffbc2 100644
> --- a/sysdeps/x86/cpu-features.c
> +++ b/sysdeps/x86/cpu-features.c
> @@ -27,7 +27,7 @@
>  extern void TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *)
>    attribute_hidden;
>  
> -#ifdef SHARED
> +#if defined SHARED && defined __x86_64__
>  static void
>  TUNABLE_CALLBACK (set_plt_rewrite) (tunable_val_t *valp)
>  {
> @@ -1125,8 +1125,10 @@ no_cpuid:
>  #endif
>  
>  #ifdef SHARED
> +# ifdef __x86_64__
>    TUNABLE_GET (plt_rewrite, tunable_val_t *,
>  	       TUNABLE_CALLBACK (set_plt_rewrite));
> +# endif
>  #else
>    /* NB: In libc.a, call init_cacheinfo.  */
>    init_cacheinfo ();
> diff --git a/sysdeps/x86/ldsodefs.h b/sysdeps/x86/ldsodefs.h
> index b2a6d71513..50dc81c022 100644
> --- a/sysdeps/x86/ldsodefs.h
> +++ b/sysdeps/x86/ldsodefs.h
> @@ -61,7 +61,6 @@ struct La_x32_retval;
>  				     struct La_x86_64_retval *,		\
>  				     const char *)
>  
> -#include <cet-control.h>
>  #include_next <ldsodefs.h>
>  
>  #endif
> diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile
> index e8babc9a4e..90f4ecfd26 100644
> --- a/sysdeps/x86_64/Makefile
> +++ b/sysdeps/x86_64/Makefile
> @@ -10,7 +10,7 @@ LDFLAGS-rtld += -Wl,-z,nomark-plt
>  endif
>  
>  ifeq ($(subdir),csu)
> -gen-as-const-headers += link-defines.sym
> +gen-as-const-headers += features-offsets.sym link-defines.sym
>  endif
>  
>  ifeq ($(subdir),gmon)
> diff --git a/sysdeps/x86/dl-procruntime.c b/sysdeps/x86_64/dl-procruntime.c
> similarity index 97%
> rename from sysdeps/x86/dl-procruntime.c
> rename to sysdeps/x86_64/dl-procruntime.c
> index 15b3d0d878..7078581778 100644
> --- a/sysdeps/x86/dl-procruntime.c
> +++ b/sysdeps/x86_64/dl-procruntime.c
> @@ -1,4 +1,4 @@
> -/* Data for processor runtime information.  x86 version.
> +/* Data for processor runtime information.  x86-64 version.
>     Copyright (C) 2018-2024 Free Software Foundation, Inc.
>     This file is part of the GNU C Library.
>  
> diff --git a/sysdeps/x86_64/dl-trampoline.S b/sysdeps/x86_64/dl-trampoline.S
> index 4c1ba5c9af..b2e7e0f69b 100644
> --- a/sysdeps/x86_64/dl-trampoline.S
> +++ b/sysdeps/x86_64/dl-trampoline.S
> @@ -19,6 +19,7 @@
>  #include <config.h>
>  #include <sysdep.h>
>  #include <cpu-features-offsets.h>
> +#include <features-offsets.h>
>  #include <link-defines.h>
>  #include <isa-level.h>
>  
> diff --git a/sysdeps/x86/cet-control.h b/sysdeps/x86_64/feature-control.h
> similarity index 92%
> rename from sysdeps/x86/cet-control.h
> rename to sysdeps/x86_64/feature-control.h
> index f09f193e9b..4c8727e844 100644
> --- a/sysdeps/x86/cet-control.h
> +++ b/sysdeps/x86_64/feature-control.h
> @@ -1,4 +1,4 @@
> -/* x86 CET tuning.
> +/* x86-64 feature tuning.
>     This file is part of the GNU C Library.
>     Copyright (C) 2018-2024 Free Software Foundation, Inc.
>  
> @@ -16,8 +16,8 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> -#ifndef _CET_CONTROL_H
> -#define _CET_CONTROL_H
> +#ifndef _X86_64_FEATURE_CONTROL_H
> +#define _X86_64_FEATURE_CONTROL_H
>  
>  /* For each CET feature, IBT and SHSTK, valid control values.  */
>  enum dl_x86_cet_control
> @@ -50,4 +50,4 @@ struct dl_x86_feature_control
>    enum dl_plt_rewrite_control plt_rewrite : 2;
>  };
>  
> -#endif /* cet-control.h */
> +#endif /* feature-control.h */
> diff --git a/sysdeps/x86_64/features-offsets.sym b/sysdeps/x86_64/features-offsets.sym
> new file mode 100644
> index 0000000000..9e4be3393a
> --- /dev/null
> +++ b/sysdeps/x86_64/features-offsets.sym
> @@ -0,0 +1,6 @@
> +#define SHARED 1
> +
> +#include <ldsodefs.h>
> +
> +RTLD_GLOBAL_RO_DL_X86_CPU_FEATURES_OFFSET offsetof (struct rtld_global_ro, _dl_x86_cpu_features)
> +RTLD_GLOBAL_DL_X86_FEATURE_1_OFFSET offsetof (struct rtld_global, _dl_x86_feature_1)
> diff --git a/sysdeps/x86_64/ldsodefs.h b/sysdeps/x86_64/ldsodefs.h
> new file mode 100644
> index 0000000000..0f468ddf5b
> --- /dev/null
> +++ b/sysdeps/x86_64/ldsodefs.h
> @@ -0,0 +1,26 @@
> +/* Run-time dynamic linker data structures for loaded ELF shared objects.
> +   x86-64 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/>.  */
> +
> +#ifndef	_X86_64_LDSODEFS_H
> +#define	_X86_64_LDSODEFS_H	1
> +
> +#include <feature-control.h>
> +#include_next <ldsodefs.h>
> +
> +#endif