i386: Remove CET support bits
authorH.J. Lu <hjl.tools@gmail.com>
Tue, 9 Jan 2024 20:23:27 +0000 (12:23 -0800)
committerH.J. Lu <hjl.tools@gmail.com>
Wed, 10 Jan 2024 13:20:20 +0000 (05:20 -0800)
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.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
12 files changed:
sysdeps/i386/dl-machine.h
sysdeps/i386/dl-trampoline.S
sysdeps/unix/sysv/linux/x86_64/dl-cet.h
sysdeps/x86/cpu-features-offsets.sym
sysdeps/x86/cpu-features.c
sysdeps/x86/ldsodefs.h
sysdeps/x86_64/Makefile
sysdeps/x86_64/dl-procruntime.c [moved from sysdeps/x86/dl-procruntime.c with 97% similarity]
sysdeps/x86_64/dl-trampoline.S
sysdeps/x86_64/feature-control.h [moved from sysdeps/x86/cet-control.h with 92% similarity]
sysdeps/x86_64/features-offsets.sym [new file with mode: 0644]
sysdeps/x86_64/ldsodefs.h [new file with mode: 0644]

index c69ae16..fc1ef96 100644 (file)
@@ -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;
index 2632020..6c14d46 100644 (file)
@@ -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
index 94e9b9a..a00c7ee 100644 (file)
@@ -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)
index 5429f60..6a8fd29 100644 (file)
@@ -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)
index 9ca307f..46bdaff 100644 (file)
@@ -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 ();
index b2a6d71..50dc81c 100644 (file)
@@ -61,7 +61,6 @@ struct La_x32_retval;
                                     struct La_x86_64_retval *,         \
                                     const char *)
 
-#include <cet-control.h>
 #include_next <ldsodefs.h>
 
 #endif
index e8babc9..90f4ecf 100644 (file)
@@ -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)
similarity index 97%
rename from sysdeps/x86/dl-procruntime.c
rename to sysdeps/x86_64/dl-procruntime.c
index 15b3d0d..7078581 100644 (file)
@@ -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.
 
index 4c1ba5c..b2e7e0f 100644 (file)
@@ -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>
 
similarity index 92%
rename from sysdeps/x86/cet-control.h
rename to sysdeps/x86_64/feature-control.h
index f09f193..4c8727e 100644 (file)
@@ -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 (file)
index 0000000..9e4be33
--- /dev/null
@@ -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 (file)
index 0000000..0f468dd
--- /dev/null
@@ -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