mirror of
https://sourceware.org/git/glibc.git
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Linux: Consolidate auxiliary vector parsing (redo)
And optimize it slightly.
This is commit 8c8510ab27
revised.
In _dl_aux_init in elf/dl-support.c, use an explicit loop
and -fno-tree-loop-distribute-patterns to avoid memset.
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
This commit is contained in:
parent
1fe00d3eb6
commit
73fc4e28b9
@ -160,6 +160,11 @@ ifeq (yes,$(have-loop-to-function))
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CFLAGS-rtld.c += -fno-tree-loop-distribute-patterns
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endif
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ifeq (yes,$(have-loop-to-function))
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# Likewise, during static library startup, memset is not yet available.
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CFLAGS-dl-support.c = -fno-tree-loop-distribute-patterns
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endif
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# Compile rtld itself without stack protection.
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# Also compile all routines in the static library that are elided from
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# the shared libc because they are in libc.a in the same way.
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@ -44,6 +44,7 @@
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#include <dl-vdso-setup.h>
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#include <dl-auxv.h>
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#include <dl-find_object.h>
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#include <array_length.h>
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extern char *__progname;
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char **_dl_argv = &__progname; /* This is checked for some error messages. */
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@ -240,93 +241,25 @@ __rtld_lock_define_initialized_recursive (, _dl_load_tls_lock)
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#ifdef HAVE_AUX_VECTOR
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#include <dl-parse_auxv.h>
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int _dl_clktck;
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void
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_dl_aux_init (ElfW(auxv_t) *av)
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{
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int seen = 0;
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uid_t uid = 0;
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gid_t gid = 0;
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#ifdef NEED_DL_SYSINFO
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/* NB: Avoid RELATIVE relocation in static PIE. */
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GL(dl_sysinfo) = DL_SYSINFO_DEFAULT;
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#endif
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_dl_auxv = av;
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for (; av->a_type != AT_NULL; ++av)
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switch (av->a_type)
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{
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case AT_PAGESZ:
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if (av->a_un.a_val != 0)
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GLRO(dl_pagesize) = av->a_un.a_val;
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break;
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case AT_CLKTCK:
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GLRO(dl_clktck) = av->a_un.a_val;
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break;
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case AT_PHDR:
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GL(dl_phdr) = (const void *) av->a_un.a_val;
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break;
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case AT_PHNUM:
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GL(dl_phnum) = av->a_un.a_val;
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break;
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case AT_PLATFORM:
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GLRO(dl_platform) = (void *) av->a_un.a_val;
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break;
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case AT_HWCAP:
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GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
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break;
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case AT_HWCAP2:
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GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val;
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break;
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case AT_FPUCW:
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GLRO(dl_fpu_control) = av->a_un.a_val;
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break;
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#ifdef NEED_DL_SYSINFO
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case AT_SYSINFO:
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GL(dl_sysinfo) = av->a_un.a_val;
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break;
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#endif
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#ifdef NEED_DL_SYSINFO_DSO
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case AT_SYSINFO_EHDR:
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GL(dl_sysinfo_dso) = (void *) av->a_un.a_val;
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break;
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#endif
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case AT_UID:
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uid ^= av->a_un.a_val;
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seen |= 1;
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break;
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case AT_EUID:
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uid ^= av->a_un.a_val;
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seen |= 2;
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break;
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case AT_GID:
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gid ^= av->a_un.a_val;
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seen |= 4;
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break;
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case AT_EGID:
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gid ^= av->a_un.a_val;
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seen |= 8;
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break;
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case AT_SECURE:
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seen = -1;
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__libc_enable_secure = av->a_un.a_val;
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__libc_enable_secure_decided = 1;
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break;
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case AT_RANDOM:
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_dl_random = (void *) av->a_un.a_val;
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break;
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case AT_MINSIGSTKSZ:
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_dl_minsigstacksize = av->a_un.a_val;
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break;
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DL_PLATFORM_AUXV
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}
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if (seen == 0xf)
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{
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__libc_enable_secure = uid != 0 || gid != 0;
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__libc_enable_secure_decided = 1;
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}
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dl_parse_auxv_t auxv_values;
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/* Use an explicit initialization loop here because memset may not
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be available yet. */
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for (int i = 0; i < array_length (auxv_values); ++i)
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auxv_values[i] = 0;
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_dl_parse_auxv (av, auxv_values);
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}
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#endif
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@ -20,16 +20,8 @@
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extern long __libc_alpha_cache_shape[4];
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#define DL_PLATFORM_AUXV \
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case AT_L1I_CACHESHAPE: \
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__libc_alpha_cache_shape[0] = av->a_un.a_val; \
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break; \
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case AT_L1D_CACHESHAPE: \
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__libc_alpha_cache_shape[1] = av->a_un.a_val; \
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break; \
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case AT_L2_CACHESHAPE: \
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__libc_alpha_cache_shape[2] = av->a_un.a_val; \
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break; \
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case AT_L3_CACHESHAPE: \
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__libc_alpha_cache_shape[3] = av->a_un.a_val; \
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break;
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#define DL_PLATFORM_AUXV \
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__libc_alpha_cache_shape[0] = auxv_values[AT_L1I_CACHESHAPE]; \
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__libc_alpha_cache_shape[1] = auxv_values[AT_L1D_CACHESHAPE]; \
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__libc_alpha_cache_shape[2] = auxv_values[AT_L2_CACHESHAPE]; \
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__libc_alpha_cache_shape[3] = auxv_values[AT_L3_CACHESHAPE];
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61
sysdeps/unix/sysv/linux/dl-parse_auxv.h
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61
sysdeps/unix/sysv/linux/dl-parse_auxv.h
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@ -0,0 +1,61 @@
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/* Parse the Linux auxiliary vector.
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Copyright (C) 1995-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <elf.h>
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#include <entry.h>
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#include <fpu_control.h>
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#include <ldsodefs.h>
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#include <link.h>
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typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1];
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/* Copy the auxiliary vector into AUXV_VALUES and set up GLRO
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variables. */
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static inline
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void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values)
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{
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auxv_values[AT_ENTRY] = (ElfW(Addr)) ENTRY_POINT;
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auxv_values[AT_PAGESZ] = EXEC_PAGESIZE;
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auxv_values[AT_FPUCW] = _FPU_DEFAULT;
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/* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */
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_Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
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"CONSTANT_MINSIGSTKSZ is constant");
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auxv_values[AT_MINSIGSTKSZ] = CONSTANT_MINSIGSTKSZ;
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for (; av->a_type != AT_NULL; av++)
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if (av->a_type <= AT_MINSIGSTKSZ)
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auxv_values[av->a_type] = av->a_un.a_val;
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GLRO(dl_pagesize) = auxv_values[AT_PAGESZ];
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__libc_enable_secure = auxv_values[AT_SECURE];
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GLRO(dl_platform) = (void *) auxv_values[AT_PLATFORM];
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GLRO(dl_hwcap) = auxv_values[AT_HWCAP];
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GLRO(dl_hwcap2) = auxv_values[AT_HWCAP2];
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GLRO(dl_clktck) = auxv_values[AT_CLKTCK];
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GLRO(dl_fpu_control) = auxv_values[AT_FPUCW];
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_dl_random = (void *) auxv_values[AT_RANDOM];
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GLRO(dl_minsigstacksize) = auxv_values[AT_MINSIGSTKSZ];
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GLRO(dl_sysinfo_dso) = (void *) auxv_values[AT_SYSINFO_EHDR];
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#ifdef NEED_DL_SYSINFO
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if (GLRO(dl_sysinfo_dso) != NULL)
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GLRO(dl_sysinfo) = auxv_values[AT_SYSINFO];
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#endif
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DL_PLATFORM_AUXV
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}
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@ -18,15 +18,14 @@
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#include <_itoa.h>
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#include <assert.h>
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#include <dl-hwcap-check.h>
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#include <dl-auxv.h>
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#include <dl-osinfo.h>
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#include <dl-parse_auxv.h>
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#include <dl-procinfo.h>
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#include <dl-tunables.h>
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#include <elf.h>
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#include <entry.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <fpu_control.h>
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#include <ldsodefs.h>
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#include <libc-internal.h>
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#include <libintl.h>
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@ -43,10 +42,9 @@
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#include <unistd.h>
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#include <dl-machine.h>
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#include <dl-hwcap-check.h>
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#ifdef SHARED
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# include <dl-auxv.h>
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extern char **_environ attribute_hidden;
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extern char _end[] attribute_hidden;
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@ -64,20 +62,20 @@ void *_dl_random attribute_relro = NULL;
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# define DL_STACK_END(cookie) ((void *) (cookie))
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#endif
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ElfW(Addr)
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_dl_sysdep_start (void **start_argptr,
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void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
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ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
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/* Arguments passed to dl_main. */
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struct dl_main_arguments
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{
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const ElfW(Phdr) *phdr = NULL;
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ElfW(Word) phnum = 0;
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const ElfW(Phdr) *phdr;
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ElfW(Word) phnum;
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ElfW(Addr) user_entry;
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ElfW(auxv_t) *av;
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#ifdef NEED_DL_SYSINFO
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uintptr_t new_sysinfo = 0;
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#endif
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};
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__libc_stack_end = DL_STACK_END (start_argptr);
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/* Separate function, so that dl_main can be called without the large
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array on the stack. */
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static void
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_dl_sysdep_parse_arguments (void **start_argptr,
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struct dl_main_arguments *args)
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{
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_dl_argc = (intptr_t) *start_argptr;
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_dl_argv = (char **) (start_argptr + 1); /* Necessary aliasing violation. */
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_environ = _dl_argv + _dl_argc + 1;
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@ -89,75 +87,26 @@ _dl_sysdep_start (void **start_argptr,
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break;
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}
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user_entry = (ElfW(Addr)) ENTRY_POINT;
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GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */
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dl_parse_auxv_t auxv_values = { 0, };
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_dl_parse_auxv (GLRO(dl_auxv), auxv_values);
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/* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */
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_Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
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"CONSTANT_MINSIGSTKSZ is constant");
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GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ;
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args->phdr = (const ElfW(Phdr) *) auxv_values[AT_PHDR];
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args->phnum = auxv_values[AT_PHNUM];
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args->user_entry = auxv_values[AT_ENTRY];
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}
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for (av = GLRO(dl_auxv); av->a_type != AT_NULL; av++)
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switch (av->a_type)
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{
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case AT_PHDR:
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phdr = (void *) av->a_un.a_val;
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break;
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case AT_PHNUM:
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phnum = av->a_un.a_val;
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break;
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case AT_PAGESZ:
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GLRO(dl_pagesize) = av->a_un.a_val;
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break;
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case AT_ENTRY:
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user_entry = av->a_un.a_val;
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break;
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case AT_SECURE:
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__libc_enable_secure = av->a_un.a_val;
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break;
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case AT_PLATFORM:
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GLRO(dl_platform) = (void *) av->a_un.a_val;
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break;
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case AT_HWCAP:
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GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
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break;
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case AT_HWCAP2:
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GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val;
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break;
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case AT_CLKTCK:
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GLRO(dl_clktck) = av->a_un.a_val;
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break;
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case AT_FPUCW:
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GLRO(dl_fpu_control) = av->a_un.a_val;
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break;
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#ifdef NEED_DL_SYSINFO
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case AT_SYSINFO:
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new_sysinfo = av->a_un.a_val;
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break;
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#endif
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case AT_SYSINFO_EHDR:
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GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
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break;
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case AT_RANDOM:
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_dl_random = (void *) av->a_un.a_val;
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break;
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case AT_MINSIGSTKSZ:
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GLRO(dl_minsigstacksize) = av->a_un.a_val;
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break;
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DL_PLATFORM_AUXV
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}
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ElfW(Addr)
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_dl_sysdep_start (void **start_argptr,
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void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
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ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
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{
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__libc_stack_end = DL_STACK_END (start_argptr);
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struct dl_main_arguments dl_main_args;
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_dl_sysdep_parse_arguments (start_argptr, &dl_main_args);
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dl_hwcap_check ();
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#ifdef NEED_DL_SYSINFO
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if (new_sysinfo != 0)
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{
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/* Only set the sysinfo value if we also have the vsyscall DSO. */
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if (GLRO(dl_sysinfo_dso) != 0)
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GLRO(dl_sysinfo) = new_sysinfo;
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}
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#endif
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__tunables_init (_environ);
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/* Initialize DSO sorting algorithm after tunables. */
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@ -188,8 +137,9 @@ _dl_sysdep_start (void **start_argptr,
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if (__builtin_expect (__libc_enable_secure, 0))
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__libc_check_standard_fds ();
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(*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv));
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return user_entry;
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(*dl_main) (dl_main_args.phdr, dl_main_args.phnum,
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&dl_main_args.user_entry, GLRO(dl_auxv));
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return dl_main_args.user_entry;
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}
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void
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@ -16,15 +16,5 @@
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <ldsodefs.h>
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#if IS_IN (libc) && !defined SHARED
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int GLRO(dl_cache_line_size);
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#endif
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/* Scan the Aux Vector for the "Data Cache Block Size" entry and assign it
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to dl_cache_line_size. */
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#define DL_PLATFORM_AUXV \
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case AT_DCACHEBSIZE: \
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GLRO(dl_cache_line_size) = av->a_un.a_val; \
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break;
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#define DL_PLATFORM_AUXV \
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GLRO(dl_cache_line_size) = auxv_values[AT_DCACHEBSIZE];
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4
sysdeps/unix/sysv/linux/powerpc/dl-support.c
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4
sysdeps/unix/sysv/linux/powerpc/dl-support.c
Normal file
@ -0,0 +1,4 @@
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#include <elf/dl-support.c>
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/* Populated from the auxiliary vector. */
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int _dl_cache_line_size;
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