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439 lines
13 KiB
439 lines
13 KiB
commit ff900fad89df7fa12750c018993a12cc02474646 |
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Author: Florian Weimer <fweimer@redhat.com> |
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Date: Mon Feb 28 11:50:41 2022 +0100 |
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Linux: Consolidate auxiliary vector parsing (redo) |
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And optimize it slightly. |
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This is commit 8c8510ab2790039e58995ef3a22309582413d3ff revised. |
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In _dl_aux_init in elf/dl-support.c, use an explicit loop |
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and -fno-tree-loop-distribute-patterns to avoid memset. |
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Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> |
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(cherry picked from commit 73fc4e28b9464f0e13edc719a5372839970e7ddb) |
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diff --git a/elf/Makefile b/elf/Makefile |
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index c89a6a58690646ee..6423ebbdd7708a14 100644 |
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--- a/elf/Makefile |
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+++ b/elf/Makefile |
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@@ -148,6 +148,11 @@ 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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+ |
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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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diff --git a/elf/dl-support.c b/elf/dl-support.c |
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index f29dc965f4d10648..a2e45e7b14e3a6b9 100644 |
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--- a/elf/dl-support.c |
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+++ b/elf/dl-support.c |
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@@ -43,6 +43,7 @@ |
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#include <dl-vdso.h> |
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#include <dl-vdso-setup.h> |
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#include <dl-auxv.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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@@ -241,93 +242,25 @@ __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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+ |
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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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- |
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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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diff --git a/sysdeps/unix/sysv/linux/alpha/dl-auxv.h b/sysdeps/unix/sysv/linux/alpha/dl-auxv.h |
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index 1aa9dca80d189ebe..8c99e776a0af9cef 100644 |
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--- a/sysdeps/unix/sysv/linux/alpha/dl-auxv.h |
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+++ b/sysdeps/unix/sysv/linux/alpha/dl-auxv.h |
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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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diff --git a/sysdeps/unix/sysv/linux/dl-parse_auxv.h b/sysdeps/unix/sysv/linux/dl-parse_auxv.h |
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new file mode 100644 |
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index 0000000000000000..bf9374371eb217fc |
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--- /dev/null |
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+++ b/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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+ |
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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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+ |
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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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+ |
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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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+ |
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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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+ |
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+typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1]; |
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+ |
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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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+ |
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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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+ |
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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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+ |
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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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+ |
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+ DL_PLATFORM_AUXV |
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+} |
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diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c |
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index 3487976b06ad7f58..56db828fc6985de6 100644 |
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--- a/sysdeps/unix/sysv/linux/dl-sysdep.c |
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+++ b/sysdeps/unix/sysv/linux/dl-sysdep.c |
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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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- |
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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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@@ -89,74 +87,25 @@ _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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|
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- dl_hwcap_check (); |
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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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|
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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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+ dl_hwcap_check (); |
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__tunables_init (_environ); |
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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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|
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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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diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h b/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h |
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index 36ba0f3e9e45f3e2..7f35fb531ba22098 100644 |
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--- a/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h |
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+++ b/sysdeps/unix/sysv/linux/powerpc/dl-auxv.h |
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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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|
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-#include <ldsodefs.h> |
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- |
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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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- |
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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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diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-support.c b/sysdeps/unix/sysv/linux/powerpc/dl-support.c |
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new file mode 100644 |
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index 0000000000000000..abe68a704946b90f |
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--- /dev/null |
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+++ b/sysdeps/unix/sysv/linux/powerpc/dl-support.c |
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@@ -0,0 +1,4 @@ |
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+#include <elf/dl-support.c> |
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+ |
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+/* Populated from the auxiliary vector. */ |
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+int _dl_cache_line_size;
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