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fix regression in pre-v7 arm on kernels with kuser helper removed 

the arm atomics/TLS runtime selection code is called from
__set_thread_area and depends on having libc.auxv and __hwcap
available. commit 71f099cb7d moved the
first call to __set_thread_area to the top of dynamic linking stage 3,
before this data is made available, causing the runtime detection code
to always see __hwcap as zero and thereby select the atomics/TLS
implementations based on kuser helper.

upcoming work on superh will use similar runtime detection.

ideally this early-init code should be cleanly refactored and shared
between the dynamic linker and static-linked startup.
This commit is contained in:
Rich Felker 2015-06-07 20:55:23 +00:00
parent 32f3c4f706
commit 75ce450395
1 changed files with 14 additions and 17 deletions
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31
src/ldso/dynlink.c
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@ -1192,6 +1192,17 @@ _Noreturn void __dls3(size_t *sp)
char **argv_orig = argv;
char **envp = argv+argc+1;
/* Find aux vector just past environ[] and use it to initialize
* global data that may be needed before we can make syscalls. */
__environ = envp;
for (i=argc+1; argv[i]; i++);
libc.auxv = auxv = (void *)(argv+i+1);
decode_vec(auxv, aux, AUX_CNT);
__hwcap = aux[AT_HWCAP];
libc.page_size = aux[AT_PAGESZ];
libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
|| aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
/* Setup early thread pointer in builtin_tls for ldso/libc itself to
* use during dynamic linking. If possible it will also serve as the
* thread pointer at runtime. */
@ -1200,25 +1211,11 @@ _Noreturn void __dls3(size_t *sp)
a_crash();
}
/* Find aux vector just past environ[] */
for (i=argc+1; argv[i]; i++)
if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
env_path = argv[i]+16;
else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
env_preload = argv[i]+11;
auxv = (void *)(argv+i+1);
decode_vec(auxv, aux, AUX_CNT);
/* Only trust user/env if kernel says we're not suid/sgid */
if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
|| aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
env_path = 0;
env_preload = 0;
libc.secure = 1;
if (!libc.secure) {
env_path = getenv("LD_LIBRARY_PATH");
env_preload = getenv("LD_PRELOAD");
}
libc.page_size = aux[AT_PAGESZ];
libc.auxv = auxv;
/* If the main program was already loaded by the kernel,
* AT_PHDR will point to some location other than the dynamic