[PATCH v2] Linux: Call dl_hwcap_check earlier, before full auxiliary vector parse
Florian Weimer
fweimer@redhat.com
Mon Jun 17 14:46:32 GMT 2024
The full parsing routine may need the memset function, which could
require non-baseline ISA support.
---
v2: Remove spurious braces from sysdeps/powerpc/powerpc64/le/dl-hwcap-check.h.
sysdeps/generic/dl-hwcap-check.h | 5 ++++-
sysdeps/powerpc/powerpc64/le/dl-hwcap-check.h | 22 ++++++++++++++++++----
sysdeps/s390/s390-64/dl-hwcap-check.h | 20 +++++++++++++++++---
sysdeps/unix/sysv/linux/dl-sysdep.c | 20 +++++++++++++-------
4 files changed, 52 insertions(+), 15 deletions(-)
diff --git a/sysdeps/generic/dl-hwcap-check.h b/sysdeps/generic/dl-hwcap-check.h
index 55efd129be..65dba6d1a0 100644
--- a/sysdeps/generic/dl-hwcap-check.h
+++ b/sysdeps/generic/dl-hwcap-check.h
@@ -22,7 +22,10 @@
static inline void
dl_hwcap_check (void)
{
- /* The generic implementation does not perform any checks. */
+ /* The generic implementation does not perform any checks. Specific
+ implementations may assume that GLRO(dl_auxv) has been
+ initialized (if it exists), but GLRO(dl_hwcap), GLRO(dl_hwcap2)
+ have not been set at this point. */
}
#endif /* _DL_HWCAP_CHECK_H */
diff --git a/sysdeps/powerpc/powerpc64/le/dl-hwcap-check.h b/sysdeps/powerpc/powerpc64/le/dl-hwcap-check.h
index 6d463f0511..d7b2a2ca4d 100644
--- a/sysdeps/powerpc/powerpc64/le/dl-hwcap-check.h
+++ b/sysdeps/powerpc/powerpc64/le/dl-hwcap-check.h
@@ -25,13 +25,27 @@
static inline void
dl_hwcap_check (void)
{
+#if defined GCCMACRO_ARCH_PWR9 || defined GCCMACRO__FLOAT128_HARDWARE__ \
+ || defined GCCMACRO_ARCH_PWR10 || defined GCCMACRO__PCREL__ \
+ || defined GCCMACRO__MMA__
+ /* Early auxiliary vector parsing, to avoid ISA dependencies in
+ later full parsing. */
+ unsigned long int dl_hwcap2 = 0;
+ for (ElfW(auxv_t) *av = GLRO(dl_auxv); av->a_type != AT_NULL; av++)
+ if (av->a_type == AT_HWCAP2)
+ {
+ dl_hwcap2 = av->a_un.a_val;
+ break;
+ }
+#endif
+
#ifdef GCCMACRO_ARCH_PWR9
- if ((GLRO (dl_hwcap2) & PPC_FEATURE2_ARCH_3_00) == 0)
+ if ((dl_hwcap2 & PPC_FEATURE2_ARCH_3_00) == 0)
_dl_fatal_printf ("\
Fatal glibc error: CPU lacks ISA 3.00 support (POWER9 or later required)\n");
#endif
#ifdef GCCMACRO__FLOAT128_HARDWARE__
- if ((GLRO (dl_hwcap2) & PPC_FEATURE2_HAS_IEEE128) == 0)
+ if ((dl_hwcap2 & PPC_FEATURE2_HAS_IEEE128) == 0)
_dl_fatal_printf ("\
Fatal glibc error: CPU lacks float128 support (POWER 9 or later required)\n");
#endif
@@ -39,12 +53,12 @@ Fatal glibc error: CPU lacks float128 support (POWER 9 or later required)\n");
running on POWER9 because there are faulting PCREL instructions
before this point. */
#if defined GCCMACRO_ARCH_PWR10 || defined GCCMACRO__PCREL__
- if ((GLRO (dl_hwcap2) & PPC_FEATURE2_ARCH_3_1) == 0)
+ if ((dl_hwcap2 & PPC_FEATURE2_ARCH_3_1) == 0)
_dl_fatal_printf ("\
Fatal glibc error: CPU lacks ISA 3.10 support (POWER10 or later required)\n");
#endif
#ifdef GCCMACRO__MMA__
- if ((GLRO (dl_hwcap2) & PPC_FEATURE2_MMA) == 0)
+ if ((dl_hwcap2 & PPC_FEATURE2_MMA) == 0)
_dl_fatal_printf ("\
Fatal glibc error: CPU lacks MMA support (POWER10 or later required)\n");
#endif
diff --git a/sysdeps/s390/s390-64/dl-hwcap-check.h b/sysdeps/s390/s390-64/dl-hwcap-check.h
index 6ad3242cc9..ee67ebf76e 100644
--- a/sysdeps/s390/s390-64/dl-hwcap-check.h
+++ b/sysdeps/s390/s390-64/dl-hwcap-check.h
@@ -26,16 +26,30 @@ static inline void
dl_hwcap_check (void)
{
#if defined __ARCH__
+# if GCCMACRO__ARCH__ >= 12
+ /* Early auxiliary vector parsing, to avoid ISA dependencies in
+ later full parsing. */
+ unsigned long int dl_hwcap = 0;
+ {
+ for (ElfW(auxv_t) *av = GLRO(dl_auxv); av->a_type != AT_NULL; av++)
+ if (av->a_type == AT_HWCAP)
+ {
+ dl_hwcap = av->a_un.a_val;
+ break;
+ }
+ }
+# endif
+
# if GCCMACRO__ARCH__ >= 14
- if (!(GLRO(dl_hwcap) & HWCAP_S390_VXRS_PDE2))
+ if (!(dl_hwcap & HWCAP_S390_VXRS_PDE2))
_dl_fatal_printf ("\
Fatal glibc error: CPU lacks VXRS_PDE2 support (z16 or later required)\n");
# elif GCCMACRO__ARCH__ >= 13
- if (!(GLRO(dl_hwcap) & HWCAP_S390_VXRS_EXT2))
+ if (!(dl_hwcap & HWCAP_S390_VXRS_EXT2))
_dl_fatal_printf ("\
Fatal glibc error: CPU lacks VXRS_EXT2 support (z15 or later required)\n");
# elif GCCMACRO__ARCH__ >= 12
- if (!(GLRO(dl_hwcap) & HWCAP_S390_VXE))
+ if (!(dl_hwcap & HWCAP_S390_VXE))
_dl_fatal_printf ("\
Fatal glibc error: CPU lacks VXE support (z14 or later required)\n");
# endif
diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c
index e1b14e9eb3..c54100c8a5 100644
--- a/sysdeps/unix/sysv/linux/dl-sysdep.c
+++ b/sysdeps/unix/sysv/linux/dl-sysdep.c
@@ -70,11 +70,10 @@ struct dl_main_arguments
ElfW(Addr) user_entry;
};
-/* Separate function, so that dl_main can be called without the large
- array on the stack. */
+/* First part of argument parsing, up to and including GLRO(dl_auxv)
+ initialization. */
static void
-_dl_sysdep_parse_arguments (void **start_argptr,
- struct dl_main_arguments *args)
+_dl_sysdep_parse_arguments_1 (void **start_argptr)
{
_dl_argc = (intptr_t) *start_argptr;
_dl_argv = (char **) (start_argptr + 1); /* Necessary aliasing violation. */
@@ -86,7 +85,13 @@ _dl_sysdep_parse_arguments (void **start_argptr,
GLRO(dl_auxv) = (ElfW(auxv_t) *) (tmp + 1);
break;
}
+}
+/* Separate function, so that dl_main can be called without the large
+ array on the stack. */
+static void __attribute__ ((noinline))
+_dl_sysdep_parse_arguments_2 (struct dl_main_arguments *args)
+{
dl_parse_auxv_t auxv_values = { 0, };
_dl_parse_auxv (GLRO(dl_auxv), auxv_values);
@@ -102,11 +107,12 @@ _dl_sysdep_start (void **start_argptr,
{
__libc_stack_end = DL_STACK_END (start_argptr);
- struct dl_main_arguments dl_main_args;
- _dl_sysdep_parse_arguments (start_argptr, &dl_main_args);
-
+ _dl_sysdep_parse_arguments_1 (start_argptr);
dl_hwcap_check ();
+ struct dl_main_arguments dl_main_args;
+ _dl_sysdep_parse_arguments_2 (&dl_main_args);
+
__tunables_init (_environ);
/* Initialize DSO sorting algorithm after tunables. */
base-commit: 55eb99e9a9d840ba452b128be14d6529c2dde039
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