From: Alan Modra <amodra@gmail.com>
To: libc-alpha@sourceware.org
Cc: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>,
Alan Modra <amodra@gmail.com>
Subject: [PATCH v2 2/4] powerpc64: Set up thread register for _dl_relocate_static_pie
Date: Mon, 28 Feb 2022 17:10:50 +1030 [thread overview]
Message-ID: <20220228064052.3413334-3-amodra@gmail.com> (raw)
In-Reply-To: <20220228064052.3413334-1-amodra@gmail.com>
libgcc ifunc resolvers that access hwcap via a field in the tcb can't
be called until the thread pointer is set up. Other ifunc resolvers
might need access to at_platform. This patch sets up a fake thread
pointer early to a copy of tcbhead_t. hwcapinfo.c already had local
variables for hwcap and at_platform, replace them with an entire
tcbhead_t. It's not that large and this way we easily ensure hwcap
and at_platform are at the same relative offsets as they are in the
real thread block.
The patch also conditionally disables part of tst-tlsifunc-static,
"bar address read from IFUNC resolver is incorrect". We can't get a
proper address for a thread variable before glibc initialises tls.
diff --git a/sysdeps/powerpc/hwcapinfo.c b/sysdeps/powerpc/hwcapinfo.c
index e030e322bd..afde05f863 100644
--- a/sysdeps/powerpc/hwcapinfo.c
+++ b/sysdeps/powerpc/hwcapinfo.c
@@ -20,8 +20,7 @@
#include <shlib-compat.h>
#include <dl-procinfo.h>
-uint64_t __tcb_hwcap __attribute__ ((visibility ("hidden")));
-uint32_t __tcb_platform __attribute__ ((visibility ("hidden")));
+tcbhead_t __tcb __attribute__ ((visibility ("hidden")));
/* This function parses the HWCAP/HWCAP2 fields, adding the previous supported
ISA bits, as well as converting the AT_PLATFORM string to a number. This
@@ -34,7 +33,7 @@ __tcb_parse_hwcap_and_convert_at_platform (void)
uint64_t h1, h2;
/* Read AT_PLATFORM string from auxv and convert it to a number. */
- __tcb_platform = _dl_string_platform (GLRO (dl_platform));
+ __tcb.at_platform = _dl_string_platform (GLRO (dl_platform));
/* Read HWCAP and HWCAP2 from auxv. */
h1 = GLRO (dl_hwcap);
@@ -66,8 +65,7 @@ __tcb_parse_hwcap_and_convert_at_platform (void)
/* Consolidate both HWCAP and HWCAP2 into a single doubleword so that
we can read both in a single load later. */
- __tcb_hwcap = h2;
- __tcb_hwcap = (h1 << 32) | __tcb_hwcap;
+ __tcb.hwcap = (h1 << 32) | (h2 & 0xffffffff);
}
#if IS_IN (rtld)
diff --git a/sysdeps/powerpc/hwcapinfo.h b/sysdeps/powerpc/hwcapinfo.h
index ac462835ce..1f5e0bcb51 100644
--- a/sysdeps/powerpc/hwcapinfo.h
+++ b/sysdeps/powerpc/hwcapinfo.h
@@ -21,8 +21,7 @@
#ifndef HWCAPINFO_H
# define HWCAPINFO_H
-extern uint64_t __tcb_hwcap attribute_hidden;
-extern uint32_t __tcb_platform attribute_hidden;
+extern tcbhead_t __tcb attribute_hidden;
extern void __tcb_parse_hwcap_and_convert_at_platform (void);
diff --git a/sysdeps/powerpc/nptl/tls.h b/sysdeps/powerpc/nptl/tls.h
index b80d39ad41..22b0075235 100644
--- a/sysdeps/powerpc/nptl/tls.h
+++ b/sysdeps/powerpc/nptl/tls.h
@@ -45,8 +45,6 @@
#ifndef __ASSEMBLER__
-# include <hwcapinfo.h>
-
/* Get system call information. */
# include <sysdep.h>
@@ -100,6 +98,8 @@ typedef struct
dtv_t *dtv;
} tcbhead_t;
+# include <hwcapinfo.h>
+
/* This is the size of the initial TCB. */
# define TLS_INIT_TCB_SIZE 0
@@ -137,8 +137,8 @@ typedef struct
# define TLS_INIT_TP(tcbp) \
({ \
__thread_register = (void *) (tcbp) + TLS_TCB_OFFSET; \
- THREAD_SET_HWCAP (__tcb_hwcap); \
- THREAD_SET_AT_PLATFORM (__tcb_platform); \
+ THREAD_SET_HWCAP (__tcb.hwcap); \
+ THREAD_SET_AT_PLATFORM (__tcb.at_platform); \
NULL; \
})
diff --git a/sysdeps/powerpc/powerpc64/dl-machine.h b/sysdeps/powerpc/powerpc64/dl-machine.h
index 6fab5cbe81..bb0ccd0811 100644
--- a/sysdeps/powerpc/powerpc64/dl-machine.h
+++ b/sysdeps/powerpc/powerpc64/dl-machine.h
@@ -559,6 +559,27 @@ elf_machine_plt_value (struct link_map *map, const Elf64_Rela *reloc,
#define ARCH_LA_PLTEXIT ppc64v2_gnu_pltexit
#endif
+#if ENABLE_STATIC_PIE && !defined SHARED && !IS_IN (rtld)
+#include <libc-diag.h>
+#include <tcb-offsets.h>
+
+/* Set up r13 for _dl_relocate_static_pie so that libgcc ifuncs that
+ normally access the tcb copy of hwcap will see __tcb.hwcap. */
+
+static inline void __attribute__ ((always_inline))
+ppc_init_fake_thread_pointer (void)
+{
+ DIAG_PUSH_NEEDS_COMMENT;
+ /* We are playing pointer tricks. Silence gcc warning. */
+ DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Warray-bounds");
+ __thread_register = (char *) &__tcb.hwcap - TCB_HWCAP;
+ DIAG_POP_NEEDS_COMMENT;
+}
+
+#define ELF_MACHINE_BEFORE_RTLD_RELOC(map, dynamic_info) \
+ ppc_init_fake_thread_pointer ();
+#endif /* ENABLE_STATIC_PIE && !defined SHARED && !IS_IN (rtld) */
+
#endif /* dl_machine_h */
#ifdef RESOLVE_MAP
diff --git a/sysdeps/powerpc/tst-tlsifunc-static.c b/sysdeps/powerpc/tst-tlsifunc-static.c
index c0ff8972a9..438b27c0ec 100644
--- a/sysdeps/powerpc/tst-tlsifunc-static.c
+++ b/sysdeps/powerpc/tst-tlsifunc-static.c
@@ -16,4 +16,5 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
+#define TST_TLSIFUNC_STATIC 1
#include "tst-tlsifunc.c"
diff --git a/sysdeps/powerpc/tst-tlsifunc.c b/sysdeps/powerpc/tst-tlsifunc.c
index 92313e68f4..6b256c6229 100644
--- a/sysdeps/powerpc/tst-tlsifunc.c
+++ b/sysdeps/powerpc/tst-tlsifunc.c
@@ -101,11 +101,14 @@ do_test (void)
if (&bar == bar_ptr)
printf ("PASS: bar address read from IFUNC resolver is correct.\n");
+#if !defined TST_TLSIFUNC_STATIC || !defined PIC \
+ || !defined PI_STATIC_AND_HIDDEN
else
{
printf ("FAIL: bar address read from IFUNC resolver is incorrect.\n");
ret = 1;
}
+#endif
if (tcb_test ())
printf ("PASS: tcb_test IFUNC resolver called once.\n");
next prev parent reply other threads:[~2022-02-28 6:41 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-23 12:42 [PowerPC64] Use medium model toc accesses throughout Alan Modra
2022-01-24 3:47 ` [PATCH 2/5] [PowerPC64] Set up thread register for _dl_relocate_static_pie Alan Modra
2022-02-16 23:02 ` Paul E Murphy
2022-02-19 0:49 ` Alan Modra
2022-01-24 3:50 ` [PATCH 3/5] [PowerPC] Relocate stinfo->main Alan Modra
2022-01-24 4:48 ` H.J. Lu
2022-01-24 6:51 ` Alan Modra
2022-01-24 3:52 ` [PATCH 4/5] Constify a variable in dl_vdso_vsym Alan Modra
2022-01-24 4:06 ` [PATCH 5/5] Enable static-pie on powerpc64 Alan Modra
2022-01-27 18:39 ` Florian Weimer
2022-01-28 8:45 ` Alan Modra
2022-01-28 17:48 ` [PowerPC64] Use medium model toc accesses throughout Paul E Murphy
2022-01-29 1:24 ` Alan Modra
2022-02-28 6:40 ` [PATCH v2 0/4] PowerPC64 static-pie Alan Modra
2022-02-28 6:40 ` [PATCH v2 1/4] powerpc64: Use medium model toc accesses throughout Alan Modra
2022-04-08 22:28 ` Tulio Magno Quites Machado Filho
2022-02-28 6:40 ` Alan Modra [this message]
2022-04-08 22:28 ` [PATCH v2 2/4] powerpc64: Set up thread register for _dl_relocate_static_pie Tulio Magno Quites Machado Filho
2022-02-28 6:40 ` [PATCH v2 3/4] powerpc: Relocate stinfo->main Alan Modra
2022-04-08 22:32 ` Tulio Magno Quites Machado Filho
2022-02-28 6:40 ` [PATCH v2 4/4] powerpc64: Enable static-pie Alan Modra
2022-04-08 22:49 ` Tulio Magno Quites Machado Filho
2022-04-14 1:16 ` Alan Modra
2022-04-14 3:42 ` Fangrui Song
2022-04-20 7:21 ` [PATCH v3] " Alan Modra
2022-03-04 12:48 ` [PATCH v2 0/4] PowerPC64 static-pie Alan Modra
2022-04-08 8:06 ` Alan Modra
2022-04-09 0:14 ` Fangrui Song
2022-04-14 0:33 ` Alan Modra
2022-04-14 1:54 ` DT_RELR without libc.so dependency H.J. Lu
2022-04-14 3:43 ` Fangrui Song
2022-04-14 5:18 ` Alan Modra
2022-04-14 17:55 ` H.J. Lu
2022-04-08 22:27 ` [PATCH v2 0/4] PowerPC64 static-pie Tulio Magno Quites Machado Filho
2022-04-11 1:38 ` Alan Modra
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