From 69e8dca2e581b69499e9719543cb8e74e2d6063c Mon Sep 17 00:00:00 2001
From: skrll <skrll@NetBSD.org>
Date: Fri, 18 Jan 2019 11:59:03 +0000
Subject: [PATCH] Adapt
https://svnweb.freebsd.org/base?view=revision&revision=342113 to NetBSD.
This brings us resolving for dynamically loaded libraries and makes
tests/libexec/ld.elf_so/t_thread_local_dtor pass.
With suggestions from joerg@
---
libexec/ld.elf_so/arch/aarch64/mdreloc.c | 109 ++++++-------
libexec/ld.elf_so/arch/aarch64/rtld_start.S | 164 ++++++++++++++++----
2 files changed, 181 insertions(+), 92 deletions(-)
diff --git a/libexec/ld.elf_so/arch/aarch64/mdreloc.c b/libexec/ld.elf_so/arch/aarch64/mdreloc.c
index 58f4dc834845..1118cf71c3a6 100644
--- a/libexec/ld.elf_so/arch/aarch64/mdreloc.c
+++ b/libexec/ld.elf_so/arch/aarch64/mdreloc.c
@@ -1,4 +1,4 @@
-/* $NetBSD: mdreloc.c,v 1.12 2018/11/23 11:26:05 skrll Exp $ */
+/* $NetBSD: mdreloc.c,v 1.13 2019/01/18 11:59:03 skrll Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -60,7 +60,7 @@
#include <sys/cdefs.h>
#ifndef lint
-__RCSID("$NetBSD: mdreloc.c,v 1.12 2018/11/23 11:26:05 skrll Exp $");
+__RCSID("$NetBSD: mdreloc.c,v 1.13 2019/01/18 11:59:03 skrll Exp $");
#endif /* not lint */
#include <sys/types.h>
@@ -70,17 +70,16 @@ __RCSID("$NetBSD: mdreloc.c,v 1.12 2018/11/23 11:26:05 skrll Exp $");
#include "rtld.h"
struct tls_data {
- int64_t index;
- Obj_Entry *obj;
- const Elf_Rela *rela;
+ size_t td_tlsindex;
+ Elf_Addr td_tlsoffs;
};
void _rtld_bind_start(void);
void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
Elf_Addr _rtld_bind(const Obj_Entry *, Elf_Word);
-void *_rtld_tlsdesc(void *);
+void *_rtld_tlsdesc_static(void *);
+void *_rtld_tlsdesc_undef(void *);
void *_rtld_tlsdesc_dynamic(void *);
-int64_t _rtld_tlsdesc_handle(struct tls_data *, u_int);
/*
* AARCH64 PLT looks like this;
@@ -117,67 +116,63 @@ _rtld_setup_pltgot(const Obj_Entry *obj)
}
static struct tls_data *
-_rtld_tlsdesc_alloc(Obj_Entry *obj, const Elf_Rela *rela)
+_rtld_tlsdesc_alloc(size_t tlsindex, Elf_Addr offs)
{
struct tls_data *tlsdesc;
tlsdesc = xmalloc(sizeof(*tlsdesc));
- tlsdesc->index = -1;
- tlsdesc->obj = obj;
- tlsdesc->rela = rela;
+ tlsdesc->td_tlsindex = tlsindex;
+ tlsdesc->td_tlsoffs = offs;
return tlsdesc;
}
-static int64_t
-_rtld_tlsdesc_handle_locked(struct tls_data *tlsdesc, u_int flags)
+static void
+_rtld_tlsdesc_fill(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *where, u_int flags)
{
- const Elf_Rela *rela;
const Elf_Sym *def;
const Obj_Entry *defobj;
- Obj_Entry *obj;
+ Elf_Addr offs = 0;
+ unsigned long symnum = ELF_R_SYM(rela->r_info);
- rela = tlsdesc->rela;
- obj = tlsdesc->obj;
+ if (symnum != 0) {
+ def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
+ flags);
+ if (def == NULL)
+ _rtld_die();
+ if (def == &_rtld_sym_zero) {
+ /* Weak undefined thread variable */
+ where[0] = (Elf_Addr)_rtld_tlsdesc_undef;
+ where[1] = rela->r_addend;
- def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, flags);
- if (def == NULL)
- _rtld_die();
+ rdbg(("TLSDESC %s (weak) in %s --> %p",
+ obj->strtab + obj->symtab[symnum].st_name,
+ obj->path, (void *)where[1]));
- tlsdesc->index = defobj->tlsoffset + def->st_value + rela->r_addend +
- sizeof(struct tls_tcb);
-
- return tlsdesc->index;
-}
-
-int64_t
-_rtld_tlsdesc_handle(struct tls_data *tlsdesc, u_int flags)
-{
- sigset_t mask;
-
- /* We have already found the index, return it */
- if (tlsdesc->index >= 0)
- return tlsdesc->index;
-
- _rtld_exclusive_enter(&mask);
- /* tlsdesc->index may have been set by another thread */
- if (tlsdesc->index == -1)
- _rtld_tlsdesc_handle_locked(tlsdesc, flags);
- _rtld_exclusive_exit(&mask);
-
- return tlsdesc->index;
-}
-
-static void
-_rtld_tlsdesc_fill(Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *where)
-{
- if (ELF_R_SYM(rela->r_info) == 0) {
- where[0] = (Elf_Addr)_rtld_tlsdesc;
- where[1] = obj->tlsoffset + rela->r_addend +
- sizeof(struct tls_tcb);
+ return;
+ }
+ offs = def->st_value;
} else {
+ defobj = obj;
+ }
+ offs += rela->r_addend;
+
+ if (defobj->tls_done) {
+ /* Variable is in initialy allocated TLS segment */
+ where[0] = (Elf_Addr)_rtld_tlsdesc_static;
+ where[1] = defobj->tlsoffset + offs +
+ sizeof(struct tls_tcb);
+
+ rdbg(("TLSDESC %s --> %p static",
+ obj->path, (void *)where[1]));
+ } else {
+ /* TLS offset is unknown at load time, use dynamic resolving */
where[0] = (Elf_Addr)_rtld_tlsdesc_dynamic;
- where[1] = (Elf_Addr)_rtld_tlsdesc_alloc(obj, rela);
+ where[1] = (Elf_Addr)_rtld_tlsdesc_alloc(defobj->tlsindex, offs);
+
+ rdbg(("TLSDESC %s in %s --> %p dynamic (%zu, %p)",
+ obj->strtab + obj->symtab[symnum].st_name,
+ obj->path, (void *)where[1], defobj->tlsindex, (void *)offs));
}
}
@@ -276,7 +271,7 @@ _rtld_relocate_nonplt_objects(Obj_Entry *obj)
break;
case R_TYPE(TLSDESC):
- _rtld_tlsdesc_fill(obj, rela, where);
+ _rtld_tlsdesc_fill(obj, rela, where, 0);
break;
case R_TLS_TYPE(TLS_DTPREL):
@@ -344,7 +339,7 @@ _rtld_relocate_plt_lazy(Obj_Entry *obj)
rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where));
break;
case R_TYPE(TLSDESC):
- _rtld_tlsdesc_fill(obj, rela, where);
+ _rtld_tlsdesc_fill(obj, rela, where, SYMLOOK_IN_PLT);
break;
}
}
@@ -408,11 +403,7 @@ _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela,
*tp = new_value;
break;
case R_TYPE(TLSDESC):
- if (ELF_R_SYM(rela->r_info) != 0) {
- struct tls_data *tlsdesc = (struct tls_data *)where[1];
- if (tlsdesc->index == -1)
- _rtld_tlsdesc_handle_locked(tlsdesc, SYMLOOK_IN_PLT);
- }
+ _rtld_tlsdesc_fill(obj, rela, where, SYMLOOK_IN_PLT);
break;
}
diff --git a/libexec/ld.elf_so/arch/aarch64/rtld_start.S b/libexec/ld.elf_so/arch/aarch64/rtld_start.S
index b361809a3a7d..319d80feb479 100644
--- a/libexec/ld.elf_so/arch/aarch64/rtld_start.S
+++ b/libexec/ld.elf_so/arch/aarch64/rtld_start.S
@@ -1,4 +1,4 @@
-/* $NetBSD: rtld_start.S,v 1.3 2018/09/20 18:41:05 jakllsch Exp $ */
+/* $NetBSD: rtld_start.S,v 1.4 2019/01/18 11:59:03 skrll Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -60,7 +60,7 @@
#include <machine/asm.h>
-RCSID("$NetBSD: rtld_start.S,v 1.3 2018/09/20 18:41:05 jakllsch Exp $")
+RCSID("$NetBSD: rtld_start.S,v 1.4 2019/01/18 11:59:03 skrll Exp $")
/*
* void _rtld_start(void (*cleanup)(void), const Obj_Entry *obj,
@@ -145,47 +145,145 @@ ENTRY_NP(_rtld_bind_start)
br x17 /* call bound function */
END(_rtld_bind_start)
-
-ENTRY(_rtld_tlsdesc)
+/*
+ * struct rel_tlsdesc {
+ * uint64_t resolver_fnc;
+ * uint64_t resolver_arg;
+ *
+ *
+ * uint64_t _rtld_tlsdesc_static(struct rel_tlsdesc *);
+ *
+ * Resolver function for TLS symbols resolved at load time
+ */
+ENTRY(_rtld_tlsdesc_static)
+ .cfi_startproc
ldr x0, [x0, #8]
ret
-END(_rtld_tlsdesc)
+ .cfi_endproc
+END(_rtld_tlsdesc_static)
/*
- * uint64_t _rtld_tlsdesc_dynamic(struct tlsdesc *);
+ * uint64_t _rtld_tlsdesc_undef(void);
*
- * TODO: We could lookup the saved index here to skip saving the entire stack.
+ * Resolver function for weak and undefined TLS symbols
+ */
+ENTRY(_rtld_tlsdesc_undef)
+ .cfi_startproc
+ str x1, [sp, #-16]!
+ .cfi_adjust_cfa_offset 16
+
+ mrs x1, tpidr_el0
+ ldr x0, [x0, #8]
+ sub x0, x0, x1
+
+ ldr x1, [sp], #16
+ .cfi_adjust_cfa_offset -16
+ .cfi_endproc
+ ret
+END(_rtld_tlsdesc_undef)
+
+/*
+ * uint64_t _rtld_tlsdesc_dynamic(struct rel_tlsdesc *);
+ *
+ * Resolver function for TLS symbols from dlopen()
*/
ENTRY(_rtld_tlsdesc_dynamic)
- /* Store any registers we may use in rtld_tlsdesc_handle */
- stp x29, x30, [sp, #-(10 * 16)]!
- mov x29, sp
- stp x1, x2, [sp, #(1 * 16)]
- stp x3, x4, [sp, #(2 * 16)]
- stp x5, x6, [sp, #(3 * 16)]
- stp x7, x8, [sp, #(4 * 16)]
- stp x9, x10, [sp, #(5 * 16)]
- stp x11, x12, [sp, #(6 * 16)]
- stp x13, x14, [sp, #(7 * 16)]
- stp x15, x16, [sp, #(8 * 16)]
- stp x17, x18, [sp, #(9 * 16)]
+ .cfi_startproc
+
+ /* Save registers used in fast path */
+ stp x1, x2, [sp, #(-2 * 16)]!
+ stp x3, x4, [sp, #(1 * 16)]
+ .cfi_adjust_cfa_offset 2 * 16
+ .cfi_rel_offset x1, 0
+ .cfi_rel_offset x2, 8
+ .cfi_rel_offset x3, 16
+ .cfi_rel_offset x4, 24
+
+ /* Test fastpath - inlined version of __tls_get_addr. */
+
+ ldr x1, [x0, #8] /* tlsdesc ptr */
+ mrs x4, tpidr_el0
+ ldr x0, [x4] /* DTV pointer (tcb->tcb_dtv) */
+
+ ldr x3, [x0, #-8] /* DTV_MAX_INDEX(dtv) */
+ ldr x2, [x1, #0] /* tlsdesc->td_tlsindex */
+ cmp x2, x3
+ b.lt 1f /* Slow path */
+
+ ldr x3, [x0, x2, lsl #3] /* dtv[tlsdesc->td_tlsindex] */
+ cbz x3, 1f
+
+ /* Return (dtv[tlsdesc->td_tlsindex] + tlsdesc->td_tlsoffs - tp) */
+ ldr x2, [x1, #8] /* tlsdesc->td_tlsoffs */
+ add x2, x2, x3
+ sub x0, x2, x4
+
+ /* Restore registers and return */
+ ldp x3, x4, [sp, #(1 * 16)]
+ ldp x1, x2, [sp], #(2 * 16)
+ .cfi_adjust_cfa_offset -2 * 16
+ ret
+
+ /*
+ * Slow path
+ * return _rtld_tls_get_addr(tp, tlsdesc->td_tlsindex, tlsdesc->td_tlsoffs);
+ *
+ */
+1:
+ /* Save all interger registers */
+ stp x29, x30, [sp, #-(8 * 16)]!
+ .cfi_adjust_cfa_offset 8 * 16
+ .cfi_rel_offset x29, 0
+ .cfi_rel_offset x30, 8
+
+ stp x5, x6, [sp, #(1 * 16)]
+ stp x7, x8, [sp, #(2 * 16)]
+ stp x9, x10, [sp, #(3 * 16)]
+ stp x11, x12, [sp, #(4 * 16)]
+ stp x13, x14, [sp, #(5 * 16)]
+ stp x15, x16, [sp, #(6 * 16)]
+ stp x17, x18, [sp, #(7 * 16)]
+ .cfi_rel_offset x5, 16
+ .cfi_rel_offset x6, 24
+ .cfi_rel_offset x7, 32
+ .cfi_rel_offset x8, 40
+ .cfi_rel_offset x9, 48
+ .cfi_rel_offset x10, 56
+ .cfi_rel_offset x11, 64
+ .cfi_rel_offset x12, 72
+ .cfi_rel_offset x13, 80
+ .cfi_rel_offset x14, 88
+ .cfi_rel_offset x15, 96
+ .cfi_rel_offset x16, 104
+ .cfi_rel_offset x17, 112
+ .cfi_rel_offset x18, 120
/* Find the tls offset */
- ldr x0, [x0, #8]
- mov x1, #1
- bl _rtld_tlsdesc_handle
+ mov x0, x4 /* tp */
+ mov x3, x1 /* tlsdesc ptr */
+ ldr x1, [x3, #0] /* tlsdesc->td_tlsindex */
+ ldr x2, [x3, #8] /* tlsdesc->td_tlsoffs */
+ bl _rtld_tls_get_addr
+ mrs x1, tpidr_el0
+ sub x0, x0, x1
- /* Restore the registers */
- ldp x17, x18, [sp, #(9 * 16)]
- ldp x15, x16, [sp, #(8 * 16)]
- ldp x13, x14, [sp, #(7 * 16)]
- ldp x11, x12, [sp, #(6 * 16)]
- ldp x9, x10, [sp, #(5 * 16)]
- ldp x7, x8, [sp, #(4 * 16)]
- ldp x5, x6, [sp, #(3 * 16)]
- ldp x3, x4, [sp, #(2 * 16)]
- ldp x1, x2, [sp, #(1 * 16)]
- ldp x29, x30, [sp], #(10 * 16)
+ /* Restore slow path registers */
+ ldp x17, x18, [sp, #(7 * 16)]
+ ldp x15, x16, [sp, #(6 * 16)]
+ ldp x13, x14, [sp, #(5 * 16)]
+ ldp x11, x12, [sp, #(4 * 16)]
+ ldp x9, x10, [sp, #(3 * 16)]
+ ldp x7, x8, [sp, #(2 * 16)]
+ ldp x5, x6, [sp, #(1 * 16)]
+ ldp x29, x30, [sp], #(8 * 16)
+ .cfi_adjust_cfa_offset -8 * 16
+ .cfi_restore x29
+ .cfi_restore x30
+ /* Restore fast path registers and return */
+ ldp x3, x4, [sp, #16]
+ ldp x1, x2, [sp], #(2 * 16)
+ .cfi_adjust_cfa_offset -2 * 16
+ .cfi_endproc
ret
END(_rtld_tlsdesc_dynamic)