[src/trunk]: src/lib/libc/tls Mirror the ld.elf_so logic for handling alignin...

[joerg <joerg%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/452e253b84ac
branches:  trunk
changeset: 846264:452e253b84ac
user:      joerg <joerg%NetBSD.org@localhost>
date:      Thu Nov 07 22:25:21 2019 +0000

description:
Mirror the ld.elf_so logic for handling aligning the TLS size.
Most noticable, recompute the start of the TLS area for variant I
relative to the TCB. This makes a difference when the segment size and
base alignment don't agree.

diffstat:

 lib/libc/tls/tls.c |  23 +++++++++++++----------
 1 files changed, 13 insertions(+), 10 deletions(-)

diffs (63 lines):

diff -r 7fa9653aca0a -r 452e253b84ac lib/libc/tls/tls.c
--- a/lib/libc/tls/tls.c        Thu Nov 07 22:00:37 2019 +0000
+++ b/lib/libc/tls/tls.c        Thu Nov 07 22:25:21 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tls.c,v 1.11 2019/11/05 22:22:42 joerg Exp $   */
+/*     $NetBSD: tls.c,v 1.12 2019/11/07 22:25:21 joerg Exp $   */
 
 /*-
  * Copyright (c) 2011 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: tls.c,v 1.11 2019/11/05 22:22:42 joerg Exp $");
+__RCSID("$NetBSD: tls.c,v 1.12 2019/11/07 22:25:21 joerg Exp $");
 
 #include "namespace.h"
 
@@ -86,14 +86,16 @@
 
        if (initial_thread_tcb == NULL) {
 #ifdef __HAVE_TLS_VARIANT_II
-               tls_size = roundup2(tls_size, alignof(max_align_t));
+               tls_allocation = roundup2(tls_size, alignof(max_align_t));
+#else
+               tls_allocation = tls_size;
 #endif
-               tls_allocation = tls_size + sizeof(*tcb);
 
-               initial_thread_tcb = p = mmap(NULL, tls_allocation,
-                   PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
+               initial_thread_tcb = p = mmap(NULL,
+                   tls_allocation + sizeof(*tcb), PROT_READ | PROT_WRITE,
+                   MAP_ANON, -1, 0);
        } else {
-               p = calloc(1, tls_allocation);
+               p = calloc(1, tls_allocation + sizeof(*tcb));
        }
        if (p == NULL) {
                static const char msg[] =  "TLS allocation failed, terminating\n";
@@ -106,7 +108,8 @@
        p += sizeof(struct tls_tcb);
 #else
        /* LINTED tls_size is rounded above */
-       tcb = (struct tls_tcb *)(p + tls_size);
+       tcb = (struct tls_tcb *)(p + tls_allocation);
+       p = (uint8_t *)tcb - tls_size;
        tcb->tcb_self = tcb;
 #endif
        memcpy(p, tls_initaddr, tls_initsize);
@@ -126,10 +129,10 @@
        p = (uint8_t *)tcb;
 #else
        /* LINTED */
-       p = (uint8_t *)tcb - tls_size;
+       p = (uint8_t *)tcb - tls_allocation;
 #endif
        if (p == initial_thread_tcb)
-               munmap(p, tls_allocation);
+               munmap(p, tls_allocation + sizeof(*tcb));
        else
                free(p);
 }