You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
125 lines
5.1 KiB
125 lines
5.1 KiB
commit 533bb7c2ae156ff2d49b2e0b20b33810ba5e2721 |
|
Author: Siddhesh Poyarekar <siddhesh@redhat.com> |
|
Date: Wed Nov 12 19:30:24 2014 +0530 |
|
|
|
Fix stack alignment when loader is invoked directly |
|
|
|
The s390 ABI requires the stack pointer to be aligned at 8-bytes. |
|
When a program is invoked as an argument to the dynamic linker, |
|
_dl_start_user adjusts the stack to remove the dynamic linker |
|
arguments so that the program sees only its name and arguments. This |
|
may result in the stack being misaligned since each argument shift is |
|
only a word and not a double-word. |
|
|
|
This is now fixed shifting argv and envp down instead of shifting argc |
|
up and reclaiming the stack. This requires _dl_argv to be adjusted |
|
and hence, is no longer relro. |
|
|
|
diff --git glibc-2.17-c758a686/sysdeps/s390/s390-32/dl-machine.h glibc-2.17-c758a686/sysdeps/s390/s390-32/dl-machine.h |
|
index c56185c..79f8ef9 100644 |
|
--- glibc-2.17-c758a686/sysdeps/s390/s390-32/dl-machine.h |
|
+++ glibc-2.17-c758a686/sysdeps/s390/s390-32/dl-machine.h |
|
@@ -166,18 +166,49 @@ _dl_start_user:\n\ |
|
# See if we were run as a command with the executable file\n\ |
|
# name as an extra leading argument.\n\ |
|
l %r1,_dl_skip_args@GOT12(0,%r12)\n\ |
|
- l %r1,0(%r1) # load _dl_skip_args\n\ |
|
+ l %r1,0(%r1) # load _dl_skip_args\n\ |
|
+ ltr %r1,%r1\n\ |
|
+ je .L4 # Skip the arg adjustment if there were none.\n\ |
|
# Get the original argument count.\n\ |
|
l %r0,96(%r15)\n\ |
|
# Subtract _dl_skip_args from it.\n\ |
|
sr %r0,%r1\n\ |
|
- # Adjust the stack pointer to skip _dl_skip_args words.\n\ |
|
- sll %r1,2\n\ |
|
- ar %r15,%r1\n\ |
|
- # Set the back chain to zero again\n\ |
|
- xc 0(4,%r15),0(%r15)\n\ |
|
# Store back the modified argument count.\n\ |
|
st %r0,96(%r15)\n\ |
|
+ # Copy argv and envp forward to account for skipped argv entries.\n\ |
|
+ # We skipped at least one argument or we would not get here.\n\ |
|
+ la %r6,100(%r15) # Destination pointer i.e. &argv[0]\n\ |
|
+ lr %r5,%r6\n\ |
|
+ lr %r0,%r1\n\ |
|
+ sll %r0,2\n # Number of skipped bytes.\n\ |
|
+ ar %r5,%r0 # Source pointer = Dest + Skipped args.\n\ |
|
+ # argv copy loop:\n\ |
|
+.L1: l %r7,0(%r5) # Load a word from the source.\n\ |
|
+ st %r7,0(%r6) # Store the word in the destination.\n\ |
|
+ ahi %r5,4\n\ |
|
+ ahi %r6,4\n\ |
|
+ ltr %r7,%r7\n\ |
|
+ jne .L1 # Stop after copying the NULL.\n\ |
|
+ # envp copy loop:\n\ |
|
+.L2: l %r7,0(%r5) # Load a word from the source.\n\ |
|
+ st %r7,0(%r6) # Store the word in the destination.\n\ |
|
+ ahi %r5,4\n\ |
|
+ ahi %r6,4\n\ |
|
+ ltr %r7,%r7\n\ |
|
+ jne .L2 # Stop after copying the NULL.\n\ |
|
+ # Now we have to zero out the envp entries after NULL to allow\n\ |
|
+ # start.S to properly find auxv by skipping zeroes.\n\ |
|
+ # zero out loop:\n\ |
|
+ lhi %r7,0\n\ |
|
+.L3: st %r7,0(%r6) # Store zero.\n\ |
|
+ ahi %r6,4 # Advance dest pointer.\n\ |
|
+ ahi %r1,-1 # Subtract one from the word count.\n\ |
|
+ ltr %r1,%r1\n\ |
|
+ jne .L3 # Keep copying if the word count is non-zero.\n\ |
|
+ # Adjust _dl_argv\n\ |
|
+ la %r6,100(%r15)\n\ |
|
+ l %r1,_dl_argv@GOT12(0,%r12)\n\ |
|
+ st %r6,0(%r1)\n\ |
|
# The special initializer gets called with the stack just\n\ |
|
# as the application's entry point will see it; it can\n\ |
|
# switch stacks if it moves these contents over.\n\ |
|
@@ -185,7 +216,7 @@ _dl_start_user:\n\ |
|
# Call the function to run the initializers.\n\ |
|
# Load the parameters:\n\ |
|
# (%r2, %r3, %r4, %r5) = (_dl_loaded, argc, argv, envp)\n\ |
|
- l %r2,_rtld_local@GOT(%r12)\n\ |
|
+.L4: l %r2,_rtld_local@GOT(%r12)\n\ |
|
l %r2,0(%r2)\n\ |
|
l %r3,96(%r15)\n\ |
|
la %r4,100(%r15)\n\ |
|
@@ -198,6 +229,9 @@ _dl_start_user:\n\ |
|
l %r14,_dl_fini@GOT(%r12)\n\ |
|
# Free stack frame\n\ |
|
ahi %r15,96\n\ |
|
+ # Reload argc and argv for the user's entry point.\n\ |
|
+ # l %r2,0(%r15)\n\ |
|
+ # la %r3,4(%r15)\n\ |
|
# Jump to the user's entry point (saved in %r8).\n\ |
|
br %r8\n\ |
|
.Llit:\n\ |
|
diff --git glibc-2.17-c758a686/sysdeps/s390/s390-32/dl-sysdep.h glibc-2.17-c758a686/sysdeps/s390/s390-32/dl-sysdep.h |
|
new file mode 100644 |
|
index 0000000..b992778 |
|
--- /dev/null |
|
+++ glibc-2.17-c758a686/sysdeps/s390/s390-32/dl-sysdep.h |
|
@@ -0,0 +1,23 @@ |
|
+/* System-specific settings for dynamic linker code. S/390 version. |
|
+ Copyright (C) 2014 Free Software Foundation, Inc. |
|
+ This file is part of the GNU C Library. |
|
+ |
|
+ The GNU C Library is free software; you can redistribute it and/or |
|
+ modify it under the terms of the GNU Lesser General Public |
|
+ License as published by the Free Software Foundation; either |
|
+ version 2.1 of the License, or (at your option) any later version. |
|
+ |
|
+ The GNU C Library is distributed in the hope that it will be useful, |
|
+ but WITHOUT ANY WARRANTY; without even the implied warranty of |
|
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
|
+ Lesser General Public License for more details. |
|
+ |
|
+ You should have received a copy of the GNU Lesser General Public |
|
+ License along with the GNU C Library. If not, see |
|
+ <http://www.gnu.org/licenses/>. */ |
|
+ |
|
+#include_next <dl-sysdep.h> |
|
+ |
|
+/* _dl_argv cannot be attribute_relro, because _dl_start_user |
|
+ might write into it after _dl_start returns. */ |
|
+#define DL_ARGV_NOT_RELRO 1
|
|
|