Unicorn CPU emulator framework (ARM, AArch64, M68K, Mips, Sparc, X86)
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Peter Maydell 3fc86e1901
target/arm: Don't abort on M-profile exception return in linux-user mode
An attempt to do an exception-return (branch to one of the magic
addresses) in linux-user mode for M-profile should behave like
a normal branch, because linux-user mode is always going to be
in 'handler' mode. This used to work, but we broke it when we added
support for the M-profile security extension in commit d02a8698d7ae2bfed.

In that commit we allowed even handler-mode calls to magic return
values to be checked for and dealt with by causing an
EXCP_EXCEPTION_EXIT exception to be taken, because this is
needed for the FNC_RETURN return-from-non-secure-function-call
handling. For system mode we added a check in do_v7m_exception_exit()
to make any spurious calls from Handler mode behave correctly, but
forgot that linux-user mode would also be affected.

How an attempted return-from-non-secure-function-call in linux-user
mode should be handled is not clear -- on real hardware it would
result in return to secure code (not to the Linux kernel) which
could then handle the error in any way it chose. For QEMU we take
the simple approach of treating this erroneous return the same way
it would be handled on a CPU without the security extensions --
treat it as a normal branch.

The upshot of all this is that for linux-user mode we should never
do any of the bx_excret magic, so the code change is simple.

This ought to be a weird corner case that only affects broken guest
code (because Linux user processes should never be attempting to do
exception returns or NS function returns), except that the code that
assigns addresses in RAM for the process and stack in our linux-user
code does not attempt to avoid this magic address range, so
legitimate code attempting to return to a trampoline routine on the
stack can fall into this case. This change fixes those programs,
but we should also look at restricting the range of memory we
use for M-profile linux-user guests to the area that would be
real RAM in hardware.

Backports commit 9027d3fba605d8f6093342ebe4a1da450d374630 from qemu
2019-11-18 16:30:43 -05:00
bindings Removed hardcoded CP0C3_ULRI (#1098) 2019-08-08 20:08:57 -04:00
docs fix invalid script path (#975) (#976) 2019-02-28 17:02:06 -05:00
include x86: setup FS & GS base 2019-08-08 20:26:45 -04:00
msvc msvc: Define CONFIG_TCG 2019-01-30 13:52:30 -05:00
qemu target/arm: Don't abort on M-profile exception return in linux-user mode 2019-11-18 16:30:43 -05:00
samples target/riscv: Initial introduction of the RISC-V target 2019-03-08 21:46:10 -05:00
tests Add missing x86_vec regression test 2019-02-28 17:08:19 -05:00
.appveyor.yml MSYS test (#852) 2017-06-25 10:11:35 +08:00
.gitignore target/riscv: Initial introduction of the RISC-V target 2019-03-08 21:46:10 -05:00
.travis.yml use new travis osx image and brew (#935) 2018-01-05 10:29:49 +08:00
AUTHORS.TXT import 2015-08-21 15:04:50 +08:00
Brewfile Update Brewfile 2017-09-30 17:36:44 +07:00
ChangeLog update ChangeLog 2017-04-20 13:28:02 +08:00
config.mk Fix document file extension 2016-08-08 17:33:49 +09:00
COPYING import 2015-08-21 15:04:50 +08:00
COPYING_GLIB glib_compat: add COPYING_GLIB 2016-12-27 10:15:08 +08:00
COPYING.LGPL2 LGPL2 for all header files under include/unicorn/ 2017-12-16 10:08:42 +08:00
CREDITS.TXT Adding Philippe Antoine to CREDITS 2018-10-06 04:50:10 -04:00
install-cmocka-linux.sh Start moving examples in S files (#851) 2017-06-25 10:14:22 +08:00
list.c callback to count number of instructions in uc_emu_start() should be executed first. fix #727 2017-06-16 13:22:38 +08:00
make.sh remove broken iOS builds (#1109) 2019-08-08 20:09:05 -04:00
Makefile uc: Restore armeb target 2019-04-19 15:29:25 -04:00
msvc.bat add msvc.bat 2017-04-21 15:35:40 +08:00
pkgconfig.mk bump extra version to 2 2017-04-21 15:30:40 +08:00
README.md add Clojure 2017-12-23 00:32:33 +08:00
uc.c uc: Restore armeb target 2019-04-19 15:29:25 -04:00
windows_export.bat Make the call out to visual studio extremely resilient 2017-01-02 03:32:48 -08:00

Unicorn Engine

Join the chat at https://gitter.im/unicorn-engine/chat

Build Status Build status

Unicorn is a lightweight, multi-platform, multi-architecture CPU emulator framework based on QEMU.

Unicorn offers some unparalleled features:

  • Multi-architecture: ARM, ARM64 (ARMv8), M68K, MIPS, SPARC, and X86 (16, 32, 64-bit)
  • Clean/simple/lightweight/intuitive architecture-neutral API
  • Implemented in pure C language, with bindings for Crystal, Clojure, Visual Basic, Perl, Rust, Ruby, Python, Java, .NET, Go, Delphi/Free Pascal and Haskell.
  • Native support for Windows & *nix (with Mac OSX, Linux, *BSD & Solaris confirmed)
  • High performance via Just-In-Time compilation
  • Support for fine-grained instrumentation at various levels
  • Thread-safety by design
  • Distributed under free software license GPLv2

Further information is available at http://www.unicorn-engine.org

License

This project is released under the GPL license.

Compilation & Docs

See docs/COMPILE.md file for how to compile and install Unicorn.

More documentation is available in docs/README.md.

Contact

Contact us via mailing list, email or twitter for any questions.

Contribute

If you want to contribute, please pick up something from our Github issues.

We also maintain a list of more challenged problems in a TODO list.

CREDITS.TXT records important contributors of our project.