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Mathieu Desnoyers authored
Use udf as the guard instruction for the restartable sequence abort handler. Previously, the chosen signature was not a valid instruction, based on the assumption that it could always sit in a literal pool. However, there are compilation environments in which literal pools are not available, for instance execute-only code. Therefore, we need to choose a signature value that is also a valid instruction. Handle compiling with -mbig-endian on ARMv6+, which generates binaries with mixed code vs data endianness (little endian code, big endian data). Else mismatch between code endianness for the generated signatures and data endianness for the RSEQ_SIG parameter passed to the rseq registration will trigger application segmentation faults when the kernel try to abort rseq critical sections. Prior to ARMv6, -mbig-endian generates big-endian code and data, so endianness should not be reversed in that case. Signed-off-by:
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> CC: Peter Zijlstra <peterz@infradead.org> CC: Thomas Gleixner <tglx@linutronix.de> CC: Joel Fernandes <joelaf@google.com> CC: Catalin Marinas <catalin.marinas@arm.com> CC: Dave Watson <davejwatson@fb.com> CC: Will Deacon <will.deacon@arm.com> CC: Shuah Khan <shuah@kernel.org> CC: Andi Kleen <andi@firstfloor.org> CC: linux-kselftest@vger.kernel.org CC: "H . Peter Anvin" <hpa@zytor.com> CC: Chris Lameter <cl@linux.com> CC: Russell King <linux@arm.linux.org.uk> CC: Michael Kerrisk <mtk.manpages@gmail.com> CC: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com> CC: Paul Turner <pjt@google.com> CC: Boqun Feng <boqun.feng@gmail.com> CC: Josh Triplett <josh@joshtriplett.org> CC: Steven Rostedt <rostedt@goodmis.org> CC: Ben Maurer <bmaurer@fb.com> CC: linux-api@vger.kernel.org CC: Andy Lutomirski <luto@amacapital.net> CC: Andrew Morton <akpm@linux-foundation.org> CC: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Shuah Khan <skhan@linuxfoundation.org>
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