linux-hardened/Documentation/arm64
Suzuki K. Poulose 2d888f48e0 arm64: Emulate SETEND for AArch32 tasks
Emulate deprecated 'setend' instruction for AArch32 bit tasks.

	setend [le/be] - Sets the endianness of EL0

On systems with CPUs which support mixed endian at EL0, the hardware
support for the instruction can be enabled by setting the SCTLR_EL1.SED
bit. Like the other emulated instructions it is controlled by an entry in
/proc/sys/abi/. For more information see :
	Documentation/arm64/legacy_instructions.txt

The instruction is emulated by setting/clearing the SPSR_EL1.E bit, which
will be reflected in the PSTATE.E in AArch32 context.

This patch also restores the native endianness for the execution of signal
handlers, since the process could have changed the endianness.

Note: All CPUs on the system must have mixed endian support at EL0. Once the
handler is registered, hotplugging a CPU which doesn't support mixed endian,
could lead to unexpected results/behavior in applications.

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-01-23 17:11:44 +00:00
..
booting.txt KVM/ARM New features for 3.17 include: 2014-08-05 09:47:45 +02:00
legacy_instructions.txt arm64: Emulate SETEND for AArch32 tasks 2015-01-23 17:11:44 +00:00
memory.txt Documentation/arm64/memory.txt: fix typo 2014-10-20 17:55:38 +01:00
tagged-pointers.txt arm64: documentation: tighten up tagged pointer documentation 2013-09-20 09:56:06 +01:00