linux.git/arch/arm/kernel/asm-offsets.c, branch v4.16

ARM: 8708/1: NOMMU: Rework MPU to be mostly done in C

2017-10-23T15:58:59+00:00

Currently, there are several issues with how MPU is setup:

 1. We won't boot if MPU is missing
 2. We won't boot if use XIP
 3. Further extension of MPU setup requires asm skills

The 1st point can be relaxed, so we can continue with boot CPU even if
MPU is missed and fail boot for secondaries only. To address the 2nd
point we could create region covering CONFIG_XIP_PHYS_ADDR - _end and
that might work for the first stage of MPU enable, but due to MPU's
alignment requirement we could cover too much, IOW we need more
flexibility in how we're partitioning memory regions... and it'd be
hardly possible to archive because of the 3rd point.

This patch is trying to address 1st and 3rd issues and paves the path
for 2nd and further improvements.

The most visible change introduced with this patch is that we start
using mpu_rgn_info array (as it was supposed?), so change in MPU setup
done by boot CPU is recorded there and feed to secondaries. It
allows us to keep minimal region setup for boot CPU and do the rest in
C. Since we start programming MPU regions in C evaluation of MPU
constrains (number of regions supported and minimal region order) can
be done once, which in turn open possibility to free-up "probe"
region early.

Tested-by: Szemző András 
Tested-by: Alexandre TORGUE 
Tested-by: Benjamin Gaignard 
Signed-off-by: Vladimir Murzin 
Signed-off-by: Russell King

ARM: signal handling support for FDPIC_FUNCPTRS functions

2017-09-10T23:31:46+00:00

Signal handlers are not direct function pointers but pointers to function
descriptor in that case. Therefore we must retrieve the actual function
address and load the GOT value into r9 from the descriptor before branching
to the actual handler.

If a restorer is provided, we also have to load its address and GOT from
its descriptor. That descriptor address and the code to load it is pushed
onto the stack to be executed as soon as the signal handler returns.

However, to be compatible with NX stacks, the FDPIC bounce code is also
copied to the signal page along with the other code stubs. Therefore this
code must get at the descriptor address whether it executes from the stack
or the signal page. To do so we use the stack pointer which points at the
signal stack frame where the descriptor address was stored. Because the
rt signal frame is different from the simpler frame, two versions of the
bounce code are needed, and two variants (ARM and Thumb) as well. The
asm-offsets facility is used to determine the actual offset in the signal
frame for each version, meaning that struct sigframe and rt_sigframe had
to be moved to a separate file.

Signed-off-by: Nicolas Pitre 
Acked-by: Mickael GUENE 
Tested-by: Vincent Abriou 
Tested-by: Andras Szemzo

ARM: save and reset the address limit when entering an exception

2016-07-07T15:01:01+00:00

When we enter an exception, the current address limit should not apply
to the exception context: if the exception context wishes to access
kernel space via the user accessors (eg, perf code), it must explicitly
request such access.

Acked-by: Will Deacon 
Signed-off-by: Russell King

ARM: introduce svc_pt_regs structure

2016-06-22T18:54:52+00:00

Since the privileged mode pt_regs are an extended version of the saved
userland pt_regs, introduce a new svc_pt_regs structure to describe this
layout.

Acked-by: Will Deacon 
Signed-off-by: Russell King

ARM: rename S_FRAME_SIZE to PT_REGS_SIZE

2016-06-22T18:54:28+00:00

S_FRAME_SIZE is no longer the size of the kernel stack frame, so this
name is misleading.  It is the size of the kernel pt_regs structure.
Name it so.

Acked-by: Will Deacon 
Signed-off-by: Russell King

ARM: KVM: Remove unused hyp_pc field

2016-02-29T18:34:15+00:00

This field was never populated, and the panic code already
does something similar. Delete the related code.

Acked-by: Christoffer Dall 
Signed-off-by: Marc Zyngier

ARM: KVM: Cleanup asm-offsets.c

2016-02-29T18:34:15+00:00

Since we don't have much assembler left, most of the KVM stuff
in asm-offsets.c is now superfluous. Let's get rid of it.

Acked-by: Christoffer Dall 
Signed-off-by: Marc Zyngier

ARM: KVM: Move GP registers into the CPU context structure

2016-02-29T18:34:12+00:00

Continuing our rework of the CPU context, we now move the GP
registers into the CPU context structure.

Reviewed-by: Christoffer Dall 
Signed-off-by: Marc Zyngier

ARM: KVM: Move CP15 array into the CPU context structure

2016-02-29T18:34:12+00:00

Continuing our rework of the CPU context, we now move the CP15
array into the CPU context structure. As this causes quite a bit
of churn, we introduce the vcpu_cp15() macro that abstract the
location of the actual array. This will probably help next time
we have to revisit that code.

Reviewed-by: Christoffer Dall 
Signed-off-by: Marc Zyngier

ARM: KVM: Move VFP registers to a CPU context structure

2016-02-29T18:34:12+00:00

In order to turn the WS code into something that looks a bit
more like the arm64 version, move the VFP registers into a
CPU context container for both the host and the guest.

Reviewed-by: Christoffer Dall 
Signed-off-by: Marc Zyngier