In Thumb2 mode, the stack register r13 is deprecated if the
destination register is the program counter (r15). Similar to
head.S, head-nommu.S uses r13 to store the return address used
after configuring the CPU's CP15 register. However, since we do
not enable a MMU, there will be no address switch and it is
possible to use branch with link instruction to call
__after_proc_init.

Avoid using r13 completely by using bl to call __after_proc_init
and get rid of __secondary_switched.

Beside removing unnecessary complexity, this also fixes a
compiler warning when compiling a !MMU kernel:
Warning: Use of r13 as a source register is deprecated when r15
is the destination register.

Tested-?by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Conflicts:
	arch/arm/kernel/head.S

These options make it possible to overwrites the data and instruction
prefetching behavior of the arm pl310 cache controller.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Commit cb1293e2 ("ARM: 8375/1: disable some options on ARMv7-M")
causes the build to on ARMv7-M machines:

  CC      arch/arm/kernel/asm-offsets.s
In file included from include/linux/sem.h:5:0,
                 from include/linux/sched.h:35,
                 from arch/arm/kernel/asm-offsets.c:14:
include/linux/rcupdate.h: In function 'rcu_read_lock_sched_held':
include/linux/rcupdate.h:539:2: error: implicit declaration of function
'arch_irqs_disabled' [-Werror=implicit-function-declaration]
  return preempt_count() != 0 || irqs_disabled();

asm-generic/irqflags.h provides an implementation of arch_irqs_disabled().
Lets grab an implementation from there!
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

When dma-coherent transfers are enabled, the mmap call must
not change the pg_prot flags in the vma struct.

Split the arm_dma_mmap into a common and specific parts,
and add a "arm_coherent_dma_mmap" implementation that does
not alter the page protection flags.

Tested on a topic-miami board (Zynq) using the ACP port
to transfer data between FPGA and CPU using the Dyplo
framework. Without this patch, byte-wise access to mmapped
coherent DMA memory was about 20x slower because of the
memory being marked as non-cacheable, and transfer speeds
would not exceed 240MB/s.

After this patch, the mapped memory is cacheable and the
transfer speed is again 600MB/s (limited by the FPGA) when
the data is in the L2 cache, while data integrity is being
maintained.

The patch has no effect on non-coherent DMA.
Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Fixes the TCM initialisation code to handle TCM banks that are
present but inaccessible due to TrustZone configuration.  This is
the default case when enabling the non-secure world.  It may also
be the case that that the user decided to use TCM for TrustZone.

This change has exposed a bug in handling of TCM where no TCM bank
was usable (the 0 size TCM case).  This change addresses the
resulting hang.

This code only handles the ARMv6 TCMTR register format, and will not
work correctly on boards that use the ARMv7 (or any other) format.
This is handled by performing an early exit from the initialisation
function when the TCMTR reports any format other than v6.
Signed-off-by: Michael van der Westhuizen <michael@smart-africa.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

When using a toolchain with gold as the default linker, the VDSO build
fails:

  VDSO    arch/arm/vdso/vdso.so.raw
  HOSTCC  arch/arm/vdso/vdsomunge
  MUNGE   arch/arm/vdso/vdso.so.dbg
  OBJCOPY arch/arm/vdso/vdso.so
BFD: arch/arm/vdso/vdso.so: Not enough room for program headers, try
linking with -N

For whatever reason, ld.gold is omitting an exidx program header that
ld.bfd emits, and even when I work around that, I don't get a working
VDSO.

For now, instead of supporting gold (which will fail to link the
kernel anyway since it does not implement --pic-veneer), direct the
compiler to use the traditional bfd linker.  This is accomplished by
using -fuse-ld, which is implemented in GCC 4.8 and later.

Note: one limitation of this is that if the toolchain is configured
to use gold by default, and the bfd linker is not in $PATH, the VDSO
build will fail:

  VDSO    arch/arm/vdso/vdso.so.raw
collect2: fatal error: cannot find 'ld'

This will happen if CROSS_COMPILE begins with a path such as
/opt/bin/arm-linux-gnu- but /opt/bin is not in $PATH.  This is
considered an acceptable corner-case limitation and is easily worked
around.

Additonal note: we use cc-option instead of cc-ldoption so that
-fuse-ld=bfd is placed in the command line if the compiler recognizes
the option.  Using cc-ldoption results in an attempt to link, which
fails in the situation just described, causing -fuse-ld=bfd to be
omitted and gold to be used for the VDSO link, which is what we're
trying to prevent.
Reported-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Currently the VDSO's link options are kind of a mess spread between

ccflags-y and cmd_vdsold.  Collect linker directives into one
variable, VDSO_LDFLAGS, and use that in cmd_vdsold.
Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

A recent change in kernel/acct.c added a new warning for many
configurations on ARM:

kernel/acct.c: In function 'acct_pin_kill':
arch/arm/include/asm/cmpxchg.h:122:3: warning: value computed is not used [-Wunused-value]

The code is in fact correct, it's just a cmpxchg() call that
intentionally ignores the result, and no other code does that.  The
warning does not show up on x86 because of the way that its cmpxchg()
macro is written. This changes the ARM implementation to use a similar
construct with a compound expression instead of a typecast, which causes
the compiler to not complain about an unused result.

Fix the other macros in this file in a similar way, and place them
just below their function implementations.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

We want link errors if xchg() is called for a variable size we do not
support.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Vybrids has 112 peripheral interrupts which can be routed to the
Cortex-M4's NVIC interrupt controller.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Commit 5261ef2ea836 ("ARM: 8366/1: move Dual-Timer SP804 driver to
drivers/clocksource") moved SP804 to drivers/clocksource resulting in
it being selectable on platforms/architectures without the config
GENERIC_SCHED_CLOCK enabled. Due to that, it results in the following
build failure(e.g. x86_64 allmodconfig)

drivers/built-in.o: In function `__sp804_clocksource_and_sched_clock_init':
(.init.text+0x1a0e7): undefined reference to `sched_clock_register'

This patch fixes the build by making ARM_TIMER_SP804 depend on
GENERIC_SCHED_CLOCK

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The ARM Dual-Timer SP804 module is peripheral found not only on ARM32
platforms but also on ARM64 platforms.

This patch moves the driver out of arch/arm to driver/clocksource
so that it can be used on ARM64 platforms also.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Olof Johansson <olof@lixom.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The header asm/hardware/arm_timer.h is included in various machine
specific files to access TIMER_CTRL and initialise to a known state.

This patch introduces a new function sp804_timer_disable to disable
the SP804 timers and uses the same for initialising the timers to
known(off) state, thereby removing the dependency on the header
asm/hardware/arm_timer.h

This change is in prepartion to move sp804 timer support out of arch/arm
so that it can be used on ARM64 platforms.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The new veneer support for loadable modules on ARM uses the
__opcode_to_mem_thumb32() function to count R_ARM_THM_CALL
and R_ARM_THM_JUMP24 relocations.

However, this function is not defined for big-endian kernels
on ARMv5 or before, causing a compile-time error:

arch/arm/kernel/module-plts.c: In function 'count_plts':
arch/arm/kernel/module-plts.c:124:9: error: implicit declaration of function '__opcode_to_mem_thumb32' [-Werror=implicit-function-declaration]
         __opcode_to_mem_thumb32(0x07ff2fff)))
         ^

As we know that this part of the function is only needed for
Thumb2 kernels, and that those can never happen with BE32,
we can avoid the error by enclosing the code in an #ifdef.

Fixes: 7d485f64 ("ARM: 8220/1: allow modules outside of bl range")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Put secondary_startup_arm() prototype in arch/arm/include/asm/smp.h
so users doesn't have to add extern prototype in their code.
Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

secondary_startup_arm is used as ARM mode secondary start up function
when ther kernel is compiled in THUMB mode, however the label itself
is still in .thumb mode. readelf shows:

160979: c020a581   120 FUNC    GLOBAL DEFAULT    2 secondary_startup_arm

Make sure the label is in ARM mode as well.
Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Tested-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Document that r13 is not a stack in the initialisation function, in
case anyone gets other ideas.

Document the registers available for the errata workarounds, and
specifically which registers contain parts of the MIDR register, as
well as which registers must be preserved.

Lastly, use the lowest numbered available register (r0) rather than
r10 for temporary storage.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

We already have the main ID register available in r9, there's no need
to refetch it.  Use the saved value.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Rather than having a long sprawling __v7_setup function, which is hard
to maintain properly, move the CPU errata out of line.

While doing this, it was discovered that the Cortex-A15 errata had been
incorrectly added:

	ldr	r10, =0x00000c08	@ Cortex-A8 primary part number
	teq	r0, r10
	bne	2f
/* Cortex-A8 errata */
	b	3f
2:	ldr	r10, =0x00000c09	@ Cortex-A9 primary part number
	teq	r0, r10
	bne	3f
/* Cortex-A9 errata */
3:	ldr	r10, =0x00000c0f	@ Cortex-A15 primary part number
	teq	r0, r10
	bne	4f
/* Cortex-A15 errata */
4:

This results in the Cortex-A15 test always being executed after the
Cortex-A8 and Cortex-A9 errata, which is obviously not what is intended.
The 'b 3f' labels should have been updated to 'b 4f'.  The new structure
of:

	/* Cortex-A8 Errata */
	ldr	r10, =0x00000c08	@ Cortex-A8 primary part number
	teq	r0, r10
	beq	__ca8_errata

	/* Cortex-A9 Errata */
	ldr	r10, =0x00000c09	@ Cortex-A9 primary part number
	teq	r0, r10
	beq	__ca9_errata

	/* Cortex-A15 Errata */
	ldr	r10, =0x00000c0f	@ Cortex-A15 primary part number
	teq	r0, r10
	beq	__ca15_errata

__errata_finish:

is much cleaner and easier to see that this kind of thing doesn't
happen.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Re-engineer the LPAE TTBR setup code.  Rather than passing some shifted
address in order to fit in a CPU register, pass either a full physical
address (in the case of r4, r5 for TTBR0) or a PFN (for TTBR1).

This removes the ARCH_PGD_SHIFT hack, and the last dangerous user of
cpu_set_ttbr() in the secondary CPU startup code path (which was there
to re-set TTBR1 to the appropriate high physical address space on
Keystone2.)
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Eliminate the needless nommu version of this function, and get rid of
the proc_info_list structure argument - we no longer need this in order
to fix up the page table entries.
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Re-implement the physical address space switching to be architecturally
compliant.  This involves flushing the caches, disabling the MMU, and
only then updating the page tables.  Once that is complete, the system
can be brought back up again.

Since we disable the MMU, we need to do the update in assembly code.
Luckily, the entries which need updating are fairly trivial, and are
all setup by the early assembly code.  We can merely adjust each entry
by the delta required.

Not only does this fix the code to be architecturally compliant, but it
fixes a couple of bugs too:

1. The original code would only ever update the first L2 entry covering
   a fraction of the kernel; the remainder were left untouched.
2. The L2 entries covering the DTB blob were likewise untouched.

This solution fixes up all entries.
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The init_meminfo() method is not about initialising meminfo - it's about
fixing up the physical to virtual translation so that we use a different
physical address space, possibly above the 4GB physical address space.
Therefore, the name "init_meminfo()" is confusing.

Rename it to pv_fixup() instead.
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

There is no point platform code doing this, let's move it into the
generic code so it doesn't get duplicated.
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Make the init_meminfo function return the offset to be applied to the
phys-to-virt translation constants.  This allows us to move the update
into generic code, along with the requirements for this update.

This avoids platforms having to know the details of the phys-to-virt
translation support.
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

We ideally want the init_meminfo function to do nothing but return the
delta to be applied to PHYS_OFFSET - it should do nothing else.  As we
can detect in platform init code whether we are running in the high
physical address space, move the platform notifier initialisation
entirely into the platform init code.
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Move current sa11x0 IRQ driver to the irqchip subsystem.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Prepare for moving sa1100 irq driver to irqchip infrastructure - split
sa1100_init_irq into helper code and irq parts.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The feroceon copypage implementation cannot be built when targetting an
ARMv4 CPU, so we need to pass the march=armv5te flag manually to gcc
when building this file. This is obviously safe since that code will
not be executed on ARMv4.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/net/built-in.o: In function `bpf_jit_compile':
:(.text+0x2758): undefined reference to `set_memory_ro'
arch/arm/net/built-in.o: In function `bpf_jit_free':
:(.text+0x27ac): undefined reference to `set_memory_rw'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

It's obviously pointless to dump page tables when the MMU is disabled,
and even trying to build this code results in numerous build errors
like these:

../arch/arm/mm/dump.c:56:11: error: 'L_PTE_USER' undeclared here (not in a function)
   .mask = L_PTE_USER,
           ^
../arch/arm/mm/dump.c:61:11: error: 'L_PTE_RDONLY' undeclared here (not in a function)
   .mask = L_PTE_RDONLY,
           ^
../arch/arm/mm/dump.c:66:11: error: 'L_PTE_XN' undeclared here (not in a function)
   .mask = L_PTE_XN,
           ^
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Kprobes, irqflags tracing and kexec don't currently build on
kernels targetting ARMv7-M, so for now, we should just disallow
those combinations.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Atmel at91x40 is gone, so we no longer have any platform using
either of these two, and we get randconfig failures on NOMMU
kernels if they accidentally get enabled on something that conflicts
with ARMv4T.

This stops short of removing the entire CPU support for now,
but as nothing selects these, it is basically dead code.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The branch profiling code cannot work outside of the main
kernel and just causes link errors if we try to use it in
the decompressor. Disabling it here matches what we do
for other architectures.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

KGDB requires code patching, which only works on little-endian
or newer big-endian (BE8) machines but not on the older big-endian
ones (BE32) where it results in this build error:

arch/arm/kernel/patch.c: In function '__patch_text_real':
arch/arm/kernel/patch.c:93:4: error: implicit declaration of function '__opcode_to_mem_thumb32' [-Werror=implicit-function-declaration]
    insn = __opcode_to_mem_thumb32(insn);

This adds a Kconfig dependency to avoid the broken case and
for all other symbols that require code patching.

Fixes: 23a4e405 ("arm: kgdb: Handle read-only text / modules")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Any SMP kernel now requires the irq_work code after
generic_smp_call_function_single_interrupt() started using it,
or we get:

kernel/built-in.o: In function `flush_smp_call_function_queue':
:(.text+0x4dc3a): undefined reference to `irq_work_run'

Fixes: 47885016 ("irq_work: Implement remote queueing")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Use ioremap() and readl/writel_relaxed() to access IRQ controller
registers.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>