3497 Commits

Author SHA1 Message Date
Ard Biesheuvel
7a8ca84a25 ARM: entry: fix unwinder problems caused by IRQ stacks
The IRQ stacks series made some changes to the unwinder, to permit
unwinding across different stacks. This is needed because otherwise, the
call stack would terminate at the point where the stack switch between
the task stack and the IRQ stack occurs, which would defeat any
diagnostics that rely on timer interrupts, such as RCU stall detection.

Unfortunately, getting the unwind annotations correct turns out to be
difficult, given that this now involves a frame pointer which needs to
point into the right location in the task stack when unwinding from the
IRQ stack. Getting this wrong for an exception handling routine results
in the stack pointer to be unwound from the wrong location, causing any
subsequent unwind attempts to cause all kinds of issues, as reported by
Naresh here [0].

So let's simplify this, by deferring the stack switch to
call_with_stack(), which already has the correct unwind annotations, and
removing all the complicated handling of the stack frame from the IRQ
exception entrypoint itself.

[0] https://lore.kernel.org/all/CA+G9fYtpy8VgK+ag6OsA9TDrwi5YGU4hu7GM8xwpO7v6LrCD4Q@mail.gmail.com/

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-03-11 12:59:32 +00:00
Russell King (Oracle)
c46c2c9b43 ARM: unwind: set frame.pc correctly for current-thread unwinding
When e.g. a WARN_ON() is encountered, we attempt to unwind the current
thread. To do this, we set frame.pc to unwind_backtrace, which means it
points at the beginning of the function. However, the rest of the state
is initialised from within the function, which means the function
prologue has already been run.

This can be confusing, and with a recent patch from Ard, can result in
the unwinder misbehaving if we want to be strict about the PC value.

If we correctly initialise the state so it is self-consistent (in other
words, set frame.pc to the location we are initialising it) then we
eliminate this confusion, and avoid possible future issues.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-03-11 10:55:28 +00:00
Ard Biesheuvel
6845d64d51 ARM: 9184/1: return_address: disable again for CONFIG_ARM_UNWIND=y
Commit 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI
unwinder") removed the dummy version of return_address() that was
provided for the CONFIG_ARM_UNWIND=y case, on the assumption that the
removal of the kernel_text_address() call from unwind_frame() in the
preceding patch made it safe to do so.

However, this turns out not to be the case: Corentin reports warnings
about suspicious RCU usage and other strange behavior that seems to
originate in the stack unwinding that occurs in return_address().

Given that the function graph tracer (which is what these changes were
enabling for CONFIG_ARM_UNWIND=y builds) does not appear to care about
this distinction, let's revert return_address() to the old state.

Cc: Corentin Labbe <clabbe.montjoie@gmail.com>
Fixes: 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI unwinder")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reported-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-03-07 11:43:12 +00:00
Ard Biesheuvel
8167937647 ARM: 9183/1: unwind: avoid spurious warnings on bogus code addresses
Corentin reports that since commit 538b9265c063 ("ARM: unwind: track
location of LR value in stack frame"), numerous spurious warnings are
emitted into the kernel log:

  [    0.000000] unwind: Index not found c0f0c440
  [    0.000000] unwind: Index not found 00000000
  [    0.000000] unwind: Index not found c0f0c440
  [    0.000000] unwind: Index not found 00000000

This is due to the fact that the commit in question removes a check
whether the PC value in the unwound frame is actually a kernel text
address, on the assumption that such an address will not be associated
with valid unwind data to begin with, which is checked right after.

The reason for removing this check was that unwind_frame() will be
called by the ftrace graph tracer code, which means that it can no
longer be safely instrumented itself, or any code that it calls, as it
could cause infinite recursion.

In order to prevent the spurious diagnostics, let's add back the call to
kernel_text_address(), but this time, only call it if no unwind data
could be found for the address in question. This is more efficient for
the common successful case, and should avoid any unintended recursion,
considering that kernel_text_address() will only be called if no unwind
data was found.

Cc: Corentin Labbe <clabbe.montjoie@gmail.com>
Fixes: 538b9265c063 ("ARM: unwind: track location of LR value in stack frame")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-03-07 11:43:12 +00:00
Ard Biesheuvel
41918ec82e ARM: ftrace: enable the graph tracer with the EABI unwinder
Enable the function graph tracer in combination with the EABI unwinder,
so that Thumb2 builds or Clang ARM builds can make use of it.

This involves using the unwinder to locate the return address of an
instrumented function on the stack, so that it can be overridden and
made to refer to the ftrace handling routines that need to be called at
function return.

Given that for these builds, it is not guaranteed that the value of the
link register is stored on the stack, fall back to the stack slot that
will be used by the ftrace exit code to restore LR in the instrumented
function's execution context.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-09 09:13:59 +01:00
Ard Biesheuvel
538b9265c0 ARM: unwind: track location of LR value in stack frame
The ftrace graph tracer needs to override the return address of an
instrumented function, in order to install a hook that gets invoked when
the function returns again.

Currently, we only support this when building for ARM using GCC with
frame pointers, as in this case, it is guaranteed that the function will
reload LR from [FP, #-4] in all cases, and we can simply pass that
address to the ftrace code.

In order to support this for configurations that rely on the EABI
unwinder, such as Thumb2 builds, make the unwinder keep track of the
address from which LR was unwound, permitting ftrace to make use of this
in a subsequent patch.

Drop the call to is_kernel_text_address(), which is problematic in terms
of ftrace recursion, given that it may be instrumented itself. The call
is redundant anyway, as no unwind directives will be found unless the PC
points to memory that is known to contain executable code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2022-02-09 09:13:43 +01:00
Ard Biesheuvel
953f534a7e ARM: ftrace: enable HAVE_FUNCTION_GRAPH_FP_TEST
Fix the frame pointer handling in the function graph tracer entry and
exit code so we can enable HAVE_FUNCTION_GRAPH_FP_TEST. Instead of using
FP directly (which will have different values between the entry and exit
pieces of the function graph tracer), use the value of SP at entry and
exit, as we can derive the former value from the frame pointer.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-09 09:12:33 +01:00
Ard Biesheuvel
65aa7e342a ARM: ftrace: avoid unnecessary literal loads
Avoid explicit literal loads and instead, use accessor macros that
generate the optimal sequence depending on the architecture revision
being targeted.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-09 09:12:33 +01:00
Ard Biesheuvel
d119678708 ARM: ftrace: avoid redundant loads or clobbering IP
Tweak the ftrace return paths to avoid redundant loads of SP, as well as
unnecessary clobbering of IP.

This also fixes the inconsistency of using MOV to perform a function
return, which is sub-optimal on recent micro-architectures but more
importantly, does not perform an interworking return, unlike compiler
generated function returns in Thumb2 builds.

Let's fix this by popping PC from the stack like most ordinary code
does.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-09 09:12:32 +01:00
Ard Biesheuvel
dc438db582 ARM: ftrace: use trampolines to keep .init.text in branching range
Kernel images that are large in comparison to the range of a direct
branch may fail to work as expected with ftrace, as patching a direct
branch to one of the core ftrace routines may not be possible from the
.init.text section, if it is emitted too far away from the normal .text
section.

This is more likely to affect Thumb2 builds, given that its range is
only -/+ 16 MiB (as opposed to ARM which has -/+ 32 MiB), but may occur
in either ISA.

To work around this, add a couple of trampolines to .init.text and
swap these in when the ftrace patching code is operating on callers in
.init.text.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-09 09:12:32 +01:00
Ard Biesheuvel
ad1c2f39fd ARM: ftrace: use ADD not POP to counter PUSH at entry
The compiler emitted hook used for ftrace consists of a PUSH {LR} to
preserve the link register, followed by a branch-and-link (BL) to
__gnu_mount_nc. Dynamic ftrace patches away the latter to turn the
combined sequence into a NOP, using a POP {LR} instruction.

This is not necessary, since the link register does not get clobbered in
this case, and simply adding #4 to the stack pointer is sufficient, and
avoids a memory access that may take a few cycles to resolve depending
on the micro-architecture.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-09 09:12:32 +01:00
Ard Biesheuvel
dd88b03ff0 ARM: ftrace: ensure that ADR takes the Thumb bit into account
Using ADR to take the address of 'ftrace_stub' via a local label
produces an address that has the Thumb bit cleared, which means the
subsequent comparison is guaranteed to fail. Instead, use the badr
macro, which forces the Thumb bit to be set.

Fixes: a3ba87a61499 ("ARM: 6316/1: ftrace: add Thumb-2 support")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2022-02-09 09:12:32 +01:00
Ard Biesheuvel
57a420435e ARM: drop pointless SMP check on secondary startup path
Only SMP systems use the secondary startup path by definition, so there
is no need for SMP conditionals there.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2022-01-25 09:53:52 +01:00
Ard Biesheuvel
d31e23aff0 ARM: mm: make vmalloc_seq handling SMP safe
Rework the vmalloc_seq handling so it can be used safely under SMP, as
we started using it to ensure that vmap'ed stacks are guaranteed to be
mapped by the active mm before switching to a task, and here we need to
ensure that changes to the page tables are visible to other CPUs when
they observe a change in the sequence count.

Since LPAE needs none of this, fold a check against it into the
vmalloc_seq counter check after breaking it out into a separate static
inline helper.

Given that vmap'ed stacks are now also supported on !SMP configurations,
let's drop the WARN() that could potentially now fire spuriously.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2022-01-25 09:53:52 +01:00
Ard Biesheuvel
aa0a20f521 ARM: entry: avoid clobbering R9 in IRQ handler
Avoid using R9 in the IRQ handler code, as the entry code uses it for
tsk, and expects it to remain untouched between the IRQ entry and exit
code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2022-01-25 09:53:52 +01:00
Ard Biesheuvel
75fa4adc4f ARM: smp: elide HWCAP_TLS checks or __entry_task updates on SMP+v6
Use the SMP_ON_UP patching framework to elide HWCAP_TLS tests from the
context switch and return to userspace code paths, as SMP systems are
guaranteed to have this h/w capability.

At the same time, omit the update of __entry_task if the system is
detected to be UP at runtime, as in that case, the value is never used.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2022-01-25 09:53:52 +01:00
Ard Biesheuvel
d6905849f8 ARM: assembler: define a Kconfig symbol for group relocation support
Nathan reports the group relocations go out of range in pathological
cases such as allyesconfig kernels, which have little chance of actually
booting but are still used in validation.

So add a Kconfig symbol for this feature, and make it depend on
!COMPILE_TEST.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2022-01-24 21:02:34 +01:00
Ard Biesheuvel
8b806b82bc ARM: mm: switch to swapper_pg_dir early for vmap'ed stack
When onlining a CPU, switch to swapper_pg_dir as soon as possible so
that it is guaranteed that the vmap'ed stack is mapped before it is
used.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2022-01-24 20:37:55 +01:00
Ard Biesheuvel
cafc0eab16 ARM: v7m: enable support for IRQ stacks
Enable support for IRQ stacks on !MMU, and add the code to the IRQ entry
path to switch to the IRQ stack if not running from it already.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-06 12:49:17 +01:00
Ard Biesheuvel
9c46929e79 ARM: implement THREAD_INFO_IN_TASK for uniprocessor systems
On UP systems, only a single task can be 'current' at the same time,
which means we can use a global variable to track it. This means we can
also enable THREAD_INFO_IN_TASK for those systems, as in that case,
thread_info is accessed via current rather than the other way around,
removing the need to store thread_info at the base of the task stack.
This, in turn, permits us to enable IRQ stacks and vmap'ed stacks on UP
systems as well.

To partially mitigate the performance overhead of this arrangement, use
a ADD/ADD/LDR sequence with the appropriate PC-relative group
relocations to load the value of current when needed. This means that
accessing current will still only require a single load as before,
avoiding the need for a literal to carry the address of the global
variable in each function. However, accessing thread_info will now
require this load as well.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-06 12:49:17 +01:00
Ard Biesheuvel
c275591037 ARM: smp: defer TPIDRURO update for SMP v6 configurations too
Defer TPIDURO updates for user space until exit also for CPU_V6+SMP
configurations so that we can decide at runtime whether to use it to
carry the current pointer, provided that we are running on a CPU that
actually implements this register. This is needed for
THREAD_INFO_IN_TASK support for UP systems, which requires that all SMP
capable systems use the TPIDRURO based access to 'current' as the only
remaining alternative will be a global variable which only works on UP.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-06 12:49:17 +01:00
Ard Biesheuvel
7b9896c352 ARM: percpu: add SMP_ON_UP support
Permit the use of the TPIDRPRW system register for carrying the per-CPU
offset in generic SMP configurations that also target non-SMP capable
ARMv6 cores. This uses the SMP_ON_UP code patching framework to turn all
TPIDRPRW accesses into reads/writes of entry #0 in the __per_cpu_offset
array.

While at it, switch over some existing direct TPIDRPRW accesses in asm
code to invocations of a new helper that is patched in the same way when
necessary.

Note that CPU_V6+SMP without SMP_ON_UP results in a kernel that does not
boot on v6 CPUs without SMP extensions, so add this dependency to
Kconfig as well.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-06 12:49:17 +01:00
Ard Biesheuvel
4e918ab13e ARM: assembler: add optimized ldr/str macros to load variables from memory
We will be adding variable loads to various hot paths, so it makes sense
to add a helper macro that can load variables from asm code without the
use of literal pool entries. On v7 or later, we can simply use MOVW/MOVT
pairs, but on earlier cores, this requires a bit of hackery to emit a
instruction sequence that implements this using a sequence of ADD/LDR
instructions.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-06 12:49:16 +01:00
Ard Biesheuvel
1fa8c4b195 ARM: module: implement support for PC-relative group relocations
Add support for the R_ARM_ALU_PC_Gn_NC and R_ARM_LDR_PC_G2 group
relocations [0] so we can use them in modules. These will be used to
load the current task pointer from a global variable without having to
rely on a literal pool entry to carry the address of this variable,
which may have a significant negative impact on cache utilization for
variables that are used often and in many different places, as each
occurrence will result in a literal pool entry and therefore a line in
the D-cache.

[0] 'ELF for the ARM architecture'
    https://github.com/ARM-software/abi-aa/releases

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-06 12:49:16 +01:00
Ard Biesheuvel
831a469bc1 ARM: entry: preserve thread_info pointer in switch_to
Tweak the UP stack protector handling code so that the thread info
pointer is preserved in R7 until set_current is called. This is needed
for a subsequent patch that implements THREAD_INFO_IN_TASK and
set_current for UP as well.

This also means we will prefer the per-task protector on UP systems that
implement the thread ID registers, so tweak the preprocessor
conditionals to reflect this.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-06 12:49:16 +01:00
Vladimir Murzin
52d2408717 irqchip: nvic: Use GENERIC_IRQ_MULTI_HANDLER
Rather then restructuring the ARMv7M entrly logic per TODO, just move
NVIC to GENERIC_IRQ_MULTI_HANDLER.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-06 12:49:16 +01:00
Arnd Bergmann
54f481a230 ARM: remove old-style irq entry
The last user of arch_irq_handler_default is gone now, so the
entry-macro-multi.S file and all references to mach/entry-macro.S can
be removed, as well as the asm_do_IRQ() entrypoint into the interrupt
handling routines implemented in C.

Note: The ARMv7-M entry still uses its own top-level IRQ entry, calling
nvic_handle_irq() from assembly. This could be changed to go through
generic_handle_arch_irq() as well, but it's unclear to me if there are
any benefits.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[ardb: keep irq_handler macro as it carries all the IRQ stack handling]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2021-12-06 12:49:11 +01:00
Arnd Bergmann
6f5d248d05 ARM: iop32x: use GENERIC_IRQ_MULTI_HANDLER
iop32x uses the entry-macro.S file for both the IRQ entry and for
hooking into the arch_ret_to_user code path. This is done because the
cp6 registers have to be enabled before accessing any of the interrupt
controller registers but have to be disabled when running in user space.

There is also a lazy-enable logic in cp6.c, but during a hardirq, we
know it has to be enabled.

Both the cp6-enable code and the code to read the IRQ status can be
lifted into the normal generic_handle_arch_irq() path, but the
cp6-disable code has to remain in the user return code. As nothing
other than iop32x uses this hook, just open-code it there with an
ifdef for the platform that can eventually be removed when iop32x
has reached the end of its life.

The cp6-enable path in the IRQ entry has an extra cp_wait barrier that
the trap version does not have, but it is harmless to do it in both
cases to simplify the logic here at the cost of a few extra cycles
for the trap.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-06 12:49:04 +01:00
Ard Biesheuvel
a1c510d0ad ARM: implement support for vmap'ed stacks
Wire up the generic support for managing task stack allocations via vmalloc,
and implement the entry code that detects whether we faulted because of a
stack overrun (or future stack overrun caused by pushing the pt_regs array)

While this adds a fair amount of tricky entry asm code, it should be
noted that it only adds a TST + branch to the svc_entry path. The code
implementing the non-trivial handling of the overflow stack is emitted
out-of-line into the .text section.

Since on ARM, we rely on do_translation_fault() to keep PMD level page
table entries that cover the vmalloc region up to date, we need to
ensure that we don't hit such a stale PMD entry when accessing the
stack. So we do a dummy read from the new stack while still running from
the old one on the context switch path, and bump the vmalloc_seq counter
when PMD level entries in the vmalloc range are modified, so that the MM
switch fetches the latest version of the entries.

Note that we need to increase the per-mode stack by 1 word, to gain some
space to stash a GPR until we know it is safe to touch the stack.
However, due to the cacheline alignment of the struct, this does not
actually increase the memory footprint of the struct stack array at all.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:33 +01:00
Ard Biesheuvel
ae5cc07da8 ARM: entry: rework stack realignment code in svc_entry
The original Thumb-2 enablement patches updated the stack realignment
code in svc_entry to work around the lack of a STMIB instruction in
Thumb-2, by subtracting 4 from the frame size, inverting the sense of
the misaligment check, and changing to a STMIA instruction and a final
stack push of a 4 byte quantity that results in the stack becoming
aligned at the end of the sequence. It also pushes and pops R0 to the
stack in order to have a temp register that Thumb-2 allows in general
purpose ALU instructions, as TST using SP is not permitted.

Both are a bit problematic for vmap'ed stacks, as using the stack is
only permitted after we decide that we did not overflow the stack, or
have already switched to the overflow stack.

As for the alignment check: the current approach creates a corner case
where, if the initial SUB of SP ends up right at the start of the stack,
we will end up subtracting another 8 bytes and overflowing it.  This
means we would need to add the overflow check *after* the SUB that
deliberately misaligns the stack. However, this would require us to keep
local state (i.e., whether we performed the subtract or not) across the
overflow check, but without any GPRs or stack available.

So let's switch to an approach where we don't use the stack, and where
the alignment check of the stack pointer occurs in the usual way, as
this is guaranteed not to result in overflow. This means we will be able
to do the overflow check first.

While at it, switch to R1 so the mode stack pointer in R0 remains
accessible.

Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:33 +01:00
Ard Biesheuvel
b832faec33 ARM: switch_to: clean up Thumb2 code path
The load-multiple instruction that essentially performs the switch_to
operation in ARM mode, by loading all callee save registers as well the
stack pointer and the program counter, is split into 3 separate loads
for Thumb-2, with the IP register used as a temporary to capture the
value of R4 before it gets overwritten.

We can clean this up a bit, by sticking with a single LDMIA instruction,
but one that pops SP and PC into IP and LR, respectively, and by using
ordinary move register and branch instructions to get those values into
SP and PC. This also allows us to move the set_current call closer to
the assignment of SP, reducing the window where those are mutually out
of sync. This is especially relevant for CONFIG_VMAP_STACK, which is
being introduced in a subsequent patch, where we need to issue a load
that might fault from the new stack while running from the old one, to
ensure that stale PMD entries in the VMALLOC space are synced up.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:32 +01:00
Ard Biesheuvel
532319b9c4 ARM: unwind: disregard unwind info before stack frame is set up
When unwinding the stack from a stack overflow, we are likely to start
from a stack push instruction, given that this is the most common way to
grow the stack for compiler emitted code. This push instruction rarely
appears anywhere else than at offset 0x0 of the function, and if it
doesn't, the compiler tends to split up the unwind annotations, given
that the stack frame layout is apparently not the same throughout the
function.

This means that, in the general case, if the frame's PC points at the
first instruction covered by a certain unwind entry, there is no way the
stack frame that the unwind entry describes could have been created yet,
and so we are still on the stack frame of the caller in that case. So
treat this as a special case, and return with the new PC taken from the
frame's LR, without applying the unwind transformations to the virtual
register set.

This permits us to unwind the call stack on stack overflow when the
overflow was caused by a stack push on function entry.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:32 +01:00
Ard Biesheuvel
9974f85776 ARM: run softirqs on the per-CPU IRQ stack
Now that we have enabled IRQ stacks, any softIRQs that are handled over
the back of a hard IRQ will run from the IRQ stack as well. However, any
synchronous softirq processing that happens when re-enabling softIRQs
from task context will still execute on that task's stack.

Since any call to local_bh_enable() at any level in the task's call
stack may trigger a softIRQ processing run, which could potentially
cause a task stack overflow if the combined stack footprints exceed the
stack's size, let's run these synchronous invocations of do_softirq() on
the IRQ stack as well.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:32 +01:00
Ard Biesheuvel
d4664b6c98 ARM: implement IRQ stacks
Now that we no longer rely on the stack pointer to access the current
task struct or thread info, we can implement support for IRQ stacks
cleanly as well.

Define a per-CPU IRQ stack and switch to this stack when taking an IRQ,
provided that we were not already using that stack in the interrupted
context. This is never the case for IRQs taken from user space, but ones
taken while running in the kernel could fire while one taken from user
space has not completed yet.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:31 +01:00
Ard Biesheuvel
4ab6827081 ARM: unwind: dump exception stack from calling frame
The existing code that dumps the contents of the pt_regs structure
passed to __entry routines does so while unwinding the callee frame, and
dereferences the stack pointer as a struct pt_regs*. This will no longer
work when we enable support for IRQ or overflow stacks, because the
struct pt_regs may live on the task stack, while we are executing from
another stack.

The unwinder has access to this information, but only while unwinding
the calling frame. So let's combine the exception stack dumping code
with the handling of the calling frame as well. By printing it before
dumping the caller/callee addresses, the output order is preserved.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:31 +01:00
Ard Biesheuvel
8cdfdf7fe4 ARM: export dump_mem() to other objects
The unwind info based stack unwinder will make its own call to
dump_mem() to dump the exception stack, so give it external linkage.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:31 +01:00
Ard Biesheuvel
b6506981f8 ARM: unwind: support unwinding across multiple stacks
Implement support in the unwinder for dealing with multiple stacks.
This will be needed once we add support for IRQ stacks, or for the
overflow stack used by the vmap'ed stacks code.

This involves tracking the unwind opcodes that either update the virtual
stack pointer from another virtual register, or perform an explicit
subtract on the virtual stack pointer, and updating the low and high
bounds that we use to sanitize the stack pointer accordingly.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:31 +01:00
Ard Biesheuvel
08572cd419 ARM: remove some dead code
This code appears to be no longer used so let's get rid of it.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
2021-12-03 15:11:31 +01:00
Linus Torvalds
dcd68326d2 Devicetree updates for v5.16:
- Convert /reserved-memory bindings to schemas
 
 - Convert a bunch of NFC bindings to schemas
 
 - Convert bindings to schema: Xilinx USB, Freescale DDR controller, Arm
   CCI-400, UBlox Neo-6M, 1-Wire GPIO, MSI controller, ASpeed LPC, OMAP
   and Inside-Secure HWRNG, register-bit-led, OV5640, Silead GSL1680,
   Elan ekth3000, Marvell bluetooth, TI wlcore, TI bluetooth, ESP ESP8089,
   tlm,trusted-foundations, Microchip cap11xx, Ralink SoCs and boards,
   and TI sysc
 
 - New binding schemas for: msi-ranges, Aspeed UART routing controller,
   palmbus, Xylon LogiCVC display controller, Mediatek's MT7621 SDRAM
   memory controller, and Apple M1 PCIe host
 
 - Run schema checks for %.dtb targets
 
 - Improve build time when using DT_SCHEMA_FILES
 
 - Improve error message when dtschema is not found
 
 - Various doc reference fixes in MAINTAINERS
 
 - Convert architectures to common CPU h/w ID parsing function
   of_get_cpu_hwid().
 
 - Allow for empty NUMA node IDs which may be hotplugged
 
 - Cleanup of __fdt_scan_reserved_mem()
 
 - Constify device_node parameters
 
 - Update dtc to upstream v1.6.1-19-g0a3a9d3449c8. Adds new checks
   'node_name_vs_property_name' and 'interrupt_map'.
 
 - Enable dtc 'unit_address_format' warning by default
 
 - Fix unittest EXPECT text for gpio hog errors
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Merge tag 'devicetree-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull devicetree updates from Rob Herring:

 - Convert /reserved-memory bindings to schemas

 - Convert a bunch of NFC bindings to schemas

 - Convert bindings to schema: Xilinx USB, Freescale DDR controller, Arm
   CCI-400, UBlox Neo-6M, 1-Wire GPIO, MSI controller, ASpeed LPC, OMAP
   and Inside-Secure HWRNG, register-bit-led, OV5640, Silead GSL1680,
   Elan ekth3000, Marvell bluetooth, TI wlcore, TI bluetooth, ESP
   ESP8089, tlm,trusted-foundations, Microchip cap11xx, Ralink SoCs and
   boards, and TI sysc

 - New binding schemas for: msi-ranges, Aspeed UART routing controller,
   palmbus, Xylon LogiCVC display controller, Mediatek's MT7621 SDRAM
   memory controller, and Apple M1 PCIe host

 - Run schema checks for %.dtb targets

 - Improve build time when using DT_SCHEMA_FILES

 - Improve error message when dtschema is not found

 - Various doc reference fixes in MAINTAINERS

 - Convert architectures to common CPU h/w ID parsing function
   of_get_cpu_hwid().

 - Allow for empty NUMA node IDs which may be hotplugged

 - Cleanup of __fdt_scan_reserved_mem()

 - Constify device_node parameters

 - Update dtc to upstream v1.6.1-19-g0a3a9d3449c8. Adds new checks
   'node_name_vs_property_name' and 'interrupt_map'.

 - Enable dtc 'unit_address_format' warning by default

 - Fix unittest EXPECT text for gpio hog errors

* tag 'devicetree-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (97 commits)
  dt-bindings: net: ti,bluetooth: Document default max-speed
  dt-bindings: pci: rcar-pci-ep: Document r8a7795
  dt-bindings: net: qcom,ipa: IPA does support up to two iommus
  of/fdt: Remove of_scan_flat_dt() usage for __fdt_scan_reserved_mem()
  of: unittest: document intentional interrupt-map provider build warning
  of: unittest: fix EXPECT text for gpio hog errors
  of/unittest: Disable new dtc node_name_vs_property_name and interrupt_map warnings
  scripts/dtc: Update to upstream version v1.6.1-19-g0a3a9d3449c8
  dt-bindings: arm: firmware: tlm,trusted-foundations: Convert txt bindings to yaml
  dt-bindings: display: tilcd: Fix endpoint addressing in example
  dt-bindings: input: microchip,cap11xx: Convert txt bindings to yaml
  dt-bindings: ufs: exynos-ufs: add exynosautov9 compatible
  dt-bindings: ufs: exynos-ufs: add io-coherency property
  dt-bindings: mips: convert Ralink SoCs and boards to schema
  dt-bindings: display: xilinx: Fix example with psgtr
  dt-bindings: net: nfc: nxp,pn544: Convert txt bindings to yaml
  dt-bindings: Add a help message when dtschema tools are missing
  dt-bindings: bus: ti-sysc: Update to use yaml binding
  dt-bindings: sram: Allow numbers in sram region node name
  dt-bindings: display: Document the Xylon LogiCVC display controller
  ...
2021-11-02 22:22:13 -07:00
Linus Torvalds
ab2e7f4b46 ARM development for 5.16:
- Rejig task/thread info to place thread info in task struct
 - Amba bus cleanups (removing unused functions)
 - Handle Amba device probe without IRQ domains
 - Parse linux,usable-memory-range in decompressor
 - Mark OCRAM as read-only after initialisation
 - Refactor page fault handling
 - Fix PXN handling with LPAE kernels
 - Warning and build fixes from Arnd
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Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM updates from Russell King:

 - Rejig task/thread info to place thread info in task struct

 - Amba bus cleanups (removing unused functions)

 - Handle Amba device probe without IRQ domains

 - Parse linux,usable-memory-range in decompressor

 - Mark OCRAM as read-only after initialisation

 - Refactor page fault handling

 - Fix PXN handling with LPAE kernels

 - Warning and build fixes from Arnd

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (32 commits)
  ARM: 9151/1: Thumb2: avoid __builtin_thread_pointer() on Clang
  ARM: 9150/1: Fix PID_IN_CONTEXTIDR regression when THREAD_INFO_IN_TASK=y
  ARM: 9147/1: add printf format attribute to early_print()
  ARM: 9146/1: RiscPC needs older gcc version
  ARM: 9145/1: patch: fix BE32 compilation
  ARM: 9144/1: forbid ftrace with clang and thumb2_kernel
  ARM: 9143/1: add CONFIG_PHYS_OFFSET default values
  ARM: 9142/1: kasan: work around LPAE build warning
  ARM: 9140/1: allow compile-testing without machine record
  ARM: 9137/1: disallow CONFIG_THUMB with ARMv4
  ARM: 9136/1: ARMv7-M uses BE-8, not BE-32
  ARM: 9135/1: kprobes: address gcc -Wempty-body warning
  ARM: 9101/1: sa1100/assabet: convert LEDs to gpiod APIs
  ARM: 9131/1: mm: Fix PXN process with LPAE feature
  ARM: 9130/1: mm: Provide die_kernel_fault() helper
  ARM: 9126/1: mm: Kill page table base print in show_pte()
  ARM: 9127/1: mm: Cleanup access_error()
  ARM: 9129/1: mm: Kill task_struct argument for __do_page_fault()
  ARM: 9128/1: mm: Refactor the __do_page_fault()
  ARM: imx6: mark OCRAM mapping read-only
  ...
2021-11-02 11:33:15 -07:00
Russell King (Oracle)
11779842dd Merge branches 'devel-stable' and 'misc' into for-linus 2021-11-02 09:04:22 +00:00
Linus Torvalds
79ef0c0014 Tracing updates for 5.16:
- kprobes: Restructured stack unwinder to show properly on x86 when a stack
   dump happens from a kretprobe callback.
 
 - Fix to bootconfig parsing
 
 - Have tracefs allow owner and group permissions by default (only denying
   others). There's been pressure to allow non root to tracefs in a
   controlled fashion, and using groups is probably the safest.
 
 - Bootconfig memory managament updates.
 
 - Bootconfig clean up to have the tools directory be less dependent on
   changes in the kernel tree.
 
 - Allow perf to be traced by function tracer.
 
 - Rewrite of function graph tracer to be a callback from the function tracer
   instead of having its own trampoline (this change will happen on an arch
   by arch basis, and currently only x86_64 implements it).
 
 - Allow multiple direct trampolines (bpf hooks to functions) be batched
   together in one synchronization.
 
 - Allow histogram triggers to add variables that can perform calculations
   against the event's fields.
 
 - Use the linker to determine architecture callbacks from the ftrace
   trampoline to allow for proper parameter prototypes and prevent warnings
   from the compiler.
 
 - Extend histogram triggers to key off of variables.
 
 - Have trace recursion use bit magic to determine preempt context over if
   branches.
 
 - Have trace recursion disable preemption as all use cases do anyway.
 
 - Added testing for verification of tracing utilities.
 
 - Various small clean ups and fixes.
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Merge tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - kprobes: Restructured stack unwinder to show properly on x86 when a
   stack dump happens from a kretprobe callback.

 - Fix to bootconfig parsing

 - Have tracefs allow owner and group permissions by default (only
   denying others). There's been pressure to allow non root to tracefs
   in a controlled fashion, and using groups is probably the safest.

 - Bootconfig memory managament updates.

 - Bootconfig clean up to have the tools directory be less dependent on
   changes in the kernel tree.

 - Allow perf to be traced by function tracer.

 - Rewrite of function graph tracer to be a callback from the function
   tracer instead of having its own trampoline (this change will happen
   on an arch by arch basis, and currently only x86_64 implements it).

 - Allow multiple direct trampolines (bpf hooks to functions) be batched
   together in one synchronization.

 - Allow histogram triggers to add variables that can perform
   calculations against the event's fields.

 - Use the linker to determine architecture callbacks from the ftrace
   trampoline to allow for proper parameter prototypes and prevent
   warnings from the compiler.

 - Extend histogram triggers to key off of variables.

 - Have trace recursion use bit magic to determine preempt context over
   if branches.

 - Have trace recursion disable preemption as all use cases do anyway.

 - Added testing for verification of tracing utilities.

 - Various small clean ups and fixes.

* tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (101 commits)
  tracing/histogram: Fix semicolon.cocci warnings
  tracing/histogram: Fix documentation inline emphasis warning
  tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together
  tracing: Show size of requested perf buffer
  bootconfig: Initialize ret in xbc_parse_tree()
  ftrace: do CPU checking after preemption disabled
  ftrace: disable preemption when recursion locked
  tracing/histogram: Document expression arithmetic and constants
  tracing/histogram: Optimize division by a power of 2
  tracing/histogram: Covert expr to const if both operands are constants
  tracing/histogram: Simplify handling of .sym-offset in expressions
  tracing: Fix operator precedence for hist triggers expression
  tracing: Add division and multiplication support for hist triggers
  tracing: Add support for creating hist trigger variables from literal
  selftests/ftrace: Stop tracing while reading the trace file by default
  MAINTAINERS: Update KPROBES and TRACING entries
  test_kprobes: Move it from kernel/ to lib/
  docs, kprobes: Remove invalid URL and add new reference
  samples/kretprobes: Fix return value if register_kretprobe() failed
  lib/bootconfig: Fix the xbc_get_info kerneldoc
  ...
2021-11-01 20:05:19 -07:00
Linus Torvalds
9a7e0a90a4 Scheduler updates:
- Revert the printk format based wchan() symbol resolution as it can leak
    the raw value in case that the symbol is not resolvable.
 
  - Make wchan() more robust and work with all kind of unwinders by
    enforcing that the task stays blocked while unwinding is in progress.
 
  - Prevent sched_fork() from accessing an invalid sched_task_group
 
  - Improve asymmetric packing logic
 
  - Extend scheduler statistics to RT and DL scheduling classes and add
    statistics for bandwith burst to the SCHED_FAIR class.
 
  - Properly account SCHED_IDLE entities
 
  - Prevent a potential deadlock when initial priority is assigned to a
    newly created kthread. A recent change to plug a race between cpuset and
    __sched_setscheduler() introduced a new lock dependency which is now
    triggered. Break the lock dependency chain by moving the priority
    assignment to the thread function.
 
  - Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.
 
  - Improve idle balancing in general and especially for NOHZ enabled
    systems.
 
  - Provide proper interfaces for live patching so it does not have to
    fiddle with scheduler internals.
 
  - Add cluster aware scheduling support.
 
  - A small set of tweaks for RT (irqwork, wait_task_inactive(), various
    scheduler options and delaying mmdrop)
 
  - The usual small tweaks and improvements all over the place
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Merge tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Thomas Gleixner:

 - Revert the printk format based wchan() symbol resolution as it can
   leak the raw value in case that the symbol is not resolvable.

 - Make wchan() more robust and work with all kind of unwinders by
   enforcing that the task stays blocked while unwinding is in progress.

 - Prevent sched_fork() from accessing an invalid sched_task_group

 - Improve asymmetric packing logic

 - Extend scheduler statistics to RT and DL scheduling classes and add
   statistics for bandwith burst to the SCHED_FAIR class.

 - Properly account SCHED_IDLE entities

 - Prevent a potential deadlock when initial priority is assigned to a
   newly created kthread. A recent change to plug a race between cpuset
   and __sched_setscheduler() introduced a new lock dependency which is
   now triggered. Break the lock dependency chain by moving the priority
   assignment to the thread function.

 - Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.

 - Improve idle balancing in general and especially for NOHZ enabled
   systems.

 - Provide proper interfaces for live patching so it does not have to
   fiddle with scheduler internals.

 - Add cluster aware scheduling support.

 - A small set of tweaks for RT (irqwork, wait_task_inactive(), various
   scheduler options and delaying mmdrop)

 - The usual small tweaks and improvements all over the place

* tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits)
  sched/fair: Cleanup newidle_balance
  sched/fair: Remove sysctl_sched_migration_cost condition
  sched/fair: Wait before decaying max_newidle_lb_cost
  sched/fair: Skip update_blocked_averages if we are defering load balance
  sched/fair: Account update_blocked_averages in newidle_balance cost
  x86: Fix __get_wchan() for !STACKTRACE
  sched,x86: Fix L2 cache mask
  sched/core: Remove rq_relock()
  sched: Improve wake_up_all_idle_cpus() take #2
  irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT
  irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT
  irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
  sched/rt: Annotate the RT balancing logic irqwork as IRQ_WORK_HARD_IRQ
  sched: Add cluster scheduler level for x86
  sched: Add cluster scheduler level in core and related Kconfig for ARM64
  topology: Represent clusters of CPUs within a die
  sched: Disable -Wunused-but-set-variable
  sched: Add wrapper for get_wchan() to keep task blocked
  x86: Fix get_wchan() to support the ORC unwinder
  proc: Use task_is_running() for wchan in /proc/$pid/stat
  ...
2021-11-01 13:48:52 -07:00
Linus Torvalds
5a47ebe98e Updates for the interrupt subsystem:
Core changes:
 
   - Prevent a potential deadlock when initial priority is assigned to a
     newly created interrupt thread. A recent change to plug a race between
     cpuset and __sched_setscheduler() introduced a new lock dependency
     which is now triggered. Break the lock dependency chain by moving the
     priority assignment to the thread function.
 
   - A couple of small updates to make the irq core RT safe.
 
   - Confine the irq_cpu_online/offline() API to the only left unfixable
     user Cavium Octeon so that it does not grow new usage.
 
   - A small documentation update
 
  Driver changes:
 
   - A large cross architecture rework to move irq_enter/exit() into the
     architecture code to make addressing the NOHZ_FULL/RCU issues simpler.
 
   - The obligatory new irq chip driver for Microchip EIC
 
   - Modularize a few irq chip drivers
 
   - Expand usage of devm_*() helpers throughout the driver code
 
   - The usual small fixes and improvements all over the place
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Merge tag 'irq-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq updates from Thomas Gleixner:
 "Updates for the interrupt subsystem:

  Core changes:

   - Prevent a potential deadlock when initial priority is assigned to a
     newly created interrupt thread. A recent change to plug a race
     between cpuset and __sched_setscheduler() introduced a new lock
     dependency which is now triggered. Break the lock dependency chain
     by moving the priority assignment to the thread function.

   - A couple of small updates to make the irq core RT safe.

   - Confine the irq_cpu_online/offline() API to the only left unfixable
     user Cavium Octeon so that it does not grow new usage.

   - A small documentation update

  Driver changes:

   - A large cross architecture rework to move irq_enter/exit() into the
     architecture code to make addressing the NOHZ_FULL/RCU issues
     simpler.

   - The obligatory new irq chip driver for Microchip EIC

   - Modularize a few irq chip drivers

   - Expand usage of devm_*() helpers throughout the driver code

   - The usual small fixes and improvements all over the place"

* tag 'irq-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
  h8300: Fix linux/irqchip.h include mess
  dt-bindings: irqchip: renesas-irqc: Document r8a774e1 bindings
  MIPS: irq: Avoid an unused-variable error
  genirq: Hide irq_cpu_{on,off}line() behind a deprecated option
  irqchip/mips-gic: Get rid of the reliance on irq_cpu_online()
  MIPS: loongson64: Drop call to irq_cpu_offline()
  irq: remove handle_domain_{irq,nmi}()
  irq: remove CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
  irq: riscv: perform irqentry in entry code
  irq: openrisc: perform irqentry in entry code
  irq: csky: perform irqentry in entry code
  irq: arm64: perform irqentry in entry code
  irq: arm: perform irqentry in entry code
  irq: add a (temporary) CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
  irq: nds32: avoid CONFIG_HANDLE_DOMAIN_IRQ
  irq: arc: avoid CONFIG_HANDLE_DOMAIN_IRQ
  irq: add generic_handle_arch_irq()
  irq: unexport handle_irq_desc()
  irq: simplify handle_domain_{irq,nmi}()
  irq: mips: simplify do_domain_IRQ()
  ...
2021-11-01 13:09:10 -07:00
Linus Torvalds
c2b43854aa ARM updates for 5.15:
- Fix clang-related relocation warning in futex code
 - Fix incorrect use of get_kernel_nofault()
 - Fix bad code generation in __get_user_check() when kasan is enabled
 - Ensure TLB function table is correctly aligned
 - Remove duplicated string function definitions in decompressor
 - Fix link-time orphan section warnings
 - Fix old-style function prototype for arch_init_kprobes()
 - Only warn about XIP address when not compile testing
 - Handle BE32 big endian for keystone2 remapping
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Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM fixes from Russell King:

 - Fix clang-related relocation warning in futex code

 - Fix incorrect use of get_kernel_nofault()

 - Fix bad code generation in __get_user_check() when kasan is enabled

 - Ensure TLB function table is correctly aligned

 - Remove duplicated string function definitions in decompressor

 - Fix link-time orphan section warnings

 - Fix old-style function prototype for arch_init_kprobes()

 - Only warn about XIP address when not compile testing

 - Handle BE32 big endian for keystone2 remapping

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 9148/1: handle CONFIG_CPU_ENDIAN_BE32 in arch/arm/kernel/head.S
  ARM: 9141/1: only warn about XIP address when not compile testing
  ARM: 9139/1: kprobes: fix arch_init_kprobes() prototype
  ARM: 9138/1: fix link warning with XIP + frame-pointer
  ARM: 9134/1: remove duplicate memcpy() definition
  ARM: 9133/1: mm: proc-macros: ensure *_tlb_fns are 4B aligned
  ARM: 9132/1: Fix __get_user_check failure with ARM KASAN images
  ARM: 9125/1: fix incorrect use of get_kernel_nofault()
  ARM: 9122/1: select HAVE_FUTEX_CMPXCHG
2021-10-25 10:28:52 -07:00
Arnd Bergmann
336fe1d6c2 ARM: 9140/1: allow compile-testing without machine record
A lot of randconfig builds end up not selecting any machine type at
all. This is generally fine for the purpose of compile testing, but
of course it means that the kernel is not usable on actual hardware,
and it causes a warning about this fact.

As most of the build bots now force-enable CONFIG_COMPILE_TEST for
randconfig builds, use that as a guard to control whether we warn
on this type of broken configuration.

We could do the same for the missing-cpu-type warning, but those
configurations fail to build much earlier.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2021-10-25 13:12:34 +01:00
LABBE Corentin
00568b8a63 ARM: 9148/1: handle CONFIG_CPU_ENDIAN_BE32 in arch/arm/kernel/head.S
My intel-ixp42x-welltech-epbx100 no longer boot since 4.14.
This is due to commit 463dbba4d189 ("ARM: 9104/2: Fix Keystone 2 kernel
mapping regression")
which forgot to handle CONFIG_CPU_ENDIAN_BE32 as possible BE config.

Suggested-by: Krzysztof Hałasa <khalasa@piap.pl>
Fixes: 463dbba4d189 ("ARM: 9104/2: Fix Keystone 2 kernel mapping regression")
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2021-10-25 13:11:34 +01:00
Mark Rutland
a7b0872e96 irq: arm: perform irqentry in entry code
In preparation for removing HANDLE_DOMAIN_IRQ_IRQENTRY, have arch/arm
perform all the irqentry accounting in its entry code.

For configurations with CONFIG_GENERIC_IRQ_MULTI_HANDLER, we can use
generic_handle_arch_irq(). Other than asm_do_IRQ(), all C calls to
handle_IRQ() are from irqchip handlers which will be called from
generic_handle_arch_irq(), so to avoid double accounting IRQ entry, the
entry logic is moved from handle_IRQ() into asm_do_IRQ().

For ARMv7M the entry assembly is tightly coupled with the NVIC irqchip, and
while the entry code should logically live under arch/arm/, moving the
entry logic there makes things more convoluted. So for now, place the
entry logic in the NVIC irqchip, but separated into a separate
function to make the split of responsibility clear.

For all other configurations without CONFIG_GENERIC_IRQ_MULTI_HANDLER,
IRQ entry is already handled in arch code, and requires no changes.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
2021-10-25 10:05:31 +01:00
Masami Hiramatsu
fed240d9c9 ARM: Recover kretprobe modified return address in stacktrace
Since the kretprobe replaces the function return address with
the kretprobe_trampoline on the stack, arm unwinder shows it
instead of the correct return address.

This finds the correct return address from the per-task
kretprobe_instances list and verify it is in between the
caller fp and callee fp.

Note that this supports both GCC and clang if CONFIG_FRAME_POINTER=y
and CONFIG_ARM_UNWIND=n. For the ARM unwinder, this is still
not working correctly.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-10-22 12:16:53 -04:00
Masami Hiramatsu
b3ea5d56f2 ARM: clang: Do not rely on lr register for stacktrace
Currently the stacktrace on clang compiled arm kernel uses the 'lr'
register to find the first frame address from pt_regs. However, that
is wrong after calling another function, because the 'lr' register
is used by 'bl' instruction and never be recovered.

As same as gcc arm kernel, directly use the frame pointer (r11) of
the pt_regs to find the first frame address.

Note that this fixes kretprobe stacktrace issue only with
CONFIG_UNWINDER_FRAME_POINTER=y. For the CONFIG_UNWINDER_ARM,
we need another fix.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-10-22 12:16:53 -04:00