As done in arm, this change makes it easy to confirm we invoke syscall
related hooks, including syscall tracepoint, audit and seccomp which would
be implemented later, in correct order. That is, undoing operations in the
opposite order on exit that they were done on entry.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NAKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Commit 8f34a1da ("arm64: ptrace: use HW_BREAKPOINT_EMPTY type for
disabled breakpoints") fixed an issue with GDB trying to zero breakpoint
control registers. The problem there is that the arch hw_breakpoint code
will attempt to create a (disabled), execute breakpoint of length 0.

This will fail validation and report unexpected failure to GDB. To avoid
this, we treated disabled breakpoints as HW_BREAKPOINT_EMPTY, but that
seems to have broken with recent kernels, causing watchpoints to be
treated as TYPE_INST in the core code and returning ENOSPC for any
further breakpoints.

This patch fixes the problem by prioritising the `enable' field of the
breakpoint: if it is cleared, we simply update the perf_event_attr to
indicate that the thing is disabled and don't bother changing either the
type or the length. This reinforces the behaviour that the breakpoint
control register is essentially read-only apart from the enable bit
when disabling a breakpoint.

Cc: <stable@vger.kernel.org>
Reported-by: NAaron Liu <liucy214@gmail.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

On a BE system the wrong half of the X registers is retrieved/written
when attempting to get/set the value of aarch32 registers through
ptrace.

Ensure that types are the correct width so that the relevant
casting occurs.
Signed-off-by: NMatthew Leach <matthew.leach@arm.com>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

The software breakpoint handlers are hooked in directly from ptrace,
which makes it difficult to add additional handlers for things like
kprobes and kgdb.

This patch moves the handling code into debug-monitors.c, where we can
dispatch to different debug subsystems more easily.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

If a debugger tries to zero a hardware debug control register, the
kernel will try to infer both the type and length of the breakpoint
in order to sanity-check against the requested regset type. This will
fail because the encoding will appear as a zero-length breakpoint.

This patch changes the control register setting so that disabled
breakpoints are treated as HW_BREAKPOINT_EMPTY and no further
sanity-checking is required.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

The user_hwdebug_state structure contains implicit padding to conform to
the alignment requirements of the AArch64 ABI (namely that aggregates
must be aligned to their most aligned member).

This patch fixes the ptrace functions operating on struct
user_hwdebug_state so that the padding is handled correctly.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch adds #ifdef __KERNEL__ guards around the COMPAT_* definitions
to avoid exporting them to user. AArch32 user requiring the kernel
headers must use those generated with ARCH=arm.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>

The use of regsets has removed the need for many private ptrace requests,
so remove the corresponding definitions from the user-visible ptrace.h
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch adds ptrace, debug monitors and hardware breakpoints support.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NOlof Johansson <olof@lixom.net>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>