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Subject[PATCH v11 00/19] arm: KGDB NMI/FIQ support
This patchset makes it possible to use kgdb's NMI infrastructure on ARM

The patches are seperated into three distinct groups:

1. arm specific changes; these provide multi-platform support for FIQ
(including raising an IPI using FIQ to ensure effective SMP support)
and extend ARM KGDB support to use the features provided.

2. irqchip changes; updates to the gic and vic drivers to provide
support for routing certain interrupt sources to FIQ.

3. serial changes; driver support to allow the UART interrupt to be
routed to FIQ. The already mainlined kgdb NMI infrastructure (mostly
found in drivers/tty/serial/kgdb_nmi.c) will re-route the kgdb
console UART's interrupt signal from IRQ to FIQ. Naturally the UART
will no longer function normally and will instead be managed by kgdb
using the polled I/O functions. Any character delivered to the UART
causes the kgdb handler function to be called.

Tested on qemu (versatile), STiH416 (B2020 board) and Freescale i.MX6
quad (wandboard).

Changes since v10:

- Removed use of RCU notifier chains to encourage code review by
ensuring no driver can use FIQ without touching code in arch/arm/kernel
(Russell King)

Changes since v9:

- Split PL011 code movement into a seperate patch (Peter Hurley)
- Use container_of() to convert pointers to uart_amba_port (Peter
- Clean up redundant code from pl011_poll_init (Peter Hurley)
- Call do_unexp_fiq() if we receive a FIQ and CONFIG_FIQ is not set.
- Ensure irq-gic.c does not call FIQ functions unless CONFIG_FIQ is set.
- Introduced patch to avoid ttyNMI0 being enabled by default
(replaces architecture dependant enable/disable logic).
- Fixed bug in kgdb_fiq_enable_nmi() that causes SysRq-g (non-NMI
debugging) to wedge the debugger.

Changes since v8:

- Significant rework to separate the FIQ exception handler from kgdb.
This allows other features typically implemented using NMI on x86
to reuse the same exception handling code (Russell King)
- Reunited arch/arm and driver code into a single patch series again.
- Added support for raising IPIs using FIQ (makes kgdb quiesce must
more robust).
- Introduced a workaround for GICv1 devices to avoid FIQs being
spuriously handled as IRQs.

Changes since v7:

- Introduced ack_fiq() to complement eoi_fiq(). Without this it is
not possible to meet the GIC specification (previous versions worked
when tested but are unpredictable according to the specification).
ack_fiq() also makes is possible for drivers for devices with multiple
interrupt lines to discover the interrupt source correctly.

Changes since v6:

- Corrected off-by-one comparison in has_fiq() (Nicolas Pitre)
- Rewrote the FIQ stack initialization (Nicolas Pitre). This fixes a
serious data corruption bug due to bad stack mismanagement.
- Introduced __fiq_abt to ensure lr_abt and spsr_abt are saved and
restored if we fast-interrupt an abort (Russell King).
- Significantly improved the commenting of the exception handlers.
- Added a call to trace_hardirqs_on() if we clear the I bit as we
exit the exception handler.

Changes since v5:

- Separated anything not strictly impacting arch/arm.
- Fixed a spurious add/remove of code within the series (there was
broken code in intermediate patches)

For previous changes see:

Daniel Thompson (18):
arm: fiq: Add callbacks to manage FIQ routings
arm: fiq: Allow ACK and EOI to be passed to the intc
arm: fiq: Replace default FIQ handler
arm: smp: Introduce a special IPI signalled using FIQ
arm: KGDB/KDB FIQ support
irqchip: gic: Provide support for interrupt grouping
irqchip: gic: Add support for FIQ management
irqchip: gic: Remove spin locks from eoi_irq
irqchip: gic: Add support for IPI FIQ
irqchip: gic: Group 0 workaround.
irqchip: vic: Add support for FIQ management
serial: kgdb_nmi: No CON_ENABLED by default
serial: amba-pl011: Use container_of() to get uart_amba_port
serial: amba-pl011: Move pl011_hwinit()
serial: amba-pl011: Pass FIQ information to KGDB.
serial: asc: Add support for KGDB's FIQ/NMI mode
serial: asc: Adopt readl_/writel_relaxed()
serial: imx: Add support for KGDB's FIQ/NMI mode

Dirk Behme (1):
serial: imx: clean up imx_poll_get_char()

arch/arm/Kconfig | 2 +
arch/arm/Kconfig.debug | 19 +++
arch/arm/include/asm/fiq.h | 17 +++
arch/arm/include/asm/hardirq.h | 2 +-
arch/arm/include/asm/kgdb.h | 5 +
arch/arm/include/asm/smp.h | 7 +
arch/arm/kernel/entry-armv.S | 129 +++++++++++++++--
arch/arm/kernel/fiq.c | 146 ++++++++++++++++++-
arch/arm/kernel/kgdb.c | 112 ++++++++++++++-
arch/arm/kernel/setup.c | 8 +-
arch/arm/kernel/smp.c | 15 ++
arch/arm/mach-versatile/core.c | 2 +-
drivers/irqchip/irq-gic.c | 302 +++++++++++++++++++++++++++++++++++++---
drivers/irqchip/irq-vic.c | 92 +++++++++---
drivers/tty/serial/Kconfig | 2 +-
drivers/tty/serial/amba-pl011.c | 143 +++++++++++--------
drivers/tty/serial/imx.c | 88 +++++++-----
drivers/tty/serial/kgdb_nmi.c | 5 +-
drivers/tty/serial/st-asc.c | 27 +++-
include/linux/irqchip/arm-gic.h | 3 +
include/linux/irqchip/arm-vic.h | 6 +-
21 files changed, 975 insertions(+), 157 deletions(-)


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