| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
This patch was triggered by a remark from Russell that
introducing a call to the waituart (needed to fix debug prints
on the Qualcomm platforms) was dangerous because in some cases
this will involve waiting for a modem CTS (clear to send)
signal, and debug messages would maybe not work on platforms
with no modem connected to the UART port: they will just
hang waiting for the modem to assert CTS and this might never
happen.
Looking through all UART debug drivers implementing the waituart
macro I discovered that all users except two actually use this
macro to check if the UART is ready for TX, let's call this
TXRDY.
Only two debug UART drivers actually check for CTS:
- arch/arm/include/debug/8250.S
- arch/arm/include/debug/tegra.S
The former is very significant since the 8250 is possibly
the most common UART on the planet.
We have the following problem: the semantics of waituart are
ambiguous making it dangerous to introduce the macro to debug
code fixing debug prints for Qualcomm. To start to pry this
problem apart, this patch does the following:
- Convert all debug UART drivers to define two macros:
- waituartcts with the clear semantic to wait for CTS
to be asserted
- waituarttxrdy with the clear semantic to wait for the TX
capability of the UART to be ready
- When doing this take care to assign the right function to
each drivers macro, so they now do exactly the above.
- Update the three sites in the kernel invoking the waituart
macro to call waituartcts/waituarttxrdy in sequence, so that
the functional impact on the kernel should be zero.
After this we can start to change the code sites using this
code to do the right thing.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
|
|
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Pull ARM updates from Russell King:
"Low priority fixes and updates for ARM:
- add some missing includes
- efficiency improvements in system call entry code when tracing is
enabled
- ensure ARMv6+ is always built as EABI
- export save_stack_trace_tsk()
- fix fatal signal handling during mm fault
- build translation table base address register from scratch
- appropriately align the .data section to a word boundary where we
rely on that data being word aligned"
* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8691/1: Export save_stack_trace_tsk()
ARM: 8692/1: mm: abort uaccess retries upon fatal signal
ARM: 8690/1: lpae: build TTB control register value from scratch in v7_ttb_setup
ARM: align .data section
ARM: always enable AEABI for ARMv6+
ARM: avoid saving and restoring registers unnecessarily
ARM: move PC value into r9
ARM: obtain thread info structure later
ARM: use aliases for registers in entry-common
ARM: 8689/1: scu: add missing errno include
ARM: 8688/1: pm: add missing types include
|
|
Robert Jarzmik reports that his PXA25x system fails to boot with 4.12,
failing at __flush_whole_cache in arch/arm/mm/proc-xscale.S:215:
0xc0019e20 <+0>: ldr r1, [pc, #788]
0xc0019e24 <+4>: ldr r0, [r1] <== here
with r1 containing 0xc06f82cd, which is the address of "clean_addr".
Examination of the System.map shows:
c06f22c8 D user_pmd_table
c06f22cc d __warned.19178
c06f22cd d clean_addr
indicating that a .data.unlikely section has appeared just before the
.data section from proc-xscale.S. According to objdump -h, it appears
that our assembly files default their .data alignment to 2**0, which
is bad news if the preceding .data section size is not power-of-2
aligned at link time.
Add the appropriate .align directives to all assembly files in arch/arm
that are missing them where we require an appropriate alignment.
Reported-by: Robert Jarzmik <robert.jarzmik@free.fr>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
|
|
We want to use generic 8250 debug_ll code to get DEBUG_UNCOMPRESS
working and to simplify the code. The old debug_ll code is no longer
needed and the machine ID based detection is no longer used.
Note that for most part there's no need to keep DEBUG_LL enabled.
We now have CONFIG_SERIAL_EARLYCON working very early as long as
the kernel cmdline has "earlycon" in it and the board specific dts
file has chosen configured with with the port using stdout-path.
Cc: Hoeun Ryu <hoeun.ryu@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Tony Lindgren <tony@atomide.com>
|
|
We want to use generic 8250 debug_ll code to get DEBUG_UNCOMPRESS
working and to simplify the code. The old debug_ll code is no longer
needed and the machine ID based detection is no longer used.
Note that for most part there's no need to keep DEBUG_LL enabled.
We now have CONFIG_SERIAL_EARLYCON working very early as long as
the kernel cmdline has "earlycon" in it and the board specific dts
file has chosen configured with with the port using stdout-path.
Cc: Hoeun Ryu <hoeun.ryu@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Tony Lindgren <tony@atomide.com>
|
|
We want to use generic 8250 debug_ll code to get DEBUG_UNCOMPRESS
working and to simplify the code. The old debug_ll code is no longer
needed and the machine ID based detection is no longer used.
Note that for most part there's no need to keep DEBUG_LL enabled.
We now have CONFIG_SERIAL_EARLYCON working very early as long as
the kernel cmdline has "earlycon" in it and the board specific dts
file has chosen configured with with the port using stdout-path.
Cc: Hoeun Ryu <hoeun.ryu@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Tony Lindgren <tony@atomide.com>
|
|
We want to use generic 8250 debug_ll code to get DEBUG_UNCOMPRESS
working and to simplify the code. The old debug_ll code is no longer
needed and the machine ID based detection is no longer used.
Note that for most part there's no need to keep DEBUG_LL enabled.
We now have CONFIG_SERIAL_EARLYCON working very early as long as
the kernel cmdline has "earlycon" in it and the board specific dts
file has chosen configured with with the port using stdout-path.
Cc: Hoeun Ryu <hoeun.ryu@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Tony Lindgren <tony@atomide.com>
|
|
Add multiplatform debug_ll support by stripping away
the custom hacks to detect the port from debug-macro.S.
Note that this now requires the specific debug_ll port to
be selected in the .config.
The old debug-macro.S will be removed a bit later
once we are sure things work properly with multiplatform
enabled.
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
|
