refactor(console): disable getc() by default

The ability to read a character from the console constitutes an attack
vector into TF-A, as it gives attackers a means to inject arbitrary
data into TF-A

refactor(console): disable getc() by default

The ability to read a character from the console constitutes an attack
vector into TF-A, as it gives attackers a means to inject arbitrary
data into TF-A. It is dangerous to keep that feature enabled if not
strictly necessary, especially in production firmware builds.

Thus, we need a way to disable this feature. Moreover, when it is
disabled, all related code should be eliminated from the firmware
binaries, such that no remnant/dead getc() code remains in memory,
which could otherwise be used as a gadget as part of a bigger security
attack.

This patch disables getc() feature by default. For legitimate getc()
use cases [1], it can be explicitly enabled by building TF-A with
ENABLE_CONSOLE_GETC=1.

The following changes are introduced when getc() is disabled:

- The multi-console framework no longer provides the console_getc()
function.

- If the console driver selected by the platform attempts to register
a getc() callback into the multi-console framework then TF-A will
now fail to build.

If registered through the assembly function finish_console_register():
- On AArch64, you'll get:
Error: undefined symbol CONSOLE_T_GETC used as an immediate value.
- On AArch32, you'll get:
Error: internal_relocation (type: OFFSET_IMM) not fixed up

If registered through the C function console_register(), this requires
populating a struct console with a getc field, which will trigger:
error: 'console_t' {aka 'struct console'} has no member named 'getc'

- All console drivers which previously registered a getc() callback
have been modified to do so only when ENABLE_CONSOLE_GETC=1.

[1] Example of such use cases would be:
- Firmware recovery: retrieving a golden BL2 image over the console in
order to repair a broken firmware on a bricked board.
- Factory CLI tool: Drive some soak tests through the console.

Discussed on TF-A mailing list here:
https://lists.trustedfirmware.org/archives/list/tf-a@lists.trustedfirmware.org/thread/YS7F6RCNTWBTEOBLAXIRTXWIOYINVRW7/

Change-Id: Icb412304cd23dbdd7662df7cf8992267b7975cc5
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>

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fix(cadence): update console flush uart driver

The implementation of code changes manages the transmit FIFO (TxFIFO)
in the UART driver. The added code snippet includes a sequence of
instructions th

fix(cadence): update console flush uart driver

The implementation of code changes manages the transmit FIFO (TxFIFO)
in the UART driver. The added code snippet includes a sequence of
instructions that ensures efficient handling of data transmission
and synchronization with the host software.

The code first checks the TxFIFO empty flag to determine whether
there is data available for transmission. If the TxFIFO is not empty,
the code waits until it becomes empty, ensuring that the transmit
operation is synchronized with the availability of data.
Subsequently, the code monitors the transmit operation's activity
status. It waits until the transmit operation becomes inactive,
indicating the completion of the previous transmission.

This synchronization step ensures that new data can be added to the
TxFIFO without causing any loss of transmission time.

Update console_flush() function, the function waits for the
Transmitter FIFO to empty and checks the transmitter's active state.
If the transmitter is in an active state, it means it is currently
shifting out a character.

Signed-off-by: Prasad Kummari <prasad.kummari@amd.com>
Change-Id: I9d6c05bdfb9270924b40bf1f6ecb5fe541a2242e

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cadence: Change logic in uart driver

Write char if fifo is empty. If this is done like this all chars are
printed. Because origin code just put that chars to fifo and in case of
reset messages were

cadence: Change logic in uart driver

Write char if fifo is empty. If this is done like this all chars are
printed. Because origin code just put that chars to fifo and in case of
reset messages were missing.

Before this change chars are put to fifo and only check before adding if
fifo is full. The patch is changing this logic that it is adding char only
when fifo is empty to make sure that in case of reset (by another SW for
example) all chars are printed. Maybe one char can be missed but for IP
itself it is much easier to send just one char compare to full fifo.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Change-Id: Ic24c2c1252bce24be2aed68ee29477ca4a549e5f

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Don't return error information from console_flush

And from crash_console_flush.

We ignore the error information return by console_flush in _every_
place where we call it, and casting the return typ

Don't return error information from console_flush

And from crash_console_flush.

We ignore the error information return by console_flush in _every_
place where we call it, and casting the return type to void does not
work around the MISRA violation that this causes. Instead, we collect
the error information from the driver (to avoid changing that API), and
don't return it to the caller.

Change-Id: I1e35afe01764d5c8f0efd04f8949d333ffb688c1
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>

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