I built a certain driver as module (m) for Linux, the spi-imx by NXP. Nontheless, Linux probes this driver when booting. I'm struggling to find out what process/other module/driver requests this spi-imx driver. A depmod does not show any dependencies between the spi-imx an other modules (except for the spidev as submodule).
After some research, I found out that Linux automatically (?) calls modprobe when it detects a new device. So does Linux actually call modprobe because the ecSPI'S status in the device tree as "okay"? If so, how can I prevent this? I would like to dynamically load the spi-imx from a user space application via modprobe. The story behind it: a coprocessor uses this SPI line in parallel to the Linux boot process. This interferes of course and interrupts the coprocessor's use of the SPI line. When the coprocessor has finished its transfer via SPI (a boot mechanism as well), it should hand over the SPI line to Linux.
I'm very thankful for any kind of tips, links, hints and comments on this.
Thanks a lot for the answers. As you guys mentioned, I also found out that Linux itself probes the device if present ("okay").
One possible solution is to complete cut off the modprobe call via an entry like "install spi-imx /bin/false" in the *.conf file. But that makes it impossible to load the driver via modprobe, for Linux and for user space.
"blacklist spi-imx" inside a *.conf located at /etc/modprobe.d/ is the way to prevent Linux from probing the driver when booting. After that, a modprobe from user space can successfully load the driver afterwards.
Thanks again & best regards
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I'm trying to enable boot in bios legacy mode with no success.
Just as test case I'm using an old Ubuntu server image (bionic-server-cloudimg-i386.img).
This what I did:
Under %simics%/simics-qsp-cpu-6.0.1/targets/qsp-x86 I modified qsp-client-core.simics file as below:
# In order to run this, the QSP-x86 (2096), QSP-CPU (8112) and
# QSP-Clear-Linux (4094) packages should be installed.
decl {
! Script that runs the Quick Start Platform (QSP) with a client processor core.
params from "%simics%/targets/qsp-x86/qsp-clear-linux.simics"
default cpu_comp_class = "x86-coffee-lake"
default num_cores = 4
default enable_efi = FALSE
}
$disk0_image="/home/peppe/Scrivania/bionic.craff"
#$disk0_image="/opt/simics/simics-qsp-clear-linux-6.0.9/targets/qsp-x86/images/cl-b28910-v2.craff"
run-command-file "%simics%/targets/qsp-x86/qsp-clear-linux.simics"
When I run this file, the boot gets stuck with "Start PXE over IPv4" message (i.e. Simics doesn't find the UEFI partition and try to boot from network).
If I run the same file with cl-b28910-v2.craff image all works fine.
Note when it comes to bionic image I tried both with the raw format and with the craff format.
Also note the same bionic image boots as expected in QEMU.
My question: is the param enable_efi = FALSE enough to force Simics to boot in legacy mode?
If no what else do I have to do ?
The QSP really only supports booting from UEFI, and only a UEFI binary is shipping with the platform. All modern operating systems boot from UEFI anyway, so this should not be a big deal.
Indeed QSP model is not shipped with legacy BIOS image, but this does not prevent you from creating such and enable it on QSP model yourself. In particular, microvm or regular bios.bin (SeaBIOS?) from QEMU might work with some changes (removing QEMU specifics).
I have started a bare-metal application for AArch64. The bare-metal application should implement a simple kernel (for memory/device management and exception handling) and an userland which can made syscalls to output something over the UART via printf() as example. Currently I'm working on the kernel at EL1. The indent is to put kernel and userland in a single ELF binary, because I don't have implemented an filesystem driver and ELF support yet.
The kernel should reside at address 0xC0000000 and the main application (userland) at 0x40000000 as example. But I will change this addresses later. Is it possible to pass two linker scripts to GNU ld? I realize that I must use different sections for kernel and userland.
Or in another question:
Is my indent even possible? Okay it's maybe a generic question, but currently didn't find a similar question here.
From the LD manual: https://man7.org/linux/man-pages/man1/ld.1.html, it's said:
Multiple -T options accumulate.
Just use it like this: -T script1.ld -T script2.ld
I'm trying to get MSI-X working on an iMX6 (Freescale/NXP/Qualcomm) CPU in Linux v4.1 for a PCIe character device driver. Whenever I call either pci_enable_msix() or pci_enable_msix_range() or pci_enable_msix_exact() I get an EINVAL value returned. I do have the CONFIG_PCI_MSI option selected in the kernel configuration and I am also able to get single MSI working with pci_enable_msi(), but I cannot get multiple MSI working either.
I have tested my driver code on an Intel i7 running kernel v3 with the same PCIe hardware attached and I was able to get MSI-X working without any problems so I know my code is correctly written and the hardware is correctly functioning.
When running on the iMX6 I can use lspci -v to view that the hardware has MSI-X capabilities and see the number of IRQs it allows. I can even get the same correct number in my driver when calling pci_msix_vec_count().Questions
Are there any other kernel configuration flags I need to set?
Is there anything specific to the iMX6 CPU I need to consider?
Does anyone have any experience with the iMX6 and either MSI-X or
multiple MSI?
I have a hard drive was crypted by TryeCrypt,a custom edtion ,self input password,and i have found this 40-bytes password via MBR debugging, but can't mount it using standard version 7.1a.
what i want is get some files from this hard drive,good news is,this hard drive is bootable and it is a windows xp sp2,but a fullscreen app was auto startup and any input(keyboard,mouse etc.) was blocked,therefore,the only way to touch it is debugging it with vmware gdb stub.
The ida's remote dbg debugger is working very well, now I touch the guest's memory, edit it's codes, set breakpoints and the symbols was loaded.
so the question is,how can I start a process via patching the kernel?
What I thinking is,build a winddk project , implement a driver to do this with user APC, and then disassemble it to get it's assembler code ,and then patch it into guest via ida.
Any idea? thanks.
I'd like to start service before user mode is loaded (in kernel mode).
The reason is I wanna run several system applications(asm code to write data to BIOS) that are not allowed in user mode (privileges problem).
That's why I got an idea: 1. Write windows service 2. Start and run it in kernel mode
Is it possible?
Are there any other ways to solve the problem?
I don't usually use Vista (use linux instead), that's why I'm asking.
Windows services are user-mode applications. To run in kernel-mode you should write a driver. (So-called "legacy" driver will be enough, see Driver Development Part 1: Introduction to Drivers).