understanding linux kernel 4th edition

) Initial program stack (. Stack)5) executable code and data required for shared libraries6) Heap (. Heap)Cache, and access to disk and other block devices is too slow compared to the time of RAM access.Device driver, the kernel interacts with the I/O device through device drivers (devices driver). Device drivers are included in the kernel and consist of data structures and functions that control one or mor

From Get Linux3.1.1 version of the core source code and build a good reading environment began, to now around two months time, during the Google a large and small article, just clear a little thought and found a reading of the mouth. A good guide for kernel beginners is more important than anything, and the methodology for Linux kernel learning can refer to the

* 1024 * 1024;/* We don't want to having this area swapped out, lock it */Vma->vm_flags |= vm_locked;if (Remap_page_range (VMA, Vma->vm_start, offset, size, page_shared)){PRINTK ("Remap page range failed/n");Return-enxio;}return (0);} The function of the Remap_page_range function is to construct a new page table for mapping a physical address, which implements the mapping between kernel space and user space, with the following prototype:

contains the instruction address that generated the exception, then this error is caused by an illegal system call parameter, otherwise, it is caused by a more serious bug.Linux defines a few exception tables. The main exception table is generated automatically by the C compiler when the kernel program image is established. It is stored in the __ex_table section of the kernel code, and its starting and end

any of its child processes execution state.For example: a process can create a child process to perform a specific task, and then call some library functions such as wait () to check whether the child process terminates. If the child process terminates, its terminating designator tells the parent process whether the task has completed successfully.To follow these design choices, the Unix kernel is not allowed to discard data contained in the Process

] "M" (NEXT->THREAD.IP), \68 \*/* Regparm parameters for __switch_to (): */\[Prev] "a" (prev), \[Next] "D" (next) \72 \__switch_canary_iparam \74 \:/* Reloaded Segment Registers */\"Memory"); \(0)Second, the experimental processExperimental content1. Understand the timing of process scheduling in Linux systems, you can search the kernel code for the schedule () function, see where the schedule () is called,

Concurrent execution Quantity: If there is only one then the CPU must switch to the user state.Suspend the process's switch request: If there is any request, the kernel must execute the process dispatch; otherwise, return control to the current process.Pending signal: If a signal is sent to the current process, it must be processed.Single-Step mode: If the debugger is tracking the execution of the current process, it must resume stepping before the p

the 129th item in the page directory The physical address of the page table in the page directory that must contain the process If no other linear address is assigned to the process, the remaining 1023 items in the careers directory are filled with 0 The value in the Middle 10 (table field) is 0-0x03f, so only the first 64 bits of the page table are meaningful, and the remaining 960 are filled with 0 Assume that a thread reads bytes

PS: Brother Bird's third edition of private dishes printing problemsThe above meaning: D refers to the directoryFile Owner permissions: R readable w writable, X, can run,Permissions for the same group: R readable, this paragraph has a-number, which means not writable, X is operationalOther non-group permissions: R Readable, this paragraph also has a-number, indicating not writable, X can runThere is a 2 in the back, which means there are 2 files, the

back to the Linuxkernel directory, start the kernel with the following command and stop for debugging before the CPU runs the code:Qemu-kernel LINUX-3.18.6/ARCH/X86/BOOT/BZIMAGE-INITRD Rootfs.img-s-SNext, we can split a new shell window horizontally, then start GDB debugging with the following commandgdb (gdb) file Linux