March 2020 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

which "make" target simply builds the scripts/dtc/dtc executable?
by rpjday＠crashcourse.ca March 18, 2020

March 18, 2020

colleague has a kernel-compile infrastructure which builds the kernel just fine, but croaks trying to compile .dts files, complaining that there is no "./scripts/dtc/dtc" file. ok, so that sounds like whatever it is that compiles dtc.c (and friends) into dtc is being omitted. i just want to test whatever make target would normally compile that, but i'm having trouble figuring which make processing does that. is there a top-level target that wanders into scripts/dtc, and compiles that? rday p.s. i'm testing this on x86, which typically doesn't use dtb files, and there are no .dts files, so i'm looking for the target that would normally compile into "dtc", even though there's nothing that really needs it, if that makes a difference. i thought "make scripts_dtc" would do it, but that didn't seem to make any difference. thoughts?

3 2

(no subject)
by Sankalp Bhardwaj March 17, 2020

March 17, 2020

Where to get started?? I am interested in understanding how the kernel works but have no prior knowledge... Please help!!

4 3

New text
by Ruben Safir March 15, 2020

March 15, 2020

is there currently a rfecommended text to learn kernel development from? -- So many immigrant groups have swept through our town that Brooklyn, like Atlantis, reaches mythological proportions in the mind of the world - RI Safir 1998 http://www.mrbrklyn.com DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002 http://www.nylxs.com - Leadership Development in Free Software http://www2.mrbrklyn.com/resources - Unpublished Archive http://www.coinhangout.com - coins! http://www.brooklyn-living.com Being so tracked is for FARM ANIMALS and extermination camps, but incompatible with living as a free human being. -RI Safir 2013

5 8

Question about the "Dynamic reserved memory" patch
by 양원혁 March 13, 2020

March 13, 2020

Hi. Recently, I read about the "Dynamic reserved memory" patch. In the __reserved_mem_reserve_reg() function, I found something that I couldn't easily understand. To get help, I sent an e-mail to this mailing list. I attached the code below. static int __init __reserved_mem_reserve_reg(unsigned long node, const char *uname) { int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32); phys_addr_t base, size; int len; const __be32 *prop; int nomap, first = 1; prop = of_get_flat_dt_prop(node, "reg", &len); if (!prop) return -ENOENT; if (len && len % t_len != 0) { pr_err("Reserved memory: invalid reg property in '%s',skipping node.\n", uname); return -EINVAL; } nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL; while (len >= t_len) { base = dt_mem_next_cell(dt_root_addr_cells, &prop); size = dt_mem_next_cell(dt_root_size_cells, &prop); if (size && early_init_dt_reserve_memory_arch(base, size, nomap) == 0) pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %ld MiB\n", uname, &base, (unsigned long)size / SZ_1M); else pr_info("Reserved memory: failed to reserve memory for node '%s': base %pa, size %ld MiB\n", uname, &base, (unsigned long)size / SZ_1M); len -= t_len; if (first) { fdt_reserved_mem_save_node(node, uname, base, size); first = 0; } } return 0; } I found that fdt_reserved_mem_save_node() is called the regardless of memblock remove/reserve success. I think early_init_dt_reserve_memory_arch() can fail.(ex. for the lack of memblock's region) So I wonder there will be a situation where reserved_mem initialization will be executed without memory reservation. I would appreciate it if you let me know if I missed anything :)

2 2

Need help to get started
by m vivek March 2, 2020

March 2, 2020

Hi, I just joined the mailing list. Excited to contribute to linux kernel but finding it difficult to figure out where to start. Any help would be appreciated. PS: I've gone through some articles online which suggest to start with improving the coding style and refer to TODO from drivers/staging/. Thanks -Vivek.

4 3