Messages in this thread | | | From | Bora Şahin <> | Subject | Q: parse_cmdline_early() | Date | Sun, 2 Mar 2003 11:35:20 +0200 |
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Hi,
I have two problems with the parse_cmdline_early().
My first problem is related to mem options. ... /* * "mem=nopentium" disables the 4MB page tables. * "mem=XXX[kKmM]" defines a memory region from HIGH_MEM * to <mem>, overriding the bios size. * "mem=XXX[KkmM]@XXX[KkmM]" defines a memory region from * <start> to <start>+<mem>, overriding the bios size. */
I think this comment would be expressed better. Of the comments are understood like "start_at@mem_size". But actually "mem_size@start_at"
if (!memcmp(from, "mem=", 4)) { if (to != command_line) to--; // ok if (!memcmp(from+4, "nopentium", 9)) { from += 9+4; clear_bit(X86_FEATURE_PSE, &boot_cpu_data.x86_capability); } // ok else if (!memcmp(from+4, "exactmap", 8)) { from += 8+4; e820.nr_map = 0; userdef = 1; } // This is the problem else { /* If the user specifies memory size, we * limit the BIOS-provided memory map to * that size. exactmap can be used to specify * the exact map. mem=number can be used to * trim the existing memory map. */ unsigned long long start_at, mem_size;
mem_size = memparse(from+4, &from); if (*from == '@') { start_at = memparse(from+1, &from); add_memory_region(start_at, mem_size, E820_RAM); } else { limit_regions(mem_size); userdef=1; } } } ...
If I supply the parameter in a old fashion, that is, mem=xxx[kmg] It's OK, limit_regions is called and It works as usual. But If I supply the parameter in a new way, that is mem=128m@1m, the kernel hangs on. Only prints the screen "uncompressing Linux... Ok, booting the kernel" msg. If I understand the function correctly, there are two case:
1) mem=xx[kmg]. It works.
2) mem=exactmap and mem=xxx[kmg]@xxx[kmg] are supplied together because as if function was configured having been thought this. For example this way userdef is set. But If I supply the mem=exactmap and mem=x@x, Lilo complains and refuse it: "Invalid number". If I supply only mem=xxx[kmg]@xxx[kmg], kernel can be crashed. Because (One of the reasons) I have got 256 Mb RAM and this will overlaps the BIOS provided results. (sanitize function is not called after the parse_cmdline_early()) But this isnt and as I said the above, It crashes early-bootup phase.
These means, doesnt Lilo support mem=x@x? Version: 21.4-4 or are my assumptions true?
My second problem is in fact trivial. According to the function, If an option is omitted from command_line It seems It should be done a check.
*to = command_line ... /* among mem options */ if (to != command_line) to--;
This means an unnecessary space isnt added to 'to' variable. (If It is first option in the command_line, then there is no extra space) But there is an exception.
else if (!memcmp(from, "highmem=", 8)) highmem_pages = memparse(from+8, &from) >> PAGE_SHIFT;
Here, highmem_pages is parsed and omitted but there is no check like the above. This way, an extra space is added to 'to'. I think functions which parse command_line later is prepared but It seems there are inconsistencies.
Kernel Version: 2.4.19
Thanks in advance...
Sory for my bad English...
Regards Bora Sahin
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