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mn10300: Use early_param() to parse "mem=" parameter 

This fixes the problem that "init=" options may not be passed to kernel
correctly.

parse_mem_cmdline() of mn10300 arch gets rid of "mem=" string from
redboot_command_line. Then init_setup() parses the "init=" options from
static_command_line, which is a copy of redboot_command_line, and keeps
the pointer to the init options in execute_command variable.

Since the commit 026cee0 upstream (params: <level>_initcall-like kernel
parameters), static_command_line becomes overwritten by saved_command_line at
do_initcall_level(). Notice that saved_command_line is a command line
which includes "mem=" string.

As a result, execute_command may point to weird string by the length of
"mem=" parameter.
I noticed this problem when using the command line like this:

    mem=128M console=ttyS0,115200 init=/bin/sh

Here is the processing flow of command line parameters.
    start_kernel()
      setup_arch(&command_line)
         parse_mem_cmdline(cmdline_p)
           * strcpy(boot_command_line, redboot_command_line);
           * Remove "mem=xxx" from redboot_command_line.
           * *cmdline_p = redboot_command_line;
      setup_command_line(command_line) <-- command_line is redboot_command_line
        * strcpy(saved_command_line, boot_command_line)
        * strcpy(static_command_line, command_line)
      parse_early_param()
        strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
        parse_early_options(tmp_cmdline);
          parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
      parse_args("Booting ..", static_command_line, ...);
        init_setup() <-- save the pointer in execute_command
      rest_init()
        kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);

At this point, execute_command points to "/bin/sh" string.

    kernel_init()
      kernel_init_freeable()
        do_basic_setup()
          do_initcalls()
            do_initcall_level()
              (*) strcpy(static_command_line, saved_command_line);

Here, execute_command gets to point to "200" string !!

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
Akira Takeuchi 2013-06-28 16:53:03 +01:00 committed by David Howells
parent c6dc9f0a4e
commit e3f12a5304
1 changed files with 21 additions and 33 deletions
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54
arch/mn10300/kernel/setup.c
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@ -38,6 +38,7 @@ struct mn10300_cpuinfo boot_cpu_data;
/* For PCI or other memory-mapped resources */
unsigned long pci_mem_start = 0x18000000;
static char __initdata cmd_line[COMMAND_LINE_SIZE];
char redboot_command_line[COMMAND_LINE_SIZE] =
"console=ttyS0,115200 root=/dev/mtdblock3 rw";
@ -74,45 +75,19 @@ static const char *const mn10300_cputypes[] = {
};
/*
*
* Pick out the memory size. We look for mem=size,
* where size is "size[KkMm]"
*/
static void __init parse_mem_cmdline(char **cmdline_p)
static int __init early_mem(char *p)
{
char *from, *to, c;
/* save unparsed command line copy for /proc/cmdline */
strcpy(boot_command_line, redboot_command_line);
/* see if there's an explicit memory size option */
from = redboot_command_line;
to = redboot_command_line;
c = ' ';
for (;;) {
if (c == ' ' && !memcmp(from, "mem=", 4)) {
if (to != redboot_command_line)
to--;
memory_size = memparse(from + 4, &from);
}
c = *(from++);
if (!c)
break;
*(to++) = c;
}
*to = '\0';
*cmdline_p = redboot_command_line;
memory_size = memparse(p, &p);
if (memory_size == 0)
panic("Memory size not known\n");
memory_end = (unsigned long) CONFIG_KERNEL_RAM_BASE_ADDRESS +
memory_size;
if (memory_end > phys_memory_end)
memory_end = phys_memory_end;
return 0;
}
early_param("mem", early_mem);
/*
* architecture specific setup
@ -125,7 +100,20 @@ void __init setup_arch(char **cmdline_p)
cpu_init();
unit_setup();
smp_init_cpus();
parse_mem_cmdline(cmdline_p);
/* save unparsed command line copy for /proc/cmdline */
strlcpy(boot_command_line, redboot_command_line, COMMAND_LINE_SIZE);
/* populate cmd_line too for later use, preserving boot_command_line */
strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
*cmdline_p = cmd_line;
parse_early_param();
memory_end = (unsigned long) CONFIG_KERNEL_RAM_BASE_ADDRESS +
memory_size;
if (memory_end > phys_memory_end)
memory_end = phys_memory_end;
init_mm.start_code = (unsigned long)&_text;
init_mm.end_code = (unsigned long) &_etext;