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powerpc: Support CMDLINE_EXTEND

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Bring powerpc in line with other architectures that support extending or
overriding the bootloader provided command line.

The current behaviour is most like CMDLINE_FROM_BOOTLOADER where the
bootloader command line is preferred but the kernel config can provide a
fallback so CMDLINE_FROM_BOOTLOADER is the default. CMDLINE_EXTEND can
be used to append the CMDLINE from the kernel config to the one provided
by the bootloader.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190801225006.21952-1-chris.packham@alliedtelesis.co.nz
This commit is contained in:
Chris Packham 2019-08-02 10:50:06 +12:00 committed by Michael Ellerman
parent 6266a4dadb
commit d79fbb3a32
2 changed files with 42 additions and 12 deletions
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20
arch/powerpc/Kconfig
View File

@ -874,15 +874,33 @@ config CMDLINE
some command-line options at build time by entering them here. In
most cases you will need to specify the root device here.
choice
prompt "Kernel command line type" if CMDLINE != ""
default CMDLINE_FROM_BOOTLOADER
config CMDLINE_FROM_BOOTLOADER
bool "Use bootloader kernel arguments if available"
help
Uses the command-line options passed by the boot loader. If
the boot loader doesn't provide any, the default kernel command
string provided in CMDLINE will be used.
config CMDLINE_EXTEND
bool "Extend bootloader kernel arguments"
help
The command-line arguments provided by the boot loader will be
appended to the default kernel command string.
config CMDLINE_FORCE
bool "Always use the default kernel command string"
depends on CMDLINE_BOOL
help
Always use the default kernel command string, even if the boot
loader passes other arguments to the kernel.
This is useful if you cannot or don't want to change the
command-line options your boot loader passes to the kernel.
endchoice
config EXTRA_TARGETS
string "Additional default image types"
help

34
arch/powerpc/kernel/prom_init.c
View File

@ -303,16 +303,24 @@ static char __init *prom_strstr(const char *s1, const char *s2)
return NULL;
}
static size_t __init prom_strlcpy(char *dest, const char *src, size_t size)
static size_t __init prom_strlcat(char *dest, const char *src, size_t count)
{
size_t ret = prom_strlen(src);
size_t dsize = prom_strlen(dest);
size_t len = prom_strlen(src);
size_t res = dsize + len;
/* This would be a bug */
if (dsize >= count)
return count;
dest += dsize;
count -= dsize;
if (len >= count)
len = count-1;
memcpy(dest, src, len);
dest[len] = 0;
return res;
if (size) {
size_t len = (ret >= size) ? size - 1 : ret;
memcpy(dest, src, len);
dest[len] = '\0';
}
return ret;
}
#ifdef CONFIG_PPC_PSERIES
@ -764,10 +772,14 @@ static void __init early_cmdline_parse(void)
prom_cmd_line[0] = 0;
p = prom_cmd_line;
if ((long)prom.chosen > 0)
if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && (long)prom.chosen > 0)
l = prom_getprop(prom.chosen, "bootargs", p, COMMAND_LINE_SIZE-1);
if (IS_ENABLED(CONFIG_CMDLINE_BOOL) && (l <= 0 || p[0] == '\0')) /* dbl check */
prom_strlcpy(prom_cmd_line, CONFIG_CMDLINE, sizeof(prom_cmd_line));
if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || l <= 0 || p[0] == '\0')
prom_strlcat(prom_cmd_line, " " CONFIG_CMDLINE,
sizeof(prom_cmd_line));
prom_printf("command line: %s\n", prom_cmd_line);
#ifdef CONFIG_PPC64