Le 09/03/2021 à 01:02, Daniel Walker a écrit :
This updates the powerpc code to use the CONFIG_GENERIC_CMDLINE
option.

Cc: xe-linux-exter...@cisco.com
Signed-off-by: Ruslan Ruslichenko <rrusl...@cisco.com>
Signed-off-by: Ruslan Bilovol <rbilo...@cisco.com>
Signed-off-by: Daniel Walker <danie...@cisco.com>
---
  arch/powerpc/Kconfig            | 37 +--------------------------------
  arch/powerpc/kernel/prom.c      |  1 +
  arch/powerpc/kernel/prom_init.c | 35 ++++++++++++++++++-------------
  3 files changed, 23 insertions(+), 50 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 107bb4319e0e..276b06d5c961 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -167,6 +167,7 @@ config PPC
        select EDAC_SUPPORT
        select GENERIC_ATOMIC64                 if PPC32
        select GENERIC_CLOCKEVENTS_BROADCAST    if SMP
+       select GENERIC_CMDLINE
        select GENERIC_CMOS_UPDATE
        select GENERIC_CPU_AUTOPROBE
        select GENERIC_CPU_VULNERABILITIES      if PPC_BARRIER_NOSPEC
@@ -906,42 +907,6 @@ config PPC_DENORMALISATION
          Add support for handling denormalisation of single precision
          values.  Useful for bare metal only.  If unsure say Y here.
-config CMDLINE
-       string "Initial kernel command string"
-       default ""
-       help
-         On some platforms, there is currently no way for the boot loader to
-         pass arguments to the kernel. For these platforms, you can supply
-         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"
-       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
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index ae3c41730367..96d0a01be1b4 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -27,6 +27,7 @@
  #include <linux/irq.h>
  #include <linux/memblock.h>
  #include <linux/of.h>
+#include <linux/cmdline.h>

Why is this needed in prom.c ?

  #include <linux/of_fdt.h>
  #include <linux/libfdt.h>
  #include <linux/cpu.h>
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index e9d4eb6144e1..657241534d69 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -27,6 +27,7 @@
  #include <linux/initrd.h>
  #include <linux/bitops.h>
  #include <linux/pgtable.h>
+#include <linux/cmdline.h>
  #include <asm/prom.h>
  #include <asm/rtas.h>
  #include <asm/page.h>
@@ -242,15 +243,6 @@ static int __init prom_strcmp(const char *cs, const char 
*ct)
        return 0;
  }
-static char __init *prom_strcpy(char *dest, const char *src)
-{
-       char *tmp = dest;
-
-       while ((*dest++ = *src++) != '\0')
-               /* nothing */;
-       return tmp;
-}
-

This game with prom_strcpy() should go a separate preceeding patch.

Also, it looks like checkpatch.pl recommends to use strscpy() instead of 
strlcpy().

  static int __init prom_strncmp(const char *cs, const char *ct, size_t count)
  {
        unsigned char c1, c2;
@@ -276,6 +268,20 @@ static size_t __init prom_strlen(const char *s)
        return sc - s;
  }
+static size_t __init prom_strlcpy(char *dest, const char *src, size_t size)
+{
+       size_t ret = prom_strlen(src);
+
+       if (size) {
+               size_t len = (ret >= size) ? size - 1 : ret;
+
+               memcpy(dest, src, len);
+               dest[len] = '\0';
+       }
+       return ret;
+}
+
+
  static int __init prom_memcmp(const void *cs, const void *ct, size_t count)
  {
        const unsigned char *su1, *su2;
@@ -304,6 +310,7 @@ static char __init *prom_strstr(const char *s1, const char 
*s2)
        return NULL;
  }
+#ifdef GENERIC_CMDLINE_NEED_STRLCAT
  static size_t __init prom_strlcat(char *dest, const char *src, size_t count)
  {
        size_t dsize = prom_strlen(dest);
@@ -323,6 +330,7 @@ static size_t __init prom_strlcat(char *dest, const char 
*src, size_t count)
        return res;
}
+#endif
#ifdef CONFIG_PPC_PSERIES
  static int __init prom_strtobool(const char *s, bool *res)
@@ -775,12 +783,11 @@ static void __init early_cmdline_parse(void)
        prom_cmd_line[0] = 0;
        p = prom_cmd_line;
- if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && (long)prom.chosen > 0)
+       if ((long)prom.chosen > 0)
                l = prom_getprop(prom.chosen, "bootargs", p, 
COMMAND_LINE_SIZE-1);
- if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || l <= 0 || p[0] == '\0')
-               prom_strlcat(prom_cmd_line, " " CONFIG_CMDLINE,
-                            sizeof(prom_cmd_line));
+       cmdline_add_builtin_custom(prom_cmd_line, (l > 0 ? p : NULL), 
sizeof(prom_cmd_line),
+                                       __prombss, prom_strlcpy, prom_strlcat);

So we are referencing a function that doesn't exist (namely prom_strlcat).
But it works because cmdline_add_builtin_custom() looks like a function but is in fact an obscure macro that doesn't use prom_strlcat() unless GENERIC_CMDLINE_NEED_STRLCAT is defined.

IMHO that's awful for readability and code maintenance.

prom_printf("command line: %s\n", prom_cmd_line); @@ -2706,7 +2713,7 @@ static void __init flatten_device_tree(void) /* Add "phandle" in there, we'll need it */
        namep = make_room(&mem_start, &mem_end, 16, 1);
-       prom_strcpy(namep, "phandle");
+       prom_strlcpy(namep, "phandle", 8);

Should be in a separate patch.

        mem_start = (unsigned long)namep + prom_strlen(namep) + 1;
/* Build string array */


Christophe

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