Re: [PATCH 1/5] CMDLINE: add generic builtin command line

From: Christophe Leroy
Date: Thu Mar 04 2021 - 02:42:21 EST

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In reply to: Daniel Walker: "Re: [PATCH 1/5] CMDLINE: add generic builtin command line"
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Le 04/03/2021 à 05:47, Daniel Walker a écrit :

This code allows architectures to use a generic builtin command line.
The state of the builtin command line options across architecture is
diverse. On x86 and mips they have pretty much the same code and the
code prepends the builtin command line onto the boot loader provided
one. On powerpc there is only a builtin override and nothing else.

The code in this commit unifies the code into a generic
header file under the CONFIG_GENERIC_CMDLINE option. When this
option is enabled the architecture can call the cmdline_add_builtin()
to add the builtin command line.

WARNING:SPDX_LICENSE_TAG: Missing or malformed SPDX-License-Identifier tag in line 1
#32: FILE: include/linux/cmdline.h:1:
+#ifndef _LINUX_CMDLINE_H

CHECK:PARENTHESIS_ALIGNMENT: Alignment should match open parenthesis
#56: FILE: include/linux/cmdline.h:25:
+__cmdline_add_builtin(char *dest, const char *src, char *tmp, unsigned long length,
+ size_t (*strlcpy)(char *dest, const char *src, size_t size),

WARNING:STRLCPY: Prefer strscpy over strlcpy - see: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@xxxxxxxxxxxxxx/
#61: FILE: include/linux/cmdline.h:30:
+ strlcpy(dest, " ", length);

WARNING:STRLCPY: Prefer strscpy over strlcpy - see: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@xxxxxxxxxxxxxx/
#69: FILE: include/linux/cmdline.h:38:
+ strlcpy(tmp, CONFIG_CMDLINE_PREPEND " ", length);

WARNING:STRLCPY: Prefer strscpy over strlcpy - see: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@xxxxxxxxxxxxxx/
#71: FILE: include/linux/cmdline.h:40:
+ strlcpy(dest, tmp, length);

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#75: FILE: include/linux/cmdline.h:44:
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) ^I^I^I\$

CHECK:MACRO_ARG_REUSE: Macro argument reuse 'dest' - possible side-effects?
#75: FILE: include/linux/cmdline.h:44:
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) \
+{ \
+ if (sizeof(CONFIG_CMDLINE_PREPEND) > 1) { \
+ static label char cmdline_tmp_space[length]; \
+ __cmdline_add_builtin(dest, src, cmdline_tmp_space, length, strlcpy, strlcat); \
+ } else if (sizeof(CONFIG_CMDLINE_APPEND) > 1) { \
+ __cmdline_add_builtin(dest, src, NULL, length, strlcpy, strlcat); \
+ } \
+}

CHECK:MACRO_ARG_REUSE: Macro argument reuse 'src' - possible side-effects?
#75: FILE: include/linux/cmdline.h:44:
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) \
+{ \
+ if (sizeof(CONFIG_CMDLINE_PREPEND) > 1) { \
+ static label char cmdline_tmp_space[length]; \
+ __cmdline_add_builtin(dest, src, cmdline_tmp_space, length, strlcpy, strlcat); \
+ } else if (sizeof(CONFIG_CMDLINE_APPEND) > 1) { \
+ __cmdline_add_builtin(dest, src, NULL, length, strlcpy, strlcat); \
+ } \
+}

CHECK:MACRO_ARG_REUSE: Macro argument reuse 'length' - possible side-effects?
#75: FILE: include/linux/cmdline.h:44:
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) \
+{ \
+ if (sizeof(CONFIG_CMDLINE_PREPEND) > 1) { \
+ static label char cmdline_tmp_space[length]; \
+ __cmdline_add_builtin(dest, src, cmdline_tmp_space, length, strlcpy, strlcat); \
+ } else if (sizeof(CONFIG_CMDLINE_APPEND) > 1) { \
+ __cmdline_add_builtin(dest, src, NULL, length, strlcpy, strlcat); \
+ } \
+}

CHECK:MACRO_ARG_REUSE: Macro argument reuse 'strlcpy' - possible side-effects?
#75: FILE: include/linux/cmdline.h:44:
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) \
+{ \
+ if (sizeof(CONFIG_CMDLINE_PREPEND) > 1) { \
+ static label char cmdline_tmp_space[length]; \
+ __cmdline_add_builtin(dest, src, cmdline_tmp_space, length, strlcpy, strlcat); \
+ } else if (sizeof(CONFIG_CMDLINE_APPEND) > 1) { \
+ __cmdline_add_builtin(dest, src, NULL, length, strlcpy, strlcat); \
+ } \
+}

CHECK:MACRO_ARG_REUSE: Macro argument reuse 'strlcat' - possible side-effects?
#75: FILE: include/linux/cmdline.h:44:
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) \
+{ \
+ if (sizeof(CONFIG_CMDLINE_PREPEND) > 1) { \
+ static label char cmdline_tmp_space[length]; \
+ __cmdline_add_builtin(dest, src, cmdline_tmp_space, length, strlcpy, strlcat); \
+ } else if (sizeof(CONFIG_CMDLINE_APPEND) > 1) { \
+ __cmdline_add_builtin(dest, src, NULL, length, strlcpy, strlcat); \
+ } \
+}

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#76: FILE: include/linux/cmdline.h:45:
+{ ^I^I^I^I^I^I^I^I^I^I^I^I\$

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#77: FILE: include/linux/cmdline.h:46:
+^Iif (sizeof(CONFIG_CMDLINE_PREPEND) > 1) { ^I^I^I^I^I^I\$

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#78: FILE: include/linux/cmdline.h:47:
+^I^Istatic label char cmdline_tmp_space[length]; ^I^I^I^I^I\$

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#79: FILE: include/linux/cmdline.h:48:
+^I^I__cmdline_add_builtin(dest, src, cmdline_tmp_space, length, strlcpy, strlcat); ^I\$

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#80: FILE: include/linux/cmdline.h:49:
+^I} else if (sizeof(CONFIG_CMDLINE_APPEND) > 1) { ^I^I^I^I^I\$

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#81: FILE: include/linux/cmdline.h:50:
+^I^I__cmdline_add_builtin(dest, src, NULL, length, strlcpy, strlcat); ^I^I\$

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#82: FILE: include/linux/cmdline.h:51:
+^I} ^I^I^I^I^I^I^I^I^I^I^I\$

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#88: FILE: include/linux/cmdline.h:57:
+{^I^I^I^I^I^I^I^I ^I \$

WARNING:STRLCPY: Prefer strscpy over strlcpy - see: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@xxxxxxxxxxxxxx/
#89: FILE: include/linux/cmdline.h:58:
+ strlcpy(dest, CONFIG_CMDLINE_PREPEND " " CONFIG_CMDLINE_APPEND, \

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#90: FILE: include/linux/cmdline.h:59:
+^I^Ilength);^I^I ^I^I^I^I \$

CHECK:MACRO_ARG_REUSE: Macro argument reuse 'src' - possible side-effects?
#95: FILE: include/linux/cmdline.h:64:
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) { \
+ if (src != NULL) \
+ strlcpy(dest, src, length); \
+}

CHECK:MACRO_ARG_PRECEDENCE: Macro argument 'src' may be better as '(src)' to avoid precedence issues
#95: FILE: include/linux/cmdline.h:64:
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) { \
+ if (src != NULL) \
+ strlcpy(dest, src, length); \
+}

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#96: FILE: include/linux/cmdline.h:65:
+^Iif (src != NULL) ^I^I^I^I^I^I^I \$

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#97: FILE: include/linux/cmdline.h:66:
+^I^Istrlcpy(dest, src, length);^I ^I^I^I^I \$

WARNING:STRLCPY: Prefer strscpy over strlcpy - see: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@xxxxxxxxxxxxxx/
#97: FILE: include/linux/cmdline.h:66:
+ strlcpy(dest, src, length); \

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#100: FILE: include/linux/cmdline.h:69:
+#define cmdline_add_builtin(dest, src, length) { ^I^I^I^I\$

WARNING:SPACE_BEFORE_TAB: please, no space before tabs
#101: FILE: include/linux/cmdline.h:70:
+^Icmdline_add_builtin_custom(dest, src, length, strlcpy, strlcat); ^I\$

total: 0 errors, 20 warnings, 8 checks, 149 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
mechanically convert to the typical style using --fix or --fix-inplace.

the.patch has style problems, please review.

NOTE: Ignored message types: ARCH_INCLUDE_LINUX BIT_MACRO COMPARISON_TO_NULL DT_SPLIT_BINDING_PATCH EMAIL_SUBJECT FILE_PATH_CHANGES GLOBAL_INITIALISERS LINE_SPACING MULTIPLE_ASSIGNMENTS

NOTE: If any of the errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.

Cc: xe-linux-external@xxxxxxxxx
Signed-off-by: Ruslan Bilovol <rbilovol@xxxxxxxxx>
Signed-off-by: Daniel Walker <danielwa@xxxxxxxxx>
---
include/linux/cmdline.h | 75 +++++++++++++++++++++++++++++++++++++++++
init/Kconfig | 68 +++++++++++++++++++++++++++++++++++++
2 files changed, 143 insertions(+)
create mode 100644 include/linux/cmdline.h

diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h
new file mode 100644
index 000000000000..f44011d1a9ee
--- /dev/null
+++ b/include/linux/cmdline.h
@@ -0,0 +1,75 @@
+#ifndef _LINUX_CMDLINE_H
+#define _LINUX_CMDLINE_H
+
+/*
+ *
+ * Copyright (C) 2006,2021. Cisco Systems, Inc.
+ *
+ * Generic Append/Prepend cmdline support.
+ */
+
+#if defined(CONFIG_GENERIC_CMDLINE) && defined(CONFIG_CMDLINE_BOOL)
+
+#ifndef CONFIG_CMDLINE_OVERRIDE
+/*
+ * This function will append or prepend a builtin command line to the command
+ * line provided by the bootloader. Kconfig options can be used to alter
+ * the behavior of this builtin command line.
+ * @dest: The destination of the final appended/prepended string
+ * @src: The starting string or NULL if there isn't one.
+ * @tmp: temporary space used for prepending
+ * @length: the maximum length of the strings above.
+ */
+static inline void
+__cmdline_add_builtin(char *dest, const char *src, char *tmp, unsigned long length,
+ size_t (*strlcpy)(char *dest, const char *src, size_t size),
+ size_t (*strlcat)(char *dest, const char *src, size_t count)
+ )
+{
+ if (src != dest && src != NULL) {
+ strlcpy(dest, " ", length);
+ strlcat(dest, src, length);
+ }
+
+ if (sizeof(CONFIG_CMDLINE_APPEND) > 1)
+ strlcat(dest, " " CONFIG_CMDLINE_APPEND, length);
+
+ if (sizeof(CONFIG_CMDLINE_PREPEND) > 1) {
+ strlcpy(tmp, CONFIG_CMDLINE_PREPEND " ", length);
+ strlcat(tmp, dest, length);
+ strlcpy(dest, tmp, length);
+ }
+}
+
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) \
+{ \
+ if (sizeof(CONFIG_CMDLINE_PREPEND) > 1) { \
+ static label char cmdline_tmp_space[length]; \
+ __cmdline_add_builtin(dest, src, cmdline_tmp_space, length, strlcpy, strlcat); \
+ } else if (sizeof(CONFIG_CMDLINE_APPEND) > 1) { \
+ __cmdline_add_builtin(dest, src, NULL, length, strlcpy, strlcat); \
+ } \
+}
+#define cmdline_add_builtin(dest, src, length) \
+ cmdline_add_builtin_custom(dest, src, length, __initdata, &strlcpy, &strlcat)
+#else
+#define cmdline_add_builtin(dest, src, length) \
+{ \
+ strlcpy(dest, CONFIG_CMDLINE_PREPEND " " CONFIG_CMDLINE_APPEND, \
+ length); \
+}
+#endif /* !CONFIG_CMDLINE_OVERRIDE */
+
+#else
+#define cmdline_add_builtin_custom(dest, src, length, label, strlcpy, strlcat) { \
+ if (src != NULL) \
+ strlcpy(dest, src, length); \
+}
+
+#define cmdline_add_builtin(dest, src, length) { \
+ cmdline_add_builtin_custom(dest, src, length, strlcpy, strlcat); \
+}
+#endif /* CONFIG_GENERIC_CMDLINE */
+
+
+#endif /* _LINUX_CMDLINE_H */
diff --git a/init/Kconfig b/init/Kconfig
index 29ad68325028..28363ab07cd4 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2032,6 +2032,74 @@ config PROFILING
config TRACEPOINTS
bool
+config GENERIC_CMDLINE
+ bool
+
+if GENERIC_CMDLINE
+
+config CMDLINE_BOOL
+ bool "Built-in kernel command line"
+ help
+ Allow for specifying boot arguments to the kernel at
+ build time. On some systems (e.g. embedded ones), it is
+ necessary or convenient to provide some or all of the
+ kernel boot arguments with the kernel itself (that is,
+ to not rely on the boot loader to provide them.)
+
+ To compile command line arguments into the kernel,
+ set this option to 'Y', then fill in the
+ the boot arguments in CONFIG_CMDLINE.
+
+ Systems with fully functional boot loaders (i.e. non-embedded)
+ should leave this option set to 'N'.
+
+config CMDLINE_APPEND
+ string "Built-in kernel command string append"
+ depends on CMDLINE_BOOL
+ default ""
+ help
+ Enter arguments here that should be compiled into the kernel
+ image and used at boot time. If the boot loader provides a
+ command line at boot time, this string is appended to it to
+ form the full kernel command line, when the system boots.
+
+ However, you can use the CONFIG_CMDLINE_OVERRIDE option to
+ change this behavior.
+
+ In most cases, the command line (whether built-in or provided
+ by the boot loader) should specify the device for the root
+ file system.
+
+config CMDLINE_PREPEND
+ string "Built-in kernel command string prepend"
+ depends on CMDLINE_BOOL
+ default ""
+ help
+ Enter arguments here that should be compiled into the kernel
+ image and used at boot time. If the boot loader provides a
+ command line at boot time, this string is prepended to it to
+ form the full kernel command line, when the system boots.
+
+ However, you can use the CONFIG_CMDLINE_OVERRIDE option to
+ change this behavior.
+
+ In most cases, the command line (whether built-in or provided
+ by the boot loader) should specify the device for the root
+ file system.
+
+config CMDLINE_OVERRIDE
+ bool "Built-in command line overrides boot loader arguments"
+ depends on CMDLINE_BOOL
+ help
+ Set this option to 'Y' to have the kernel ignore the boot loader
+ command line, and use ONLY the built-in command line. In this case
+ append and prepend strings are concatenated to form the full
+ command line.
+
+ This is used to work around broken boot loaders. This should
+ be set to 'N' under normal conditions.
+endif
+
endmenu # General setup
source "arch/Kconfig"

Next message: Ravi Bangoria: "Re: [PATCH v3] powerpc/uprobes: Validation for prefixed instruction"
Previous message: Christophe Leroy: "Re: [PATCH 3/5] CMDLINE: powerpc: convert to generic builtin command line"
In reply to: Daniel Walker: "Re: [PATCH 1/5] CMDLINE: add generic builtin command line"
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