| Message ID | 20191009230936.2290413-1-paul.burton@mips.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 7784cac697351f0cc0a4bb619594c0c99348c5aa |
| Delegated to: | Paul Burton |
| Headers | show |
| Series | [v2] MIPS: cmdline: Clean up boot_command_line initialization | expand |
Hello, Paul Burton wrote: > Our current code to initialize boot_command_line is a mess. Some of this > is due to the addition of too many options over the years, and some of > this is due to workarounds for early_init_dt_scan_chosen() performing > actions specific to options from other architectures that probably > shouldn't be in generic code. > > Clean this up by introducing a new bootcmdline_init() function that > simplifies the initialization somewhat. The major changes are: > > - Because bootcmdline_init() is a function it can return early in the > CONFIG_CMDLINE_OVERRIDE case. > > - We clear boot_command_line rather than inheriting whatever > early_init_dt_scan_chosen() may have left us. This means we no longer > need to set boot_command_line to a space character in an attempt to > prevent early_init_dt_scan_chosen() from copying CONFIG_CMDLINE into > boot_command_line without us knowing about it. > > - Indirection via USE_PROM_CMDLINE, USE_DTB_CMDLINE, EXTEND_WITH_PROM & > BUILTIN_EXTEND_WITH_PROM macros is removed; they seemingly served only > to obfuscate the code. > > - The logic is cleaner, clearer & commented. > > Two minor drawbacks of this approach are: > > 1) We call of_scan_flat_dt(), which means we scan through the DT again. > The overhead is fairly minimal & shouldn't be noticeable. > > 2) cmdline_scan_chosen() duplicates a small amount of the logic from > early_init_dt_scan_chosen(). Alternatives might be to allow the > generic FDT code to keep & expose a copy of the arguments taken from > the /chosen node's bootargs property, or to introduce a function like > early_init_dt_scan_chosen() that retrieves them without modification > to handle CONFIG_CMDLINE. Neither of these sounds particularly > cleaner though, and this way we at least keep the extra work in > arch/mips. Applied to mips-next. > commit 7784cac69735 > https://git.kernel.org/mips/c/7784cac69735 > > Signed-off-by: Paul Burton <paul.burton@mips.com> Thanks, Paul [ This message was auto-generated; if you believe anything is incorrect then please email paul.burton@mips.com to report it. ]
On Wed, Oct 09, 2019 at 11:09:45PM +0000, Paul Burton wrote: > Our current code to initialize boot_command_line is a mess. Some of this > is due to the addition of too many options over the years, and some of > this is due to workarounds for early_init_dt_scan_chosen() performing > actions specific to options from other architectures that probably > shouldn't be in generic code. > > Clean this up by introducing a new bootcmdline_init() function that > simplifies the initialization somewhat. The major changes are: > > - Because bootcmdline_init() is a function it can return early in the > CONFIG_CMDLINE_OVERRIDE case. > > - We clear boot_command_line rather than inheriting whatever > early_init_dt_scan_chosen() may have left us. This means we no longer > need to set boot_command_line to a space character in an attempt to > prevent early_init_dt_scan_chosen() from copying CONFIG_CMDLINE into > boot_command_line without us knowing about it. > > - Indirection via USE_PROM_CMDLINE, USE_DTB_CMDLINE, EXTEND_WITH_PROM & > BUILTIN_EXTEND_WITH_PROM macros is removed; they seemingly served only > to obfuscate the code. > > - The logic is cleaner, clearer & commented. > > Two minor drawbacks of this approach are: > > 1) We call of_scan_flat_dt(), which means we scan through the DT again. > The overhead is fairly minimal & shouldn't be noticeable. > > 2) cmdline_scan_chosen() duplicates a small amount of the logic from > early_init_dt_scan_chosen(). Alternatives might be to allow the > generic FDT code to keep & expose a copy of the arguments taken from > the /chosen node's bootargs property, or to introduce a function like > early_init_dt_scan_chosen() that retrieves them without modification > to handle CONFIG_CMDLINE. Neither of these sounds particularly > cleaner though, and this way we at least keep the extra work in > arch/mips. > > Signed-off-by: Paul Burton <paul.burton@mips.com> > > --- > > Changes in v2: > - Keep CONFIG_MIPS_CMDLINE_DTB_EXTEND & > CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND for now. > - Hoist bootcmdline_append() into a function to avoid duplicating its > logic multiple times. > > arch/mips/kernel/setup.c | 125 ++++++++++++++++++++++++++------------- > 1 file changed, 83 insertions(+), 42 deletions(-) > > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > index 5eec13b8d222..4aeba3122972 100644 > --- a/arch/mips/kernel/setup.c > +++ b/arch/mips/kernel/setup.c > @@ -538,11 +538,88 @@ static void __init check_kernel_sections_mem(void) > } > } > > -#define USE_PROM_CMDLINE IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_BOOTLOADER) > -#define USE_DTB_CMDLINE IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB) > -#define EXTEND_WITH_PROM IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND) > -#define BUILTIN_EXTEND_WITH_PROM \ > - IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND) > +static void __init bootcmdline_append(const char *s, size_t max) > +{ > + if (!s[0] || !max) > + return; > + > + if (boot_command_line[0]) > + strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); > + > + strlcat(boot_command_line, s, max); > +} > + > +static int __init bootcmdline_scan_chosen(unsigned long node, const char *uname, > + int depth, void *data) > +{ > + bool *dt_bootargs = data; > + const char *p; > + int l; > + > + if (depth != 1 || !data || > + (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0)) > + return 0; > + > + p = of_get_flat_dt_prop(node, "bootargs", &l); > + if (p != NULL && l > 0) { > + bootcmdline_append(p, min(l, COMMAND_LINE_SIZE)); > + *dt_bootargs = true; > + } > + > + return 1; > +} > + > +static void __init bootcmdline_init(char **cmdline_p) > +{ > + bool dt_bootargs = false; > + > + /* > + * If CMDLINE_OVERRIDE is enabled then initializing the command line is > + * trivial - we simply use the built-in command line unconditionally & > + * unmodified. > + */ > + if (IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) { > + strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); > + return; > + } > + > + /* > + * If the user specified a built-in command line & > + * MIPS_CMDLINE_BUILTIN_EXTEND, then the built-in command line is > + * prepended to arguments from the bootloader or DT so we'll copy them > + * to the start of boot_command_line here. Otherwise, empty > + * boot_command_line to undo anything early_init_dt_scan_chosen() did. > + */ > + if (IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND)) > + strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); > + else > + boot_command_line[0] = 0; > + > + /* > + * If we're configured to take boot arguments from DT, look for those > + * now. > + */ > + if (IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB)) > + of_scan_flat_dt(bootcmdline_scan_chosen, &dt_bootargs); > + > + /* > + * If we didn't get any arguments from DT (regardless of whether that's > + * because we weren't configured to look for them, or because we looked > + * & found none) then we'll take arguments from the bootloader. > + * plat_mem_setup() should have filled arcs_cmdline with arguments from > + * the bootloader. > + */ > + if (IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND) || !dt_bootargs) > + bootcmdline_append(arcs_cmdline, COMMAND_LINE_SIZE); > + > + /* > + * If the user specified a built-in command line & we didn't already > + * prepend it, we append it to boot_command_line here. > + */ > + if (IS_ENABLED(CONFIG_CMDLINE_BOOL) && > + !IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND)) > + bootcmdline_append(builtin_cmdline, COMMAND_LINE_SIZE); > +} > > /* > * arch_mem_init - initialize memory management subsystem > @@ -570,48 +647,12 @@ static void __init arch_mem_init(char **cmdline_p) > { > extern void plat_mem_setup(void); > > - /* > - * Initialize boot_command_line to an innocuous but non-empty string in > - * order to prevent early_init_dt_scan_chosen() from copying > - * CONFIG_CMDLINE into it without our knowledge. We handle > - * CONFIG_CMDLINE ourselves below & don't want to duplicate its > - * content because repeating arguments can be problematic. > - */ > - strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE); > - > /* call board setup routine */ > plat_mem_setup(); > memblock_set_bottom_up(true); > > -#if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE) > - strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); > -#else > - if ((USE_PROM_CMDLINE && arcs_cmdline[0]) || > - (USE_DTB_CMDLINE && !boot_command_line[0])) > - strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); > - > - if (EXTEND_WITH_PROM && arcs_cmdline[0]) { > - if (boot_command_line[0]) > - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); > - strlcat(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); > - } > - > -#if defined(CONFIG_CMDLINE_BOOL) > - if (builtin_cmdline[0]) { > - if (boot_command_line[0]) > - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); > - strlcat(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); > - } > - > - if (BUILTIN_EXTEND_WITH_PROM && arcs_cmdline[0]) { > - if (boot_command_line[0]) > - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); > - strlcat(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); > - } > -#endif > -#endif > + bootcmdline_init(cmdline_p); > strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE); > - > *cmdline_p = command_line; > > parse_early_param(); > -- > 2.23.0 > Hi Paul, This causes a build error on malta_defconfig because CONFIG_CMDLINE_BOOL is not set so builtin_cmdline is not defined. https://travis-ci.com/ClangBuiltLinux/continuous-integration/jobs/244643074 ../arch/mips/kernel/setup.c: In function 'bootcmdline_init': ../arch/mips/kernel/setup.c:582:30: error: 'builtin_cmdline' undeclared (first use in this function); did you mean 'builtin_driver'? strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); ^~~~~~~~~~~~~~~ builtin_driver ../arch/mips/kernel/setup.c:582:30: note: each undeclared identifier is reported only once for each function it appears in Cheers, Nathan
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 5eec13b8d222..4aeba3122972 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -538,11 +538,88 @@ static void __init check_kernel_sections_mem(void) } } -#define USE_PROM_CMDLINE IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_BOOTLOADER) -#define USE_DTB_CMDLINE IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB) -#define EXTEND_WITH_PROM IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND) -#define BUILTIN_EXTEND_WITH_PROM \ - IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND) +static void __init bootcmdline_append(const char *s, size_t max) +{ + if (!s[0] || !max) + return; + + if (boot_command_line[0]) + strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); + + strlcat(boot_command_line, s, max); +} + +static int __init bootcmdline_scan_chosen(unsigned long node, const char *uname, + int depth, void *data) +{ + bool *dt_bootargs = data; + const char *p; + int l; + + if (depth != 1 || !data || + (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0)) + return 0; + + p = of_get_flat_dt_prop(node, "bootargs", &l); + if (p != NULL && l > 0) { + bootcmdline_append(p, min(l, COMMAND_LINE_SIZE)); + *dt_bootargs = true; + } + + return 1; +} + +static void __init bootcmdline_init(char **cmdline_p) +{ + bool dt_bootargs = false; + + /* + * If CMDLINE_OVERRIDE is enabled then initializing the command line is + * trivial - we simply use the built-in command line unconditionally & + * unmodified. + */ + if (IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) { + strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); + return; + } + + /* + * If the user specified a built-in command line & + * MIPS_CMDLINE_BUILTIN_EXTEND, then the built-in command line is + * prepended to arguments from the bootloader or DT so we'll copy them + * to the start of boot_command_line here. Otherwise, empty + * boot_command_line to undo anything early_init_dt_scan_chosen() did. + */ + if (IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND)) + strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); + else + boot_command_line[0] = 0; + + /* + * If we're configured to take boot arguments from DT, look for those + * now. + */ + if (IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB)) + of_scan_flat_dt(bootcmdline_scan_chosen, &dt_bootargs); + + /* + * If we didn't get any arguments from DT (regardless of whether that's + * because we weren't configured to look for them, or because we looked + * & found none) then we'll take arguments from the bootloader. + * plat_mem_setup() should have filled arcs_cmdline with arguments from + * the bootloader. + */ + if (IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND) || !dt_bootargs) + bootcmdline_append(arcs_cmdline, COMMAND_LINE_SIZE); + + /* + * If the user specified a built-in command line & we didn't already + * prepend it, we append it to boot_command_line here. + */ + if (IS_ENABLED(CONFIG_CMDLINE_BOOL) && + !IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND)) + bootcmdline_append(builtin_cmdline, COMMAND_LINE_SIZE); +} /* * arch_mem_init - initialize memory management subsystem @@ -570,48 +647,12 @@ static void __init arch_mem_init(char **cmdline_p) { extern void plat_mem_setup(void); - /* - * Initialize boot_command_line to an innocuous but non-empty string in - * order to prevent early_init_dt_scan_chosen() from copying - * CONFIG_CMDLINE into it without our knowledge. We handle - * CONFIG_CMDLINE ourselves below & don't want to duplicate its - * content because repeating arguments can be problematic. - */ - strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE); - /* call board setup routine */ plat_mem_setup(); memblock_set_bottom_up(true); -#if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE) - strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); -#else - if ((USE_PROM_CMDLINE && arcs_cmdline[0]) || - (USE_DTB_CMDLINE && !boot_command_line[0])) - strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); - - if (EXTEND_WITH_PROM && arcs_cmdline[0]) { - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); - } - -#if defined(CONFIG_CMDLINE_BOOL) - if (builtin_cmdline[0]) { - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); - } - - if (BUILTIN_EXTEND_WITH_PROM && arcs_cmdline[0]) { - if (boot_command_line[0]) - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); - } -#endif -#endif + bootcmdline_init(cmdline_p); strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE); - *cmdline_p = command_line; parse_early_param();
Our current code to initialize boot_command_line is a mess. Some of this is due to the addition of too many options over the years, and some of this is due to workarounds for early_init_dt_scan_chosen() performing actions specific to options from other architectures that probably shouldn't be in generic code. Clean this up by introducing a new bootcmdline_init() function that simplifies the initialization somewhat. The major changes are: - Because bootcmdline_init() is a function it can return early in the CONFIG_CMDLINE_OVERRIDE case. - We clear boot_command_line rather than inheriting whatever early_init_dt_scan_chosen() may have left us. This means we no longer need to set boot_command_line to a space character in an attempt to prevent early_init_dt_scan_chosen() from copying CONFIG_CMDLINE into boot_command_line without us knowing about it. - Indirection via USE_PROM_CMDLINE, USE_DTB_CMDLINE, EXTEND_WITH_PROM & BUILTIN_EXTEND_WITH_PROM macros is removed; they seemingly served only to obfuscate the code. - The logic is cleaner, clearer & commented. Two minor drawbacks of this approach are: 1) We call of_scan_flat_dt(), which means we scan through the DT again. The overhead is fairly minimal & shouldn't be noticeable. 2) cmdline_scan_chosen() duplicates a small amount of the logic from early_init_dt_scan_chosen(). Alternatives might be to allow the generic FDT code to keep & expose a copy of the arguments taken from the /chosen node's bootargs property, or to introduce a function like early_init_dt_scan_chosen() that retrieves them without modification to handle CONFIG_CMDLINE. Neither of these sounds particularly cleaner though, and this way we at least keep the extra work in arch/mips. Signed-off-by: Paul Burton <paul.burton@mips.com> --- Changes in v2: - Keep CONFIG_MIPS_CMDLINE_DTB_EXTEND & CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND for now. - Hoist bootcmdline_append() into a function to avoid duplicating its logic multiple times. arch/mips/kernel/setup.c | 125 ++++++++++++++++++++++++++------------- 1 file changed, 83 insertions(+), 42 deletions(-)