From 727eebbad1b9dea91174ea675cb64ea13484f790 Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Mon, 23 Nov 2020 16:57:31 +0100 Subject: [PATCH] ath79: Fix fallback to bootloader cmdline on empty DT bootargs The MIPS code is supposed to fall back to u-boots bootargs whenever the /chosen/bootargs property is missing. But this feature was accidentally disabled when the boot_command_line was initialized with an empty space just to work around problems with early_init_dt_scan_chosen. But this feature is necessary for some boards which have a dualboot mechanism and whose u-boot is calculating the correct partition at runtime without writing this information back to the u-boot-env. Signed-off-by: Sven Eckelmann --- ...an-up-boot_command_line-initializati.patch | 194 ++++++++++++++++++ 1 file changed, 194 insertions(+) create mode 100644 target/linux/ath79/patches-5.4/0001-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch diff --git a/target/linux/ath79/patches-5.4/0001-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch b/target/linux/ath79/patches-5.4/0001-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch new file mode 100644 index 00000000000..4cadd5a86f5 --- /dev/null +++ b/target/linux/ath79/patches-5.4/0001-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch @@ -0,0 +1,194 @@ +From: Paul Burton +Date: Wed, 9 Oct 2019 23:09:45 +0000 +Subject: MIPS: cmdline: Clean up boot_command_line initialization + +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. + +Origin: upstream, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7784cac697351f0cc0a4bb619594c0c99348c5aa +Signed-off-by: Paul Burton +Cc: linux-mips@vger.kernel.org + +diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c +index b8884de89c81e1b444b218a15519556b4a374089..e56dd6c25d46336fcb9af21326f697d0c37aac1c 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(); -- 2.30.2