[openwrt/openwrt] ath79: Fix fallback to bootloader cmdline on empty DT bootargs
LEDE Commits
lede-commits at lists.infradead.org
Tue Dec 22 13:13:44 EST 2020
ynezz pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/727eebbad1b9dea91174ea675cb64ea13484f790
commit 727eebbad1b9dea91174ea675cb64ea13484f790
Author: Sven Eckelmann <sven at narfation.org>
AuthorDate: Mon Nov 23 16:57:31 2020 +0100
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 <sven at narfation.org>
---
...e-Clean-up-boot_command_line-initializati.patch | 194 +++++++++++++++++++++
1 file changed, 194 insertions(+)
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 0000000000..4cadd5a86f
--- /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 <paul.burton at mips.com>
+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 <paul.burton at mips.com>
+Cc: linux-mips at 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 at 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();
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