gluon/patches/openwrt/0018-ath79-Fix-fallback-to-bootloader-cmdline-on-empty-DT-bootargs.patch

From: Sven Eckelmann <sven@narfation.org>
Date: Mon, 23 Nov 2020 16:57:31 +0100
Subject: 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@narfation.org>
Origin: backport, https://github.com/openwrt/openwrt/commit/727eebbad1b9dea91174ea675cb64ea13484f790

diff --git a/target/linux/ath79/patches-4.14/0038-MIPS-Setup-boot_command_line-before-plat_mem_setup.patch b/target/linux/ath79/patches-4.14/0038-MIPS-Setup-boot_command_line-before-plat_mem_setup.patch
new file mode 100644
index 0000000000000000000000000000000000000000..90d2ca7a0cb16d3f1e71779bfa551f498fd59755
--- /dev/null
+++ b/target/linux/ath79/patches-4.14/0038-MIPS-Setup-boot_command_line-before-plat_mem_setup.patch
@@ -0,0 +1,82 @@
+From: Paul Burton <paul.burton@mips.com>
+Date: Tue, 16 Jan 2018 16:47:57 +0100
+Subject: MIPS: Setup boot_command_line before plat_mem_setup
+
+Platforms using DT will typically call __dt_setup_arch from
+plat_mem_setup. This in turn calls early_init_dt_scan. When
+CONFIG_CMDLINE is set, this leads to its value being copied into
+boot_command_line by early_init_dt_scan_chosen. If this happens before
+the code setting up boot_command_line in arch_mem_init runs, that code
+will go on to append CONFIG_CMDLINE (via builtin_cmdline) to
+boot_command_line again, duplicating it. For some command line
+parameters (eg. earlycon) this can be a problem. Set up
+boot_command_line before early_init_dt_scan_chosen gets called such that
+it will not write CONFIG_CMDLINE in this scenario & the arguments aren't
+duplicated.
+
+Origin: upstream, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8ce355cf2e38afdb364d03d12b23d9cf44c3b7f1
+Signed-off-by: Paul Burton <paul.burton@mips.com>
+Acked-by: Mathieu Malaterre <malat@debian.org>
+Cc: Ralf Baechle <ralf@linux-mips.org>
+Cc: Maarten ter Huurne <maarten@treewalker.org>
+Cc: linux-mips@linux-mips.org
+Patchwork: https://patchwork.linux-mips.org/patch/18483/
+Signed-off-by: James Hogan <jhogan@kernel.org>
+
+diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
+index abd7ee9e90ab0dd0d01d970c84d90a2c4edf609b..c0f51fd4e0b3970e4f019094091578504e2f56eb 100644
+--- a/arch/mips/kernel/setup.c
++++ b/arch/mips/kernel/setup.c
+@@ -833,25 +833,6 @@ static void __init arch_mem_init(char **cmdline_p)
+ 	struct memblock_region *reg;
+ 	extern void plat_mem_setup(void);
+ 
+-	/* call board setup routine */
+-	plat_mem_setup();
+-
+-	/*
+-	 * Make sure all kernel memory is in the maps.  The "UP" and
+-	 * "DOWN" are opposite for initdata since if it crosses over
+-	 * into another memory section you don't want that to be
+-	 * freed when the initdata is freed.
+-	 */
+-	arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
+-			 PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
+-			 BOOT_MEM_RAM);
+-	arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
+-			 PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
+-			 BOOT_MEM_INIT_RAM);
+-
+-	pr_info("Determined physical RAM map:\n");
+-	print_memory_map();
+-
+ #if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE)
+ 	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+ #else
+@@ -879,6 +860,26 @@ static void __init arch_mem_init(char **cmdline_p)
+ 	}
+ #endif
+ #endif
++
++	/* call board setup routine */
++	plat_mem_setup();
++
++	/*
++	 * Make sure all kernel memory is in the maps.  The "UP" and
++	 * "DOWN" are opposite for initdata since if it crosses over
++	 * into another memory section you don't want that to be
++	 * freed when the initdata is freed.
++	 */
++	arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
++			 PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
++			 BOOT_MEM_RAM);
++	arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
++			 PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
++			 BOOT_MEM_INIT_RAM);
++
++	pr_info("Determined physical RAM map:\n");
++	print_memory_map();
++
+ 	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
+ 
+ 	*cmdline_p = command_line;
diff --git a/target/linux/ath79/patches-4.14/0039-MIPS-Fix-CONFIG_CMDLINE-handling.patch b/target/linux/ath79/patches-4.14/0039-MIPS-Fix-CONFIG_CMDLINE-handling.patch
new file mode 100644
index 0000000000000000000000000000000000000000..ab040c459454b1670b08afa2082e06637280da52
--- /dev/null
+++ b/target/linux/ath79/patches-4.14/0039-MIPS-Fix-CONFIG_CMDLINE-handling.patch
@@ -0,0 +1,119 @@
+From: Paul Burton <paul.burton@mips.com>
+Date: Thu, 27 Sep 2018 22:59:18 +0000
+Subject: MIPS: Fix CONFIG_CMDLINE handling
+
+Commit 8ce355cf2e38 ("MIPS: Setup boot_command_line before
+plat_mem_setup") fixed a problem for systems which have
+CONFIG_CMDLINE_BOOL=y & use a DT with a chosen node that has either no
+bootargs property or an empty one. In this configuration
+early_init_dt_scan_chosen() copies CONFIG_CMDLINE into
+boot_command_line, but the MIPS code doesn't know this so it appends
+CONFIG_CMDLINE (via builtin_cmdline) to boot_command_line again. The
+result is that boot_command_line contains the arguments from
+CONFIG_CMDLINE twice.
+
+That commit took the approach of simply setting up boot_command_line
+from the MIPS code before early_init_dt_scan_chosen() runs, causing it
+not to copy CONFIG_CMDLINE to boot_command_line if a chosen node with no
+bootargs property is found.
+
+Unfortunately this is problematic for systems which do have a non-empty
+bootargs property & CONFIG_CMDLINE_BOOL=y. There
+early_init_dt_scan_chosen() will overwrite boot_command_line with the
+arguments from DT, which means we lose those from CONFIG_CMDLINE
+entirely. This breaks CONFIG_MIPS_CMDLINE_DTB_EXTEND. If we have
+CONFIG_MIPS_CMDLINE_FROM_BOOTLOADER or
+CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND selected and the DT has a bootargs
+property which we should ignore, it will instead be honoured breaking
+those configurations too.
+
+Fix this by reverting commit 8ce355cf2e38 ("MIPS: Setup
+boot_command_line before plat_mem_setup") to restore the former
+behaviour, and fixing the CONFIG_CMDLINE duplication issue by
+initializing boot_command_line to a non-empty string that
+early_init_dt_scan_chosen() will not overwrite with CONFIG_CMDLINE.
+
+This is a little ugly, but cleanup in this area is on its way. In the
+meantime this is at least easy to backport & contains the ugliness
+within arch/mips/.
+
+Origin: upstream, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=951d223c6c16ed5d2a71a4d1f13c1e65d6882156
+Signed-off-by: Paul Burton <paul.burton@mips.com>
+Fixes: 8ce355cf2e38 ("MIPS: Setup boot_command_line before plat_mem_setup")
+References: https://patchwork.linux-mips.org/patch/18804/
+Patchwork: https://patchwork.linux-mips.org/patch/20813/
+Cc: Frank Rowand <frowand.list@gmail.com>
+Cc: Jaedon Shin <jaedon.shin@gmail.com>
+Cc: Mathieu Malaterre <malat@debian.org>
+Cc: Rob Herring <robh+dt@kernel.org>
+Cc: devicetree@vger.kernel.org
+Cc: linux-kernel@vger.kernel.org
+Cc: linux-mips@linux-mips.org
+Cc: stable@vger.kernel.org # v4.16+
+
+diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
+index c0f51fd4e0b3970e4f019094091578504e2f56eb..71070ec8da136495d2efed0aa79dff44149d565f 100644
+--- a/arch/mips/kernel/setup.c
++++ b/arch/mips/kernel/setup.c
+@@ -833,6 +833,34 @@ static void __init arch_mem_init(char **cmdline_p)
+ 	struct memblock_region *reg;
+ 	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();
++
++	/*
++	 * Make sure all kernel memory is in the maps.  The "UP" and
++	 * "DOWN" are opposite for initdata since if it crosses over
++	 * into another memory section you don't want that to be
++	 * freed when the initdata is freed.
++	 */
++	arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
++			 PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
++			 BOOT_MEM_RAM);
++	arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
++			 PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
++			 BOOT_MEM_INIT_RAM);
++
++	pr_info("Determined physical RAM map:\n");
++	print_memory_map();
++
+ #if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE)
+ 	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+ #else
+@@ -860,26 +888,6 @@ static void __init arch_mem_init(char **cmdline_p)
+ 	}
+ #endif
+ #endif
+-
+-	/* call board setup routine */
+-	plat_mem_setup();
+-
+-	/*
+-	 * Make sure all kernel memory is in the maps.  The "UP" and
+-	 * "DOWN" are opposite for initdata since if it crosses over
+-	 * into another memory section you don't want that to be
+-	 * freed when the initdata is freed.
+-	 */
+-	arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
+-			 PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
+-			 BOOT_MEM_RAM);
+-	arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
+-			 PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
+-			 BOOT_MEM_INIT_RAM);
+-
+-	pr_info("Determined physical RAM map:\n");
+-	print_memory_map();
+-
+ 	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
+ 
+ 	*cmdline_p = command_line;
diff --git a/target/linux/ath79/patches-4.14/0040-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch b/target/linux/ath79/patches-4.14/0040-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch
new file mode 100644
index 0000000000000000000000000000000000000000..2cba97d5e85bb863ca95c0715110b69e4964ea51
--- /dev/null
+++ b/target/linux/ath79/patches-4.14/0040-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch
@@ -0,0 +1,196 @@
+From: Paul Burton <paul.burton@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: backport, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7784cac697351f0cc0a4bb619594c0c99348c5aa
+Signed-off-by: Paul Burton <paul.burton@mips.com>
+Cc: linux-mips@vger.kernel.org
+
+diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
+index 71070ec8da136495d2efed0aa79dff44149d565f..c2b659a2e2ce0f2074f4fc13cd24283d66ac5594 100644
+--- a/arch/mips/kernel/setup.c
++++ b/arch/mips/kernel/setup.c
+@@ -822,26 +822,94 @@ static void __init request_crashkernel(struct resource *res)
+ }
+ #endif /* !defined(CONFIG_KEXEC)  */
+ 
+-#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);
++}
+ 
+ static void __init arch_mem_init(char **cmdline_p)
+ {
+ 	struct memblock_region *reg;
+ 	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();
+ 
+@@ -861,35 +929,8 @@ static void __init arch_mem_init(char **cmdline_p)
+ 	pr_info("Determined physical RAM map:\n");
+ 	print_memory_map();
+ 
+-#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();