--- zzzz-none-000/linux-4.4.271/init/main.c	2021-06-03 06:22:09.000000000 +0000
+++ hawkeye-5590-750/linux-4.4.271/init/main.c	2023-04-19 10:22:30.000000000 +0000
@@ -89,6 +89,11 @@
 #include <asm/sections.h>
 #include <asm/cacheflush.h>
 
+#ifdef CONFIG_QCA_NMI_RESERVE
+#include <avm_atheros.h>
+#include <asm/tlbmisc.h>
+#endif
+
 static int kernel_init(void *);
 
 extern void init_IRQ(void);
@@ -356,6 +361,29 @@
 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 #endif
 
+#ifdef CONFIG_MANGLE_BOOTARGS
+static void __init mangle_bootargs(char *command_line)
+{
+	char *rootdev;
+	char *rootfs;
+
+	rootdev = strstr(command_line, "root=/dev/mtdblock");
+
+	if (rootdev)
+		strncpy(rootdev, "mangled_rootblock=", 18);
+
+	rootfs = strstr(command_line, "rootfstype");
+
+	if (rootfs)
+		strncpy(rootfs, "mangled_fs", 10);
+
+}
+#else
+static void __init mangle_bootargs(char *command_line)
+{
+}
+#endif
+
 /*
  * We need to store the untouched command line for future reference.
  * We also need to store the touched command line since the parameter
@@ -477,6 +505,126 @@
 }
 #endif
 
+#ifdef CONFIG_QCA_NMI_RESERVE
+/*
+ * WARNING:
+ *	This will turn off memory mapped SPI flash access.
+ */
+
+#define ENTRY_LO_MASK		(~((1ul << 26) - 1))
+#define ENTRY_LO_V		0x2
+#define ENTRY_LO_G		0x1
+#define ENTRY_LO_C(x)		(((x) & CONF_CM_CMASK) << 2)
+
+extern void local_flush_tlb_all(void);
+extern void except_vec_nmi(void);
+
+static void *nmi_reserve;
+
+static __init bool use_nmi_relocation(void) {
+	int ret;
+	u32 relocation;
+
+	ret = of_property_read_u32(of_root, "nmi-relocation", &relocation);
+
+	if (ret != 0) {
+		return false;
+	}
+
+	return relocation == 1;
+}
+
+static __init int copy_nmi_trampoline(void)
+{
+	mm_segment_t old_fs;
+	extern char except_vec_nmi_end;
+
+	if (!nmi_reserve)
+		return -1;
+
+	memset(nmi_reserve, 0, PAGE_SIZE);
+
+	memcpy(nmi_reserve, except_vec_nmi,
+		&except_vec_nmi_end - (char *)except_vec_nmi);
+
+	old_fs = get_fs();	/* refer load_module() */
+	set_fs(KERNEL_DS);
+
+	/*
+	 * This might not be needed as the region is marked as
+	 * CONF_CM_UNCACHED. Better safe than sorry! (if that gets changed)
+	 */
+	local_flush_icache_range((unsigned long)nmi_reserve, (unsigned long)nmi_reserve + 256);
+	local_flush_data_cache_page(nmi_reserve);
+
+	set_fs(old_fs);
+
+	pr_info("[nmi] %s done\n", __func__);
+
+	return 0;
+}
+
+static __init void nmi_reserve_memory(void)
+{
+	unsigned long pa, lo0;
+
+	nmi_reserve = vmalloc(PAGE_SIZE);
+
+	if (!nmi_reserve) {
+		pr_err("[nmi] %s: ENOMEM\n", __func__);
+		return;
+	}
+
+	if ((u32)nmi_reserve != (u32)VMALLOC_START) {
+		pr_err("[nmi] %s: NMI handler reserve area (%p) != %p\n",
+			__func__, nmi_reserve, (void*)VMALLOC_START);
+		vfree(nmi_reserve);
+		nmi_reserve = NULL;
+		return;
+	}
+
+	/*
+	 * When the CPU receives the NMI, it uses the reset TLB.
+	 * Hence the 'vmalloc' mapping would not be available
+	 * temporarily. Hence, wire that TLB entry
+	 */
+	pa = virt_to_phys(nmi_reserve);
+
+	lo0 = (pa >> 12) << 6;		// PFN
+	lo0 &= ~ENTRY_LO_MASK;
+
+	lo0 |= ENTRY_LO_V | ENTRY_LO_G;
+
+	lo0 |= ENTRY_LO_C(CONF_CM_UNCACHED);	// Caching attributes
+
+	/*
+	 * TLB could already have the mapping for VMALLOC_START. Ideally, only
+	 * that entry should be removed, but don't have the patience to figure
+	 * it out :( And, since this is a one time operation during early boot,
+	 * cleaning everything should be ok.
+	 */
+	local_flush_tlb_all();
+
+	add_wired_entry(lo0, lo0, (unsigned long)nmi_reserve, PM_4K);
+
+	pr_info("[nmi] VA:PA %p:%p wired at entry 0x%x\n",
+		nmi_reserve, (void*)pa, read_c0_wired());
+}
+
+/*
+ * Probably should use 'board_nmi_handler_setup', but this works
+ */
+late_initcall(copy_nmi_trampoline);
+
+#if !defined(CONFIG_MTD_ATH_FLASH)
+void ath_spi_disable_mm(void) {
+	ath_reg_wr_nf(ATH_SPI_FS, 1);
+}
+#endif
+
+#endif /* CONFIG_QCA_NMI_RESERVE */
+
+
 /*
  * Set up kernel memory allocators
  */
@@ -492,6 +640,13 @@
 	percpu_init_late();
 	pgtable_init();
 	vmalloc_init();
+#ifdef CONFIG_QCA_NMI_RESERVE
+	if (use_nmi_relocation()) {
+		// Enable SPI soft access (and in turn disable memory mapped spi)
+		ath_spi_disable_mm();
+		nmi_reserve_memory();
+	}
+#endif
 	ioremap_huge_init();
 	kaiser_init();
 }
@@ -529,6 +684,7 @@
 	pr_notice("%s", linux_banner);
 	setup_arch(&command_line);
 	mm_init_cpumask(&init_mm);
+	mangle_bootargs(command_line);
 	setup_command_line(command_line);
 	setup_nr_cpu_ids();
 	setup_per_cpu_areas();
@@ -632,6 +788,7 @@
 #endif
 	page_ext_init();
 	debug_objects_mem_init();
+	debug_mem_usage_init();
 	kmemleak_init();
 	setup_per_cpu_pageset();
 	numa_policy_init();
@@ -968,7 +1125,8 @@
 		panic("Requested init %s failed (error %d).",
 		      execute_command, ret);
 	}
-	if (!try_to_run_init_process("/sbin/init") ||
+	if (!try_to_run_init_process("/etc/preinit") ||
+	    !try_to_run_init_process("/sbin/init") ||
 	    !try_to_run_init_process("/etc/init") ||
 	    !try_to_run_init_process("/bin/init") ||
 	    !try_to_run_init_process("/bin/sh"))