Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 48c2888..ee943ac 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -39,6 +39,8 @@
 #include "mm.h"
 #include "tcm.h"
 
+extern unsigned long __atags_pointer;
+
 /*
  * empty_zero_page is a special page that is used for
  * zero-initialized data and COW.
@@ -962,7 +964,7 @@
 		return;
 	}
 
-	if ((md->type == MT_DEVICE || md->type == MT_ROM) &&
+	if (md->type == MT_DEVICE &&
 	    md->virtual >= PAGE_OFFSET && md->virtual < FIXADDR_START &&
 	    (md->virtual < VMALLOC_START || md->virtual >= VMALLOC_END)) {
 		pr_warn("BUG: mapping for 0x%08llx at 0x%08lx out of vmalloc space\n",
@@ -1352,6 +1354,15 @@
 	for (addr = VMALLOC_START; addr < (FIXADDR_TOP & PMD_MASK); addr += PMD_SIZE)
 		pmd_clear(pmd_off_k(addr));
 
+	if (__atags_pointer) {
+		/* create a read-only mapping of the device tree */
+		map.pfn = __phys_to_pfn(__atags_pointer & SECTION_MASK);
+		map.virtual = FDT_FIXED_BASE;
+		map.length = FDT_FIXED_SIZE;
+		map.type = MT_ROM;
+		create_mapping(&map);
+	}
+
 	/*
 	 * Map the kernel if it is XIP.
 	 * It is always first in the modulearea.
@@ -1512,8 +1523,7 @@
 }
 
 #ifdef CONFIG_ARM_PV_FIXUP
-extern unsigned long __atags_pointer;
-typedef void pgtables_remap(long long offset, unsigned long pgd, void *bdata);
+typedef void pgtables_remap(long long offset, unsigned long pgd);
 pgtables_remap lpae_pgtables_remap_asm;
 
 /*
@@ -1526,7 +1536,6 @@
 	unsigned long pa_pgd;
 	unsigned int cr, ttbcr;
 	long long offset;
-	void *boot_data;
 
 	if (!mdesc->pv_fixup)
 		return;
@@ -1543,7 +1552,6 @@
 	 */
 	lpae_pgtables_remap = (pgtables_remap *)(unsigned long)__pa(lpae_pgtables_remap_asm);
 	pa_pgd = __pa(swapper_pg_dir);
-	boot_data = __va(__atags_pointer);
 	barrier();
 
 	pr_info("Switching physical address space to 0x%08llx\n",
@@ -1579,7 +1587,7 @@
 	 * needs to be assembly.  It's fairly simple, as we're using the
 	 * temporary tables setup by the initial assembly code.
 	 */
-	lpae_pgtables_remap(offset, pa_pgd, boot_data);
+	lpae_pgtables_remap(offset, pa_pgd);
 
 	/* Re-enable the caches and cacheable TLB walks */
 	asm volatile("mcr p15, 0, %0, c2, c0, 2" : : "r" (ttbcr));