Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/mm/nohash/40x.c b/arch/powerpc/mm/nohash/40x.c
new file mode 100644
index 0000000..f348104
--- /dev/null
+++ b/arch/powerpc/mm/nohash/40x.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * This file contains the routines for initializing the MMU
+ * on the 4xx series of chips.
+ * -- paulus
+ *
+ * Derived from arch/ppc/mm/init.c:
+ * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
+ * and Cort Dougan (PReP) (cort@cs.nmt.edu)
+ * Copyright (C) 1996 Paul Mackerras
+ *
+ * Derived from "arch/i386/mm/init.c"
+ * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
+ */
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/stddef.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/highmem.h>
+#include <linux/memblock.h>
+
+#include <asm/pgalloc.h>
+#include <asm/prom.h>
+#include <asm/io.h>
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
+#include <asm/mmu.h>
+#include <linux/uaccess.h>
+#include <asm/smp.h>
+#include <asm/bootx.h>
+#include <asm/machdep.h>
+#include <asm/setup.h>
+
+#include <mm/mmu_decl.h>
+
+extern int __map_without_ltlbs;
+/*
+ * MMU_init_hw does the chip-specific initialization of the MMU hardware.
+ */
+void __init MMU_init_hw(void)
+{
+ /*
+ * The Zone Protection Register (ZPR) defines how protection will
+ * be applied to every page which is a member of a given zone. At
+ * present, we utilize only two of the 4xx's zones.
+ * The zone index bits (of ZSEL) in the PTE are used for software
+ * indicators, except the LSB. For user access, zone 1 is used,
+ * for kernel access, zone 0 is used. We set all but zone 1
+ * to zero, allowing only kernel access as indicated in the PTE.
+ * For zone 1, we set a 01 binary (a value of 10 will not work)
+ * to allow user access as indicated in the PTE. This also allows
+ * kernel access as indicated in the PTE.
+ */
+
+ mtspr(SPRN_ZPR, 0x10000000);
+
+ flush_instruction_cache();
+
+ /*
+ * Set up the real-mode cache parameters for the exception vector
+ * handlers (which are run in real-mode).
+ */
+
+ mtspr(SPRN_DCWR, 0x00000000); /* All caching is write-back */
+
+ /*
+ * Cache instruction and data space where the exception
+ * vectors and the kernel live in real-mode.
+ */
+
+ mtspr(SPRN_DCCR, 0xFFFF0000); /* 2GByte of data space at 0x0. */
+ mtspr(SPRN_ICCR, 0xFFFF0000); /* 2GByte of instr. space at 0x0. */
+}
+
+#define LARGE_PAGE_SIZE_16M (1<<24)
+#define LARGE_PAGE_SIZE_4M (1<<22)
+
+unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
+{
+ unsigned long v, s, mapped;
+ phys_addr_t p;
+
+ v = KERNELBASE;
+ p = 0;
+ s = total_lowmem;
+
+ if (__map_without_ltlbs)
+ return 0;
+
+ while (s >= LARGE_PAGE_SIZE_16M) {
+ pmd_t *pmdp;
+ unsigned long val = p | _PMD_SIZE_16M | _PAGE_EXEC | _PAGE_HWWRITE;
+
+ pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
+ *pmdp++ = __pmd(val);
+ *pmdp++ = __pmd(val);
+ *pmdp++ = __pmd(val);
+ *pmdp++ = __pmd(val);
+
+ v += LARGE_PAGE_SIZE_16M;
+ p += LARGE_PAGE_SIZE_16M;
+ s -= LARGE_PAGE_SIZE_16M;
+ }
+
+ while (s >= LARGE_PAGE_SIZE_4M) {
+ pmd_t *pmdp;
+ unsigned long val = p | _PMD_SIZE_4M | _PAGE_EXEC | _PAGE_HWWRITE;
+
+ pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
+ *pmdp = __pmd(val);
+
+ v += LARGE_PAGE_SIZE_4M;
+ p += LARGE_PAGE_SIZE_4M;
+ s -= LARGE_PAGE_SIZE_4M;
+ }
+
+ mapped = total_lowmem - s;
+
+ /* If the size of RAM is not an exact power of two, we may not
+ * have covered RAM in its entirety with 16 and 4 MiB
+ * pages. Consequently, restrict the top end of RAM currently
+ * allocable so that calls to the MEMBLOCK to allocate PTEs for "tail"
+ * coverage with normal-sized pages (or other reasons) do not
+ * attempt to allocate outside the allowed range.
+ */
+ memblock_set_current_limit(mapped);
+
+ return mapped;
+}
+
+void setup_initial_memory_limit(phys_addr_t first_memblock_base,
+ phys_addr_t first_memblock_size)
+{
+ /* We don't currently support the first MEMBLOCK not mapping 0
+ * physical on those processors
+ */
+ BUG_ON(first_memblock_base != 0);
+
+ /* 40x can only access 16MB at the moment (see head_40x.S) */
+ memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000));
+}