X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=arch%2Friscv%2Fmm%2Finit.c;h=a14bf3910eec958c656ae29ab6c343af6dd0d28a;hb=d842bc6c0579ca7643eed029beabab3ac562a335;hp=269fc648ef3d84b24c99587aacf335dc36e58e23;hpb=4d4a60cede3604208c671f5a73a6edd094237b13;p=linux-2.6-microblaze.git

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 269fc648ef3d..a14bf3910eec 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -127,10 +127,17 @@ void __init mem_init(void)
 }
 
 /*
- * The default maximal physical memory size is -PAGE_OFFSET,
- * limit the memory size via mem.
+ * The default maximal physical memory size is -PAGE_OFFSET for 32-bit kernel,
+ * whereas for 64-bit kernel, the end of the virtual address space is occupied
+ * by the modules/BPF/kernel mappings which reduces the available size of the
+ * linear mapping.
+ * Limit the memory size via mem.
  */
+#ifdef CONFIG_64BIT
+static phys_addr_t memory_limit = -PAGE_OFFSET - SZ_4G;
+#else
 static phys_addr_t memory_limit = -PAGE_OFFSET;
+#endif
 
 static int __init early_mem(char *p)
 {
@@ -152,7 +159,7 @@ static void __init setup_bootmem(void)
 {
 	phys_addr_t vmlinux_end = __pa_symbol(&_end);
 	phys_addr_t vmlinux_start = __pa_symbol(&_start);
-	phys_addr_t max_mapped_addr = __pa(~(ulong)0);
+	phys_addr_t __maybe_unused max_mapped_addr;
 	phys_addr_t dram_end;
 
 #ifdef CONFIG_XIP_KERNEL
@@ -175,14 +182,21 @@ static void __init setup_bootmem(void)
 	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
 
 	dram_end = memblock_end_of_DRAM();
+
+#ifndef CONFIG_64BIT
 	/*
 	 * memblock allocator is not aware of the fact that last 4K bytes of
 	 * the addressable memory can not be mapped because of IS_ERR_VALUE
 	 * macro. Make sure that last 4k bytes are not usable by memblock
-	 * if end of dram is equal to maximum addressable memory.
+	 * if end of dram is equal to maximum addressable memory.  For 64-bit
+	 * kernel, this problem can't happen here as the end of the virtual
+	 * address space is occupied by the kernel mapping then this check must
+	 * be done in create_kernel_page_table.
 	 */
+	max_mapped_addr = __pa(~(ulong)0);
 	if (max_mapped_addr == (dram_end - 1))
 		memblock_set_current_limit(max_mapped_addr - 4096);
+#endif
 
 	min_low_pfn = PFN_UP(memblock_start_of_DRAM());
 	max_low_pfn = max_pfn = PFN_DOWN(dram_end);
@@ -570,6 +584,14 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
 	BUG_ON((kernel_map.phys_addr % map_size) != 0);
 
+#ifdef CONFIG_64BIT
+	/*
+	 * The last 4K bytes of the addressable memory can not be mapped because
+	 * of IS_ERR_VALUE macro.
+	 */
+	BUG_ON((kernel_map.virt_addr + kernel_map.size) > ADDRESS_SPACE_END - SZ_4K);
+#endif
+
 	pt_ops.alloc_pte = alloc_pte_early;
 	pt_ops.get_pte_virt = get_pte_virt_early;
 #ifndef __PAGETABLE_PMD_FOLDED
@@ -709,6 +731,8 @@ static void __init setup_vm_final(void)
 		if (start <= __pa(PAGE_OFFSET) &&
 		    __pa(PAGE_OFFSET) < end)
 			start = __pa(PAGE_OFFSET);
+		if (end >= __pa(PAGE_OFFSET) + memory_limit)
+			end = __pa(PAGE_OFFSET) + memory_limit;
 
 		map_size = best_map_size(start, end - start);
 		for (pa = start; pa < end; pa += map_size) {