x86: map all RAM if ACPI

ACPI tables can lurk anywhere. Map all memory so they can be
read.

Signed-off-by: Andrew Boie <[email protected]>

arch/Kconfig

@@ -62,7 +62,6 @@ config X86
 	select ARCH_HAS_TIMING_FUNCTIONS
 	select ARCH_HAS_THREAD_LOCAL_STORAGE
 	select ARCH_HAS_DEMAND_PAGING
-	select ARCH_MAPS_ALL_RAM
 	help
 	  x86 architecture
 

arch/x86/Kconfig

@@ -95,6 +95,7 @@ endchoice
 
 config ACPI
 	bool "ACPI (Advanced Configuration and Power Interface) support"
+	select ARCH_MAPS_ALL_RAM
 	help
 	  Allow retrieval of platform configuration at runtime.
 

arch/x86/gen_mmu.py

@@ -457,10 +457,15 @@ def main():
     debug("building %s" % pclass.__name__)
 
     vm_base = syms["CONFIG_KERNEL_VM_BASE"]
-    vm_size = syms["CONFIG_KERNEL_VM_SIZE"]
+    # Work around #31562
+    vm_size = syms["CONFIG_KERNEL_VM_SIZE"] & 0xFFFFFFFF
 
-    image_base = syms["z_mapped_start"]
-    image_size = syms["z_mapped_size"]
+    if isdef("CONFIG_ARCH_MAPS_ALL_RAM"):
+        image_base = syms["CONFIG_SRAM_BASE_ADDRESS"]
+        image_size = syms["CONFIG_SRAM_SIZE"] * 1024
+    else:
+        image_base = syms["z_mapped_start"]
+        image_size = syms["z_mapped_size"]
     ptables_phys = syms["z_x86_pagetables_start"]
 
     debug("Address space: 0x%x - 0x%x size %x" %
@@ -471,6 +476,9 @@ def main():
 
     is_perm_regions = isdef("CONFIG_SRAM_REGION_PERMISSIONS")
 
+    if image_size >= vm_size:
+        error("VM size is too small (have 0x%x need more than 0x%x)" % (vm_size, image_size))
+
     if is_perm_regions:
         # Don't allow execution by default for any pages. We'll adjust this
         # in later calls to pt.set_region_perms()

tests/arch/x86/pagetables/src/main.c

@@ -159,6 +159,22 @@ void test_ram_perms(void)
 			      PRI_ENTRY, flags, pos, expected);
 	}
 #endif /* CONFIG_X86_64 */
+
+#ifdef CONFIG_ARCH_MAPS_ALL_RAM
+	/* All RAM page frame entries aside from 0x0 must have a mapping.
+	 * We currently identity-map on x86, no conversion necessary other than a cast
+	 */
+	for (pos = (uint8_t *)Z_PHYS_RAM_START; pos < (uint8_t *)Z_PHYS_RAM_END;
+	     pos += CONFIG_MMU_PAGE_SIZE) {
+		if (pos == NULL) {
+			continue;
+		}
+
+		entry = get_entry(&flags, pos);
+		zassert_true((flags & MMU_P) != 0,
+			     "address %p isn't mapped", pos);
+	}
+#endif
 }
 
 /**