x86/module: enable ROX caches for module text on 64 bit

Enable execmem's cache of PMD_SIZE'ed pages mapped as ROX for module text
allocations on 64 bit.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mike Rapoport (Microsoft) <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Tested-by: kdevops <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Borislav Petkov (AMD) <[email protected]>
Cc: Brian Cain <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Guo Ren <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: John Paul Adrian Glaubitz <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Masami Hiramatsu (Google) <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Russell King <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Stafford Horne <[email protected]>
Cc: Steven Rostedt (Google) <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Uladzislau Rezki (Sony) <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: rppt

arch/x86/Kconfig

@@ -83,6 +83,7 @@ config X86
 	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
 	select ARCH_HAS_EARLY_DEBUG		if KGDB
 	select ARCH_HAS_ELF_RANDOMIZE
+	select ARCH_HAS_EXECMEM_ROX		if X86_64
 	select ARCH_HAS_FAST_MULTIPLIER
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL

arch/x86/mm/init.c

@@ -1053,18 +1053,53 @@ unsigned long arch_max_swapfile_size(void)
 #ifdef CONFIG_EXECMEM
 static struct execmem_info execmem_info __ro_after_init;
 
+#ifdef CONFIG_ARCH_HAS_EXECMEM_ROX
+void execmem_fill_trapping_insns(void *ptr, size_t size, bool writeable)
+{
+	/* fill memory with INT3 instructions */
+	if (writeable)
+		memset(ptr, INT3_INSN_OPCODE, size);
+	else
+		text_poke_set(ptr, INT3_INSN_OPCODE, size);
+}
+#endif
+
 struct execmem_info __init *execmem_arch_setup(void)
 {
 	unsigned long start, offset = 0;
+	enum execmem_range_flags flags;
+	pgprot_t pgprot;
 
 	if (kaslr_enabled())
 		offset = get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
 
 	start = MODULES_VADDR + offset;
 
+	if (IS_ENABLED(CONFIG_ARCH_HAS_EXECMEM_ROX)) {
+		pgprot = PAGE_KERNEL_ROX;
+		flags = EXECMEM_KASAN_SHADOW | EXECMEM_ROX_CACHE;
+	} else {
+		pgprot = PAGE_KERNEL;
+		flags = EXECMEM_KASAN_SHADOW;
+	}
+
 	execmem_info = (struct execmem_info){
 		.ranges = {
-			[EXECMEM_DEFAULT] = {
+			[EXECMEM_MODULE_TEXT] = {
+				.flags	= flags,
+				.start	= start,
+				.end	= MODULES_END,
+				.pgprot	= pgprot,
+				.alignment = MODULE_ALIGN,
+			},
+			[EXECMEM_KPROBES ... EXECMEM_BPF] = {
+				.flags	= EXECMEM_KASAN_SHADOW,
+				.start	= start,
+				.end	= MODULES_END,
+				.pgprot	= PAGE_KERNEL,
+				.alignment = MODULE_ALIGN,
+			},
+			[EXECMEM_MODULE_DATA] = {
 				.flags	= EXECMEM_KASAN_SHADOW,
 				.start	= start,
 				.end	= MODULES_END,