1 files changed, 53 insertions, 9 deletions

diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index b7abfad4fd7d..1fc6d1ff92d3 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -19,6 +19,8 @@
 #include <linux/moduleloader.h>
 #include <linux/bug.h>
 #include <asm/alternative.h>
+#include <asm/nospec-branch.h>
+#include <asm/facility.h>
 
 #if 0
 #define DEBUGP printk
@@ -156,7 +158,11 @@ int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 	me->arch.got_offset = me->core_layout.size;
 	me->core_layout.size += me->arch.got_size;
 	me->arch.plt_offset = me->core_layout.size;
-	me->core_layout.size += me->arch.plt_size;
+	if (me->arch.plt_size) {
+		if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_call_disable)
+			me->arch.plt_size += PLT_ENTRY_SIZE;
+		me->core_layout.size += me->arch.plt_size;
+	}
 	return 0;
 }
 
@@ -310,9 +316,21 @@ static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
 			unsigned int *ip;
 			ip = me->core_layout.base + me->arch.plt_offset +
 				info->plt_offset;
-			ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */
-			ip[1] = 0x100a0004;
-			ip[2] = 0x07f10000;
+			ip[0] = 0x0d10e310;	/* basr 1,0  */
+			ip[1] = 0x100a0004;	/* lg	1,10(1) */
+			if (IS_ENABLED(CONFIG_EXPOLINE) &&
+			    !nospec_call_disable) {
+				unsigned int *ij;
+				ij = me->core_layout.base +
+					me->arch.plt_offset +
+					me->arch.plt_size - PLT_ENTRY_SIZE;
+				ip[2] = 0xa7f40000 +	/* j __jump_r1 */
+					(unsigned int)(u16)
+					(((unsigned long) ij - 8 -
+					  (unsigned long) ip) / 2);
+			} else {
+				ip[2] = 0x07f10000;	/* br %r1 */
+			}
 			ip[3] = (unsigned int) (val >> 32);
 			ip[4] = (unsigned int) val;
 			info->plt_initialized = 1;
@@ -418,16 +436,42 @@ int module_finalize(const Elf_Ehdr *hdr,
 		    struct module *me)
 {
 	const Elf_Shdr *s;
-	char *secstrings;
+	char *secstrings, *secname;
+	void *aseg;
+
+	if (IS_ENABLED(CONFIG_EXPOLINE) &&
+	    !nospec_call_disable && me->arch.plt_size) {
+		unsigned int *ij;
+
+		ij = me->core_layout.base + me->arch.plt_offset +
+			me->arch.plt_size - PLT_ENTRY_SIZE;
+		if (test_facility(35)) {
+			ij[0] = 0xc6000000;	/* exrl	%r0,.+10	*/
+			ij[1] = 0x0005a7f4;	/* j	.		*/
+			ij[2] = 0x000007f1;	/* br	%r1		*/
+		} else {
+			ij[0] = 0x44000000 | (unsigned int)
+				offsetof(struct lowcore, br_r1_trampoline);
+			ij[1] = 0xa7f40000;	/* j	.		*/
+		}
+	}
 
 	secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
-		if (!strcmp(".altinstructions", secstrings + s->sh_name)) {
-			/* patch .altinstructions */
-			void *aseg = (void *)s->sh_addr;
+		aseg = (void *) s->sh_addr;
+		secname = secstrings + s->sh_name;
 
+		if (!strcmp(".altinstructions", secname))
+			/* patch .altinstructions */
 			apply_alternatives(aseg, aseg + s->sh_size);
-		}
+
+		if (IS_ENABLED(CONFIG_EXPOLINE) &&
+		    (!strcmp(".nospec_call_table", secname)))
+			nospec_call_revert(aseg, aseg + s->sh_size);
+
+		if (IS_ENABLED(CONFIG_EXPOLINE) &&
+		    (!strcmp(".nospec_return_table", secname)))
+			nospec_return_revert(aseg, aseg + s->sh_size);
 	}
 
 	jump_label_apply_nops(me);