ARM: fixup SMP alternatives in modules

With certain configurations, we inline the unlock functions in modules,
which results in SMP alternatives being created in modules.  We need to
fix those up when loading a module to prevent undefined instruction
faults.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 21 insertions, 1 deletions

diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index 2cfe816..6d4105e 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -22,6 +22,7 @@
 
 #include <asm/pgtable.h>
 #include <asm/sections.h>
+#include <asm/smp_plat.h>
 #include <asm/unwind.h>
 
 #ifdef CONFIG_XIP_KERNEL
@@ -268,12 +269,28 @@ struct mod_unwind_map {
 	const Elf_Shdr *txt_sec;
 };
 
+static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
+	const Elf_Shdr *sechdrs, const char *name)
+{
+	const Elf_Shdr *s, *se;
+	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+
+	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
+		if (strcmp(name, secstrs + s->sh_name) == 0)
+			return s;
+
+	return NULL;
+}
+
+extern void fixup_smp(const void *, unsigned long);
+
 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 		    struct module *mod)
 {
+	const Elf_Shdr * __maybe_unused s = NULL;
 #ifdef CONFIG_ARM_UNWIND
 	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
-	const Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;
+	const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
 	struct mod_unwind_map maps[ARM_SEC_MAX];
 	int i;
 
@@ -315,6 +332,9 @@ int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 					         maps[i].txt_sec->sh_addr,
 					         maps[i].txt_sec->sh_size);
 #endif
+	s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
+	if (s && !is_smp())
+		fixup_smp((void *)s->sh_addr, s->sh_size);
 	return 0;
 }