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-rw-r--r--arch/arm64/Makefile3
-rw-r--r--arch/arm64/include/asm/module.h2
-rw-r--r--arch/arm64/kernel/Makefile3
-rw-r--r--arch/arm64/kernel/ftrace-mod.S18
-rw-r--r--arch/arm64/kernel/ftrace.c14
-rw-r--r--arch/arm64/kernel/module-plts.c12
-rw-r--r--arch/arm64/kernel/module.lds1
7 files changed, 22 insertions, 31 deletions
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index b35788c909f1..b481b4a7c011 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -83,9 +83,6 @@ endif
ifeq ($(CONFIG_ARM64_MODULE_PLTS),y)
KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/arm64/kernel/module.lds
-ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
-KBUILD_LDFLAGS_MODULE += $(objtree)/arch/arm64/kernel/ftrace-mod.o
-endif
endif
# Default value
diff --git a/arch/arm64/include/asm/module.h b/arch/arm64/include/asm/module.h
index 11d4aaee82e1..4f766178fa6f 100644
--- a/arch/arm64/include/asm/module.h
+++ b/arch/arm64/include/asm/module.h
@@ -32,7 +32,7 @@ struct mod_arch_specific {
struct mod_plt_sec init;
/* for CONFIG_DYNAMIC_FTRACE */
- void *ftrace_trampoline;
+ struct plt_entry *ftrace_trampoline;
};
#endif
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 8265dd790895..067baace74a0 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -61,6 +61,3 @@ extra-y += $(head-y) vmlinux.lds
ifeq ($(CONFIG_DEBUG_EFI),y)
AFLAGS_head.o += -DVMLINUX_PATH="\"$(realpath $(objtree)/vmlinux)\""
endif
-
-# will be included by each individual module but not by the core kernel itself
-extra-$(CONFIG_DYNAMIC_FTRACE) += ftrace-mod.o
diff --git a/arch/arm64/kernel/ftrace-mod.S b/arch/arm64/kernel/ftrace-mod.S
deleted file mode 100644
index 00c4025be4ff..000000000000
--- a/arch/arm64/kernel/ftrace-mod.S
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * Copyright (C) 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#include <linux/linkage.h>
-#include <asm/assembler.h>
-
- .section ".text.ftrace_trampoline", "ax"
- .align 3
-0: .quad 0
-__ftrace_trampoline:
- ldr x16, 0b
- br x16
-ENDPROC(__ftrace_trampoline)
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index c13b1fca0e5b..50986e388d2b 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -76,7 +76,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
if (offset < -SZ_128M || offset >= SZ_128M) {
#ifdef CONFIG_ARM64_MODULE_PLTS
- unsigned long *trampoline;
+ struct plt_entry trampoline;
struct module *mod;
/*
@@ -104,22 +104,24 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
* is added in the future, but for now, the pr_err() below
* deals with a theoretical issue only.
*/
- trampoline = (unsigned long *)mod->arch.ftrace_trampoline;
- if (trampoline[0] != addr) {
- if (trampoline[0] != 0) {
+ trampoline = get_plt_entry(addr);
+ if (!plt_entries_equal(mod->arch.ftrace_trampoline,
+ &trampoline)) {
+ if (!plt_entries_equal(mod->arch.ftrace_trampoline,
+ &(struct plt_entry){})) {
pr_err("ftrace: far branches to multiple entry points unsupported inside a single module\n");
return -EINVAL;
}
/* point the trampoline to our ftrace entry point */
module_disable_ro(mod);
- trampoline[0] = addr;
+ *mod->arch.ftrace_trampoline = trampoline;
module_enable_ro(mod, true);
/* update trampoline before patching in the branch */
smp_wmb();
}
- addr = (unsigned long)&trampoline[1];
+ addr = (unsigned long)(void *)mod->arch.ftrace_trampoline;
#else /* CONFIG_ARM64_MODULE_PLTS */
return -EINVAL;
#endif /* CONFIG_ARM64_MODULE_PLTS */
diff --git a/arch/arm64/kernel/module-plts.c b/arch/arm64/kernel/module-plts.c
index ebff6c155cac..ea640f92fe5a 100644
--- a/arch/arm64/kernel/module-plts.c
+++ b/arch/arm64/kernel/module-plts.c
@@ -120,6 +120,7 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
unsigned long core_plts = 0;
unsigned long init_plts = 0;
Elf64_Sym *syms = NULL;
+ Elf_Shdr *tramp = NULL;
int i;
/*
@@ -131,6 +132,10 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
mod->arch.core.plt = sechdrs + i;
else if (!strcmp(secstrings + sechdrs[i].sh_name, ".init.plt"))
mod->arch.init.plt = sechdrs + i;
+ else if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE) &&
+ !strcmp(secstrings + sechdrs[i].sh_name,
+ ".text.ftrace_trampoline"))
+ tramp = sechdrs + i;
else if (sechdrs[i].sh_type == SHT_SYMTAB)
syms = (Elf64_Sym *)sechdrs[i].sh_addr;
}
@@ -181,5 +186,12 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
mod->arch.init.plt_num_entries = 0;
mod->arch.init.plt_max_entries = init_plts;
+ if (tramp) {
+ tramp->sh_type = SHT_NOBITS;
+ tramp->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
+ tramp->sh_addralign = __alignof__(struct plt_entry);
+ tramp->sh_size = sizeof(struct plt_entry);
+ }
+
return 0;
}
diff --git a/arch/arm64/kernel/module.lds b/arch/arm64/kernel/module.lds
index f7c9781a9d48..22e36a21c113 100644
--- a/arch/arm64/kernel/module.lds
+++ b/arch/arm64/kernel/module.lds
@@ -1,4 +1,5 @@
SECTIONS {
.plt (NOLOAD) : { BYTE(0) }
.init.plt (NOLOAD) : { BYTE(0) }
+ .text.ftrace_trampoline (NOLOAD) : { BYTE(0) }
}