x86: Add support for 64-bit place relative relocations
Add support for R_X86_64_PC64 relocations, which operate on 64-bit
quantities holding a relative symbol reference. Also remove the
definition of R_X86_64_NUM: given that it is currently unused, it
is unclear what the new value should be.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
Link: https://lkml.kernel.org/r/20180919065144.25010-5-ard.biesheuvel@linaro.org
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 0d157d2..a357031 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -62,8 +62,7 @@
#define R_X86_64_PC16 13 /* 16 bit sign extended pc relative */
#define R_X86_64_8 14 /* Direct 8 bit sign extended */
#define R_X86_64_PC8 15 /* 8 bit sign extended pc relative */
-
-#define R_X86_64_NUM 16
+#define R_X86_64_PC64 24 /* Place relative 64-bit signed */
/*
* These are used to set parameters in the core dumps.
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index f58336a..b052e88 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -201,6 +201,12 @@
goto overflow;
#endif
break;
+ case R_X86_64_PC64:
+ if (*(u64 *)loc != 0)
+ goto invalid_relocation;
+ val -= (u64)loc;
+ *(u64 *)loc = val;
+ break;
default:
pr_err("%s: Unknown rela relocation: %llu\n",
me->name, ELF64_R_TYPE(rel[i].r_info));
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 3a6c8eb..0b08067 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -196,6 +196,7 @@
#if ELF_BITS == 64
REL_TYPE(R_X86_64_NONE),
REL_TYPE(R_X86_64_64),
+ REL_TYPE(R_X86_64_PC64),
REL_TYPE(R_X86_64_PC32),
REL_TYPE(R_X86_64_GOT32),
REL_TYPE(R_X86_64_PLT32),
@@ -782,6 +783,15 @@
add_reloc(&relocs32neg, offset);
break;
+ case R_X86_64_PC64:
+ /*
+ * Only used by jump labels
+ */
+ if (is_percpu_sym(sym, symname))
+ die("Invalid R_X86_64_PC64 relocation against per-CPU symbol %s\n",
+ symname);
+ break;
+
case R_X86_64_32:
case R_X86_64_32S:
case R_X86_64_64:
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
index 5481972..413f3519 100644
--- a/arch/x86/um/asm/elf.h
+++ b/arch/x86/um/asm/elf.h
@@ -116,8 +116,7 @@
#define R_X86_64_PC16 13 /* 16 bit sign extended pc relative */
#define R_X86_64_8 14 /* Direct 8 bit sign extended */
#define R_X86_64_PC8 15 /* 8 bit sign extended pc relative */
-
-#define R_X86_64_NUM 16
+#define R_X86_64_PC64 24 /* Place relative 64-bit signed */
/*
* This is used to ensure we don't load something for the wrong architecture.