s390/jump_label: Switch to relative references

Enable support for relative references in jump_label entries.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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: 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/20180919065144.25010-10-ard.biesheuvel@linaro.org

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 9a9c7a6fe925915f561dd48c454e1e02d5ee7a51..12dc4c1af96cd8fdea643e29533d941df0bf1671 100644 (file)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -120,6 +120,7 @@ config S390
        select HAVE_ALIGNED_STRUCT_PAGE if SLUB
        select HAVE_ARCH_AUDITSYSCALL
        select HAVE_ARCH_JUMP_LABEL
+       select HAVE_ARCH_JUMP_LABEL_RELATIVE
        select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
        select HAVE_ARCH_SECCOMP_FILTER
        select HAVE_ARCH_SOFT_DIRTY

diff --git a/arch/s390/include/asm/jump_label.h b/arch/s390/include/asm/jump_label.h
index 40f651292aa78997232c74ae5f91afc0bbea035e..e2d3e6c43395d6d0861ac5aa47a57f8e91427576 100644 (file)
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -14,41 +14,33 @@
  * We use a brcl 0,2 instruction for jump labels at compile time so it
  * can be easily distinguished from a hotpatch generated instruction.
  */
-static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
+static inline bool arch_static_branch(struct static_key *key, bool branch)
 {
-       asm_volatile_goto("0:   brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"
-               ".pushsection __jump_table, \"aw\"\n"
-               ".balign 8\n"
-               ".quad 0b, %l[label], %0\n"
-               ".popsection\n"
-               : : "X" (&((char *)key)[branch]) : : label);
-
+       asm_volatile_goto("0:   brcl    0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"
+                         ".pushsection __jump_table,\"aw\"\n"
+                         ".balign      8\n"
+                         ".long        0b-.,%l[label]-.\n"
+                         ".quad        %0-.\n"
+                         ".popsection\n"
+                         : : "X" (&((char *)key)[branch]) : : label);
        return false;
 label:
        return true;
 }
 
-static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
+static inline bool arch_static_branch_jump(struct static_key *key, bool branch)
 {
-       asm_volatile_goto("0:   brcl 15, %l[label]\n"
-               ".pushsection __jump_table, \"aw\"\n"
-               ".balign 8\n"
-               ".quad 0b, %l[label], %0\n"
-               ".popsection\n"
-               : : "X" (&((char *)key)[branch]) : : label);
-
+       asm_volatile_goto("0:   brcl 15,%l[label]\n"
+                         ".pushsection __jump_table,\"aw\"\n"
+                         ".balign      8\n"
+                         ".long        0b-.,%l[label]-.\n"
+                         ".quad        %0-.\n"
+                         ".popsection\n"
+                         : : "X" (&((char *)key)[branch]) : : label);
        return false;
 label:
        return true;
 }
 
-typedef unsigned long jump_label_t;
-
-struct jump_entry {
-       jump_label_t code;
-       jump_label_t target;
-       jump_label_t key;
-};
-
 #endif  /* __ASSEMBLY__ */
 #endif

diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c
index 43f8430fb67d50aa44d3a4636d43b83bda17951e..50a1798604a80301843e764a10bb6c1ae8f45f01 100644 (file)
--- a/arch/s390/kernel/jump_label.c
+++ b/arch/s390/kernel/jump_label.c
@@ -33,13 +33,13 @@ static void jump_label_make_branch(struct jump_entry *entry, struct insn *insn)
 {
        /* brcl 15,offset */
        insn->opcode = 0xc0f4;
-       insn->offset = (entry->target - entry->code) >> 1;
+       insn->offset = (jump_entry_target(entry) - jump_entry_code(entry)) >> 1;
 }
 
 static void jump_label_bug(struct jump_entry *entry, struct insn *expected,
                           struct insn *new)
 {
-       unsigned char *ipc = (unsigned char *)entry->code;
+       unsigned char *ipc = (unsigned char *)jump_entry_code(entry);
        unsigned char *ipe = (unsigned char *)expected;
        unsigned char *ipn = (unsigned char *)new;
 
@@ -59,6 +59,7 @@ static void __jump_label_transform(struct jump_entry *entry,
                                   enum jump_label_type type,
                                   int init)
 {
+       void *code = (void *)jump_entry_code(entry);
        struct insn old, new;
 
        if (type == JUMP_LABEL_JMP) {
@@ -69,13 +70,13 @@ static void __jump_label_transform(struct jump_entry *entry,
                jump_label_make_nop(entry, &new);
        }
        if (init) {
-               if (memcmp((void *)entry->code, &orignop, sizeof(orignop)))
+               if (memcmp(code, &orignop, sizeof(orignop)))
                        jump_label_bug(entry, &orignop, &new);
        } else {
-               if (memcmp((void *)entry->code, &old, sizeof(old)))
+               if (memcmp(code, &old, sizeof(old)))
                        jump_label_bug(entry, &old, &new);
        }
-       s390_kernel_write((void *)entry->code, &new, sizeof(new));
+       s390_kernel_write(code, &new, sizeof(new));
 }
 
 static int __sm_arch_jump_label_transform(void *data)