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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
This commit is contained in:
Heiko Carstens 2018-09-18 23:51:44 -07:00 committed by Thomas Gleixner
parent e872267b8b
commit 13ddb52c16
3 changed files with 23 additions and 29 deletions
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1
arch/s390/Kconfig
View File

@ -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

40
arch/s390/include/asm/jump_label.h
View File

@ -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

11
arch/s390/kernel/jump_label.c
View File

@ -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)