76b235c6bc
Since we've already stepped away from ENABLE is a JMP and DISABLE is a
NOP with the branch_default bits, and are going to make it even worse,
rename it to make it all clearer.
This way we don't mix multiple levels of logic attributes, but have a
plain 'physical' name for what the current instruction patching status
of a jump label is.
This is a first step in removing the naming confusion that has led to
a stream of avoidable bugs such as:
a833581e37 ("x86, perf: Fix static_key bug in load_mm_cr4()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
[ Beefed up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
110 lines
2.6 KiB
C
110 lines
2.6 KiB
C
/*
|
|
* Jump label s390 support
|
|
*
|
|
* Copyright IBM Corp. 2011
|
|
* Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/stop_machine.h>
|
|
#include <linux/jump_label.h>
|
|
#include <asm/ipl.h>
|
|
|
|
#ifdef HAVE_JUMP_LABEL
|
|
|
|
struct insn {
|
|
u16 opcode;
|
|
s32 offset;
|
|
} __packed;
|
|
|
|
struct insn_args {
|
|
struct jump_entry *entry;
|
|
enum jump_label_type type;
|
|
};
|
|
|
|
static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn)
|
|
{
|
|
/* brcl 0,0 */
|
|
insn->opcode = 0xc004;
|
|
insn->offset = 0;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
static void jump_label_bug(struct jump_entry *entry, struct insn *expected,
|
|
struct insn *new)
|
|
{
|
|
unsigned char *ipc = (unsigned char *)entry->code;
|
|
unsigned char *ipe = (unsigned char *)expected;
|
|
unsigned char *ipn = (unsigned char *)new;
|
|
|
|
pr_emerg("Jump label code mismatch at %pS [%p]\n", ipc, ipc);
|
|
pr_emerg("Found: %02x %02x %02x %02x %02x %02x\n",
|
|
ipc[0], ipc[1], ipc[2], ipc[3], ipc[4], ipc[5]);
|
|
pr_emerg("Expected: %02x %02x %02x %02x %02x %02x\n",
|
|
ipe[0], ipe[1], ipe[2], ipe[3], ipe[4], ipe[5]);
|
|
pr_emerg("New: %02x %02x %02x %02x %02x %02x\n",
|
|
ipn[0], ipn[1], ipn[2], ipn[3], ipn[4], ipn[5]);
|
|
panic("Corrupted kernel text");
|
|
}
|
|
|
|
static struct insn orignop = {
|
|
.opcode = 0xc004,
|
|
.offset = JUMP_LABEL_NOP_OFFSET >> 1,
|
|
};
|
|
|
|
static void __jump_label_transform(struct jump_entry *entry,
|
|
enum jump_label_type type,
|
|
int init)
|
|
{
|
|
struct insn old, new;
|
|
|
|
if (type == JUMP_LABEL_JMP) {
|
|
jump_label_make_nop(entry, &old);
|
|
jump_label_make_branch(entry, &new);
|
|
} else {
|
|
jump_label_make_branch(entry, &old);
|
|
jump_label_make_nop(entry, &new);
|
|
}
|
|
if (init) {
|
|
if (memcmp((void *)entry->code, &orignop, sizeof(orignop)))
|
|
jump_label_bug(entry, &orignop, &new);
|
|
} else {
|
|
if (memcmp((void *)entry->code, &old, sizeof(old)))
|
|
jump_label_bug(entry, &old, &new);
|
|
}
|
|
s390_kernel_write((void *)entry->code, &new, sizeof(new));
|
|
}
|
|
|
|
static int __sm_arch_jump_label_transform(void *data)
|
|
{
|
|
struct insn_args *args = data;
|
|
|
|
__jump_label_transform(args->entry, args->type, 0);
|
|
return 0;
|
|
}
|
|
|
|
void arch_jump_label_transform(struct jump_entry *entry,
|
|
enum jump_label_type type)
|
|
{
|
|
struct insn_args args;
|
|
|
|
args.entry = entry;
|
|
args.type = type;
|
|
|
|
stop_machine(__sm_arch_jump_label_transform, &args, NULL);
|
|
}
|
|
|
|
void arch_jump_label_transform_static(struct jump_entry *entry,
|
|
enum jump_label_type type)
|
|
{
|
|
__jump_label_transform(entry, type, 1);
|
|
}
|
|
|
|
#endif
|