linux/arch/sparc/kernel/jump_label.c
James Clarke 9d9fa23020 sparc: Handle negative offsets in arch_jump_label_transform
Additionally, if the offset will overflow the immediate for a ba,pt
instruction, fall back on a standard ba to get an extra 3 bits.

Signed-off-by: James Clarke <jrtc27@jrtc27.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-25 19:11:17 -07:00

53 lines
1.1 KiB
C

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/cpu.h>
#include <linux/jump_label.h>
#include <linux/memory.h>
#include <asm/cacheflush.h>
#ifdef HAVE_JUMP_LABEL
void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
{
u32 *insn = (u32 *) (unsigned long) entry->code;
u32 val;
if (type == JUMP_LABEL_JMP) {
s32 off = (s32)entry->target - (s32)entry->code;
bool use_v9_branch = false;
BUG_ON(off & 3);
#ifdef CONFIG_SPARC64
if (off <= 0xfffff && off >= -0x100000)
use_v9_branch = true;
#endif
if (use_v9_branch) {
/* WDISP19 - target is . + immed << 2 */
/* ba,pt %xcc, . + off */
val = 0x10680000 | (((u32) off >> 2) & 0x7ffff);
} else {
/* WDISP22 - target is . + immed << 2 */
BUG_ON(off > 0x7fffff);
BUG_ON(off < -0x800000);
/* ba . + off */
val = 0x10800000 | (((u32) off >> 2) & 0x3fffff);
}
} else {
val = 0x01000000;
}
get_online_cpus();
mutex_lock(&text_mutex);
*insn = val;
flushi(insn);
mutex_unlock(&text_mutex);
put_online_cpus();
}
#endif