linux/arch/csky/kernel/jump_label.c
Guo Ren 4e8bb4ba5a csky: Add jump-label implementation
Add jump-label implementation for static branch

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
2022-07-30 11:12:03 -04:00

55 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/memory.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#define NOP32_HI 0xc400
#define NOP32_LO 0x4820
#define BSR_LINK 0xe000
void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
{
unsigned long addr = jump_entry_code(entry);
u16 insn[2];
int ret = 0;
if (type == JUMP_LABEL_JMP) {
long offset = jump_entry_target(entry) - jump_entry_code(entry);
if (WARN_ON(offset & 1 || offset < -67108864 || offset >= 67108864))
return;
offset = offset >> 1;
insn[0] = BSR_LINK |
((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
insn[1] = (uint16_t)((unsigned long) offset & 0xffff);
} else {
insn[0] = NOP32_HI;
insn[1] = NOP32_LO;
}
ret = copy_to_kernel_nofault((void *)addr, insn, 4);
WARN_ON(ret);
flush_icache_range(addr, addr + 4);
}
void arch_jump_label_transform_static(struct jump_entry *entry,
enum jump_label_type type)
{
/*
* We use the same instructions in the arch_static_branch and
* arch_static_branch_jump inline functions, so there's no
* need to patch them up here.
* The core will call arch_jump_label_transform when those
* instructions need to be replaced.
*/
arch_jump_label_transform(entry, type);
}