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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Cadence Design Systems Inc.
#include <linux/cpu.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/memory.h>
#include <linux/stop_machine.h>
#include <linux/types.h>
#include <asm/cacheflush.h>
#define J_OFFSET_MASK 0x0003ffff
#define J_SIGN_MASK (~(J_OFFSET_MASK >> 1))
#if defined(__XTENSA_EL__)
#define J_INSN 0x6
#define NOP_INSN 0x0020f0
#elif defined(__XTENSA_EB__)
#define J_INSN 0x60000000
#define NOP_INSN 0x0f020000
#else
#error Unsupported endianness.
#endif
struct patch {
atomic_t cpu_count;
unsigned long addr;
size_t sz;
const void *data;
};
static void local_patch_text(unsigned long addr, const void *data, size_t sz)
{
memcpy((void *)addr, data, sz);
local_flush_icache_range(addr, addr + sz);
}
static int patch_text_stop_machine(void *data)
{
struct patch *patch = data;
if (atomic_inc_return(&patch->cpu_count) == 1) {
local_patch_text(patch->addr, patch->data, patch->sz);
atomic_inc(&patch->cpu_count);
} else {
while (atomic_read(&patch->cpu_count) <= num_online_cpus())
cpu_relax();
__invalidate_icache_range(patch->addr, patch->sz);
}
return 0;
}
static void patch_text(unsigned long addr, const void *data, size_t sz)
{
if (IS_ENABLED(CONFIG_SMP)) {
struct patch patch = {
.cpu_count = ATOMIC_INIT(0),
.addr = addr,
.sz = sz,
.data = data,
};
stop_machine_cpuslocked(patch_text_stop_machine,
&patch, NULL);
} else {
unsigned long flags;
local_irq_save(flags);
local_patch_text(addr, data, sz);
local_irq_restore(flags);
}
}
void arch_jump_label_transform(struct jump_entry *e,
enum jump_label_type type)
{
u32 d = (jump_entry_target(e) - (jump_entry_code(e) + 4));
u32 insn;
/* Jump only works within 128K of the J instruction. */
BUG_ON(!((d & J_SIGN_MASK) == 0 ||
(d & J_SIGN_MASK) == J_SIGN_MASK));
if (type == JUMP_LABEL_JMP) {
#if defined(__XTENSA_EL__)
insn = ((d & J_OFFSET_MASK) << 6) | J_INSN;
#elif defined(__XTENSA_EB__)
insn = ((d & J_OFFSET_MASK) << 8) | J_INSN;
#endif
} else {
insn = NOP_INSN;
}
patch_text(jump_entry_code(e), &insn, JUMP_LABEL_NOP_SIZE);
}
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