Qing Zhang 28ac0a9e04 LoongArch: modules/ftrace: Initialize PLT at load time
This patch implements ftrace trampolines through plt entry.

Tested by forcing ftrace_make_call() to use the module PLT, and then
loading up a module after setting up ftrace with:

| echo ":mod:<module-name>" > set_ftrace_filter;
| echo function > current_tracer;
| modprobe <module-name>

Since FTRACE_ADDR/FTRACE_REGS_ADDR is only defined when CONFIG_DYNAMIC_
FTRACE is selected, we wrap their usage in module_init_ftrace_plt() with
ifdeffery rather than using IS_ENABLED().

Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-12-14 08:41:54 +08:00

168 lines
3.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#include <linux/sizes.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/inst.h>
static DEFINE_RAW_SPINLOCK(patch_lock);
int larch_insn_read(void *addr, u32 *insnp)
{
int ret;
u32 val;
ret = copy_from_kernel_nofault(&val, addr, LOONGARCH_INSN_SIZE);
if (!ret)
*insnp = val;
return ret;
}
int larch_insn_write(void *addr, u32 insn)
{
int ret;
unsigned long flags = 0;
raw_spin_lock_irqsave(&patch_lock, flags);
ret = copy_to_kernel_nofault(addr, &insn, LOONGARCH_INSN_SIZE);
raw_spin_unlock_irqrestore(&patch_lock, flags);
return ret;
}
int larch_insn_patch_text(void *addr, u32 insn)
{
int ret;
u32 *tp = addr;
if ((unsigned long)tp & 3)
return -EINVAL;
ret = larch_insn_write(tp, insn);
if (!ret)
flush_icache_range((unsigned long)tp,
(unsigned long)tp + LOONGARCH_INSN_SIZE);
return ret;
}
u32 larch_insn_gen_nop(void)
{
return INSN_NOP;
}
u32 larch_insn_gen_b(unsigned long pc, unsigned long dest)
{
long offset = dest - pc;
unsigned int immediate_l, immediate_h;
union loongarch_instruction insn;
if ((offset & 3) || offset < -SZ_128M || offset >= SZ_128M) {
pr_warn("The generated b instruction is out of range.\n");
return INSN_BREAK;
}
offset >>= 2;
immediate_l = offset & 0xffff;
offset >>= 16;
immediate_h = offset & 0x3ff;
insn.reg0i26_format.opcode = b_op;
insn.reg0i26_format.immediate_l = immediate_l;
insn.reg0i26_format.immediate_h = immediate_h;
return insn.word;
}
u32 larch_insn_gen_bl(unsigned long pc, unsigned long dest)
{
long offset = dest - pc;
unsigned int immediate_l, immediate_h;
union loongarch_instruction insn;
if ((offset & 3) || offset < -SZ_128M || offset >= SZ_128M) {
pr_warn("The generated bl instruction is out of range.\n");
return INSN_BREAK;
}
offset >>= 2;
immediate_l = offset & 0xffff;
offset >>= 16;
immediate_h = offset & 0x3ff;
insn.reg0i26_format.opcode = bl_op;
insn.reg0i26_format.immediate_l = immediate_l;
insn.reg0i26_format.immediate_h = immediate_h;
return insn.word;
}
u32 larch_insn_gen_or(enum loongarch_gpr rd, enum loongarch_gpr rj, enum loongarch_gpr rk)
{
union loongarch_instruction insn;
insn.reg3_format.opcode = or_op;
insn.reg3_format.rd = rd;
insn.reg3_format.rj = rj;
insn.reg3_format.rk = rk;
return insn.word;
}
u32 larch_insn_gen_move(enum loongarch_gpr rd, enum loongarch_gpr rj)
{
return larch_insn_gen_or(rd, rj, 0);
}
u32 larch_insn_gen_lu12iw(enum loongarch_gpr rd, int imm)
{
union loongarch_instruction insn;
insn.reg1i20_format.opcode = lu12iw_op;
insn.reg1i20_format.rd = rd;
insn.reg1i20_format.immediate = imm;
return insn.word;
}
u32 larch_insn_gen_lu32id(enum loongarch_gpr rd, int imm)
{
union loongarch_instruction insn;
insn.reg1i20_format.opcode = lu32id_op;
insn.reg1i20_format.rd = rd;
insn.reg1i20_format.immediate = imm;
return insn.word;
}
u32 larch_insn_gen_lu52id(enum loongarch_gpr rd, enum loongarch_gpr rj, int imm)
{
union loongarch_instruction insn;
insn.reg2i12_format.opcode = lu52id_op;
insn.reg2i12_format.rd = rd;
insn.reg2i12_format.rj = rj;
insn.reg2i12_format.immediate = imm;
return insn.word;
}
u32 larch_insn_gen_jirl(enum loongarch_gpr rd, enum loongarch_gpr rj, unsigned long pc, unsigned long dest)
{
union loongarch_instruction insn;
insn.reg2i16_format.opcode = jirl_op;
insn.reg2i16_format.rd = rd;
insn.reg2i16_format.rj = rj;
insn.reg2i16_format.immediate = (dest - pc) >> 2;
return insn.word;
}