UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

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>
This commit is contained in:
Qing Zhang 2022-12-10 22:40:21 +08:00 committed by Huacai Chen
parent a51ac5246d
commit 28ac0a9e04
8 changed files with 148 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/loongarch/include/asm/ftrace.h
View File

@ -6,6 +6,10 @@
#ifndef _ASM_LOONGARCH_FTRACE_H
#define _ASM_LOONGARCH_FTRACE_H
#define FTRACE_PLT_IDX 0
#define FTRACE_REGS_PLT_IDX 1
#define NR_FTRACE_PLTS 2
#define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1]))
#ifdef CONFIG_FUNCTION_TRACER

3
arch/loongarch/include/asm/inst.h
View File

@ -13,10 +13,12 @@
#define ADDR_IMMMASK_LU52ID 0xFFF0000000000000
#define ADDR_IMMMASK_LU32ID 0x000FFFFF00000000
#define ADDR_IMMMASK_LU12IW 0x00000000FFFFF000
#define ADDR_IMMMASK_ADDU16ID 0x00000000FFFF0000
#define ADDR_IMMSHIFT_LU52ID 52
#define ADDR_IMMSHIFT_LU32ID 32
#define ADDR_IMMSHIFT_LU12IW 12
#define ADDR_IMMSHIFT_ADDU16ID 16
#define ADDR_IMM(addr, INSN) ((addr & ADDR_IMMMASK_##INSN) >> ADDR_IMMSHIFT_##INSN)
@ -360,6 +362,7 @@ u32 larch_insn_gen_bl(unsigned long pc, unsigned long dest);
u32 larch_insn_gen_or(enum loongarch_gpr rd, enum loongarch_gpr rj, enum loongarch_gpr rk);
u32 larch_insn_gen_move(enum loongarch_gpr rd, enum loongarch_gpr rj);
u32 larch_insn_gen_lu12iw(enum loongarch_gpr rd, int imm);
u32 larch_insn_gen_lu32id(enum loongarch_gpr rd, int imm);
u32 larch_insn_gen_lu52id(enum loongarch_gpr rd, enum loongarch_gpr rj, int imm);
u32 larch_insn_gen_jirl(enum loongarch_gpr rd, enum loongarch_gpr rj, unsigned long pc, unsigned long dest);

5
arch/loongarch/include/asm/module.h
View File

@ -20,6 +20,9 @@ struct mod_arch_specific {
struct mod_section got;
struct mod_section plt;
struct mod_section plt_idx;
/* For CONFIG_DYNAMIC_FTRACE */
struct plt_entry *ftrace_trampolines;
};
struct got_entry {
@ -49,7 +52,7 @@ static inline struct plt_entry emit_plt_entry(unsigned long val)
{
u32 lu12iw, lu32id, lu52id, jirl;
lu12iw = (lu12iw_op << 25 | (((val >> 12) & 0xfffff) << 5) | LOONGARCH_GPR_T1);
lu12iw = larch_insn_gen_lu12iw(LOONGARCH_GPR_T1, ADDR_IMM(val, LU12IW));
lu32id = larch_insn_gen_lu32id(LOONGARCH_GPR_T1, ADDR_IMM(val, LU32ID));
lu52id = larch_insn_gen_lu52id(LOONGARCH_GPR_T1, LOONGARCH_GPR_T1, ADDR_IMM(val, LU52ID));
jirl = larch_insn_gen_jirl(0, LOONGARCH_GPR_T1, 0, (val & 0xfff));

1
arch/loongarch/include/asm/module.lds.h
View File

@ -5,4 +5,5 @@ SECTIONS {
.got : { BYTE(0) }
.plt : { BYTE(0) }
.plt.idx : { BYTE(0) }
.ftrace_trampoline : { BYTE(0) }
}

93
arch/loongarch/kernel/ftrace_dyn.c
View File

@ -9,6 +9,7 @@
#include <linux/uaccess.h>
#include <asm/inst.h>
#include <asm/module.h>
static int ftrace_modify_code(unsigned long pc, u32 old, u32 new, bool validate)
{
@ -29,18 +30,78 @@ static int ftrace_modify_code(unsigned long pc, u32 old, u32 new, bool validate)
}
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
#ifdef CONFIG_MODULES
static inline int __get_mod(struct module **mod, unsigned long addr)
{
preempt_disable();
*mod = __module_text_address(addr);
preempt_enable();
if (WARN_ON(!(*mod)))
return -EINVAL;
return 0;
}
static struct plt_entry *get_ftrace_plt(struct module *mod, unsigned long addr)
{
struct plt_entry *plt = mod->arch.ftrace_trampolines;
if (addr == FTRACE_ADDR)
return &plt[FTRACE_PLT_IDX];
if (addr == FTRACE_REGS_ADDR &&
IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
return &plt[FTRACE_REGS_PLT_IDX];
return NULL;
}
static unsigned long get_plt_addr(struct module *mod, unsigned long addr)
{
struct plt_entry *plt;
plt = get_ftrace_plt(mod, addr);
if (!plt) {
pr_err("ftrace: no module PLT for %ps\n", (void *)addr);
return -EINVAL;
}
return (unsigned long)plt;
}
#endif
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr)
{
u32 old, new;
unsigned long pc;
long offset __maybe_unused;
pc = rec->ip + LOONGARCH_INSN_SIZE;
#ifdef CONFIG_MODULES
offset = (long)pc - (long)addr;
if (offset < -SZ_128M || offset >= SZ_128M) {
int ret;
struct module *mod;
ret = __get_mod(&mod, pc);
if (ret)
return ret;
addr = get_plt_addr(mod, addr);
old_addr = get_plt_addr(mod, old_addr);
}
#endif
new = larch_insn_gen_bl(pc, addr);
old = larch_insn_gen_bl(pc, old_addr);
return ftrace_modify_code(pc, old, new, true);
}
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
int ftrace_update_ftrace_func(ftrace_func_t func)
@ -91,9 +152,25 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
u32 old, new;
unsigned long pc;
long offset __maybe_unused;
pc = rec->ip + LOONGARCH_INSN_SIZE;
#ifdef CONFIG_MODULES
offset = (long)pc - (long)addr;
if (offset < -SZ_128M || offset >= SZ_128M) {
int ret;
struct module *mod;
ret = __get_mod(&mod, pc);
if (ret)
return ret;
addr = get_plt_addr(mod, addr);
}
#endif
old = larch_insn_gen_nop();
new = larch_insn_gen_bl(pc, addr);
@ -104,9 +181,25 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long ad
{
u32 old, new;
unsigned long pc;
long offset __maybe_unused;
pc = rec->ip + LOONGARCH_INSN_SIZE;
#ifdef CONFIG_MODULES
offset = (long)pc - (long)addr;
if (offset < -SZ_128M || offset >= SZ_128M) {
int ret;
struct module *mod;
ret = __get_mod(&mod, pc);
if (ret)
return ret;
addr = get_plt_addr(mod, addr);
}
#endif
new = larch_insn_gen_nop();
old = larch_insn_gen_bl(pc, addr);

11
arch/loongarch/kernel/inst.c
View File

@ -120,6 +120,17 @@ 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;

12
arch/loongarch/kernel/module-sections.c
View File

@ -6,6 +6,7 @@
#include <linux/elf.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/ftrace.h>
Elf_Addr module_emit_got_entry(struct module *mod, Elf_Shdr *sechdrs, Elf_Addr val)
{
@ -103,7 +104,7 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
char *secstrings, struct module *mod)
{
unsigned int i, num_plts = 0, num_gots = 0;
Elf_Shdr *got_sec, *plt_sec, *plt_idx_sec;
Elf_Shdr *got_sec, *plt_sec, *plt_idx_sec, *tramp = NULL;
/*
* Find the empty .plt sections.
@ -115,6 +116,8 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
mod->arch.plt.shndx = i;
else if (!strcmp(secstrings + sechdrs[i].sh_name, ".plt.idx"))
mod->arch.plt_idx.shndx = i;
else if (!strcmp(secstrings + sechdrs[i].sh_name, ".ftrace_trampoline"))
tramp = sechdrs + i;
}
if (!mod->arch.got.shndx) {
@ -170,5 +173,12 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
mod->arch.plt_idx.num_entries = 0;
mod->arch.plt_idx.max_entries = num_plts;
if (tramp) {
tramp->sh_type = SHT_NOBITS;
tramp->sh_flags = SHF_EXECINSTR | SHF_ALLOC;
tramp->sh_addralign = __alignof__(struct plt_entry);
tramp->sh_size = NR_FTRACE_PLTS * sizeof(struct plt_entry);
}
return 0;
}

21
arch/loongarch/kernel/module.c
View File

@ -15,9 +15,11 @@
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/ftrace.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <asm/alternative.h>
#include <asm/inst.h>
static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_stack_top)
{
@ -473,6 +475,23 @@ void *module_alloc(unsigned long size)
GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0));
}
static void module_init_ftrace_plt(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs, struct module *mod)
{
#ifdef CONFIG_DYNAMIC_FTRACE
struct plt_entry *ftrace_plts;
ftrace_plts = (void *)sechdrs->sh_addr;
ftrace_plts[FTRACE_PLT_IDX] = emit_plt_entry(FTRACE_ADDR);
if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
ftrace_plts[FTRACE_REGS_PLT_IDX] = emit_plt_entry(FTRACE_REGS_ADDR);
mod->arch.ftrace_trampolines = ftrace_plts;
#endif
}
int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs, struct module *mod)
{
@ -482,6 +501,8 @@ int module_finalize(const Elf_Ehdr *hdr,
for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
if (!strcmp(".altinstructions", secstrs + s->sh_name))
apply_alternatives((void *)s->sh_addr, (void *)s->sh_addr + s->sh_size);
if (!strcmp(".ftrace_trampoline", secstrs + s->sh_name))
module_init_ftrace_plt(hdr, s, mod);
}
return 0;