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| author | Qing Zhang <zhangqing@loongson.cn> | 2022-12-10 17:40:21 +0300 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2022-12-14 03:41:54 +0300 |
| commit | 28ac0a9e04d7dfb42220dc9d221164d93f20fb3a (patch) | |
| tree | 520a7c5f68595d38a141a7866846f4cf40f19c1e /arch/loongarch/kernel/module-sections.c | |
| parent | a51ac5246d2505b58229242959d2bc73d113ca50 (diff) | |
| download | linux-28ac0a9e04d7dfb42220dc9d221164d93f20fb3a.tar.xz | |
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>
Diffstat (limited to 'arch/loongarch/kernel/module-sections.c')
| -rw-r--r-- | arch/loongarch/kernel/module-sections.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/loongarch/kernel/module-sections.c b/arch/loongarch/kernel/module-sections.c index 13d9a427325a..d4dbcda1c4b0 100644 --- a/arch/loongarch/kernel/module-sections.c +++ b/arch/loongarch/kernel/module-sections.c @@ -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; } |