Hello Ard!
On 09/03/18 09:50, Ard Biesheuvel wrote:
>> +static u32 fixed_plts[] = {
>> + FTRACE_ADDR,
>> + MCOUNT_ADDR,
>> +#ifdef CONFIG_OLD_MCOUNT
>> + (unsigned long)ftrace_caller_old,
>> + (unsigned long)mcount,
>> +#endif
>> +};
>> +
> Do we need this stuff in the PLT loader if ftrace is disabled?
You are right, it probably would not even build w/o FTRACE.
I'll fix it, thanks for looking into this!
>> static bool in_init(const struct module *mod, unsigned long loc)
>> {
>> return loc - (u32)mod->init_layout.base < mod->init_layout.size;
>> @@ -31,26 +41,43 @@ u32 get_module_plt(struct module *mod, unsigned long
>> loc, Elf32_Addr val)
>> {
>> struct mod_plt_sec *pltsec = !in_init(mod, loc) ? &mod->arch.core :
>> &mod->arch.init;
>> + int idx;
>> + struct plt_entries *plt;
>> +
>> + /* Pre-allocate entries in the first plt */
>> + if (!pltsec->plt_count) {
>> + plt = (struct plt_entries *)pltsec->plt->sh_addr;
>> + for (idx = 0; idx < ARRAY_SIZE(plt->ldr); ++idx)
>> + plt->ldr[idx] = PLT_ENT_LDR;
>> + memcpy(plt->lit, fixed_plts, sizeof(fixed_plts));
>> + pltsec->plt_count = ARRAY_SIZE(fixed_plts);
>> + /*
>> + * cache the address,
>> + * ELF header is available only during module load
>> + */
>> + pltsec->plt_ent = plt;
>> + }
>> + plt = pltsec->plt_ent;
>>
>> - struct plt_entries *plt = (struct plt_entries *)pltsec->plt->sh_addr;
>> - int idx = 0;
>> + idx = ARRAY_SIZE(fixed_plts);
>> + while (idx)
>> + if (plt->lit[--idx] == val)
>> + return (u32)&plt->ldr[idx];
>>
> Same here.
--
Best regards,
Alexander Sverdlin.
