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Message-ID: <54e5e0dbefa042b1b6a9c29fe9984897@huawei.com>
Date: Thu, 25 Mar 2021 06:21:59 +0000
From: "chenjun (AM)" <chenjun102@...wei.com>
To: Ard Biesheuvel <ardb@...nel.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
Will Deacon <will.deacon@....com>,
Catalin Marinas <catalin.marinas@....com>,
"Xiangrui (Euler)" <rui.xiang@...wei.com>,
liuyanshi <liuyanshi@...wei.com>,
wuzengkun <wuzengkun@...ilicon.com>
Subject: Re: [question] insert ko failed because count_plts return 0 when
CONFIG_RANDOMIZE_BASE is not set
在 2021/3/24 16:29, Ard Biesheuvel 写道:
> On Wed, 24 Mar 2021 at 08:27, chenjun (AM) <chenjun102@...wei.com> wrote:
>>
>> Hi
>>
>> I make a Image for arm64 (without CONFIG_RANDOMIZE_BASE). And a ko (13M)
>> can not be inserted.
>>
>
> How many large modules have you loaded already? The module region is
> only 128 MB, so if your modules are huge, you may run out of space.
>
> Please check the kernel VA address and the load address of the module,
> and check whether they are more than 128 MB apart.
>
Thanks Ard
I will check it.
One more question, why is CONFIG_ARM64_MODULE_PLTS depended on
CONFIG_RANDOMIZE_BASE?
>
>> WARNING: CPU: 2 PID: 1998 at arch/arm64/kernel/module-plts.c:39
>> module_emit_plt_entry+0x100/0x118
>> ...
>> Call trace:
>> module_emit_plt_entry+0x100/0x118
>> apply_relocate_add+0x34c/0x570
>> ...
>>
>> I think the problem is that:
>> in apply_relocate_add:
>> case R_AARCH64_CALL26:
>> ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 26,
>> AARCH64_INSN_IMM_26);
>>
>> if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
>> ovf == -ERANGE) {
>> val = module_emit_plt_entry(me, sechdrs,
>> loc, &rel[i], sym); realoc_insn_imm return -ERANGE (because the ko is
>> too big?)
>>
>> in module_emit_plt_entry:
>> WARN_ON(pltsec->plt_num_entries > pltsec->plt_max_entries)
>> pltsec->plt_max_entries is 0 if CONFIG_RANDOMIZE_BASE is not be set.
>>
>> a257e02 arm64/kernel: don't ban ADRP to work around Cortex-A53 erratum
>> #843419
>> static unsigned int count_plts(Elf64_Sym *syms, Elf64_Rela *rela, int
>> num,
>> - Elf64_Word dstidx)
>> + Elf64_Word dstidx, Elf_Shdr *dstsec)
>> {
>> ...
>> switch (ELF64_R_TYPE(rela[i].r_info)) {
>> case R_AARCH64_JUMP26:
>> case R_AARCH64_CALL26:
>> + if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
>> + break;
>> +
>>
>> Why we need break if !IS_ENABLED(CONFIG_RANDOMIZE_BASE)? or any
>> restrictions on ko?
>>
>> I comment out this part of the code. the ko could be inserted, and seems
>> to work well. So is it a accepted way? or any solution for my case?
>>
>> --
>> Regards
>> Chen Jun
>>
>
--
Regards
Chen Jun
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