From: Lulu Cai <cailulu@loongson.cn>
To: Xi Ruoyao <xry111@xry111.site>, binutils@sourceware.org
Cc: xuchenghua@loongson.cn, chenglulu@loongson.cn,
liuzhensong@loongson.cn, mengqinggang@loongson.cn,
i.swmail@xen0n.name, maskray@google.com, luweining@loongson.cn,
wanglei@loongson.cn, hejinyang@loongson.cn
Subject: Re: [PATCH 1/2] LoongArch: Delete extra instructions when TLS type transition
Date: Sat, 27 Jan 2024 10:06:57 +0800 [thread overview]
Message-ID: <60e6e56c-385f-ee4f-ff74-90cf0b9e753d@loongson.cn> (raw)
In-Reply-To: <f75d5c73fb178517863368bb684f763d9d6a9a94.camel@xry111.site>
On 1/27/24 2:22 AM, Xi Ruoyao wrote:
> On Fri, 2024-01-26 at 21:55 +0800, Lulu Cai wrote:
>> This modification mainly changes the timing of type transition,
>> adds relaxation to the old LE instruction sequence, and fixes
>> bugs in extreme code models.
> I'd suggest to separate the bug fixes (requiring R_LARCH_RELAX for DESC
> and IE transition) out into one separate commit and apply it for 2.42.
> And the old LE relaxation & instruction deletion should be only applied
> for trunk (2.43). We are just toooooo close to the 2.42 release, and
> deleting instructions is always "dangerous" even if we do it very
> carefully.
>
> /* snip */
Thanks for reminding. I will send a new patch with a separate bug fix later.
>> +loongarch_can_trans_tls (bfd *input_bfd,
>> + struct bfd_link_info *info,
>> + struct elf_link_hash_entry *h,
>> + const Elf_Internal_Rela *rel,
>> + unsigned int r_type)
>> {
>> char symbol_tls_type;
>> unsigned int reloc_got_type;
>> + unsigned int r_symndx = ELFNN_R_SYM (rel->r_info);
>>
>> - if (! (IS_LOONGARCH_TLS_DESC_RELOC (r_type)
>> - || IS_LOONGARCH_TLS_IE_RELOC (r_type)))
>> + /* Only TLS DESC/IE in normal code mode will perform type
>> + transition. */
>> + if (! (IS_LOONGARCH_TLS_TRANS_RELOC (r_type)
>> + && ELFNN_R_TYPE ((rel + 1)->r_info) == R_LARCH_RELAX))
> We need to check if rel is the last relocation of the section, or rel +
> 1 may be an OOB read.
>
Agreed, I will pay attention to these later.
>> static bool
>> loongarch_relax_tls_le (bfd *abfd, asection *sec,
>> @@ -4165,31 +4198,56 @@ loongarch_relax_tls_le (bfd *abfd, asection *sec,
>> uint32_t insn = bfd_get (32, abfd, contents + rel->r_offset);
>> static uint32_t insn_rj,insn_rd;
>> symval = symval - elf_hash_table (link_info)->tls_sec->vma;
>> - /* Whether the symbol offset is in the interval (offset < 0x800). */
>> - if (ELFNN_R_TYPE ((rel + 1)->r_info == R_LARCH_RELAX) && (symval < 0x800))
>> + /* The old LE instruction sequence can be relaxed when the symbol offset
>> + is smaller than the 12-bit range. */
>> + if (ELFNN_R_TYPE ((rel + 1)->r_info) == R_LARCH_RELAX && (symval <= 0xfff))
> Likewise.
>
prev parent reply other threads:[~2024-01-27 2:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-26 13:55 Lulu Cai
2024-01-26 13:55 ` [PATCH 2/2] LoongArch: Fix some test cases for TLS transition and relax Lulu Cai
2024-01-26 18:22 ` [PATCH 1/2] LoongArch: Delete extra instructions when TLS type transition Xi Ruoyao
2024-01-27 2:06 ` Lulu Cai [this message]
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