Hi, Lulu, On Sat, Jul 30, 2022 at 11:13 AM Lulu Cheng <chengl...@loongson.cn> wrote: > > > 在 2022/7/30 上午1:17, Xi Ruoyao 写道: > > Change v2 to v3: > - Disable section anchor for addr_global symbols. > - Use -O2 in test to make sure section anchor is disabled. > > -- > > Background: > https://lore.kernel.org/loongarch/d7670b60-2782-4642-995b-7baa01779...@loongson.cn/T/#e1d47e2fe185f2e2be8fdc0784f0db2f644119379 > > Question: Do you have a better name than "addr_global"? > > I think the name can be changed to "get_through_got". What do you think of it? Is this the same thing as "movable" once we used internally?
Huacai > > Alternatives: > > 1. Just use "-mno-explicit-relocs -mla-local-with-abs" for kernel > modules. It's stupid IMO. > 2. Implement a "-maddress-local-with-got" option for GCC and use it for > kernel modules. It seems too overkill: we might create many unnecessary > GOT entries. > 3. For all variables with a section attribute, consider it global. It > may make sense, but I just checked x86_64 and riscv and they don't do > this. > 4. Implement -mcmodel=extreme and use it for kernel modules. To me > "extreme" seems really too extreme. > 5. More hacks in kernel. (Convert relocations against .data..percpu with > objtool? But objtool is not even implemented for LoongArch yet.) > > Note: I'll be mostly AFK in the following week. My attempt to finish > the kernel support for new relocs before going AFK now failed miserably > :(. > > -- >8 -- > > A linker script and/or a section attribute may locate a local object in > some way unexpected by the code model, leading to a link failure. This > happens when the Linux kernel loads a module with "local" per-CPU > variables. > > Add an attribute to explicitly mark an variable with the address > unlimited by the code model so we would be able to work around such > problems. > > > Others I think are ok.
