On Tue, Jan 03, 2023 at 10:51:35AM +0700, Alviro Iskandar Setiawan wrote: > On Thu, Dec 29, 2022 at 6:42 PM Ammar Faizi wrote: > > On 12/28/22 8:35 PM, Willy Tarreau wrote: > > > It gives me the correct code for x86_64 and i586. I don't know if other > > > architectures will want to add a prologue. I tried with "naked" but it's > > > ignored by the compiler since the function is not purely asm. Not very > > > important but given that we already have everything to perform our calls > > > it would make sense to stay on this. By the way, for the sake of > > > consistency with other syscalls, I do think the function (or label if > > > we can't do otherwise) should be called "sys_rt_sigreturn" as it just > > > performs a syscall. > > > > Will call that 'sys_rt_sigreturn' in the next series. > > >From glibc source code says: > GDB needs some intimate knowledge about it to recognize them as signal > trampolines, and make backtraces through signal handlers work right. > Important are both the names (__restore_rt) and the exact instruction > sequence. > > link: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/x86_64/sigaction.c;h=4e6d9cc32e1e18746726fa430d092de9a19ba6c6;hb=b4a5d26d8835d972995f0a0a2f805a8845bafa0b#l34 > > glibc does this: > > " .type __" #name ",@function\n" \ > "__" #name ":\n" \ > " movq $" #syscall ", %rax\n" \ > " syscall\n" \ > > where > > #name = "restore_rt" > #syscall = __NR_rt_sigreturn > > I think it should be called "__restore_rt" instead of "sys_rt_sigreturn"? > glibc also has unwind information, but we probably don't need to care > with that much OK, I wasn't aware of this. Of course, if there are some strict rules for this, let's follow them! Thanks, Willy
