Hi Guo, On Tue, Nov 24, 2020 at 08:07:07PM +0800, Guo Ren wrote: Huh, 3 years already! I've had this in my head for all this time; just didn't find the energy to act on it. > Thx Michael & Alejandro, > > Yes, the man page has no csky's. I've applied a patch to add initial documentation for it: <https://www.alejandro-colomar.es/src/alx/linux/man-pages/man-pages.git/commit/?h=contrib&id=a63979eb24aaf73f4be5799cc9579f84a3874b7d> > > C-SKY have abiv1 and abiv2 > For abiv1: There is no register for tls saving, We use trap 3 to got > tls and use set_thread_area to init ti->tp_value. > For abiv2: The r31 is the tls register. We could directly read r31 to > got r31 and use set_thread_area to init reg->tls value. > > In glibc: > # ifdef __CSKYABIV2__ > /* Define r31 as thread pointer register. */ > # define READ_THREAD_POINTER() \ > mov r0, r31; > # else > # define READ_THREAD_POINTER() \ > trap 3; > # endif > > /* Code to initially initialize the thread pointer. This might need > special attention since 'errno' is not yet available and if the > operation can cause a failure 'errno' must not be touched. */ > # define TLS_INIT_TP(tcbp) \ > ({ INTERNAL_SYSCALL_DECL (err); \ > long result_var; \ > result_var = INTERNAL_SYSCALL (set_thread_area, err, 1, \ > (char *) (tcbp) + TLS_TCB_OFFSET); \ > INTERNAL_SYSCALL_ERROR_P (result_var, err) \ > ? "unknown error" : NULL; }) > > In kernel: > SYSCALL_DEFINE1(set_thread_area, unsigned long, addr) > { > struct thread_info *ti = task_thread_info(current); > struct pt_regs *reg = current_pt_regs(); > > reg->tls = addr; > ti->tp_value = addr; > > return 0; > } > > Any comments are welcome :) I'm sorry, but I have little understanding of this syscall, and that shounds like gibberish to me :) Feel free to send a patch to improve the documentation for csky. Cheers, Alex > > > On Tue, Nov 24, 2020 at 5:51 PM Michael Kerrisk (man-pages) > <mtk.manpages@xxxxxxxxx> wrote: > > > > Hi Alex, > > > > On 11/23/20 10:31 PM, Alejandro Colomar (man-pages) wrote: > > > Hi Michael, > > > > > > SYNOPSIS > > > #include <linux/unistd.h> > > > > > > #if defined __i386__ || defined __x86_64__ > > > # include <asm/ldt.h> > > > > > > int get_thread_area(struct user_desc *u_info); > > > int set_thread_area(struct user_desc *u_info); > > > > > > #elif defined __m68k__ > > > > > > int get_thread_area(void); > > > int set_thread_area(unsigned long tp); > > > > > > #elif defined __mips__ > > > > > > int set_thread_area(unsigned long addr); > > > > > > #endif > > > > > > Note: There are no glibc wrappers for these system calls; see > > > NOTES. > > > > > > > > > $ grep -rn 'SYSCALL_DEFINE.*et_thread_area' > > > arch/csky/kernel/syscall.c:6: > > > SYSCALL_DEFINE1(set_thread_area, unsigned long, addr) > > > arch/mips/kernel/syscall.c:86: > > > SYSCALL_DEFINE1(set_thread_area, unsigned long, addr) > > > arch/x86/kernel/tls.c:191: > > > SYSCALL_DEFINE1(set_thread_area, struct user_desc __user *, u_info) > > > arch/x86/kernel/tls.c:243: > > > SYSCALL_DEFINE1(get_thread_area, struct user_desc __user *, u_info) > > > arch/x86/um/tls_32.c:277: > > > SYSCALL_DEFINE1(set_thread_area, struct user_desc __user *, user_desc) > > > arch/x86/um/tls_32.c:325: > > > SYSCALL_DEFINE1(get_thread_area, struct user_desc __user *, user_desc) > > > > > > > > > See kernel commit 4859bfca11c7d63d55175bcd85a75d6cee4b7184 > > > > > > > > > I'd change > > > - #elif defined __mips__ > > > + #elif defined(__mips__ || __csky__) > > > > > > and then change the rest of the text to add csky when appropriate. > > > Am I correct? > > > > AFAICT, you are correct. I think the reason that csky is missing is > > that the architecture was added after this manual pages was added. > > > > Thanks, > > > > Michael > > > > > > -- > > Michael Kerrisk > > Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ > > Linux/UNIX System Programming Training: http://man7.org/training/ > > > > -- > Best Regards > Guo Ren > > ML: https://lore.kernel.org/linux-csky/ -- <https://www.alejandro-colomar.es/>
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