On Thu, Jun 08, 2017 at 04:05:36PM +0100, James Morse wrote: > Hi Yury, > > On 04/06/17 13:00, Yury Norov wrote: > > From: Andrew Pinski <apinski@xxxxxxxxxx> > > > > Add a separate syscall-table for ILP32, which dispatches either to native > > LP64 system call implementation or to compat-syscalls, as appropriate. > > (I'm still reading through this series trying to understand it, but spotted this: ) > > > diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S > > index 279bc2ab10c3..7d52fe1ec6bd 100644 > > --- a/arch/arm64/kernel/entry.S > > +++ b/arch/arm64/kernel/entry.S > > @@ -577,6 +594,7 @@ el0_svc_compat: > > * AArch32 syscall handling > > */ > > adrp stbl, compat_sys_call_table // load compat syscall table pointer > > + ldr x16, [tsk, #TSK_TI_FLAGS] > > uxtw scno, w7 // syscall number in w7 (r7) > > mov sc_nr, #__NR_compat_syscalls > > b el0_svc_naked > > @@ -798,15 +816,21 @@ ENDPROC(ret_from_fork) > > .align 6 > > el0_svc: > > adrp stbl, sys_call_table // load syscall table pointer > > + ldr x16, [tsk, #TSK_TI_FLAGS] > > uxtw scno, w8 // syscall number in w8 > > mov sc_nr, #__NR_syscalls > > +#ifdef CONFIG_ARM64_ILP32 > > + tst x16, #_TIF_32BIT_AARCH64 > > + b.eq el0_svc_naked // We are using LP64 syscall table > > + adrp stbl, sys_call_ilp32_table // load ilp32 syscall table pointer > > + delouse_input_regs > > +#endif > > el0_svc_naked: // compat entry point > > stp x0, scno, [sp, #S_ORIG_X0] // save the original x0 and syscall number > > enable_dbg_and_irq > > ct_user_exit 1 > > > > > - ldr x16, [tsk, #TSK_TI_FLAGS] // check for syscall hooks > > If built with CONFIG_CONTEXT_TRACKING, ct_user_exit will call > context_tracking_user_exit(), this will clobber x16 which you depend on not > changing below: > > > > - tst x16, #_TIF_SYSCALL_WORK > > + tst x16, #_TIF_SYSCALL_WORK // check for syscall hooks > > > b.ne __sys_trace > > cmp scno, sc_nr // check upper syscall limit > > b.hs ni_sys Hi James, Thanks for the catch. I'll use x19 insteas - it's callee-saved. Yury -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
