On Mon, Apr 25, 2016 at 09:19:13PM +0300, Yury Norov wrote: > On Mon, Apr 25, 2016 at 06:26:56PM +0100, Catalin Marinas wrote: > > On Wed, Apr 06, 2016 at 01:08:42AM +0300, Yury Norov wrote: > > > --- a/arch/arm64/kernel/entry.S > > > +++ b/arch/arm64/kernel/entry.S > > > @@ -715,9 +715,13 @@ ENDPROC(ret_from_fork) > > > */ > > > .align 6 > > > el0_svc: > > > - adrp stbl, sys_call_table // load syscall table pointer > > > uxtw scno, w8 // syscall number in w8 > > > mov sc_nr, #__NR_syscalls > > > +#ifdef CONFIG_ARM64_ILP32 > > > + ldr x16, [tsk, #TI_FLAGS] > > > + tbnz x16, #TIF_32BIT_AARCH64, el0_ilp32_svc // We are using ILP32 > > > +#endif > > > > There is another ldr x16, [tsk, #TI_FLAGS] load further down in the > > el0_svc_naked block. We should rework these a bit to avoid loading the > > same location twice unnecessarily. E.g. move the ldr x16 just before > > el0_svc_naked and branch one line after in case of the ILP32 syscall. > > > > Yes, I thiks we can refactor it. Thanks for a catch. Now it's better, I think diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index cf4d1ae..21312bb 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -715,16 +715,22 @@ ENDPROC(ret_from_fork) */ .align 6 el0_svc: - adrp stbl, sys_call_table // load syscall table pointer uxtw scno, w8 // syscall number in w8 mov sc_nr, #__NR_syscalls + ldr x16, [tsk, #TI_FLAGS] +#ifdef CONFIG_ARM64_ILP32 + tbz x16, #TIF_32BIT_AARCH64, el0_lp64_svc // We are using ILP32 + adrp stbl, sys_call_ilp32_table // load ilp32 syscall table pointer + b el0_svc_naked +el0_lp64_svc: +#endif + adrp stbl, sys_call_table // load syscall table pointer 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, #TI_FLAGS] // check for syscall hooks - 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 -- 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
