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From: Lai Jiangshan <jiangshanlai+lkml@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	x86@kernel.org, "Paul E. McKenney" <paulmck@kernel.org>,
	Andy Lutomirski <luto@kernel.org>,
	Alexandre Chartre <alexandre.chartre@oracle.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Joel Fernandes <joel@joelfernandes.org>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>, Brian Gerst <brgerst@gmail.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Will Deacon <will@kernel.org>
Subject: Re: [patch V4 part 5 13/31] x86/irq: Convey vector as argument and not in ptregs
Date: Mon, 11 May 2020 23:11:43 +0800	[thread overview]
Message-ID: <CAJhGHyCePEuXjN91pSu=-yqUnafb2E5Hn8-e2UCUg0RYM0DZKA@mail.gmail.com> (raw)
In-Reply-To: <87v9l25yk7.fsf@nanos.tec.linutronix.de>

Hello

On Mon, May 11, 2020 at 10:35 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> Lai,
>
> Lai Jiangshan <jiangshanlai+lkml@gmail.com> writes:
> > On Tue, May 5, 2020 at 10:23 PM Thomas Gleixner <tglx@linutronix.de> wrote:
> >> +SYM_CODE_START(irq_entries_start)
> >> +    vector=FIRST_EXTERNAL_VECTOR
> >> +    .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
> >> +       UNWIND_HINT_IRET_REGS
> >> +       .byte   0x6a, vector
> >> +       jmp     common_interrupt
> >> +       .align  8
> >> +    vector=vector+1
> >> +    .endr
> >> +SYM_CODE_END(irq_entries_start)
> >
> > Using ".byte   0x6a, vector" is somewhat ugly.
> >
> > I hope it should be " pushq $(s8_to_s64(vector))", which can also
> > help to reduce bunches of comments about ".byte   0x6a, vector".
> >
> > However, I don't know how to implement s8_to_s64() here.
>
> Neither do I.
>
> > But at least the following code works (generates the same two-byte
> > machine code as ".byte 0x6a, vector" does):
> >
> >         .if vector < 128
> >         pushq $(vector)
> >         .else
> >         pushq $(0xffffffffffffff00+vector)
> >         .endif
>
> Only slightly less ugly and needs as much commentry as the above.

Agree.

Just FYI, I tried this later, it can work.

#define S8_TO_S64(vector) ((vector>>7)*0xffffffffffffff00+vector)

Thanks
Lai

  reply	other threads:[~2020-05-11 15:11 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05 13:53 [patch V4 part 5 00/31] x86/entry: Entry/exception code rework, Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 01/31] genirq: Provide irq_enter/exit_rcu() Thomas Gleixner
2020-05-15  5:53   ` Andy Lutomirski
2020-05-05 13:53 ` [patch V4 part 5 02/31] x86/entry: Provide helpers for execute on irqstack Thomas Gleixner
2020-05-06  8:20   ` Thomas Gleixner
2020-05-10  4:33   ` Lai Jiangshan
2020-05-11  9:07   ` Alexandre Chartre
2020-05-11 11:54     ` Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 03/31] x86/entry/64: Move softirq stack switch to C Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 04/31] x86/entry: Split idtentry_enter/exit() Thomas Gleixner
2020-05-11 12:42   ` Alexandre Chartre
2020-05-05 13:53 ` [patch V4 part 5 05/31] x86/entry: Switch XEN/PV hypercall entry to IDTENTRY Thomas Gleixner
2020-05-07  2:11   ` Boris Ostrovsky
2020-05-07  8:30     ` Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 06/31] x86/entry/64: Simplify idtentry_body Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 07/31] x86/entry: Provide idtentry_entry/exit_cond_rcu() Thomas Gleixner
2020-05-11 13:53   ` Alexandre Chartre
2020-05-11 14:13     ` Peter Zijlstra
2020-05-12 16:30     ` Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 08/31] x86/entry: Switch page fault exception to IDTENTRY_RAW Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 09/31] x86/entry: Remove the transition leftovers Thomas Gleixner
2020-05-11 14:11   ` Alexandre Chartre
2020-05-05 13:53 ` [patch V4 part 5 10/31] x86/entry: Change exit path of xen_failsafe_callback Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 11/31] x86/entry/64: Remove error_exit Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 12/31] x86/entry/32: Remove common_exception Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 13/31] x86/irq: Convey vector as argument and not in ptregs Thomas Gleixner
2020-05-10  2:44   ` Lai Jiangshan
2020-05-11 14:35     ` Thomas Gleixner
2020-05-11 15:11       ` Lai Jiangshan [this message]
2020-05-05 13:53 ` [patch V4 part 5 14/31] x86/irq/64: Provide handle_irq() Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 15/31] x86/entry: Add IRQENTRY_IRQ macro Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 16/31] x86/entry: Use idtentry for interrupts Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 17/31] x86/entry: Provide IDTENTRY_SYSVEC Thomas Gleixner
2020-05-05 13:53 ` [patch V4 part 5 18/31] x86/entry: Convert APIC interrupts to IDTENTRY_SYSVEC Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 19/31] x86/entry: Convert SMP system vectors " Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 20/31] x86/entry: Convert various system vectors Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 21/31] x86/entry: Convert KVM vectors to IDTENTRY_SYSVEC Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 22/31] x86/entry: Convert various hypervisor " Thomas Gleixner
2020-05-06 16:56   ` Wei Liu
2020-05-06 17:11     ` Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 23/31] x86/entry: Convert XEN hypercall vector " Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 24/31] x86/entry: Convert reschedule interrupt to IDTENTRY_RAW Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 25/31] x86/entry: Remove the apic/BUILD interrupt leftovers Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 26/31] x86/entry/64: Remove IRQ stack switching ASM Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 27/31] x86/entry: Make enter_from_user_mode() static Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 28/31] x86/entry/32: Remove redundant irq disable code Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 29/31] x86/entry/64: Remove TRACE_IRQS_*_DEBUG Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 30/31] x86/entry: Move paranoid irq tracing out of ASM code Thomas Gleixner
2020-05-05 13:54 ` [patch V4 part 5 31/31] x86/entry: Remove the TRACE_IRQS cruft Thomas Gleixner

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