From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: 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>,
Tom Lendacky <thomas.lendacky@amd.com>,
Wei Liu <wei.liu@kernel.org>,
Michael Kelley <mikelley@microsoft.com>,
Jason Chen CJ <jason.cj.chen@intel.com>,
Zhao Yakui <yakui.zhao@intel.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: [patch V5 35/38] x86/entry/32: Remove redundant irq disable code
Date: Tue, 12 May 2020 23:01:34 +0200 [thread overview]
Message-ID: <20200512213812.981538552@linutronix.de> (raw)
In-Reply-To: 20200512210059.056244513@linutronix.de
From: Thomas Gleixner <tglx@linutronix.de>
All exceptions/interrupts return with interrupts disabled now. No point in
doing this in ASM again.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/entry/entry_32.S | 76 ----------------------------------------------
1 file changed, 76 deletions(-)
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -51,34 +51,6 @@
.section .entry.text, "ax"
-/*
- * We use macros for low-level operations which need to be overridden
- * for paravirtualization. The following will never clobber any registers:
- * INTERRUPT_RETURN (aka. "iret")
- * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
- * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
- *
- * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
- * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
- * Allowing a register to be clobbered can shrink the paravirt replacement
- * enough to patch inline, increasing performance.
- */
-
-#ifdef CONFIG_PREEMPTION
-# define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
-#else
-# define preempt_stop(clobbers)
-#endif
-
-.macro TRACE_IRQS_IRET
-#ifdef CONFIG_TRACE_IRQFLAGS
- testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off?
- jz 1f
- TRACE_IRQS_ON
-1:
-#endif
-.endm
-
#define PTI_SWITCH_MASK (1 << PAGE_SHIFT)
/*
@@ -881,38 +853,6 @@ SYM_CODE_START(ret_from_fork)
SYM_CODE_END(ret_from_fork)
.popsection
-/*
- * Return to user mode is not as complex as all this looks,
- * but we want the default path for a system call return to
- * go as quickly as possible which is why some of this is
- * less clear than it otherwise should be.
- */
-
- # userspace resumption stub bypassing syscall exit tracing
-SYM_CODE_START_LOCAL(ret_from_exception)
- preempt_stop(CLBR_ANY)
-ret_from_intr:
-#ifdef CONFIG_VM86
- movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
- movb PT_CS(%esp), %al
- andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
-#else
- /*
- * We can be coming here from child spawned by kernel_thread().
- */
- movl PT_CS(%esp), %eax
- andl $SEGMENT_RPL_MASK, %eax
-#endif
- cmpl $USER_RPL, %eax
- jb restore_all_kernel # not returning to v8086 or userspace
-
- DISABLE_INTERRUPTS(CLBR_ANY)
- TRACE_IRQS_OFF
- movl %esp, %eax
- call prepare_exit_to_usermode
- jmp restore_all_switch_stack
-SYM_CODE_END(ret_from_exception)
-
SYM_ENTRY(__begin_SYSENTER_singlestep_region, SYM_L_GLOBAL, SYM_A_NONE)
/*
* All code from here through __end_SYSENTER_singlestep_region is subject
@@ -1147,22 +1087,6 @@ SYM_FUNC_START(entry_INT80_32)
*/
INTERRUPT_RETURN
-restore_all_kernel:
-#ifdef CONFIG_PREEMPTION
- DISABLE_INTERRUPTS(CLBR_ANY)
- cmpl $0, PER_CPU_VAR(__preempt_count)
- jnz .Lno_preempt
- testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ?
- jz .Lno_preempt
- call preempt_schedule_irq
-.Lno_preempt:
-#endif
- TRACE_IRQS_IRET
- PARANOID_EXIT_TO_KERNEL_MODE
- BUG_IF_WRONG_CR3
- RESTORE_REGS 4
- jmp .Lirq_return
-
.section .fixup, "ax"
SYM_CODE_START(asm_exc_iret_error)
pushl $0 # no error code
next prev parent reply other threads:[~2020-05-12 22:23 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-12 21:00 [patch V5 00/38] x86/entry: Entry/exception code rework - the leftovers Thomas Gleixner
2020-05-12 21:01 ` [patch V5 01/38] x86/kvm/svm: Use uninstrumented wrmsrl() to restore GS Thomas Gleixner
2020-05-13 7:11 ` Jürgen Groß
2020-05-12 21:01 ` [patch V5 02/38] x86/entry/64: Use native swapgs in asm_native_load_gs_index() Thomas Gleixner
2020-05-13 2:02 ` Steven Rostedt
2020-05-13 6:34 ` Thomas Gleixner
2020-05-13 7:12 ` Jürgen Groß
2020-05-19 19:58 ` [tip: x86/entry] x86/entry/64: Use native swapgs in asm_load_gs_index() tip-bot2 for Thomas Gleixner
2020-05-12 21:01 ` [patch V5 03/38] nmi, tracing: Provide nmi_enter/exit_notrace() Thomas Gleixner
2020-05-15 1:32 ` Steven Rostedt
2020-05-15 1:35 ` Steven Rostedt
2020-05-15 1:37 ` Steven Rostedt
2020-05-12 21:01 ` [patch V5 04/38] x86: Make hardware latency tracing explicit Thomas Gleixner
2020-05-15 1:43 ` Steven Rostedt
2020-05-15 15:08 ` Thomas Gleixner
2020-05-12 21:01 ` [patch V5 05/38] genirq: Provide irq_enter/exit_rcu() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 06/38] x86/entry: Provide helpers for execute on irqstack Thomas Gleixner
2020-05-13 21:43 ` Josh Poimboeuf
2020-05-12 21:01 ` [patch V5 07/38] x86/entry/64: Move do_softirq_own_stack() to C Thomas Gleixner
2020-05-12 21:01 ` [patch V5 08/38] x86/entry: Split idtentry_enter/exit() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 09/38] x86/entry: Switch XEN/PV hypercall entry to IDTENTRY Thomas Gleixner
2020-05-14 16:24 ` Boris Ostrovsky
2020-05-12 21:01 ` [patch V5 10/38] x86/entry/64: Simplify idtentry_body Thomas Gleixner
2020-05-12 21:01 ` [patch V5 11/38] rcu: Provide __rcu_is_watching() Thomas Gleixner
2020-05-19 19:52 ` [tip: core/rcu] " tip-bot2 for Thomas Gleixner
2020-05-12 21:01 ` [patch V5 12/38] x86/entry: Provide idtentry_entry/exit_cond_rcu() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 13/38] x86/entry: Switch page fault exception to IDTENTRY_RAW Thomas Gleixner
2020-05-12 21:01 ` [patch V5 14/38] x86/entry: Remove the transition leftovers Thomas Gleixner
2020-05-12 21:01 ` [patch V5 15/38] x86/entry: Change exit path of xen_failsafe_callback Thomas Gleixner
2020-05-12 21:01 ` [patch V5 16/38] x86/entry/64: Remove error_exit Thomas Gleixner
2020-05-12 21:01 ` [patch V5 17/38] x86/entry/32: Remove common_exception Thomas Gleixner
2020-05-12 21:01 ` [patch V5 18/38] x86/irq: Use generic irq_regs implementation Thomas Gleixner
2020-05-12 21:01 ` [patch V5 19/38] x86/irq: Convey vector as argument and not in ptregs Thomas Gleixner
2020-05-12 21:01 ` [patch V5 20/38] x86/irq/64: Provide handle_irq() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 21/38] x86/entry: Add IRQENTRY_IRQ macro Thomas Gleixner
2020-05-12 21:01 ` [patch V5 22/38] x86/entry: Use idtentry for interrupts Thomas Gleixner
2020-05-12 21:01 ` [patch V5 23/38] genirq: Provde __irq_enter/exit_raw() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 24/38] x86/entry: Provide IDTENTRY_SYSVEC Thomas Gleixner
2020-05-15 0:16 ` Boris Ostrovsky
2020-05-15 8:52 ` Thomas Gleixner
2020-05-12 21:01 ` [patch V5 25/38] x86/entry: Convert APIC interrupts to IDTENTRY_SYSVEC Thomas Gleixner
2020-05-12 21:01 ` [patch V5 26/38] x86/entry: Convert SMP system vectors " Thomas Gleixner
2020-05-12 21:01 ` [patch V5 27/38] x86/entry: Convert various system vectors Thomas Gleixner
2020-05-12 21:01 ` [patch V5 28/38] x86/entry: Convert KVM vectors to IDTENTRY_SYSVEC Thomas Gleixner
2020-05-12 21:01 ` [patch V5 29/38] x86/entry: Convert various hypervisor " Thomas Gleixner
2020-05-12 21:01 ` [patch V5 30/38] x86/entry: Convert XEN hypercall vector " Thomas Gleixner
2020-05-12 21:01 ` [patch V5 31/38] x86/entry: Convert reschedule interrupt to IDTENTRY_SYSVEC_SIMPLE Thomas Gleixner
2020-05-12 21:01 ` [patch V5 32/38] x86/entry: Remove the apic/BUILD interrupt leftovers Thomas Gleixner
2020-05-12 21:01 ` [patch V5 33/38] x86/entry/64: Remove IRQ stack switching ASM Thomas Gleixner
2020-05-12 21:01 ` [patch V5 34/38] x86/entry: Make enter_from_user_mode() static Thomas Gleixner
2020-05-12 21:01 ` Thomas Gleixner [this message]
2020-05-12 21:01 ` [patch V5 36/38] x86/entry/64: Remove TRACE_IRQS_*_DEBUG Thomas Gleixner
2020-05-12 21:01 ` [patch V5 37/38] x86/entry: Move paranoid irq tracing out of ASM code Thomas Gleixner
2020-05-12 21:01 ` [patch V5 38/38] x86/entry: Remove the TRACE_IRQS cruft Thomas Gleixner
2020-05-14 16:35 ` [patch V5 00/38] x86/entry: Entry/exception code rework - the leftovers Paul E. McKenney
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