| Message ID | 20191023123118.191230255@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | entry: Provide generic implementation for host and guest entry/exit work | expand |
On Wed, Oct 23, 2019 at 02:27:11PM +0200, Thomas Gleixner wrote: > Now that the trap handlers return with interrupts disabled, the > unconditional disabling of interrupts in the low level entry code can be > removed along with the trace calls and the misnomed preempt_stop macro. > As a consequence ret_from_exception and ret_from_intr collapse. > > Add a debug check to verify that interrupts are disabled depending on > CONFIG_DEBUG_ENTRY. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- One nit below. Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> > arch/x86/entry/entry_32.S | 21 ++++++--------------- > 1 file changed, 6 insertions(+), 15 deletions(-) > > --- a/arch/x86/entry/entry_32.S > +++ b/arch/x86/entry/entry_32.S > @@ -1207,7 +1198,7 @@ ENDPROC(common_spurious) > TRACE_IRQS_OFF > movl %esp, %eax > call do_IRQ > - jmp ret_from_intr > + jmp ret_from_exception > ENDPROC(common_interrupt) > > #define BUILD_INTERRUPT3(name, nr, fn) \ > @@ -1219,7 +1210,7 @@ ENTRY(name) \ > TRACE_IRQS_OFF \ > movl %esp, %eax; \ > call fn; \ > - jmp ret_from_intr; \ > + jmp ret_from_exception; \ This backslash is now unaligned. > ENDPROC(name) > > #define BUILD_INTERRUPT(name, nr) \ > @@ -1366,7 +1357,7 @@ ENTRY(xen_do_upcall) > #ifndef CONFIG_PREEMPTION > call xen_maybe_preempt_hcall > #endif > - jmp ret_from_intr > + jmp ret_from_exception > ENDPROC(xen_hypervisor_callback) > > /* > >
On 10/23/19 2:27 PM, Thomas Gleixner wrote: > Now that the trap handlers return with interrupts disabled, the > unconditional disabling of interrupts in the low level entry code can be > removed along with the trace calls and the misnomed preempt_stop macro. > As a consequence ret_from_exception and ret_from_intr collapse. > > Add a debug check to verify that interrupts are disabled depending on > CONFIG_DEBUG_ENTRY. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > arch/x86/entry/entry_32.S | 21 ++++++--------------- > 1 file changed, 6 insertions(+), 15 deletions(-) > Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> alex.
--- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -63,12 +63,6 @@ * 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? @@ -809,8 +803,7 @@ END(ret_from_fork) # userspace resumption stub bypassing syscall exit tracing ALIGN ret_from_exception: - preempt_stop(CLBR_ANY) -ret_from_intr: + DEBUG_ENTRY_ASSERT_IRQS_OFF #ifdef CONFIG_VM86 movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS movb PT_CS(%esp), %al @@ -825,8 +818,6 @@ END(ret_from_fork) 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 @@ -1084,7 +1075,7 @@ ENTRY(entry_INT80_32) restore_all_kernel: #ifdef CONFIG_PREEMPTION - DISABLE_INTERRUPTS(CLBR_ANY) + /* Interrupts are disabled and debug-checked */ cmpl $0, PER_CPU_VAR(__preempt_count) jnz .Lno_preempt testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ? @@ -1189,7 +1180,7 @@ END(spurious_entries_start) TRACE_IRQS_OFF movl %esp, %eax call smp_spurious_interrupt - jmp ret_from_intr + jmp ret_from_exception ENDPROC(common_spurious) #endif @@ -1207,7 +1198,7 @@ ENDPROC(common_spurious) TRACE_IRQS_OFF movl %esp, %eax call do_IRQ - jmp ret_from_intr + jmp ret_from_exception ENDPROC(common_interrupt) #define BUILD_INTERRUPT3(name, nr, fn) \ @@ -1219,7 +1210,7 @@ ENTRY(name) \ TRACE_IRQS_OFF \ movl %esp, %eax; \ call fn; \ - jmp ret_from_intr; \ + jmp ret_from_exception; \ ENDPROC(name) #define BUILD_INTERRUPT(name, nr) \ @@ -1366,7 +1357,7 @@ ENTRY(xen_do_upcall) #ifndef CONFIG_PREEMPTION call xen_maybe_preempt_hcall #endif - jmp ret_from_intr + jmp ret_from_exception ENDPROC(xen_hypervisor_callback) /*
Now that the trap handlers return with interrupts disabled, the unconditional disabling of interrupts in the low level entry code can be removed along with the trace calls and the misnomed preempt_stop macro. As a consequence ret_from_exception and ret_from_intr collapse. Add a debug check to verify that interrupts are disabled depending on CONFIG_DEBUG_ENTRY. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- arch/x86/entry/entry_32.S | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-)