Commit 633260fa authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/irq: Convey vector as argument and not in ptregs 



Device interrupts which go through do_IRQ() or the spurious interrupt
handler have their separate entry code on 64 bit for no good reason.

Both 32 and 64 bit transport the vector number through ORIG_[RE]AX in
pt_regs. Further the vector number is forced to fit into an u8 and is
complemented and offset by 0x80 so it's in the signed character
range. Otherwise GAS would expand the pushq to a 5 byte instruction for any
vector > 0x7F.

Treat the vector number like an error code and hand it to the C function as
argument. This allows to get rid of the extra entry code in a later step.

Simplify the error code push magic by implementing the pushq imm8 via a
'.byte 0x6a, vector' sequence so GAS is not able to screw it up. As the
pushq imm8 is sign extending the resulting error code needs to be truncated
to 8 bits in C code.

Originally-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202118.796915981@linutronix.de
parent 79b9c183

arch/x86/entry/calling.h

+4 −1
Original line number Diff line number Diff line
@@ -341,7 +341,10 @@ For 32-bit we have the following conventions - kernel is built with 
#endif

.endm



#endif /* CONFIG_X86_64 */

#else /* CONFIG_X86_64 */

# undef		UNWIND_HINT_IRET_REGS

# define	UNWIND_HINT_IRET_REGS

#endif /* !CONFIG_X86_64 */



.macro STACKLEAK_ERASE

#ifdef CONFIG_GCC_PLUGIN_STACKLEAK

arch/x86/entry/entry_32.S

+4 −29
Original line number Diff line number Diff line
@@ -1215,40 +1215,15 @@ SYM_FUNC_END(entry_INT80_32) 
#endif

.endm



/*

 * Build the entry stubs with some assembler magic.

 * We pack 1 stub into every 8-byte block.

 */

	.align 8

SYM_CODE_START(irq_entries_start)

    vector=FIRST_EXTERNAL_VECTOR

    .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)

	pushl	$(~vector+0x80)			/* Note: always in signed byte range */

    vector=vector+1

	jmp	common_interrupt

	.align	8

    .endr

SYM_CODE_END(irq_entries_start)



#ifdef CONFIG_X86_LOCAL_APIC

	.align 8

SYM_CODE_START(spurious_entries_start)

    vector=FIRST_SYSTEM_VECTOR

    .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)

	pushl	$(~vector+0x80)			/* Note: always in signed byte range */

    vector=vector+1

	jmp	common_spurious

	.align	8

    .endr

SYM_CODE_END(spurious_entries_start)



SYM_CODE_START_LOCAL(common_spurious)

	ASM_CLAC

	addl	$-0x80, (%esp)			/* Adjust vector into the [-256, -1] range */

	SAVE_ALL switch_stacks=1

	ENCODE_FRAME_POINTER

	TRACE_IRQS_OFF

	movl	%esp, %eax

	movl	PT_ORIG_EAX(%esp), %edx		/* get the vector from stack */

	movl	$-1, PT_ORIG_EAX(%esp)		/* no syscall to restart */

	call	smp_spurious_interrupt

	jmp	ret_from_intr

SYM_CODE_END(common_spurious)
@@ -1261,12 +1236,12 @@ SYM_CODE_END(common_spurious) 
	.p2align CONFIG_X86_L1_CACHE_SHIFT

SYM_CODE_START_LOCAL(common_interrupt)

	ASM_CLAC

	addl	$-0x80, (%esp)			/* Adjust vector into the [-256, -1] range */



	SAVE_ALL switch_stacks=1

	ENCODE_FRAME_POINTER

	TRACE_IRQS_OFF

	movl	%esp, %eax

	movl	PT_ORIG_EAX(%esp), %edx		/* get the vector from stack */

	movl	$-1, PT_ORIG_EAX(%esp)		/* no syscall to restart */

	call	do_IRQ

	jmp	ret_from_intr

SYM_CODE_END(common_interrupt)

arch/x86/entry/entry_64.S

+7 −33
Original line number Diff line number Diff line
@@ -358,34 +358,6 @@ SYM_CODE_START(ret_from_fork) 
SYM_CODE_END(ret_from_fork)

.popsection



/*

 * Build the entry stubs with some assembler magic.

 * We pack 1 stub into every 8-byte block.

 */

	.align 8

SYM_CODE_START(irq_entries_start)

    vector=FIRST_EXTERNAL_VECTOR

    .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)

	UNWIND_HINT_IRET_REGS

	pushq	$(~vector+0x80)			/* Note: always in signed byte range */

	jmp	common_interrupt

	.align	8

	vector=vector+1

    .endr

SYM_CODE_END(irq_entries_start)



	.align 8

SYM_CODE_START(spurious_entries_start)

    vector=FIRST_SYSTEM_VECTOR

    .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)

	UNWIND_HINT_IRET_REGS

	pushq	$(~vector+0x80)			/* Note: always in signed byte range */

	jmp	common_spurious

	.align	8

	vector=vector+1

    .endr

SYM_CODE_END(spurious_entries_start)



.macro DEBUG_ENTRY_ASSERT_IRQS_OFF

#ifdef CONFIG_DEBUG_ENTRY

	pushq %rax
@@ -755,13 +727,14 @@ _ASM_NOKPROBE(interrupt_entry) 
/* Interrupt entry/exit. */



/*

 * The interrupt stubs push (~vector+0x80) onto the stack and

 * The interrupt stubs push vector onto the stack and

 * then jump to common_spurious/interrupt.

 */

SYM_CODE_START_LOCAL(common_spurious)

	addq	$-0x80, (%rsp)			/* Adjust vector to [-256, -1] range */

	call	interrupt_entry

	UNWIND_HINT_REGS indirect=1

	movq	ORIG_RAX(%rdi), %rsi		/* get vector from stack */

	movq	$-1, ORIG_RAX(%rdi)		/* no syscall to restart */

	call	smp_spurious_interrupt		/* rdi points to pt_regs */

	jmp	ret_from_intr

SYM_CODE_END(common_spurious)
@@ -770,9 +743,10 @@ _ASM_NOKPROBE(common_spurious) 
/* common_interrupt is a hotpath. Align it */

	.p2align CONFIG_X86_L1_CACHE_SHIFT

SYM_CODE_START_LOCAL(common_interrupt)

	addq	$-0x80, (%rsp)			/* Adjust vector to [-256, -1] range */

	call	interrupt_entry

	UNWIND_HINT_REGS indirect=1

	movq	ORIG_RAX(%rdi), %rsi		/* get vector from stack */

	movq	$-1, ORIG_RAX(%rdi)		/* no syscall to restart */

	call	do_IRQ				/* rdi points to pt_regs */

	/* 0(%rsp): old RSP */

ret_from_intr:
@@ -1022,7 +996,7 @@ apicinterrupt RESCHEDULE_VECTOR reschedule_interrupt smp_reschedule_interrupt 
#endif



apicinterrupt ERROR_APIC_VECTOR			error_interrupt			smp_error_interrupt

apicinterrupt SPURIOUS_APIC_VECTOR		spurious_interrupt		smp_spurious_interrupt

apicinterrupt SPURIOUS_APIC_VECTOR		spurious_apic_interrupt		smp_spurious_apic_interrupt



#ifdef CONFIG_IRQ_WORK

apicinterrupt IRQ_WORK_VECTOR			irq_work_interrupt		smp_irq_work_interrupt

arch/x86/include/asm/entry_arch.h

+1 −1
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ BUILD_INTERRUPT(kvm_posted_intr_nested_ipi, POSTED_INTR_NESTED_VECTOR) 


BUILD_INTERRUPT(apic_timer_interrupt,LOCAL_TIMER_VECTOR)

BUILD_INTERRUPT(error_interrupt,ERROR_APIC_VECTOR)

BUILD_INTERRUPT(spurious_interrupt,SPURIOUS_APIC_VECTOR)

BUILD_INTERRUPT(spurious_apic_interrupt,SPURIOUS_APIC_VECTOR)

BUILD_INTERRUPT(x86_platform_ipi, X86_PLATFORM_IPI_VECTOR)



#ifdef CONFIG_IRQ_WORK

arch/x86/include/asm/hw_irq.h

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ extern asmlinkage void irq_work_interrupt(void); 
extern asmlinkage void uv_bau_message_intr1(void);



extern asmlinkage void spurious_interrupt(void);

extern asmlinkage void spurious_apic_interrupt(void);

extern asmlinkage void thermal_interrupt(void);

extern asmlinkage void reschedule_interrupt(void);

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