[PATCH 8 of 9] x86: make number of smp_call_function queues truely configurable

[Jeremy Fitzhardinge <jeremy@goop.org>]

Previously, the config option GENERIC_SMP_QUEUES was never actually
adjustable because a moderate amount of static boilerplate code had to
match.

This patch makes it truely adjustable up to the number of IPI vectors
we statically preallocate.  The various IPI handlers are generated by
looping assembler macros, and their addresses are put into an array
for C code to use to actually set the vectors up.

The default number of queues is never more than NR_CPUS, and defaults
to NR_CPUS.  Ideally this could be a runtime variable based on the
number of possible cpus, rather than a static compile-time options.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 arch/x86/Kconfig                          |    8 +++++++-
 arch/x86/kernel/entry_32.S                |   12 ++++++------
 arch/x86/kernel/entry_64.S                |   29 ++++++++++++++++-------------
 arch/x86/kernel/irqinit_32.c              |   16 ++++++----------
 arch/x86/kernel/irqinit_64.c              |   16 ++++++----------
 include/asm-x86/hw_irq.h                  |    9 +--------
 include/asm-x86/irq_vectors.h             |    3 +++
 include/asm-x86/mach-default/entry_arch.h |   29 ++++++++++++++++-------------
 8 files changed, 61 insertions(+), 61 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -182,9 +182,15 @@
 	select USE_GENERIC_SMP_HELPERS
 	default y
 
+config MAX_GENERIC_SMP_QUEUES
+       int
+       default 8
+
 config GENERIC_SMP_QUEUES
        int
-       default "8"
+       range 1 NR_CPUS if NR_CPUS <= MAX_GENERIC_SMP_QUEUES
+       range 1 MAX_GENERIC_SMP_QUEUES
+       default NR_CPUS
 
 config X86_32_SMP
 	def_bool y
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -688,8 +688,7 @@
 ENDPROC(common_interrupt)
 	CFI_ENDPROC
 
-#define __BUILD_INTERRUPT(name, func, nr)	\
-ENTRY(name)					\
+#define __BUILD_INTERRUPT(func, nr)		\
 	RING0_INT_FRAME;			\
 	pushl $~(nr);				\
 	CFI_ADJUST_CFA_OFFSET 4;		\
@@ -698,11 +697,12 @@
 	movl %esp,%eax;				\
 	call func;				\
 	jmp ret_from_intr;			\
-	CFI_ENDPROC;				\
+	CFI_ENDPROC;
+
+#define BUILD_INTERRUPT(name, nr)		\
+ENTRY(name)					\
+	__BUILD_INTERRUPT(smp_##name, nr)	\
 ENDPROC(name)
-
-#define BUILD_INTERRUPT(name, nr)	\
-	__BUILD_INTERRUPT(name, smp_##name, nr)
 
 /* The include is where all of the SMP etc. interrupts come from */
 #include "entry_arch.h"
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -870,20 +870,23 @@
 END(reschedule_interrupt)
 
 
-	.macro CALLFUNCTION_ENTRY num
-ENTRY(call_function_interrupt\num)
-	apicinterrupt CALL_FUNCTION_VECTOR_START+\num,smp_call_function_interrupt
-END(call_function_interrupt\num)
-	.endm
+.globl callfunction_interrupts
+.pushsection .rodata,"a"
+callfunction_interrupts:
+.popsection
 
-	CALLFUNCTION_ENTRY 0
-	CALLFUNCTION_ENTRY 1
-	CALLFUNCTION_ENTRY 2
-	CALLFUNCTION_ENTRY 3
-	CALLFUNCTION_ENTRY 4
-	CALLFUNCTION_ENTRY 5
-	CALLFUNCTION_ENTRY 6
-	CALLFUNCTION_ENTRY 7
+vec=0
+.rept CONFIG_GENERIC_SMP_QUEUES
+	ALIGN
+993:	apicinterrupt CALL_FUNCTION_VECTOR_START+vec, smp_call_function_interrupt
+.pushsection .rodata,"a"
+	.quad 993b
+.popsection
+	vec = vec+1
+.endr
+.pushsection .rodata,"a"
+	.size callfunction_interrupts, . - callfunction_interrupts
+.popsection
 
 ENTRY(call_function_single_interrupt)
 	apicinterrupt CALL_FUNCTION_SINGLE_VECTOR,smp_call_function_single_interrupt
diff --git a/arch/x86/kernel/irqinit_32.c b/arch/x86/kernel/irqinit_32.c
--- a/arch/x86/kernel/irqinit_32.c
+++ b/arch/x86/kernel/irqinit_32.c
@@ -121,16 +121,12 @@
 	alloc_intr_gate(RESCHEDULE_VECTOR, reschedule_interrupt);
 
 	/* IPI for generic function call */
-	BUILD_BUG_ON(CONFIG_GENERIC_SMP_QUEUES !=
-		     (CALL_FUNCTION_VECTOR_END - CALL_FUNCTION_VECTOR_START + 1));
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+0, call_function_interrupt0);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+1, call_function_interrupt1);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+2, call_function_interrupt2);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+3, call_function_interrupt3);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+4, call_function_interrupt4);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+5, call_function_interrupt5);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+6, call_function_interrupt6);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+7, call_function_interrupt7);
+	BUILD_BUG_ON(CONFIG_GENERIC_SMP_QUEUES > NUM_CALL_FUNCTION_VECTORS);
+	BUILD_BUG_ON(CONFIG_MAX_GENERIC_SMP_QUEUES != NUM_CALL_FUNCTION_VECTORS);
+
+	for(i = 0; i < CONFIG_GENERIC_SMP_QUEUES; i++)
+		alloc_intr_gate(CALL_FUNCTION_VECTOR_START+i,
+				callfunction_interrupts[i]);
 
 	/* IPI for single call function */
 	set_intr_gate(CALL_FUNCTION_SINGLE_VECTOR, call_function_single_interrupt);
diff --git a/arch/x86/kernel/irqinit_64.c b/arch/x86/kernel/irqinit_64.c
--- a/arch/x86/kernel/irqinit_64.c
+++ b/arch/x86/kernel/irqinit_64.c
@@ -188,16 +188,12 @@
 	alloc_intr_gate(RESCHEDULE_VECTOR, reschedule_interrupt);
 
 	/* IPI for generic function call */
-	BUILD_BUG_ON(CONFIG_GENERIC_SMP_QUEUES !=
-		     (CALL_FUNCTION_VECTOR_END - CALL_FUNCTION_VECTOR_START + 1));
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+0, call_function_interrupt0);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+1, call_function_interrupt1);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+2, call_function_interrupt2);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+3, call_function_interrupt3);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+4, call_function_interrupt4);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+5, call_function_interrupt5);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+6, call_function_interrupt6);
-	alloc_intr_gate(CALL_FUNCTION_VECTOR_START+7, call_function_interrupt7);
+	BUILD_BUG_ON(CONFIG_GENERIC_SMP_QUEUES > NUM_CALL_FUNCTION_VECTORS);
+	BUILD_BUG_ON(CONFIG_MAX_GENERIC_SMP_QUEUES != NUM_CALL_FUNCTION_VECTORS);
+
+	for(i = 0; i < CONFIG_GENERIC_SMP_QUEUES; i++)
+		alloc_intr_gate(CALL_FUNCTION_VECTOR_START+i,
+				callfunction_interrupts[i]);
 
 	/* IPI for generic single function call */
 	alloc_intr_gate(CALL_FUNCTION_SINGLE_VECTOR,
diff --git a/include/asm-x86/hw_irq.h b/include/asm-x86/hw_irq.h
--- a/include/asm-x86/hw_irq.h
+++ b/include/asm-x86/hw_irq.h
@@ -37,14 +37,7 @@
 extern void irq_move_cleanup_interrupt(void);
 extern void threshold_interrupt(void);
 
-extern void call_function_interrupt0(void);
-extern void call_function_interrupt1(void);
-extern void call_function_interrupt2(void);
-extern void call_function_interrupt3(void);
-extern void call_function_interrupt4(void);
-extern void call_function_interrupt5(void);
-extern void call_function_interrupt6(void);
-extern void call_function_interrupt7(void);
+extern void *callfunction_interrupts[CONFIG_GENERIC_SMP_QUEUES];
 
 extern void call_function_single_interrupt(void);
 
diff --git a/include/asm-x86/irq_vectors.h b/include/asm-x86/irq_vectors.h
--- a/include/asm-x86/irq_vectors.h
+++ b/include/asm-x86/irq_vectors.h
@@ -79,6 +79,9 @@
 #define CALL_FUNCTION_VECTOR_START	0xf0 /* f0-f7 multiple callfunction queues */
 
 #endif
+
+#define NUM_CALL_FUNCTION_VECTORS	\
+	(CALL_FUNCTION_VECTOR_END - CALL_FUNCTION_VECTOR_START + 1)
 
 /*
  * Local APIC timer IRQ vector is on a different priority level,
diff --git a/include/asm-x86/mach-default/entry_arch.h b/include/asm-x86/mach-default/entry_arch.h
--- a/include/asm-x86/mach-default/entry_arch.h
+++ b/include/asm-x86/mach-default/entry_arch.h
@@ -13,20 +13,23 @@
 BUILD_INTERRUPT(reschedule_interrupt,RESCHEDULE_VECTOR)
 BUILD_INTERRUPT(call_function_single_interrupt,CALL_FUNCTION_SINGLE_VECTOR)
 
-#define BUILD_CALLFUNCTION(n)					\
-	__BUILD_INTERRUPT(call_function_interrupt##n,		\
-			  smp_call_function_interrupt,		\
-			  CALL_FUNCTION_VECTOR_START + n)
-BUILD_CALLFUNCTION(0)
-BUILD_CALLFUNCTION(1)
-BUILD_CALLFUNCTION(2)
-BUILD_CALLFUNCTION(3)
-BUILD_CALLFUNCTION(4)
-BUILD_CALLFUNCTION(5)
-BUILD_CALLFUNCTION(6)
-BUILD_CALLFUNCTION(7)
+.pushsection .rodata,"a"
+.globl callfunction_interrupts
+callfunction_interrupts:
+.popsection
 
-#undef BUILD_CALLFUNCTION
+vec = 0
+.rept CONFIG_GENERIC_SMP_QUEUES
+	ALIGN
+1:	__BUILD_INTERRUPT(smp_call_function_interrupt, CALL_FUNCTION_VECTOR_START+vec)
+	vec = vec+1
+.pushsection .rodata,"a"
+	.long 1b
+.popsection
+.endr
+.pushsection .rodata,"a"
+	.size callfunction_interrupts, . - callfunction_interrupts
+.popsection
 #endif
 
 /*