x86/platform/uv: Remove UV BAU TLB Shootdown Handler

The Broadcast Assist Unit (BAU) TLB shootdown handler is being rewritten
to become the UV BAU APIC driver. It is designed to speed up sending
IPIs to selective CPUs within the system. Remove the current TLB
shutdown handler (tlb_uv.c) file and a couple of kernel hooks in the
interim.
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Link: https://lkml.kernel.org/r/20201005203929.148656-2-mike.travis@hpe.com

arch/x86/include/asm/idtentry.h

@@ -591,10 +591,6 @@ DECLARE_IDTENTRY_SYSVEC(CALL_FUNCTION_VECTOR,		sysvec_call_function);
 #endif
 
 #ifdef CONFIG_X86_LOCAL_APIC
-# ifdef CONFIG_X86_UV
-DECLARE_IDTENTRY_SYSVEC(UV_BAU_MESSAGE,			sysvec_uv_bau_message);
-# endif
-
 # ifdef CONFIG_X86_MCE_THRESHOLD
 DECLARE_IDTENTRY_SYSVEC(THRESHOLD_APIC_VECTOR,		sysvec_threshold);
 # endif

arch/x86/include/asm/uv/uv.h

@@ -35,10 +35,8 @@ extern int is_uv_hubbed(int uvtype);
 extern void uv_cpu_init(void);
 extern void uv_nmi_init(void);
 extern void uv_system_init(void);
-extern const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
-						 const struct flush_tlb_info *info);
 
-#else	/* X86_UV */
+#else	/* !X86_UV */
 
 static inline enum uv_system_type get_uv_system_type(void) { return UV_NONE; }
 static inline bool is_early_uv_system(void)	{ return 0; }

arch/x86/kernel/idt.c

@@ -148,9 +148,6 @@ static const __initconst struct idt_data apic_idts[] = {
 # endif
 # ifdef CONFIG_IRQ_WORK
 	INTG(IRQ_WORK_VECTOR,			asm_sysvec_irq_work),
-# endif
-# ifdef CONFIG_X86_UV
-	INTG(UV_BAU_MESSAGE,			asm_sysvec_uv_bau_message),
 # endif
 	INTG(SPURIOUS_APIC_VECTOR,		asm_sysvec_spurious_apic_interrupt),
 	INTG(ERROR_APIC_VECTOR,			asm_sysvec_error_interrupt),

arch/x86/mm/tlb.c

@@ -14,7 +14,6 @@
 #include <asm/nospec-branch.h>
 #include <asm/cache.h>
 #include <asm/apic.h>
-#include <asm/uv/uv.h>
 
 #include "mm_internal.h"
 
@@ -800,29 +799,6 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
 		trace_tlb_flush(TLB_REMOTE_SEND_IPI,
 				(info->end - info->start) >> PAGE_SHIFT);
 
-	if (is_uv_system()) {
-		/*
-		 * This whole special case is confused.  UV has a "Broadcast
-		 * Assist Unit", which seems to be a fancy way to send IPIs.
-		 * Back when x86 used an explicit TLB flush IPI, UV was
-		 * optimized to use its own mechanism.  These days, x86 uses
-		 * smp_call_function_many(), but UV still uses a manual IPI,
-		 * and that IPI's action is out of date -- it does a manual
-		 * flush instead of calling flush_tlb_func_remote().  This
-		 * means that the percpu tlb_gen variables won't be updated
-		 * and we'll do pointless flushes on future context switches.
-		 *
-		 * Rather than hooking native_flush_tlb_others() here, I think
-		 * that UV should be updated so that smp_call_function_many(),
-		 * etc, are optimal on UV.
-		 */
-		cpumask = uv_flush_tlb_others(cpumask, info);
-		if (cpumask)
-			smp_call_function_many(cpumask, flush_tlb_func_remote,
-					       (void *)info, 1);
-		return;
-	}
-
 	/*
 	 * If no page tables were freed, we can skip sending IPIs to
 	 * CPUs in lazy TLB mode. They will flush the CPU themselves

arch/x86/platform/uv/Makefile

 # SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_X86_UV)		+= tlb_uv.o bios_uv.o uv_irq.o uv_sysfs.o uv_time.o uv_nmi.o
+obj-$(CONFIG_X86_UV)		+= bios_uv.o uv_irq.o uv_sysfs.o uv_time.o uv_nmi.o