x86/hyperv: Enable build of hypervisor crashdump collection files

Enable build of the new files introduced in the earlier commits and add
call to do the setup during boot.

Signed-off-by: Mukesh Rathor <mrathor@linux.microsoft.com>
[ wei: fix build ]
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Author: mrathor99

arch/x86/hyperv/Makefile

@@ -5,4 +5,10 @@ obj-$(CONFIG_HYPERV_VTL_MODE)	+= hv_vtl.o
 
 ifdef CONFIG_X86_64
 obj-$(CONFIG_PARAVIRT_SPINLOCKS)	+= hv_spinlock.o
+
+ ifdef CONFIG_MSHV_ROOT
+  CFLAGS_REMOVE_hv_trampoline.o += -pg
+  CFLAGS_hv_trampoline.o        += -fno-stack-protector
+  obj-$(CONFIG_CRASH_DUMP)      += hv_crash.o hv_trampoline.o
+ endif
 endif

arch/x86/hyperv/hv_init.c

@@ -554,6 +554,7 @@ void __init hyperv_init(void)
 		memunmap(src);
 
 		hv_remap_tsc_clocksource();
+		hv_root_crash_init();
 	} else {
 		hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
 		wrmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);

arch/x86/include/asm/mshyperv.h

@@ -237,6 +237,15 @@ static __always_inline u64 hv_raw_get_msr(unsigned int reg)
 }
 int hv_apicid_to_vp_index(u32 apic_id);
 
+#if IS_ENABLED(CONFIG_MSHV_ROOT) && IS_ENABLED(CONFIG_CRASH_DUMP)
+void hv_root_crash_init(void);
+void hv_crash_asm32(void);
+void hv_crash_asm64(void);
+void hv_crash_asm_end(void);
+#else   /* CONFIG_MSHV_ROOT && CONFIG_CRASH_DUMP */
+static inline void hv_root_crash_init(void) {}
+#endif  /* CONFIG_MSHV_ROOT && CONFIG_CRASH_DUMP */
+
 #else /* CONFIG_HYPERV */
 static inline void hyperv_init(void) {}
 static inline void hyperv_setup_mmu_ops(void) {}