x86/of: Set the parse_smp_cfg for all the DeviceTree platforms by default

x86_dtb_parse_smp_config() must be set by DeviceTree platform for
parsing SMP configuration. Set the parse_smp_cfg pointer to
x86_dtb_parse_smp_config() by default so that all the dtb platforms
need not to assign it explicitly. Today there are only two platforms
using DeviceTree in x86, ce4100 and hv_vtl. Remove the explicit
assignment of x86_dtb_parse_smp_config() function from these.
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/1712068830-4513-3-git-send-email-ssengar@linux.microsoft.com

arch/x86/hyperv/hv_vtl.c

@@ -34,7 +34,6 @@ void __init hv_vtl_init_platform(void)
 	/* Avoid searching for BIOS MP tables */
 	x86_init.mpparse.find_mptable = x86_init_noop;
 	x86_init.mpparse.early_parse_smp_cfg = x86_init_noop;
-	x86_init.mpparse.parse_smp_cfg = x86_dtb_parse_smp_config;
 
 	x86_platform.get_wallclock = get_rtc_noop;
 	x86_platform.set_wallclock = set_rtc_noop;

arch/x86/include/asm/prom.h

@@ -24,18 +24,15 @@ extern u64 initial_dtb;
 extern void add_dtb(u64 data);
 void x86_of_pci_init(void);
 void x86_dtb_parse_smp_config(void);
+void x86_flattree_get_config(void);
 #else
 static inline void add_dtb(u64 data) { }
 static inline void x86_of_pci_init(void) { }
 static inline void x86_dtb_parse_smp_config(void) { }
+static inline void x86_flattree_get_config(void) { }
 #define of_ioapic 0
 #endif
 
-#ifdef CONFIG_OF_EARLY_FLATTREE
-void x86_flattree_get_config(void);
-#else
-static inline void x86_flattree_get_config(void) { }
-#endif
 extern char cmd_line[COMMAND_LINE_SIZE];
 
 #endif /* __ASSEMBLY__ */

arch/x86/kernel/devicetree.c

@@ -277,9 +277,9 @@ static void __init dtb_apic_setup(void)
 	dtb_ioapic_setup();
 }
 
-#ifdef CONFIG_OF_EARLY_FLATTREE
 void __init x86_flattree_get_config(void)
 {
+#ifdef CONFIG_OF_EARLY_FLATTREE
 	u32 size, map_len;
 	void *dt;
 
@@ -301,8 +301,10 @@ void __init x86_flattree_get_config(void)
 
 	if (initial_dtb)
 		early_memunmap(dt, map_len);
-}
 #endif
+	if (of_have_populated_dt())
+		x86_init.mpparse.parse_smp_cfg = x86_dtb_parse_smp_config;
+}
 
 void __init x86_dtb_parse_smp_config(void)
 {

arch/x86/platform/ce4100/ce4100.c

@@ -139,7 +139,6 @@ void __init x86_ce4100_early_setup(void)
 	x86_init.resources.probe_roms		= x86_init_noop;
 	x86_init.mpparse.find_mptable		= x86_init_noop;
 	x86_init.mpparse.early_parse_smp_cfg	= x86_init_noop;
-	x86_init.mpparse.parse_smp_cfg		= x86_dtb_parse_smp_config;
 	x86_init.pci.init			= ce4100_pci_init;
 	x86_init.pci.init_irq			= sdv_pci_init;