powerpc/64: Call setup_barrier_nospec() from setup_arch()

BugLink: https://bugs.launchpad.net/bugs/1830176

commit af375eef upstream.

Currently we require platform code to call setup_barrier_nospec(). But
if we add an empty definition for the !CONFIG_PPC_BARRIER_NOSPEC case
then we can call it in setup_arch().
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

arch/powerpc/include/asm/setup.h

@@ -37,7 +37,11 @@ enum l1d_flush_type {
 
 void setup_rfi_flush(enum l1d_flush_type, bool enable);
 void do_rfi_flush_fixups(enum l1d_flush_type types);
+#ifdef CONFIG_PPC_BARRIER_NOSPEC
 void setup_barrier_nospec(void);
+#else
+static inline void setup_barrier_nospec(void) { };
+#endif
 void do_barrier_nospec_fixups(bool enable);
 extern bool barrier_nospec_enabled;
 

arch/powerpc/kernel/setup_32.c

@@ -319,6 +319,8 @@ void __init setup_arch(char **cmdline_p)
 		ppc_md.setup_arch();
 	if ( ppc_md.progress ) ppc_md.progress("arch: exit", 0x3eab);
 
+	setup_barrier_nospec();
+
 	paging_init();
 
 	/* Initialize the MMU context management stuff */

arch/powerpc/kernel/setup_64.c

@@ -734,6 +734,8 @@ void __init setup_arch(char **cmdline_p)
 	if (ppc_md.setup_arch)
 		ppc_md.setup_arch();
 
+	setup_barrier_nospec();
+
 	paging_init();
 
 	/* Initialize the MMU context management stuff */

arch/powerpc/platforms/powernv/setup.c

@@ -123,7 +123,6 @@ static void pnv_setup_rfi_flush(void)
 		  security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV));
 
 	setup_rfi_flush(type, enable);
-	setup_barrier_nospec();
 }
 
 static void __init pnv_setup_arch(void)

arch/powerpc/platforms/pseries/setup.c

@@ -574,7 +574,6 @@ void pseries_setup_rfi_flush(void)
 		 security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR);
 
 	setup_rfi_flush(types, enable);
-	setup_barrier_nospec();
 }
 
 static void __init pSeries_setup_arch(void)