x86/platform/uv: Add return code to UV BIOS Init function

Add a return code to the UV BIOS init function that indicates the
successful initialization of the kernel/BIOS callback interface.
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hedi Berriche <hedi.berriche@hpe.com>
Cc: Justin Ernst <justin.ernst@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190910145839.895739629@stormcage.eag.rdlabs.hpecorp.netSigned-off-by: Ingo Molnar <mingo@kernel.org>

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

@@ -138,7 +138,7 @@ extern s64 uv_bios_change_memprotect(u64, u64, enum uv_memprotect);
 extern s64 uv_bios_reserved_page_pa(u64, u64 *, u64 *, u64 *);
 extern int uv_bios_set_legacy_vga_target(bool decode, int domain, int bus);
 
-extern void uv_bios_init(void);
+extern int uv_bios_init(void);
 
 extern unsigned long sn_rtc_cycles_per_second;
 extern int uv_type;

arch/x86/platform/uv/bios_uv.c

@@ -184,20 +184,20 @@ int uv_bios_set_legacy_vga_target(bool decode, int domain, int bus)
 }
 EXPORT_SYMBOL_GPL(uv_bios_set_legacy_vga_target);
 
-void uv_bios_init(void)
+int uv_bios_init(void)
 {
 	uv_systab = NULL;
 	if ((uv_systab_phys == EFI_INVALID_TABLE_ADDR) ||
 	    !uv_systab_phys || efi_runtime_disabled()) {
 		pr_crit("UV: UVsystab: missing\n");
-		return;
+		return -EEXIST;
 	}
 
 	uv_systab = ioremap(uv_systab_phys, sizeof(struct uv_systab));
 	if (!uv_systab || strncmp(uv_systab->signature, UV_SYSTAB_SIG, 4)) {
 		pr_err("UV: UVsystab: bad signature!\n");
 		iounmap(uv_systab);
-		return;
+		return -EINVAL;
 	}
 
 	/* Starting with UV4 the UV systab size is variable */
@@ -208,8 +208,9 @@ void uv_bios_init(void)
 		uv_systab = ioremap(uv_systab_phys, size);
 		if (!uv_systab) {
 			pr_err("UV: UVsystab: ioremap(%d) failed!\n", size);
-			return;
+			return -EFAULT;
 		}
 	}
 	pr_info("UV: UVsystab: Revision:%x\n", uv_systab->revision);
+	return 0;
 }