ibft, x86: Change reserve_ibft_region() to find_ibft_region()

This allows arch code could decide the way to reserve the ibft.

And we should reserve ibft as early as possible, instead of BOOTMEM
stage, in case the table is in RAM range and is not reserved by BIOS
(this will often be the case.)

Move to just after find_smp_config().

Also when CONFIG_NO_BOOTMEM=y, We will not have reserve_bootmem() anymore.

-v2: fix typo about ibft pointed by Konrad Rzeszutek Wilk <konrad@darnok.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4BB510FB.80601@kernel.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Jones <pjones@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
CC: Jan Beulich <jbeulich@novell.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/setup.c

@@ -608,6 +608,16 @@ static int __init setup_elfcorehdr(char *arg)
 early_param("elfcorehdr", setup_elfcorehdr);
 #endif
 
+static __init void reserve_ibft_region(void)
+{
+	unsigned long addr, size = 0;
+
+	addr = find_ibft_region(&size);
+
+	if (size)
+		reserve_early_overlap_ok(addr, addr + size, "ibft");
+}
+
 #ifdef CONFIG_X86_RESERVE_LOW_64K
 static int __init dmi_low_memory_corruption(const struct dmi_system_id *d)
 {
@@ -910,6 +920,8 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	find_smp_config();
 
+	reserve_ibft_region();
+
 	reserve_trampoline_memory();
 
 #ifdef CONFIG_ACPI_SLEEP
@@ -977,8 +989,6 @@ void __init setup_arch(char **cmdline_p)
 
 	dma32_reserve_bootmem();
 
-	reserve_ibft_region();
-
 #ifdef CONFIG_KVM_CLOCK
 	kvmclock_init();
 #endif

drivers/firmware/iscsi_ibft_find.c

@@ -52,7 +52,7 @@ EXPORT_SYMBOL_GPL(ibft_addr);
  * Routine used to find the iSCSI Boot Format Table. The logical
  * kernel address is set in the ibft_addr global variable.
  */
-void __init reserve_ibft_region(void)
+unsigned long __init find_ibft_region(unsigned long *sizep)
 {
 	unsigned long pos;
 	unsigned int len = 0;
@@ -78,6 +78,11 @@ void __init reserve_ibft_region(void)
 			}
 		}
 	}
-	if (ibft_addr)
-		reserve_bootmem(pos, PAGE_ALIGN(len), BOOTMEM_DEFAULT);
+	if (ibft_addr) {
+		*sizep = PAGE_ALIGN(len);
+		return pos;
+	}
+
+	*sizep = 0;
+	return 0;
 }

include/linux/iscsi_ibft.h

@@ -42,9 +42,13 @@ extern struct ibft_table_header *ibft_addr;
  * mapped address is set in the ibft_addr variable.
  */
 #ifdef CONFIG_ISCSI_IBFT_FIND
-extern void __init reserve_ibft_region(void);
+unsigned long find_ibft_region(unsigned long *sizep);
 #else
-static inline void reserve_ibft_region(void) { }
+static inline unsigned long find_ibft_region(unsigned long *sizep)
+{
+	*sizep = 0;
+	return 0;
+}
 #endif
 
 #endif /* ISCSI_IBFT_H */