x86/mce/AMD: Get address from already initialized block

The block address is saved after the block is initialized when
threshold_init_device() is called.

Use the saved block address, if available, rather than trying to
rediscover it.

This will avoid a call trace, when resuming from suspend, due to the
rdmsr_safe_on_cpu() call in get_block_address(). The rdmsr_safe_on_cpu()
call issues an IPI but we're running with interrupts disabled. This
triggers:

    WARNING: CPU: 0 PID: 11523 at kernel/smp.c:291 smp_call_function_single+0xdc/0xe0

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.14.x
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20180221101900.10326-8-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/cpu/mcheck/mce_amd.c

@@ -436,6 +436,21 @@ static u32 get_block_address(unsigned int cpu, u32 current_addr, u32 low, u32 hi
 {
 	u32 addr = 0, offset = 0;
 
+	if ((bank >= mca_cfg.banks) || (block >= NR_BLOCKS))
+		return addr;
+
+	/* Get address from already initialized block. */
+	if (per_cpu(threshold_banks, cpu)) {
+		struct threshold_bank *bankp = per_cpu(threshold_banks, cpu)[bank];
+
+		if (bankp && bankp->blocks) {
+			struct threshold_block *blockp = &bankp->blocks[block];
+
+			if (blockp)
+				return blockp->address;
+		}
+	}
+
 	if (mce_flags.smca) {
 		if (smca_get_bank_type(bank) == SMCA_RESERVED)
 			return addr;