From: Ben Hutchings <ben@decadent.org.uk>
Date: Sat, 22 Jul 2017 17:37:33 +0100
Subject: perf tools: Fix unwind build on i386
Forwarded: no

EINVAL may not be defined when building unwind-libunwind.c with
REMOTE_UNWIND_LIBUNWIND, resulting in a compiler error in
LIBUNWIND__ARCH_REG_ID().  Its only caller, access_reg(), only checks
for a negative return value and doesn't care what it is.  So change
-EINVAL to -1.

Fixes: 52ffe0ff02fc ("Support x86(32-bit) cross platform callchain unwind.")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

--- a/tools/perf/arch/x86/util/unwind-libunwind.c
+++ b/tools/perf/arch/x86/util/unwind-libunwind.c
@@ -67,7 +67,7 @@ int LIBUNWIND__ARCH_REG_ID(int regnum)
 		break;
 	default:
 		pr_err("unwind: invalid reg id %d\n", regnum);
-		return -EINVAL;
+		return -1;
 	}
 
 	return id;
@@ -107,7 +107,7 @@ int LIBUNWIND__ARCH_REG_ID(int regnum)
 		break;
 	default:
 		pr_err("unwind: invalid reg id %d\n", regnum);
-		return -EINVAL;
+		return -1;
 	}
 
 	return id;