[kvm-unit-tests PATCH 01/16] lib: Add and use static_assert() convenience wrappers

[Sean Christopherson <seanjc@xxxxxxxxxx>]

Add static_assert() to wrap _Static_assert() with stringification of the
tested expression as the assert message.  In most cases, the failed
expression is far more helpful than a human-generated message (usually
because the developer is forced to add _something_ for the message).

For API consistency, provide a double-underscore variant for specifying a
custom message.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 lib/riscv/asm/isa.h      | 4 +++-
 lib/s390x/asm/arch_def.h | 6 ++++--
 lib/s390x/fault.c        | 3 ++-
 lib/util.h               | 3 +++
 x86/lam.c                | 4 ++--
 5 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/lib/riscv/asm/isa.h b/lib/riscv/asm/isa.h
index df874173..fb3af67d 100644
--- a/lib/riscv/asm/isa.h
+++ b/lib/riscv/asm/isa.h
@@ -1,7 +1,9 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 #ifndef _ASMRISCV_ISA_H_
 #define _ASMRISCV_ISA_H_
+
 #include <bitops.h>
+#include <util.h>
 #include <asm/setup.h>
 
 /*
@@ -14,7 +16,7 @@ enum {
 	ISA_SSTC,
 	ISA_MAX,
 };
-_Static_assert(ISA_MAX <= __riscv_xlen, "Need to increase thread_info.isa");
+__static_assert(ISA_MAX <= __riscv_xlen, "Need to increase thread_info.isa");
 
 static inline bool cpu_has_extension(int cpu, int ext)
 {
diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 03adcd3c..4c11df74 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -8,6 +8,8 @@
 #ifndef _ASMS390X_ARCH_DEF_H_
 #define _ASMS390X_ARCH_DEF_H_
 
+#include <util.h>
+
 struct stack_frame {
 	struct stack_frame *back_chain;
 	uint64_t reserved;
@@ -62,7 +64,7 @@ struct psw {
 	};
 	uint64_t	addr;
 };
-_Static_assert(sizeof(struct psw) == 16, "PSW size");
+static_assert(sizeof(struct psw) == 16);
 
 #define PSW(m, a) ((struct psw){ .mask = (m), .addr = (uint64_t)(a) })
 
@@ -194,7 +196,7 @@ struct lowcore {
 	uint8_t		pad_0x1400[0x1800 - 0x1400];	/* 0x1400 */
 	uint8_t		pgm_int_tdb[0x1900 - 0x1800];	/* 0x1800 */
 } __attribute__ ((__packed__));
-_Static_assert(sizeof(struct lowcore) == 0x1900, "Lowcore size");
+static_assert(sizeof(struct lowcore) == 0x1900);
 
 extern struct lowcore lowcore;
 
diff --git a/lib/s390x/fault.c b/lib/s390x/fault.c
index a882d5d9..ad5a5f66 100644
--- a/lib/s390x/fault.c
+++ b/lib/s390x/fault.c
@@ -9,6 +9,7 @@
  */
 #include <libcflat.h>
 #include <bitops.h>
+#include <util.h>
 #include <asm/arch_def.h>
 #include <asm/page.h>
 #include <fault.h>
@@ -40,7 +41,7 @@ static void print_decode_pgm_prot(union teid teid)
 			"LAP",
 			"IEP",
 		};
-		_Static_assert(ARRAY_SIZE(prot_str) == PROT_NUM_CODES, "ESOP2 prot codes");
+		static_assert(ARRAY_SIZE(prot_str) == PROT_NUM_CODES);
 		int prot_code = teid_esop2_prot_code(teid);
 
 		printf("Type: %s\n", prot_str[prot_code]);
diff --git a/lib/util.h b/lib/util.h
index f86af6d3..00d0b47d 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -8,6 +8,9 @@
  * This work is licensed under the terms of the GNU LGPL, version 2.
  */
 
+#define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
+#define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
+
 /*
  * parse_keyval extracts the integer from a string formatted as
  * string=integer. This is useful for passing expected values to
diff --git a/x86/lam.c b/x86/lam.c
index a1c98949..ad91deaf 100644
--- a/x86/lam.c
+++ b/x86/lam.c
@@ -13,6 +13,7 @@
 #include "libcflat.h"
 #include "processor.h"
 #include "desc.h"
+#include <util.h>
 #include "vmalloc.h"
 #include "alloc_page.h"
 #include "vm.h"
@@ -236,8 +237,7 @@ static void test_lam_user(void)
 	 * address for both LAM48 and LAM57.
 	 */
 	vaddr = alloc_pages_flags(0, AREA_NORMAL);
-	_Static_assert((AREA_NORMAL_PFN & GENMASK(63, 47)) == 0UL,
-			"Identical mapping range check");
+	static_assert((AREA_NORMAL_PFN & GENMASK(63, 47)) == 0UL);
 
 	/*
 	 * Note, LAM doesn't have a global control bit to turn on/off LAM
-- 
2.49.0.1204.g71687c7c1d-goog