MPX and Protection Keys Updates

diff -puN tools/testing/selftests/x86/mpx-hw.h~x86-selftests-mpx-weird-arrays tools/testing/selftests/x86/mpx-hw.h
@@ -52,14 +52,14 @@
 struct mpx_bd_entry {
 	union {
 		char x[MPX_BOUNDS_DIR_ENTRY_SIZE_BYTES];
-		void *contents[1];
+		void *contents[0];
 	};
 } __attribute__((packed));
 
 struct mpx_bt_entry {
 	union {
 		char x[MPX_BOUNDS_TABLE_ENTRY_SIZE_BYTES];
-		unsigned long contents[1];
+		unsigned long contents[0];
 	};
 } __attribute__((packed));
 

diff -puN tools/testing/selftests/x86/protection_keys.c~x86-selftests-protection-keys-si_pkeys tools/testing/selftests/x86/protection_keys.c
@@ -250,7 +250,7 @@ void signal_handler(int signum, siginfo_
 	unsigned long ip;
 	char *fpregs;
 	u32 *pkru_ptr;
-	u64 si_pkey;
+	u64 siginfo_pkey;
 	u32 *si_pkey_ptr;
 	int pkru_offset;
 	fpregset_t fpregset;

@@ -292,9 +292,9 @@ void signal_handler(int signum, siginfo_
 	si_pkey_ptr = (u32 *)(((u8 *)si) + si_pkey_offset);
 	dprintf1("si_pkey_ptr: %p\n", si_pkey_ptr);
 	dump_mem(si_pkey_ptr - 8, 24);
-	si_pkey = *si_pkey_ptr;
-	pkey_assert(si_pkey < NR_PKEYS);
-	last_si_pkey = si_pkey;
+	siginfo_pkey = *si_pkey_ptr;
+	pkey_assert(siginfo_pkey < NR_PKEYS);
+	last_si_pkey = siginfo_pkey;
 
 	if ((si->si_code == SEGV_MAPERR) ||
 	    (si->si_code == SEGV_ACCERR) ||

@@ -306,7 +306,7 @@ void signal_handler(int signum, siginfo_
 	dprintf1("signal pkru from xsave: %08x\n", *pkru_ptr);
 	/* need __rdpkru() version so we do not do shadow_pkru checking */
 	dprintf1("signal pkru from  pkru: %08x\n", __rdpkru());
-	dprintf1("si_pkey from siginfo: %jx\n", si_pkey);
+	dprintf1("pkey from siginfo: %jx\n", siginfo_pkey);
 	*(u64 *)pkru_ptr = 0x00000000;
 	dprintf1("WARNING: set PRKU=0 to allow faulting instruction to continue\n");
 	pkru_faults++;

diff -puN tools/testing/selftests/x86/pkey-helpers.h~x86-selftests-protection-keys-write-warning tools/testing/selftests/x86/pkey-helpers.h
@@ -30,6 +30,7 @@ static inline void sigsafe_printf(const
 	if (!dprint_in_signal) {
 		vprintf(format, ap);
 	} else {
+		int ret;
 		int len = vsnprintf(dprint_in_signal_buffer,
 				    DPRINT_IN_SIGNAL_BUF_SIZE,
 				    format, ap);

@@ -39,7 +40,9 @@ static inline void sigsafe_printf(const
 		 */
 		if (len > DPRINT_IN_SIGNAL_BUF_SIZE)
 			len = DPRINT_IN_SIGNAL_BUF_SIZE;
-		write(1, dprint_in_signal_buffer, len);
+		ret = write(1, dprint_in_signal_buffer, len);
+		if (ret < 0)
+			abort();
 	}
 	va_end(ap);
 }