s390/cpufeature: Convert MACHINE_HAS_NX to cpu_has_nx()

Convert MACHINE_HAS_... to cpu_has_...() which uses test_facility() instead
of testing the machine_flags lowcore member if the feature is present.

test_facility() generates better code since it results in a static branch
without accessing memory. The branch is patched via alternatives by the
decompressor depending on the availability of the required facility.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/boot/startup.c

@@ -59,7 +59,7 @@ static void detect_facilities(void)
 	page_noexec_mask = -1UL;
 	segment_noexec_mask = -1UL;
 	region_noexec_mask = -1UL;
-	if (!test_facility(130)) {
+	if (!cpu_has_nx()) {
 		page_noexec_mask &= ~_PAGE_NOEXEC;
 		segment_noexec_mask &= ~_SEGMENT_ENTRY_NOEXEC;
 		region_noexec_mask &= ~_REGION_ENTRY_NOEXEC;

arch/s390/include/asm/cpufeature.h

@@ -23,6 +23,7 @@ enum {
 int cpu_have_feature(unsigned int nr);
 
 #define cpu_has_gs()		test_facility(133)
+#define cpu_has_nx()		test_facility(130)
 #define cpu_has_rdp()		test_facility(194)
 #define cpu_has_seq_insn()	test_facility(85)
 

arch/s390/include/asm/setup.h

@@ -29,7 +29,6 @@
 #define MACHINE_FLAG_TE		BIT(11)
 #define MACHINE_FLAG_TLB_LC	BIT(12)
 #define MACHINE_FLAG_TLB_GUEST	BIT(14)
-#define MACHINE_FLAG_NX		BIT(15)
 #define MACHINE_FLAG_SCC	BIT(17)
 #define MACHINE_FLAG_PCI_MIO	BIT(18)
 
@@ -88,7 +87,6 @@ extern unsigned long mio_wb_bit_mask;
 #define MACHINE_HAS_TE		(get_lowcore()->machine_flags & MACHINE_FLAG_TE)
 #define MACHINE_HAS_TLB_LC	(get_lowcore()->machine_flags & MACHINE_FLAG_TLB_LC)
 #define MACHINE_HAS_TLB_GUEST	(get_lowcore()->machine_flags & MACHINE_FLAG_TLB_GUEST)
-#define MACHINE_HAS_NX		(get_lowcore()->machine_flags & MACHINE_FLAG_NX)
 #define MACHINE_HAS_SCC		(get_lowcore()->machine_flags & MACHINE_FLAG_SCC)
 #define MACHINE_HAS_PCI_MIO	(get_lowcore()->machine_flags & MACHINE_FLAG_PCI_MIO)
 

arch/s390/kernel/early.c

@@ -253,8 +253,6 @@ static __init void detect_machine_facilities(void)
 		get_lowcore()->machine_flags |= MACHINE_FLAG_TLB_LC;
 	if (test_facility(129))
 		system_ctl_set_bit(0, CR0_VECTOR_BIT);
-	if (test_facility(130))
-		get_lowcore()->machine_flags |= MACHINE_FLAG_NX;
 	if (test_facility(139) && (tod_clock_base.tod >> 63)) {
 		/* Enabled signed clock comparator comparisons */
 		get_lowcore()->machine_flags |= MACHINE_FLAG_SCC;

arch/s390/mm/dump_pagetables.c

@@ -1,4 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
+
+#include <linux/cpufeature.h>
 #include <linux/set_memory.h>
 #include <linux/ptdump.h>
 #include <linux/seq_file.h>
@@ -167,7 +169,7 @@ bool ptdump_check_wx(void)
 		},
 	};
 
-	if (!MACHINE_HAS_NX)
+	if (!cpu_has_nx())
 		return true;
 	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
 	if (st.wx_pages) {

arch/s390/mm/fault.c

@@ -11,6 +11,7 @@
 
 #include <linux/kernel_stat.h>
 #include <linux/mmu_context.h>
+#include <linux/cpufeature.h>
 #include <linux/perf_event.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
@@ -366,7 +367,7 @@ void do_protection_exception(struct pt_regs *regs)
 		 */
 		return handle_fault_error_nolock(regs, 0);
 	}
-	if (unlikely(MACHINE_HAS_NX && teid.b56)) {
+	if (unlikely(cpu_has_nx() && teid.b56)) {
 		regs->int_parm_long = (teid.addr * PAGE_SIZE) | (regs->psw.addr & PAGE_MASK);
 		return handle_fault_error_nolock(regs, SEGV_ACCERR);
 	}

arch/s390/mm/init.c

@@ -8,6 +8,7 @@
  *    Copyright (C) 1995  Linus Torvalds
  */
 
+#include <linux/cpufeature.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
@@ -117,7 +118,7 @@ void mark_rodata_ro(void)
 {
 	unsigned long size = __end_ro_after_init - __start_ro_after_init;
 
-	if (MACHINE_HAS_NX)
+	if (cpu_has_nx())
 		system_ctl_set_bit(0, CR0_INSTRUCTION_EXEC_PROTECTION_BIT);
 	__set_memory_ro(__start_ro_after_init, __end_ro_after_init);
 	pr_info("Write protected read-only-after-init data: %luk\n", size >> 10);

arch/s390/mm/pageattr.c

@@ -3,6 +3,7 @@
  * Copyright IBM Corp. 2011
  * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
  */
+#include <linux/cpufeature.h>
 #include <linux/hugetlb.h>
 #include <linux/proc_fs.h>
 #include <linux/vmalloc.h>
@@ -373,7 +374,7 @@ int __set_memory(unsigned long addr, unsigned long numpages, unsigned long flags
 	unsigned long end;
 	int rc;
 
-	if (!MACHINE_HAS_NX)
+	if (!cpu_has_nx())
 		flags &= ~(SET_MEMORY_NX | SET_MEMORY_X);
 	if (!flags)
 		return 0;