[PATCH 6.12.y 1/3] s390/cpufeature: Convert MACHINE_HAS_SEQ_INSN to cpu_has_seq_insn()

[Sasha Levin <sashal@kernel.org>]

From: Heiko Carstens <hca@linux.ibm.com>

[ Upstream commit 679b110bb662fc107f38ebd5088af56a156dd82f ]

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>
Stable-dep-of: 31475b88110c ("s390/mm: Fix __ptep_rdp() inline assembly")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/include/asm/cpufeature.h |  4 ++++
 arch/s390/include/asm/setup.h      |  2 --
 arch/s390/kernel/early.c           |  2 --
 arch/s390/kernel/ftrace.c          | 11 ++++++-----
 arch/s390/kernel/kprobes.c         |  5 +++--
 5 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/arch/s390/include/asm/cpufeature.h b/arch/s390/include/asm/cpufeature.h
index 9312046137531..496d0758b902f 100644
--- a/arch/s390/include/asm/cpufeature.h
+++ b/arch/s390/include/asm/cpufeature.h
@@ -9,6 +9,8 @@
 #ifndef __ASM_S390_CPUFEATURE_H
 #define __ASM_S390_CPUFEATURE_H
 
+#include <asm/facility.h>
+
 enum {
 	S390_CPU_FEATURE_MSA,
 	S390_CPU_FEATURE_VXRS,
@@ -20,4 +22,6 @@ enum {
 
 int cpu_have_feature(unsigned int nr);
 
+#define cpu_has_seq_insn()	test_facility(85)
+
 #endif /* __ASM_S390_CPUFEATURE_H */
diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index 70b920b32827e..50b943f301553 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -34,7 +34,6 @@
 #define MACHINE_FLAG_SCC	BIT(17)
 #define MACHINE_FLAG_PCI_MIO	BIT(18)
 #define MACHINE_FLAG_RDP	BIT(19)
-#define MACHINE_FLAG_SEQ_INSN	BIT(20)
 
 #define LPP_MAGIC		BIT(31)
 #define LPP_PID_MASK		_AC(0xffffffff, UL)
@@ -96,7 +95,6 @@ extern unsigned long mio_wb_bit_mask;
 #define MACHINE_HAS_SCC		(get_lowcore()->machine_flags & MACHINE_FLAG_SCC)
 #define MACHINE_HAS_PCI_MIO	(get_lowcore()->machine_flags & MACHINE_FLAG_PCI_MIO)
 #define MACHINE_HAS_RDP		(get_lowcore()->machine_flags & MACHINE_FLAG_RDP)
-#define MACHINE_HAS_SEQ_INSN	(get_lowcore()->machine_flags & MACHINE_FLAG_SEQ_INSN)
 
 /*
  * Console mode. Override with conmode=
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 0c054e2d1e03e..4d0112adbcaa6 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -269,8 +269,6 @@ static __init void detect_machine_facilities(void)
 	}
 	if (test_facility(194))
 		get_lowcore()->machine_flags |= MACHINE_FLAG_RDP;
-	if (test_facility(85))
-		get_lowcore()->machine_flags |= MACHINE_FLAG_SEQ_INSN;
 }
 
 static inline void save_vector_registers(void)
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 0b6e62d1d8b87..29dae4c4009bd 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -13,6 +13,7 @@
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/kmsan-checks.h>
+#include <linux/cpufeature.h>
 #include <linux/kprobes.h>
 #include <linux/execmem.h>
 #include <trace/syscall.h>
@@ -69,7 +70,7 @@ static const char *ftrace_shared_hotpatch_trampoline(const char **end)
 
 bool ftrace_need_init_nop(void)
 {
-	return !MACHINE_HAS_SEQ_INSN;
+	return !cpu_has_seq_insn();
 }
 
 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
@@ -189,7 +190,7 @@ static int ftrace_modify_trampoline_call(struct dyn_ftrace *rec,
 int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 		       unsigned long addr)
 {
-	if (MACHINE_HAS_SEQ_INSN)
+	if (cpu_has_seq_insn())
 		return ftrace_patch_branch_insn(rec->ip, old_addr, addr);
 	else
 		return ftrace_modify_trampoline_call(rec, old_addr, addr);
@@ -213,8 +214,8 @@ static int ftrace_patch_branch_mask(void *addr, u16 expected, bool enable)
 int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
 		    unsigned long addr)
 {
-	/* Expect brcl 0xf,... for the !MACHINE_HAS_SEQ_INSN case */
-	if (MACHINE_HAS_SEQ_INSN)
+	/* Expect brcl 0xf,... for the !cpu_has_seq_insn() case */
+	if (cpu_has_seq_insn())
 		return ftrace_patch_branch_insn(rec->ip, addr, 0);
 	else
 		return ftrace_patch_branch_mask((void *)rec->ip, 0xc0f4, false);
@@ -234,7 +235,7 @@ static int ftrace_make_trampoline_call(struct dyn_ftrace *rec, unsigned long add
 
 int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
-	if (MACHINE_HAS_SEQ_INSN)
+	if (cpu_has_seq_insn())
 		return ftrace_patch_branch_insn(rec->ip, 0, addr);
 	else
 		return ftrace_make_trampoline_call(rec, addr);
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 8b80ea57125f3..c450120b44749 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -13,6 +13,7 @@
 #include <linux/ptrace.h>
 #include <linux/preempt.h>
 #include <linux/stop_machine.h>
+#include <linux/cpufeature.h>
 #include <linux/kdebug.h>
 #include <linux/uaccess.h>
 #include <linux/extable.h>
@@ -153,7 +154,7 @@ void arch_arm_kprobe(struct kprobe *p)
 {
 	struct swap_insn_args args = {.p = p, .arm_kprobe = 1};
 
-	if (MACHINE_HAS_SEQ_INSN) {
+	if (cpu_has_seq_insn()) {
 		swap_instruction(&args);
 		text_poke_sync();
 	} else {
@@ -166,7 +167,7 @@ void arch_disarm_kprobe(struct kprobe *p)
 {
 	struct swap_insn_args args = {.p = p, .arm_kprobe = 0};
 
-	if (MACHINE_HAS_SEQ_INSN) {
+	if (cpu_has_seq_insn()) {
 		swap_instruction(&args);
 		text_poke_sync();
 	} else {
-- 
2.51.0