[PATCH 6.12.y 2/3] s390/cpufeature: Convert MACHINE_HAS_RDP to cpu_has_rdp()

[Sasha Levin <sashal@kernel.org>]

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

[ Upstream commit 15a36036e792f4eec0fc59833dde688024e036fc ]

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 | 1 +
 arch/s390/include/asm/pgtable.h    | 5 +++--
 arch/s390/include/asm/setup.h      | 2 --
 arch/s390/kernel/early.c           | 2 --
 4 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/s390/include/asm/cpufeature.h b/arch/s390/include/asm/cpufeature.h
index 496d0758b902f..641a2780fd5a6 100644
--- a/arch/s390/include/asm/cpufeature.h
+++ b/arch/s390/include/asm/cpufeature.h
@@ -22,6 +22,7 @@ enum {
 
 int cpu_have_feature(unsigned int nr);
 
+#define cpu_has_rdp()		test_facility(194)
 #define cpu_has_seq_insn()	test_facility(85)
 
 #endif /* __ASM_S390_CPUFEATURE_H */
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 5ee73f245a0c0..4714640f0c403 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -14,6 +14,7 @@
 
 #include <linux/sched.h>
 #include <linux/mm_types.h>
+#include <linux/cpufeature.h>
 #include <linux/page-flags.h>
 #include <linux/radix-tree.h>
 #include <linux/atomic.h>
@@ -1302,7 +1303,7 @@ static inline void flush_tlb_fix_spurious_fault(struct vm_area_struct *vma,
 	 * PTE does not have _PAGE_PROTECT set, to avoid unnecessary overhead.
 	 * A local RDP can be used to do the flush.
 	 */
-	if (MACHINE_HAS_RDP && !(pte_val(*ptep) & _PAGE_PROTECT))
+	if (cpu_has_rdp() && !(pte_val(*ptep) & _PAGE_PROTECT))
 		__ptep_rdp(address, ptep, 0, 0, 1);
 }
 #define flush_tlb_fix_spurious_fault flush_tlb_fix_spurious_fault
@@ -1317,7 +1318,7 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma,
 {
 	if (pte_same(*ptep, entry))
 		return 0;
-	if (MACHINE_HAS_RDP && !mm_has_pgste(vma->vm_mm) && pte_allow_rdp(*ptep, entry))
+	if (cpu_has_rdp() && !mm_has_pgste(vma->vm_mm) && pte_allow_rdp(*ptep, entry))
 		ptep_reset_dat_prot(vma->vm_mm, addr, ptep, entry);
 	else
 		ptep_xchg_direct(vma->vm_mm, addr, ptep, entry);
diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index 50b943f301553..07e7dab27dfac 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -33,7 +33,6 @@
 #define MACHINE_FLAG_GS		BIT(16)
 #define MACHINE_FLAG_SCC	BIT(17)
 #define MACHINE_FLAG_PCI_MIO	BIT(18)
-#define MACHINE_FLAG_RDP	BIT(19)
 
 #define LPP_MAGIC		BIT(31)
 #define LPP_PID_MASK		_AC(0xffffffff, UL)
@@ -94,7 +93,6 @@ extern unsigned long mio_wb_bit_mask;
 #define MACHINE_HAS_GS		(get_lowcore()->machine_flags & MACHINE_FLAG_GS)
 #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)
 
 /*
  * Console mode. Override with conmode=
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 4d0112adbcaa6..a6f248ea01007 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -267,8 +267,6 @@ static __init void detect_machine_facilities(void)
 		get_lowcore()->machine_flags |= MACHINE_FLAG_PCI_MIO;
 		/* the control bit is set during PCI initialization */
 	}
-	if (test_facility(194))
-		get_lowcore()->machine_flags |= MACHINE_FLAG_RDP;
 }
 
 static inline void save_vector_registers(void)
-- 
2.51.0