linux-kernel - [PATCH v4 09/11] s390/mm: Simplify get_fault

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Message-ID: <20241022120601.167009-10-imbrenda@linux.ibm.com>
Date: Tue, 22 Oct 2024 14:05:59 +0200
From: Claudio Imbrenda <imbrenda@...ux.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: borntraeger@...ibm.com, nsg@...ux.ibm.com, nrb@...ux.ibm.com,
        frankja@...ux.ibm.com, seiden@...ux.ibm.com, hca@...ux.ibm.com,
        agordeev@...ux.ibm.com, gor@...ux.ibm.com,
        gerald.schaefer@...ux.ibm.com, kvm@...r.kernel.org,
        linux-s390@...r.kernel.org, david@...hat.com
Subject: [PATCH v4 09/11] s390/mm: Simplify get_fault_type()

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

With the gmap code gone get_fault_type() can be simplified:

- every fault with user_mode(regs) == true must be a fault in user address
  space

- every fault with user_mode(regs) == false is only a fault in user
  address space if the used address space is the secondary address space

- every other fault is within the kernel address space

Signed-off-by: Heiko Carstens <hca@...ux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@...ux.ibm.com>
---
 arch/s390/mm/fault.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index e48910b0b816..6e96fc7905fc 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -68,17 +68,10 @@ static enum fault_type get_fault_type(struct pt_regs *regs)
 {
 	union teid teid = { .val = regs->int_parm_long };
 
-	if (likely(teid.as == PSW_BITS_AS_PRIMARY)) {
-		if (user_mode(regs))
-			return USER_FAULT;
-		return KERNEL_FAULT;
-	}
-	if (teid.as == PSW_BITS_AS_SECONDARY)
+	if (user_mode(regs))
 		return USER_FAULT;
-	/* Access register mode, not used in the kernel */
-	if (teid.as == PSW_BITS_AS_ACCREG)
+	if (teid.as == PSW_BITS_AS_SECONDARY)
 		return USER_FAULT;
-	/* Home space -> access via kernel ASCE */
 	return KERNEL_FAULT;
 }
 
-- 
2.47.0