linux-kernel - [PATCH v2 28/43] powerpc/64e: Call bad_page_fault() from do_page

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Message-Id: <b2878184d4c21faa8af55b60e52c83f391272112.1615291473.git.christophe.leroy@csgroup.eu>
Date:   Tue,  9 Mar 2021 12:09:54 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, npiggin@...il.com
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 28/43] powerpc/64e: Call bad_page_fault() from
 do_page_fault()

book3e/64 is the last one calling __bad_page_fault()
from assembly.

Save non volatile registers before calling do_page_fault()
and modify do_page_fault() to call __bad_page_fault()
for all platforms.

Then it can be refactored by the call of bad_page_fault()
which avoids the duplication of the exception table search.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/kernel/exceptions-64e.S |  8 +-------
 arch/powerpc/mm/fault.c              | 17 ++++-------------
 2 files changed, 5 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index e8eb9992a270..b60f89078a3f 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -1010,15 +1010,9 @@ storage_fault_common:
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	ld	r14,PACA_EXGEN+EX_R14(r13)
 	ld	r15,PACA_EXGEN+EX_R15(r13)
+	bl	save_nvgprs
 	bl	do_page_fault
-	cmpdi	r3,0
-	bne-	1f
 	b	ret_from_except_lite
-1:	bl	save_nvgprs
-	mr	r4,r3
-	addi	r3,r1,STACK_FRAME_OVERHEAD
-	bl	__bad_page_fault
-	b	ret_from_except
 
 /*
  * Alignment exception doesn't fit entirely in the 0x100 bytes so it
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 2e54bac99a22..7bcff3fca110 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -541,24 +541,15 @@ NOKPROBE_SYMBOL(___do_page_fault);
 
 static long __do_page_fault(struct pt_regs *regs)
 {
-	const struct exception_table_entry *entry;
 	long err;
 
 	err = ___do_page_fault(regs, regs->dar, regs->dsisr);
 	if (likely(!err))
-		return err;
-
-	entry = search_exception_tables(regs->nip);
-	if (likely(entry)) {
-		instruction_pointer_set(regs, extable_fixup(entry));
 		return 0;
-	} else if (!IS_ENABLED(CONFIG_PPC_BOOK3E_64)) {
-		__bad_page_fault(regs, err);
-		return 0;
-	} else {
-		/* 32 and 64e handle the bad page fault in asm */
-		return err;
-	}
+
+	bad_page_fault(regs, err);
+
+	return 0;
 }
 NOKPROBE_SYMBOL(__do_page_fault);
 
-- 
2.25.0