From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
npiggin@gmail.com
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v1 5/5] powerpc/fault: Perform exception fixup in do_page_fault()
Date: Thu, 6 Aug 2020 17:15:32 +0000 (UTC) [thread overview]
Message-ID: <5748c8f5cf0a9b3686169e2c7709107e6aaec408.1596734105.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <7baae4086cbb9ffb08c933b065ff7d29dbc03dd6.1596734104.git.christophe.leroy@csgroup.eu>
Exception fixup doesn't require the heady full regs saving,
do it from do_page_fault() directly.
For that, split bad_page_fault() in two parts.
As bad_page_fault() can also be called from other places than
handle_page_fault(), it will still perform exception fixup and
fallback on __bad_page_fault().
handle_page_fault() directly calls __bad_page_fault() as the
exception fixup will now be done by do_page_fault()
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/kernel/entry_32.S | 2 +-
arch/powerpc/kernel/exceptions-64e.S | 2 +-
arch/powerpc/kernel/exceptions-64s.S | 2 +-
arch/powerpc/mm/fault.c | 33 ++++++++++++++++++++--------
4 files changed, 27 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index f4d0af8e1136..c198786591f9 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -678,7 +678,7 @@ handle_page_fault:
mr r5,r3
addi r3,r1,STACK_FRAME_OVERHEAD
lwz r4,_DAR(r1)
- bl bad_page_fault
+ bl __bad_page_fault
b ret_from_except_full
#ifdef CONFIG_PPC_BOOK3S_32
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index d9ed79415100..dd9161ea5da8 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -1024,7 +1024,7 @@ storage_fault_common:
mr r5,r3
addi r3,r1,STACK_FRAME_OVERHEAD
ld r4,_DAR(r1)
- bl bad_page_fault
+ bl __bad_page_fault
b ret_from_except
/*
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index f7d748b88705..2cb3bcfb896d 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -3254,7 +3254,7 @@ handle_page_fault:
mr r5,r3
addi r3,r1,STACK_FRAME_OVERHEAD
ld r4,_DAR(r1)
- bl bad_page_fault
+ bl __bad_page_fault
b interrupt_return
/* We have a data breakpoint exception - handle it */
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index edde169ba3a6..bd6e397eb84a 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -542,10 +542,20 @@ NOKPROBE_SYMBOL(__do_page_fault);
int do_page_fault(struct pt_regs *regs, unsigned long address,
unsigned long error_code)
{
+ const struct exception_table_entry *entry;
enum ctx_state prev_state = exception_enter();
int rc = __do_page_fault(regs, address, error_code);
exception_exit(prev_state);
- return rc;
+ if (likely(!rc))
+ return 0;
+
+ entry = search_exception_tables(regs->nip);
+ if (unlikely(!entry))
+ return rc;
+
+ instruction_pointer_set(regs, extable_fixup(entry));
+
+ return 0;
}
NOKPROBE_SYMBOL(do_page_fault);
@@ -554,17 +564,10 @@ NOKPROBE_SYMBOL(do_page_fault);
* It is called from the DSI and ISI handlers in head.S and from some
* of the procedures in traps.c.
*/
-void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
+void __bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
{
- const struct exception_table_entry *entry;
int is_write = page_fault_is_write(regs->dsisr);
- /* Are we prepared to handle this fault? */
- if ((entry = search_exception_tables(regs->nip)) != NULL) {
- regs->nip = extable_fixup(entry);
- return;
- }
-
/* kernel has accessed a bad area */
switch (TRAP(regs)) {
@@ -598,3 +601,15 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
die("Kernel access of bad area", regs, sig);
}
+
+void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
+{
+ const struct exception_table_entry *entry;
+
+ /* Are we prepared to handle this fault? */
+ entry = search_exception_tables(instruction_pointer(regs));
+ if (entry)
+ instruction_pointer_set(regs, extable_fixup(entry));
+ else
+ __bad_page_fault(regs, address, sig);
+}
--
2.25.0
next prev parent reply other threads:[~2020-08-06 17:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-06 17:15 [PATCH v1 1/5] powerpc/mm: sanity_check_fault() should work for all, not only BOOK3S Christophe Leroy
2020-08-06 17:15 ` [PATCH v1 2/5] powerpc/fault: Unnest definition of page_fault_is_write() and page_fault_is_bad() Christophe Leroy
2020-09-08 8:44 ` Nicholas Piggin
2020-08-06 17:15 ` [PATCH v1 3/5] powerpc/fault: Reorder tests in bad_kernel_fault() Christophe Leroy
2020-09-08 8:46 ` Nicholas Piggin
2020-08-06 17:15 ` [PATCH v1 4/5] powerpc/fault: Avoid heavy search_exception_tables() verification Christophe Leroy
2020-09-08 8:54 ` Nicholas Piggin
2020-09-09 6:04 ` Aneesh Kumar K.V
2020-09-09 6:20 ` Christophe Leroy
2020-09-14 2:23 ` Nicholas Piggin
2020-08-06 17:15 ` Christophe Leroy [this message]
2020-08-06 21:07 ` [PATCH v1 5/5] powerpc/fault: Perform exception fixup in do_page_fault() kernel test robot
2020-09-08 9:13 ` Nicholas Piggin
2020-09-08 8:43 ` [PATCH v1 1/5] powerpc/mm: sanity_check_fault() should work for all, not only BOOK3S Nicholas Piggin
2020-09-08 8:56 ` Christophe Leroy
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