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author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2020-12-09 05:29:25 +0000 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-09 23:48:14 +1100 |
commit | 5f1888a077069988218805534f56b983b6d5710c (patch) | |
tree | 71256d5dd482c324023c1df2f469a358389dc12e | |
parent | cbd7e6ca0210db05c315a27bb5db5a482f2772ce (diff) | |
download | linux-stable-5f1888a077069988218805534f56b983b6d5710c.tar.gz linux-stable-5f1888a077069988218805534f56b983b6d5710c.tar.bz2 linux-stable-5f1888a077069988218805534f56b983b6d5710c.zip |
powerpc/fault: Perform exception fixup in do_page_fault()
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>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bd07d6fef9237614cd6d318d8f19faeeadaa816b.1607491748.git.christophe.leroy@csgroup.eu
-rw-r--r-- | arch/powerpc/include/asm/bug.h | 1 | ||||
-rw-r--r-- | arch/powerpc/kernel/entry_32.S | 2 | ||||
-rw-r--r-- | arch/powerpc/kernel/exceptions-64e.S | 2 | ||||
-rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 2 | ||||
-rw-r--r-- | arch/powerpc/mm/fault.c | 33 |
5 files changed, 28 insertions, 12 deletions
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index ba0500872cce..464f8ca8a5c9 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -113,6 +113,7 @@ struct pt_regs; extern int do_page_fault(struct pt_regs *, unsigned long, unsigned long); extern void bad_page_fault(struct pt_regs *, unsigned long, int); +void __bad_page_fault(struct pt_regs *regs, unsigned long address, int sig); extern void _exception(int, struct pt_regs *, int, unsigned long); extern void _exception_pkey(struct pt_regs *, unsigned long, int); extern void die(const char *, struct pt_regs *, long); diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 58177c71dfd4..1c9b0ccc2172 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -684,7 +684,7 @@ 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 f579ce46eef2..74d07dc0bb48 100644 --- a/arch/powerpc/kernel/exceptions-64e.S +++ b/arch/powerpc/kernel/exceptions-64e.S @@ -1023,7 +1023,7 @@ 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 1c8f1b90e174..e02ad6fefa46 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -3259,7 +3259,7 @@ 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 389a2a875262..8961b44f350c 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -545,10 +545,20 @@ 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); @@ -557,17 +567,10 @@ 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)) { @@ -601,3 +604,15 @@ 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); +} |