There are a number of conditions in the DSISR that represent
conditions for which there is no point looking for a VMA or
trying to update a PTE. In fact, POWER9 adds a few with bad
AMOs, bad "paste" instruction etc...
This improve our existing code to use symbolic constants for
all DSISR bits, properly avoid hash_page() for the new bits,
and handle both the old and new bits early in do_page_fault()
Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
--
This obsoletes
[PATCH] powerpc: Hande page faults for bad paste and bad AMO
Note: We should further update 32-bit etc... to do something
similar, or even consolidate the code.
According to architectures back to 1.07 and 32-bit 6xx PEM,
those low DSISR bits are 0 on all other implementations, and
we do mask out the SRR1 bits on instruction interrupts, so
I think such consolidation, at least for BookS should be trivial
but I will leave it as a separate patch.
---
arch/powerpc/include/asm/reg.h | 18 ++++++++++++++++++
arch/powerpc/kernel/exceptions-64s.S | 6 ++++--
arch/powerpc/mm/fault.c | 21 +++++++++++++++++++++
3 files changed, 43 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 7e50e47..bf5f8ff 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -272,16 +272,34 @@
#define SPRN_DAR 0x013 /* Data Address Register */
#define SPRN_DBCR 0x136 /* e300 Data Breakpoint Control Reg */
#define SPRN_DSISR 0x012 /* Data Storage Interrupt Status Register */
+#define DSISR_BAD_DIRECT_ST 0x80000000 /* Direct store error
(obsolete) */
#define DSISR_NOHPTE 0x40000000 /* no translation found */
+#define DSISR_ATT_CONFLICT 0x20000000 /* Attribute conflicts (P9) */
#define DSISR_PROTFAULT 0x08000000 /* protection fault */
#define DSISR_BADACCESS 0x04000000 /* bad access to CI or G */
#define DSISR_ISSTORE 0x02000000 /* access was a store */
#define DSISR_DABRMATCH 0x00400000 /* hit data breakpoint */
#define DSISR_NOSEGMENT 0x00200000 /* SLB miss */
#define DSISR_KEYFAULT 0x00200000 /* Key fault */
+#define DSISR_BAD_EXT_CTRL 0x00100000 /* External control error
(obsolete) */
#define DSISR_UNSUPP_MMU 0x00080000 /* Unsupported MMU config */
#define DSISR_SET_RC 0x00040000 /* Failed setting of R/C bits */
#define DSISR_PGDIRFAULT 0x00020000 /* Fault on page directory */
+#define DSISR_BAD_COPYPASTE 0x00000008 /* Copy/Paste on wrong mem
type */
+#define DSISR_BAD_AMO 0x00000004 /* Incorrect AMO opcode
*/
+#define DSISR_BAD_CI_LDST 0x00000002 /* CI load/store with DR=1 or
in G=0 HV space */
+
+/* Don't bother going to hash_page for any of these */
+#define DSISR_DONT_HASH (DSISR_BAD_DIRECT_ST | \
+ DSISR_ATT_CONFLICT | \
+ DSISR_BADACCESS | \
+ DSISR_DABRMATCH | \
+ DSISR_BAD_EXT_CTRL | \
+ DSISR_UNSUPP_MMU | \
+ DSISR_BAD_COPYPASTE | \
+ DSISR_BAD_AMO | \
+ DSISR_BAD_CI_LDST)
+
#define SPRN_TBRL 0x10C /* Time Base Read Lower Register (user, R/O) */
#define SPRN_TBRU 0x10D /* Time Base Read Upper Register (user, R/O) */
#define SPRN_CIR 0x11B /* Chip Information Register (hyper, R/0) */
diff --git a/arch/powerpc/kernel/exceptions-64s.S
b/arch/powerpc/kernel/exceptions-64s.S
index 5204bd6..58ad8ae 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1413,8 +1413,10 @@ USE_TEXT_SECTION()
.balign IFETCH_ALIGN_BYTES
do_hash_page:
#ifdef CONFIG_PPC_STD_MMU_64
- andis. r0,r4,0xa450 /* weird error? */
- bne- handle_page_fault /* if not, try to insert a HPTE */
+ lis r0,DSISR_DONT_HASH@h
+ ori r0,r0,DSISR_DONT_HASH@l
+ and. r0,r0,r4
+ bne- handle_page_fault
CURRENT_THREAD_INFO(r11, r1)
lwz r0,TI_PREEMPT(r11) /* If we're in an "NMI" */
andis. r0,r0,NMI_MASK@h /* (i.e. an irq when soft-disabled) */
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 0266c66..e55cb5c 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -337,6 +337,27 @@ int do_page_fault(struct pt_regs *regs, unsigned long
address,
}
#endif /* CONFIG_PPC_ICSWX */
+#ifdef CONFIG_PPC_STD_MMU_64
+ /*
+ * These faults indicate various errors that can't be recovered
+ * by updating the PTE, there is no point handling them any later
+ * than here. I also noticed in some case the DAR isn't being set
+ * propertly (DSISR_BAD_COPYPASTE for example).
+ */
+ if (error_code & (DSISR_ATT_CONFLICT |
+ DSISR_BADACCESS |
+ DSISR_UNSUPP_MMU |
+ DSISR_BAD_COPYPASTE |
+ DSISR_BAD_AMO |
+ DSISR_BAD_CI_LDST)) {
+ if (user_mode(regs))
+ _exception(SIGBUS, regs, BUS_OBJERR, address);
+ else
+ rc = SIGBUS;
+ goto bail;
+ }
+#endif /* CONFIG_PPC_STD_MMU_64 */
+
if (notify_page_fault(regs))
goto bail;
