| Message ID | 1500021087.2865.86.camel@kernel.crashing.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
Benjamin Herrenschmidt <benh@kernel.crashing.org> writes: > 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() > Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> > Signed-off-by: Benjamin Herrenschmidt <benh@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;
On Fri, 2017-07-14 at 18:31 +1000, Benjamin Herrenschmidt wrote: > 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 <benh@kernel.crashing.org> > -- > Looks reasonable Acked-by: Balbir Singh <bsingharora@gmail.com>
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;
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 <benh@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(-)