Handle Data and Instruction exceptions caused by memory protection-key.
The CPU will detect the key fault if the HPTE is already programmed with the key.
However if the HPTE is not hashed, a key fault will not be detected by the hardware. The software will detect pkey violation in such a case.
Signed-off-by: Ram Pai linuxram@us.ibm.com Signed-off-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com --- arch/powerpc/include/asm/reg.h | 1 - arch/powerpc/kernel/exceptions-64s.S | 2 +- arch/powerpc/mm/fault.c | 22 ++++++++++++++++++++++ 3 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index b779f3c..ffc9990 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -312,7 +312,6 @@ DSISR_BAD_EXT_CTRL) #define DSISR_BAD_FAULT_64S (DSISR_BAD_FAULT_32S | \ DSISR_ATTR_CONFLICT | \ - DSISR_KEYFAULT | \ DSISR_UNSUPP_MMU | \ DSISR_PRTABLE_FAULT | \ DSISR_ICSWX_NO_CT | \ diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index e441b46..804e804 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1521,7 +1521,7 @@ USE_TEXT_SECTION() .balign IFETCH_ALIGN_BYTES do_hash_page: #ifdef CONFIG_PPC_BOOK3S_64 - lis r0,(DSISR_BAD_FAULT_64S|DSISR_DABRMATCH)@h + lis r0,(DSISR_BAD_FAULT_64S | DSISR_DABRMATCH | DSISR_KEYFAULT)@h ori r0,r0,DSISR_BAD_FAULT_64S@l and. r0,r4,r0 /* weird error? */ bne- handle_page_fault /* if not, try to insert a HPTE */ diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 4797d08..943a91e 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -427,6 +427,11 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+ if (error_code & DSISR_KEYFAULT) { + _exception(SIGSEGV, regs, SEGV_PKUERR, address); + return 0; + } + /* * We want to do this outside mmap_sem, because reading code around nip * can result in fault, which will cause a deadlock when called with @@ -498,6 +503,23 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, * the fault. */ fault = handle_mm_fault(vma, address, flags); + +#ifdef CONFIG_PPC_MEM_KEYS + /* + * if the HPTE is not hashed, hardware will not detect + * a key fault. Lets check if we failed because of a + * software detected key fault. + */ + if (unlikely(fault & VM_FAULT_SIGSEGV) && + !arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, + is_exec, 0)) { + int pkey = vma_pkey(vma); + + if (likely(pkey)) + return __bad_area(regs, address, SEGV_PKUERR); + } +#endif /* CONFIG_PPC_MEM_KEYS */ + major |= fault & VM_FAULT_MAJOR;
/*