From 4f6deb8cbab532a8d7250bc09234c1795ecb5e2c Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 27 Jul 2016 17:50:26 -0700 Subject: sparc: Don't leak context bits into thread->fault_address On pre-Niagara systems, we fetch the fault address on data TLB exceptions from the TLB_TAG_ACCESS register. But this register also contains the context ID assosciated with the fault in the low 13 bits of the register value. This propagates into current_thread_info()->fault_address and can cause trouble later on. So clear the low 13-bits out of the TLB_TAG_ACCESS value in the cases where it matters. Reported-by: Mikulas Patocka Signed-off-by: David S. Miller --- arch/sparc/kernel/dtlb_prot.S | 4 ++-- arch/sparc/kernel/ktlb.S | 12 ++++++++++++ arch/sparc/kernel/tsb.S | 12 ++++++++++-- 3 files changed, 24 insertions(+), 4 deletions(-) (limited to 'arch/sparc') diff --git a/arch/sparc/kernel/dtlb_prot.S b/arch/sparc/kernel/dtlb_prot.S index d668ca149e64..4087a62f96b0 100644 --- a/arch/sparc/kernel/dtlb_prot.S +++ b/arch/sparc/kernel/dtlb_prot.S @@ -25,13 +25,13 @@ /* PROT ** ICACHE line 2: More real fault processing */ ldxa [%g4] ASI_DMMU, %g5 ! Put tagaccess in %g5 + srlx %g5, PAGE_SHIFT, %g5 + sllx %g5, PAGE_SHIFT, %g5 ! Clear context ID bits bgu,pn %xcc, winfix_trampoline ! Yes, perform winfixup mov FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4 ba,pt %xcc, sparc64_realfault_common ! Nope, normal fault nop nop - nop - nop /* PROT ** ICACHE line 3: Unused... */ nop diff --git a/arch/sparc/kernel/ktlb.S b/arch/sparc/kernel/ktlb.S index ef0d8e9e1210..f22bec0db645 100644 --- a/arch/sparc/kernel/ktlb.S +++ b/arch/sparc/kernel/ktlb.S @@ -20,6 +20,10 @@ kvmap_itlb: mov TLB_TAG_ACCESS, %g4 ldxa [%g4] ASI_IMMU, %g4 + /* The kernel executes in context zero, therefore we do not + * need to clear the context ID bits out of %g4 here. + */ + /* sun4v_itlb_miss branches here with the missing virtual * address already loaded into %g4 */ @@ -128,6 +132,10 @@ kvmap_dtlb: mov TLB_TAG_ACCESS, %g4 ldxa [%g4] ASI_DMMU, %g4 + /* The kernel executes in context zero, therefore we do not + * need to clear the context ID bits out of %g4 here. + */ + /* sun4v_dtlb_miss branches here with the missing virtual * address already loaded into %g4 */ @@ -251,6 +259,10 @@ kvmap_dtlb_longpath: nop .previous + /* The kernel executes in context zero, therefore we do not + * need to clear the context ID bits out of %g5 here. + */ + be,pt %xcc, sparc64_realfault_common mov FAULT_CODE_DTLB, %g4 ba,pt %xcc, winfix_trampoline diff --git a/arch/sparc/kernel/tsb.S b/arch/sparc/kernel/tsb.S index be98685c14c6..d568c8207af7 100644 --- a/arch/sparc/kernel/tsb.S +++ b/arch/sparc/kernel/tsb.S @@ -29,13 +29,17 @@ */ tsb_miss_dtlb: mov TLB_TAG_ACCESS, %g4 + ldxa [%g4] ASI_DMMU, %g4 + srlx %g4, PAGE_SHIFT, %g4 ba,pt %xcc, tsb_miss_page_table_walk - ldxa [%g4] ASI_DMMU, %g4 + sllx %g4, PAGE_SHIFT, %g4 tsb_miss_itlb: mov TLB_TAG_ACCESS, %g4 + ldxa [%g4] ASI_IMMU, %g4 + srlx %g4, PAGE_SHIFT, %g4 ba,pt %xcc, tsb_miss_page_table_walk - ldxa [%g4] ASI_IMMU, %g4 + sllx %g4, PAGE_SHIFT, %g4 /* At this point we have: * %g1 -- PAGE_SIZE TSB entry address @@ -284,6 +288,10 @@ tsb_do_dtlb_fault: nop .previous + /* Clear context ID bits. */ + srlx %g5, PAGE_SHIFT, %g5 + sllx %g5, PAGE_SHIFT, %g5 + be,pt %xcc, sparc64_realfault_common mov FAULT_CODE_DTLB, %g4 ba,pt %xcc, winfix_trampoline -- cgit v1.2.3-70-g09d2