Date: Wed, 20 Jun 2018 17:37:56 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r335453 - stable/11/sys/amd64/amd64 Message-ID: <201806201737.w5KHbueT095443@repo.freebsd.org>
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Author: kib Date: Wed Jun 20 17:37:55 2018 New Revision: 335453 URL: https://svnweb.freebsd.org/changeset/base/335453 Log: MFC r332994 (by tychon): Handle potential alignment adjustment of the exception frame by hardware. Modified: stable/11/sys/amd64/amd64/exception.S Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/amd64/amd64/exception.S ============================================================================== --- stable/11/sys/amd64/amd64/exception.S Wed Jun 20 17:20:39 2018 (r335452) +++ stable/11/sys/amd64/amd64/exception.S Wed Jun 20 17:37:55 2018 (r335453) @@ -341,6 +341,9 @@ page_cr2: * On the stack, we have the hardware interrupt frame to return * to usermode (faulted) and another frame with error code, for * fault. For PTI, copy both frames to the main thread stack. + * Handle the potential 16-byte alignment adjustment incurred + * during the second fault by copying both frames independently + * while unwinding the stack in between. */ .macro PROTF_ENTRY name,trapno \name\()_pti_doreti: @@ -351,7 +354,11 @@ page_cr2: movq %rax,%cr3 movq PCPU(RSP0),%rax subq $2*PTI_SIZE-3*8,%rax /* no err, %rax, %rdx in faulted frame */ - MOVE_STACKS (PTI_SIZE / 4 - 3) + MOVE_STACKS (PTI_SIZE / 8) + addq $PTI_SIZE,%rax + movq PTI_RSP(%rsp),%rsp + MOVE_STACKS (PTI_SIZE / 8 - 3) + subq $PTI_SIZE,%rax movq %rax,%rsp popq %rdx popq %rax
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