Date: Wed, 11 Nov 2015 01:32:35 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r290668 - in stable: 10/sys/i386/i386 10/sys/i386/include 9/sys/i386/i386 9/sys/i386/include Message-ID: <201511110132.tAB1WZVK001531@repo.freebsd.org>
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Author: jhb Date: Wed Nov 11 01:32:35 2015 New Revision: 290668 URL: https://svnweb.freebsd.org/changeset/base/290668 Log: MFC 284324,290164: Workaround debuggers that try to read the full 32-bit words holding selectors in trapframes. 284324: Ensure that the upper 16 bits of segment registers manually saved in trapframes are cleared by explicitly pushing a zero and then moving the segment register into the low 16 bits. Certain Intel processors treat a push of a segment register as a move of the segment register into the low 16 bits leaving the upper 16 bits of the word in the stack unchanged. 290164: Use movw instead of movl (or plain mov) when moving segment registers into memory. This is a nop on clang's assembler, but some assemblers complain if the size suffix is incorrect. Modified: stable/10/sys/i386/i386/exception.s stable/10/sys/i386/include/asmacros.h Directory Properties: stable/10/ (props changed) Changes in other areas also in this revision: Modified: stable/9/sys/i386/i386/exception.s stable/9/sys/i386/include/asmacros.h Directory Properties: stable/9/sys/ (props changed) Modified: stable/10/sys/i386/i386/exception.s ============================================================================== --- stable/10/sys/i386/i386/exception.s Wed Nov 11 00:45:41 2015 (r290667) +++ stable/10/sys/i386/i386/exception.s Wed Nov 11 01:32:35 2015 (r290668) @@ -158,9 +158,12 @@ IDTVEC(xmm) .type alltraps,@function alltraps: pushal - pushl %ds - pushl %es - pushl %fs + pushl $0 + movw %ds,(%esp) + pushl $0 + movw %es,(%esp) + pushl $0 + movw %fs,(%esp) alltraps_with_regs_pushed: SET_KERNEL_SREGS cld @@ -234,9 +237,12 @@ IDTVEC(lcall_syscall) pushl $7 /* sizeof "lcall 7,0" */ subl $4,%esp /* skip over tf_trapno */ pushal - pushl %ds - pushl %es - pushl %fs + pushl $0 + movw %ds,(%esp) + pushl $0 + movw %es,(%esp) + pushl $0 + movw %fs,(%esp) SET_KERNEL_SREGS cld FAKE_MCOUNT(TF_EIP(%esp)) @@ -260,9 +266,12 @@ IDTVEC(int0x80_syscall) pushl $2 /* sizeof "int 0x80" */ subl $4,%esp /* skip over tf_trapno */ pushal - pushl %ds - pushl %es - pushl %fs + pushl $0 + movw %ds,(%esp) + pushl $0 + movw %es,(%esp) + pushl $0 + movw %fs,(%esp) SET_KERNEL_SREGS cld FAKE_MCOUNT(TF_EIP(%esp)) @@ -417,13 +426,16 @@ doreti_iret: doreti_iret_fault: subl $8,%esp pushal - pushl %ds + pushl $0 + movw %ds,(%esp) .globl doreti_popl_ds_fault doreti_popl_ds_fault: - pushl %es + pushl $0 + movw %es,(%esp) .globl doreti_popl_es_fault doreti_popl_es_fault: - pushl %fs + pushl $0 + movw %fs,(%esp) .globl doreti_popl_fs_fault doreti_popl_fs_fault: sti Modified: stable/10/sys/i386/include/asmacros.h ============================================================================== --- stable/10/sys/i386/include/asmacros.h Wed Nov 11 00:45:41 2015 (r290667) +++ stable/10/sys/i386/include/asmacros.h Wed Nov 11 01:32:35 2015 (r290668) @@ -146,9 +146,12 @@ pushl $0 ; /* dummy error code */ \ pushl $0 ; /* dummy trap type */ \ pushal ; /* 8 ints */ \ - pushl %ds ; /* save data and extra segments ... */ \ - pushl %es ; \ - pushl %fs + pushl $0 ; /* save data and extra segments ... */ \ + movw %ds,(%esp) ; \ + pushl $0 ; \ + movw %es,(%esp) ; \ + pushl $0 ; \ + movw %fs,(%esp) #define POP_FRAME \ popl %fs ; \
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