Date: Sat, 12 May 2018 11:07:00 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r333526 - head/sys/i386/include Message-ID: <201805121107.w4CB70pa093874@repo.freebsd.org>
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Author: kib Date: Sat May 12 11:06:59 2018 New Revision: 333526 URL: https://svnweb.freebsd.org/changeset/base/333526 Log: Kernel entry from vm86 mode, where PCB_VM86CALL pcb flag is not set, is executed on the right stack already. No copy from the entry stack to the kstack must be performed for vm86 bios call code to function. To access the pcb flags on kernel entry, unconditionally switch to kernel address space if vm86 mode is detected. This fixes very early vm86 bios calls, typically done when boot is performed by boot2 without loader, and kernel falls back to BIOS calls to get SMAP. Reported by: bde Sponsored by: The FreeBSD Foundation Modified: head/sys/i386/include/asmacros.h Modified: head/sys/i386/include/asmacros.h ============================================================================== --- head/sys/i386/include/asmacros.h Sat May 12 11:02:39 2018 (r333525) +++ head/sys/i386/include/asmacros.h Sat May 12 11:06:59 2018 (r333526) @@ -212,11 +212,17 @@ .macro KENTER testl $PSL_VM, TF_EFLAGS(%esp) - jnz 1f - testb $SEL_RPL_MASK, TF_CS(%esp) - jz 2f -1: MOVE_STACKS -2: + jz 1f + LOAD_KCR3 + movl PCPU(CURPCB), %eax + testl $PCB_VM86CALL, PCB_FLAGS(%eax) + jnz 3f + NMOVE_STACKS + jmp 2f +1: testb $SEL_RPL_MASK, TF_CS(%esp) + jz 3f +2: MOVE_STACKS +3: .endm #endif /* LOCORE */
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