Date: Mon, 15 May 2017 20:52:44 +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: r318318 - in head/sys: amd64/acpica amd64/amd64 x86/acpica Message-ID: <201705152052.v4FKqiHV025648@repo.freebsd.org>
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Author: kib Date: Mon May 15 20:52:43 2017 New Revision: 318318 URL: https://svnweb.freebsd.org/changeset/base/318318 Log: Ensure that resume path on amd64 only accesses page tables for normal operation after processor is configured to allow all required features. In particular, NX must be enabled in EFER, otherwise load of page table element with nx bit set causes reserved bit page fault. Since malloc uses direct mapping for small allocations, in particular for the suspension pcbs, and DMAP is nx after r316767, this commit tripped fault on resume path. Restore complete state of EFER while wakeup code is still executing with custom page table, before calling resumectx, instead of trying to guess which features might be needed before resumectx restored EFER on its own. Bisected and tested by: trasz Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Modified: head/sys/amd64/acpica/acpi_wakecode.S head/sys/amd64/amd64/cpu_switch.S head/sys/x86/acpica/acpi_wakeup.c Modified: head/sys/amd64/acpica/acpi_wakecode.S ============================================================================== --- head/sys/amd64/acpica/acpi_wakecode.S Mon May 15 20:41:29 2017 (r318317) +++ head/sys/amd64/acpica/acpi_wakecode.S Mon May 15 20:52:43 2017 (r318318) @@ -156,11 +156,12 @@ wakeup_32: /* * Enable EFER.LME so that we get long mode when all the prereqs are * in place. In this case, it turns on when CR0_PG is finally enabled. - * Pick up a few other EFER bits that we'll use need we're here. + * Also it picks up a few other EFER bits that we'll use need we're + * here, like SYSCALL and NX enable. */ movl $MSR_EFER, %ecx - rdmsr - orl $EFER_LME | EFER_SCE, %eax + movl wakeup_efer - wakeup_start(%ebx), %eax + movl wakeup_efer + 4 - wakeup_start(%ebx), %edx wrmsr /* @@ -276,6 +277,8 @@ wakeup_pcb: .quad 0 wakeup_ret: .quad 0 +wakeup_efer: + .quad 0 wakeup_gdt: .word 0 .quad 0 Modified: head/sys/amd64/amd64/cpu_switch.S ============================================================================== --- head/sys/amd64/amd64/cpu_switch.S Mon May 15 20:41:29 2017 (r318317) +++ head/sys/amd64/amd64/cpu_switch.S Mon May 15 20:52:43 2017 (r318318) @@ -396,7 +396,7 @@ ENTRY(resumectx) movl 4 + PCB_KGSBASE(%rdi),%edx wrmsr - /* Restore EFER. */ + /* Restore EFER one more time. */ movl $MSR_EFER,%ecx movl PCB_EFER(%rdi),%eax wrmsr Modified: head/sys/x86/acpica/acpi_wakeup.c ============================================================================== --- head/sys/x86/acpica/acpi_wakeup.c Mon May 15 20:41:29 2017 (r318317) +++ head/sys/x86/acpica/acpi_wakeup.c Mon May 15 20:52:43 2017 (r318318) @@ -223,7 +223,9 @@ acpi_sleep_machdep(struct acpi_softc *sc WAKECODE_FIXUP(resume_beep, uint8_t, (acpi_resume_beep != 0)); WAKECODE_FIXUP(reset_video, uint8_t, (acpi_reset_video != 0)); -#ifndef __amd64__ +#ifdef __amd64__ + WAKECODE_FIXUP(wakeup_efer, uint64_t, rdmsr(MSR_EFER)); +#else WAKECODE_FIXUP(wakeup_cr4, register_t, pcb->pcb_cr4); #endif WAKECODE_FIXUP(wakeup_pcb, struct pcb *, pcb);
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