68 lines
2.1 KiB
Diff
68 lines
2.1 KiB
Diff
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# HG changeset patch
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# User David Vrabel <david.vrabel@citrix.com>
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# Date 1328196538 0
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# Node ID dcc6d57e4c07728693c685a2cfa7f094ef726267
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# Parent 7091b2e4cc2cff07ad1bf24ba7b9506bae071fa8
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x86: avoid deadlock after a PCI SERR NMI
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If a PCI System Error (SERR) is asserted it causes an NMI. If this NMI
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occurs while the CPU is in printk() then Xen may deadlock as
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pci_serr_error() calls console_force_unlock() which screws up the
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console lock.
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printk() isn't safe to call from NMI context so defer the diagnostic
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message to a softirq.
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Signed-off-by: David Vrabel <david.vrabel@citrix.com>
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Tested-by: George Dunlap <george.dunlap@eu.citrix.com>
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Committed-by: Keir Fraser <keir@xen.org>
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--- a/xen/arch/x86/traps.c
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+++ b/xen/arch/x86/traps.c
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@@ -3137,6 +3137,11 @@ static void nmi_mce_softirq(void)
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st->vcpu = NULL;
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}
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+static void pci_serr_softirq(void)
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+{
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+ printk("\n\nNMI - PCI system error (SERR)\n");
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+}
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+
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void async_exception_cleanup(struct vcpu *curr)
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{
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int trap;
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@@ -3223,10 +3228,11 @@ static void nmi_dom0_report(unsigned int
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static void pci_serr_error(struct cpu_user_regs *regs)
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{
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- console_force_unlock();
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- printk("\n\nNMI - PCI system error (SERR)\n");
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-
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outb((inb(0x61) & 0x0f) | 0x04, 0x61); /* clear-and-disable the PCI SERR error line. */
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+
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+ /* Would like to print a diagnostic here but can't call printk()
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+ from NMI context -- raise a softirq instead. */
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+ raise_softirq(PCI_SERR_SOFTIRQ);
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}
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static void io_check_error(struct cpu_user_regs *regs)
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@@ -3529,6 +3535,7 @@ void __init trap_init(void)
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cpu_init();
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open_softirq(NMI_MCE_SOFTIRQ, nmi_mce_softirq);
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+ open_softirq(PCI_SERR_SOFTIRQ, pci_serr_softirq);
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}
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long register_guest_nmi_callback(unsigned long address)
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--- a/xen/include/asm-x86/softirq.h
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+++ b/xen/include/asm-x86/softirq.h
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@@ -6,6 +6,7 @@
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#define VCPU_KICK_SOFTIRQ (NR_COMMON_SOFTIRQS + 2)
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#define MACHINE_CHECK_SOFTIRQ (NR_COMMON_SOFTIRQS + 3)
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-#define NR_ARCH_SOFTIRQS 4
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+#define PCI_SERR_SOFTIRQ (NR_COMMON_SOFTIRQS + 4)
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+#define NR_ARCH_SOFTIRQS 5
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#endif /* __ASM_SOFTIRQ_H__ */
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