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3d034aecd8
The following calltrace is possible now:
handle_sysrq
machine_emergency_restart
mach_reboot_fixups
pci_get_device
pci_get_subsys
down_read
The patch skips reboot fixup if called from sysrq-B code.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
75 lines
1.9 KiB
C
75 lines
1.9 KiB
C
/*
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* linux/arch/i386/kernel/reboot_fixups.c
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*
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* This is a good place to put board specific reboot fixups.
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*
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* List of supported fixups:
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* geode-gx1/cs5530a - Jaya Kumar <jayalk@intworks.biz>
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* geode-gx/lx/cs5536 - Andres Salomon <dilinger@debian.org>
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*
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*/
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#include <asm/delay.h>
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#include <linux/pci.h>
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#include <linux/interrupt.h>
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#include <asm/reboot_fixups.h>
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#include <asm/msr.h>
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static void cs5530a_warm_reset(struct pci_dev *dev)
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{
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/* writing 1 to the reset control register, 0x44 causes the
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cs5530a to perform a system warm reset */
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pci_write_config_byte(dev, 0x44, 0x1);
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udelay(50); /* shouldn't get here but be safe and spin-a-while */
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return;
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}
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static void cs5536_warm_reset(struct pci_dev *dev)
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{
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/*
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* 6.6.2.12 Soft Reset (DIVIL_SOFT_RESET)
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* writing 1 to the LSB of this MSR causes a hard reset.
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*/
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wrmsrl(0x51400017, 1ULL);
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udelay(50); /* shouldn't get here but be safe and spin a while */
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}
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struct device_fixup {
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unsigned int vendor;
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unsigned int device;
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void (*reboot_fixup)(struct pci_dev *);
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};
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static struct device_fixup fixups_table[] = {
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{ PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5530_LEGACY, cs5530a_warm_reset },
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{ PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA, cs5536_warm_reset },
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};
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/*
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* we see if any fixup is available for our current hardware. if there
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* is a fixup, we call it and we expect to never return from it. if we
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* do return, we keep looking and then eventually fall back to the
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* standard mach_reboot on return.
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*/
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void mach_reboot_fixups(void)
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{
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struct device_fixup *cur;
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struct pci_dev *dev;
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int i;
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/* we can be called from sysrq-B code. In such a case it is
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* prohibited to dig PCI */
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if (in_interrupt())
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return;
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for (i=0; i < ARRAY_SIZE(fixups_table); i++) {
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cur = &(fixups_table[i]);
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dev = pci_get_device(cur->vendor, cur->device, NULL);
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if (!dev)
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continue;
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cur->reboot_fixup(dev);
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}
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}
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