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https://github.com/torvalds/linux
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6a1ea279c2
Add a restricted version of fixup_exception() to be used during early boot only. In particular, this doesn't support the try..catch variant since we may not have a thread_info set up yet. This relies on the exception table being sorted already at build time. Link: http://lkml.kernel.org/r/1334794610-5546-1-git-send-email-hpa@zytor.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
55 lines
1.2 KiB
C
55 lines
1.2 KiB
C
#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <asm/uaccess.h>
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int fixup_exception(struct pt_regs *regs)
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{
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const struct exception_table_entry *fixup;
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#ifdef CONFIG_PNPBIOS
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if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs))) {
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extern u32 pnp_bios_fault_eip, pnp_bios_fault_esp;
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extern u32 pnp_bios_is_utter_crap;
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pnp_bios_is_utter_crap = 1;
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printk(KERN_CRIT "PNPBIOS fault.. attempting recovery.\n");
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__asm__ volatile(
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"movl %0, %%esp\n\t"
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"jmp *%1\n\t"
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: : "g" (pnp_bios_fault_esp), "g" (pnp_bios_fault_eip));
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panic("do_trap: can't hit this");
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}
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#endif
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fixup = search_exception_tables(regs->ip);
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if (fixup) {
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/* If fixup is less than 16, it means uaccess error */
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if (fixup->fixup < 16) {
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current_thread_info()->uaccess_err = 1;
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regs->ip += fixup->fixup;
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return 1;
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}
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regs->ip = fixup->fixup;
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return 1;
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}
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return 0;
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}
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/* Restricted version used during very early boot */
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int __init early_fixup_exception(unsigned long *ip)
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{
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const struct exception_table_entry *fixup;
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fixup = search_exception_tables(*ip);
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if (fixup) {
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if (fixup->fixup < 16)
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return 0; /* Not supported during early boot */
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*ip = fixup->fixup;
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return 1;
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}
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return 0;
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}
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