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https://github.com/edk2-porting/linux-next.git
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6d48583ba9
Introduce fixup_exception() on 64-bit and use it in kprobes to eliminate an #ifdef. Only 64-bit needs search_extable() due to a stepping bug. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
63 lines
1.3 KiB
C
63 lines
1.3 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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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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#ifdef CONFIG_X86_64
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/*
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* Need to defined our own search_extable on X86_64 to work around
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* a B stepping K8 bug.
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*/
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const struct exception_table_entry *
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search_extable(const struct exception_table_entry *first,
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const struct exception_table_entry *last,
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unsigned long value)
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{
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/* B stepping K8 bug */
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if ((value >> 32) == 0)
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value |= 0xffffffffUL << 32;
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while (first <= last) {
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const struct exception_table_entry *mid;
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long diff;
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mid = (last - first) / 2 + first;
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diff = mid->insn - value;
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if (diff == 0)
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return mid;
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else if (diff < 0)
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first = mid+1;
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else
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last = mid-1;
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}
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return NULL;
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}
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#endif
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