47 lines
1.2 KiB
C
47 lines
1.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/err.h>
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#include <linux/mm.h>
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#include <asm/current.h>
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#include <asm/traps.h>
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#include <asm/vdso.h>
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struct vdso_exception_table_entry {
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int insn, fixup;
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};
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bool fixup_vdso_exception(struct pt_regs *regs, int trapnr,
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unsigned long error_code, unsigned long fault_addr)
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{
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const struct vdso_image *image = current->mm->context.vdso_image;
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const struct vdso_exception_table_entry *extable;
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unsigned int nr_entries, i;
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unsigned long base;
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/*
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* Do not attempt to fixup #DB or #BP. It's impossible to identify
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* whether or not a #DB/#BP originated from within an SGX enclave and
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* SGX enclaves are currently the only use case for vDSO fixup.
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*/
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if (trapnr == X86_TRAP_DB || trapnr == X86_TRAP_BP)
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return false;
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if (!current->mm->context.vdso)
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return false;
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base = (unsigned long)current->mm->context.vdso + image->extable_base;
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nr_entries = image->extable_len / (sizeof(*extable));
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extable = image->extable;
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for (i = 0; i < nr_entries; i++) {
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if (regs->ip == base + extable[i].insn) {
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regs->ip = base + extable[i].fixup;
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regs->di = trapnr;
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regs->si = error_code;
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regs->dx = fault_addr;
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return true;
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}
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}
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return false;
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}
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