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bffe30dd9f
The #VC handler must run in atomic context and cannot sleep. This is a
problem when it tries to fetch instruction bytes from user-space via
copy_from_user().
Introduce a insn_fetch_from_user_inatomic() helper which uses
__copy_from_user_inatomic() to safely copy the instruction bytes to
kernel memory in the #VC handler.
Fixes: 5e3427a7bc ("x86/sev-es: Handle instruction fetches from user-space")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org # v5.10+
Link: https://lkml.kernel.org/r/20210303141716.29223-6-joro@8bytes.org
31 lines
1.2 KiB
C
31 lines
1.2 KiB
C
#ifndef _ASM_X86_INSN_EVAL_H
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#define _ASM_X86_INSN_EVAL_H
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/*
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* A collection of utility functions for x86 instruction analysis to be
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* used in a kernel context. Useful when, for instance, making sense
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* of the registers indicated by operands.
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*/
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#include <linux/compiler.h>
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#include <linux/bug.h>
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#include <linux/err.h>
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#include <asm/ptrace.h>
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#define INSN_CODE_SEG_ADDR_SZ(params) ((params >> 4) & 0xf)
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#define INSN_CODE_SEG_OPND_SZ(params) (params & 0xf)
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#define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4))
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bool insn_has_rep_prefix(struct insn *insn);
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void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs);
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int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs);
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int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs);
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unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx);
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int insn_get_code_seg_params(struct pt_regs *regs);
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int insn_fetch_from_user(struct pt_regs *regs,
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unsigned char buf[MAX_INSN_SIZE]);
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int insn_fetch_from_user_inatomic(struct pt_regs *regs,
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unsigned char buf[MAX_INSN_SIZE]);
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bool insn_decode(struct insn *insn, struct pt_regs *regs,
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unsigned char buf[MAX_INSN_SIZE], int buf_size);
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#endif /* _ASM_X86_INSN_EVAL_H */
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