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linux/arch/x86/include/asm/insn-eval.h
Peter Zijlstra 4b5305decc x86/extable: Extend extable functionality
In order to remove further .fixup usage, extend the extable
infrastructure to take additional information from the extable entry
sites.

Specifically add _ASM_EXTABLE_TYPE_REG() and EX_TYPE_IMM_REG that
extend the existing _ASM_EXTABLE_TYPE() by taking an additional
register argument and encoding that and an s16 immediate into the
existing s32 type field. This limits the actual types to the first
byte, 255 seem plenty.

Also add a few flags into the type word, specifically CLEAR_AX and
CLEAR_DX which clear the return and extended return register.

Notes:
 - due to the % in our register names it's hard to make it more
   generally usable as arm64 did.
 - the s16 is far larger than used in these patches, future extentions
   can easily shrink this to get more bits.
 - without the bitfield fix this will not compile, because: 0xFF > -1
   and we can't even extract the TYPE field.

[nathanchance: Build fix for clang-lto builds:
 https://lkml.kernel.org/r/20211210234953.3420108-1-nathan@kernel.org
]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20211110101325.303890153@infradead.org
2021-12-11 09:09:46 +01:00

34 lines
1.3 KiB
C

#ifndef _ASM_X86_INSN_EVAL_H
#define _ASM_X86_INSN_EVAL_H
/*
* A collection of utility functions for x86 instruction analysis to be
* used in a kernel context. Useful when, for instance, making sense
* of the registers indicated by operands.
*/
#include <linux/compiler.h>
#include <linux/bug.h>
#include <linux/err.h>
#include <asm/ptrace.h>
#define INSN_CODE_SEG_ADDR_SZ(params) ((params >> 4) & 0xf)
#define INSN_CODE_SEG_OPND_SZ(params) (params & 0xf)
#define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4))
int pt_regs_offset(struct pt_regs *regs, int regno);
bool insn_has_rep_prefix(struct insn *insn);
void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs);
int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs);
int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs);
unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx);
int insn_get_code_seg_params(struct pt_regs *regs);
int insn_get_effective_ip(struct pt_regs *regs, unsigned long *ip);
int insn_fetch_from_user(struct pt_regs *regs,
unsigned char buf[MAX_INSN_SIZE]);
int insn_fetch_from_user_inatomic(struct pt_regs *regs,
unsigned char buf[MAX_INSN_SIZE]);
bool insn_decode_from_regs(struct insn *insn, struct pt_regs *regs,
unsigned char buf[MAX_INSN_SIZE], int buf_size);
#endif /* _ASM_X86_INSN_EVAL_H */