diff options
Diffstat (limited to 'arch/x86/lib/insn-eval.c')
| -rw-r--r-- | arch/x86/lib/insn-eval.c | 72 |
1 files changed, 55 insertions, 17 deletions
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index 4229950a5d78..2bf07e18e38c 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -232,7 +232,7 @@ static int resolve_default_seg(struct insn *insn, struct pt_regs *regs, int off) * resolve_seg_reg() - obtain segment register index * @insn: Instruction with operands * @regs: Register values as seen when entering kernel mode - * @regoff: Operand offset, in pt_regs, used to deterimine segment register + * @regoff: Operand offset, in pt_regs, used to determine segment register * * Determine the segment register associated with the operands and, if * applicable, prefixes and the instruction pointed by @insn. @@ -517,7 +517,7 @@ static int get_reg_offset(struct insn *insn, struct pt_regs *regs, * @insn: Instruction containing ModRM byte * @regs: Register values as seen when entering kernel mode * @offs1: Offset of the first operand register - * @offs2: Offset of the second opeand register, if applicable + * @offs2: Offset of the second operand register, if applicable * * Obtain the offset, in pt_regs, of the registers indicated by the ModRM byte * in @insn. This function is to be used with 16-bit address encodings. The @@ -576,7 +576,7 @@ static int get_reg_offset_16(struct insn *insn, struct pt_regs *regs, * If ModRM.mod is 0 and ModRM.rm is 110b, then we use displacement- * only addressing. This means that no registers are involved in * computing the effective address. Thus, ensure that the first - * register offset is invalild. The second register offset is already + * register offset is invalid. The second register offset is already * invalid under the aforementioned conditions. */ if ((X86_MODRM_MOD(insn->modrm.value) == 0) && @@ -1415,6 +1415,25 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs) } } +static unsigned long insn_get_effective_ip(struct pt_regs *regs) +{ + unsigned long seg_base = 0; + + /* + * If not in user-space long mode, a custom code segment could be in + * use. This is true in protected mode (if the process defined a local + * descriptor table), or virtual-8086 mode. In most of the cases + * seg_base will be zero as in USER_CS. + */ + if (!user_64bit_mode(regs)) { + seg_base = insn_get_seg_base(regs, INAT_SEG_REG_CS); + if (seg_base == -1L) + return 0; + } + + return seg_base + regs->ip; +} + /** * insn_fetch_from_user() - Copy instruction bytes from user-space memory * @regs: Structure with register values as seen when entering kernel mode @@ -1431,24 +1450,43 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs) */ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) { - unsigned long seg_base = 0; + unsigned long ip; int not_copied; - /* - * If not in user-space long mode, a custom code segment could be in - * use. This is true in protected mode (if the process defined a local - * descriptor table), or virtual-8086 mode. In most of the cases - * seg_base will be zero as in USER_CS. - */ - if (!user_64bit_mode(regs)) { - seg_base = insn_get_seg_base(regs, INAT_SEG_REG_CS); - if (seg_base == -1L) - return 0; - } + ip = insn_get_effective_ip(regs); + if (!ip) + return 0; + + not_copied = copy_from_user(buf, (void __user *)ip, MAX_INSN_SIZE); + return MAX_INSN_SIZE - not_copied; +} + +/** + * insn_fetch_from_user_inatomic() - Copy instruction bytes from user-space memory + * while in atomic code + * @regs: Structure with register values as seen when entering kernel mode + * @buf: Array to store the fetched instruction + * + * Gets the linear address of the instruction and copies the instruction bytes + * to the buf. This function must be used in atomic context. + * + * Returns: + * + * Number of instruction bytes copied. + * + * 0 if nothing was copied. + */ +int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) +{ + unsigned long ip; + int not_copied; + + ip = insn_get_effective_ip(regs); + if (!ip) + return 0; - not_copied = copy_from_user(buf, (void __user *)(seg_base + regs->ip), - MAX_INSN_SIZE); + not_copied = __copy_from_user_inatomic(buf, (void __user *)ip, MAX_INSN_SIZE); return MAX_INSN_SIZE - not_copied; } |