On 01/25/17 12:23, Ricardo Neri wrote:
- case UMIP_SMSW:
dummy_value = CR0_STATE;
Unless the user space process is running in 64-bit mode this value should be & 0xffff. I'm not sure if we should even support fixing up UMIP instructions in 64-bit mode.
Also, please put an explicit /* fall through */ here.
- /*
* These two instructions return a 16-bit value. We return
* all zeros. This is equivalent to a null descriptor for
* str and sldt.
*/
- case UMIP_SLDT:
- case UMIP_STR:
/* if operand is a register, it is zero-extended*/
if (X86_MODRM_MOD(insn->modrm.value) == 3) {
memset(data, 0, insn->opnd_bytes);
*data_size = insn->opnd_bytes;
/* if not, only the two least significant bytes are copied */
} else {
*data_size = 2;
}
memcpy(data, &dummy_value, sizeof(dummy_value));
break;
- default:
return -EINVAL;
- }
- return 0;
+bool fixup_umip_exception(struct pt_regs *regs) +{
- struct insn insn;
- unsigned char buf[MAX_INSN_SIZE];
- /* 10 bytes is the maximum size of the result of UMIP instructions */
- unsigned char dummy_data[10] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+#ifdef CONFIG_X86_64
- int x86_64 = user_64bit_mode(regs);
+#else
- int x86_64 = 0;
+#endif
Again, could we simply do:
if (user_64bit_mode(regs)) return false;
or are there known users of these instructions *in 64-bit mode*?
-hpa