cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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hvconsole.c (1931B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * hvconsole.c
      4 * Copyright (C) 2004 Hollis Blanchard, IBM Corporation
      5 * Copyright (C) 2004 IBM Corporation
      6 *
      7 * Additional Author(s):
      8 *  Ryan S. Arnold <rsa@us.ibm.com>
      9 *
     10 * LPAR console support.
     11 */
     12
     13#include <linux/kernel.h>
     14#include <linux/export.h>
     15#include <linux/errno.h>
     16#include <asm/hvcall.h>
     17#include <asm/hvconsole.h>
     18#include <asm/plpar_wrappers.h>
     19
     20/**
     21 * hvc_get_chars - retrieve characters from firmware for denoted vterm adapter
     22 * @vtermno: The vtermno or unit_address of the adapter from which to fetch the
     23 *	data.
     24 * @buf: The character buffer into which to put the character data fetched from
     25 *	firmware.
     26 * @count: not used?
     27 */
     28int hvc_get_chars(uint32_t vtermno, char *buf, int count)
     29{
     30	long ret;
     31	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
     32	unsigned long *lbuf = (unsigned long *)buf;
     33
     34	ret = plpar_hcall(H_GET_TERM_CHAR, retbuf, vtermno);
     35	lbuf[0] = be64_to_cpu(retbuf[1]);
     36	lbuf[1] = be64_to_cpu(retbuf[2]);
     37
     38	if (ret == H_SUCCESS)
     39		return retbuf[0];
     40
     41	return 0;
     42}
     43
     44EXPORT_SYMBOL(hvc_get_chars);
     45
     46
     47/**
     48 * hvc_put_chars: send characters to firmware for denoted vterm adapter
     49 * @vtermno: The vtermno or unit_address of the adapter from which the data
     50 *	originated.
     51 * @buf: The character buffer that contains the character data to send to
     52 *	firmware. Must be at least 16 bytes, even if count is less than 16.
     53 * @count: Send this number of characters.
     54 */
     55int hvc_put_chars(uint32_t vtermno, const char *buf, int count)
     56{
     57	unsigned long *lbuf = (unsigned long *) buf;
     58	long ret;
     59
     60
     61	/* hcall will ret H_PARAMETER if 'count' exceeds firmware max.*/
     62	if (count > MAX_VIO_PUT_CHARS)
     63		count = MAX_VIO_PUT_CHARS;
     64
     65	ret = plpar_hcall_norets(H_PUT_TERM_CHAR, vtermno, count,
     66				 cpu_to_be64(lbuf[0]),
     67				 cpu_to_be64(lbuf[1]));
     68	if (ret == H_SUCCESS)
     69		return count;
     70	if (ret == H_BUSY)
     71		return -EAGAIN;
     72	return -EIO;
     73}
     74
     75EXPORT_SYMBOL(hvc_put_chars);