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3325b4d857
The s390_hypfs filesystem is deprecated and shouldn't be used due to its rather odd semantics. It creates a whole directory structure with static file contents so a user can read a consistent state while within that directory. Writing to its update attribute will remove and rebuild nearly the whole filesystem, so that again a user can read a consistent state, even if multiple files need to be read. Given that this wastes a lot of CPU cycles, and involves a lot of code, binary interfaces have been added quite a couple of years ago, which simply pass the binary data to user space, and let user space decode the data. This is the preferred and only way how the data should be retrieved. The assumption is that there are no users of the s390_hypfs filesystem. However instead of just removing the code, and having to revert in case there are actually users, factor the filesystem code out and make it only available via a new config option. This config option is supposed to be disabled. If it turns out there are no complaints the filesystem code can be removed probably in a couple of years. Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
141 lines
3.3 KiB
C
141 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Hypervisor filesystem for Linux on s390. z/VM implementation.
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*
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* Copyright IBM Corp. 2006
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* Author(s): Michael Holzheu <holzheu@de.ibm.com>
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*/
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/vmalloc.h>
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#include <asm/extable.h>
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#include <asm/diag.h>
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#include <asm/ebcdic.h>
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#include <asm/timex.h>
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#include "hypfs_vm.h"
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#include "hypfs.h"
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#define DBFS_D2FC_HDR_VERSION 0
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static char local_guest[] = " ";
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static char all_guests[] = "* ";
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static char *all_groups = all_guests;
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char *diag2fc_guest_query;
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static int diag2fc(int size, char* query, void *addr)
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{
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unsigned long residual_cnt;
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unsigned long rc;
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struct diag2fc_parm_list parm_list;
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memcpy(parm_list.userid, query, DIAG2FC_NAME_LEN);
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ASCEBC(parm_list.userid, DIAG2FC_NAME_LEN);
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memcpy(parm_list.aci_grp, all_groups, DIAG2FC_NAME_LEN);
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ASCEBC(parm_list.aci_grp, DIAG2FC_NAME_LEN);
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parm_list.addr = (unsigned long)addr;
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parm_list.size = size;
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parm_list.fmt = 0x02;
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rc = -1;
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diag_stat_inc(DIAG_STAT_X2FC);
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asm volatile(
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" diag %0,%1,0x2fc\n"
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"0: nopr %%r7\n"
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EX_TABLE(0b,0b)
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: "=d" (residual_cnt), "+d" (rc) : "0" (&parm_list) : "memory");
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if ((rc != 0 ) && (rc != -2))
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return rc;
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else
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return -residual_cnt;
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}
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/*
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* Allocate buffer for "query" and store diag 2fc at "offset"
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*/
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void *diag2fc_store(char *query, unsigned int *count, int offset)
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{
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void *data;
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int size;
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do {
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size = diag2fc(0, query, NULL);
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if (size < 0)
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return ERR_PTR(-EACCES);
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data = vmalloc(size + offset);
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if (!data)
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return ERR_PTR(-ENOMEM);
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if (diag2fc(size, query, data + offset) == 0)
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break;
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vfree(data);
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} while (1);
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*count = (size / sizeof(struct diag2fc_data));
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return data;
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}
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void diag2fc_free(const void *data)
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{
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vfree(data);
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}
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struct dbfs_d2fc_hdr {
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u64 len; /* Length of d2fc buffer without header */
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u16 version; /* Version of header */
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union tod_clock tod_ext; /* TOD clock for d2fc */
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u64 count; /* Number of VM guests in d2fc buffer */
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char reserved[30];
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} __attribute__ ((packed));
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struct dbfs_d2fc {
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struct dbfs_d2fc_hdr hdr; /* 64 byte header */
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char buf[]; /* d2fc buffer */
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} __attribute__ ((packed));
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static int dbfs_diag2fc_create(void **data, void **data_free_ptr, size_t *size)
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{
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struct dbfs_d2fc *d2fc;
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unsigned int count;
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d2fc = diag2fc_store(diag2fc_guest_query, &count, sizeof(d2fc->hdr));
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if (IS_ERR(d2fc))
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return PTR_ERR(d2fc);
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store_tod_clock_ext(&d2fc->hdr.tod_ext);
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d2fc->hdr.len = count * sizeof(struct diag2fc_data);
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d2fc->hdr.version = DBFS_D2FC_HDR_VERSION;
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d2fc->hdr.count = count;
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memset(&d2fc->hdr.reserved, 0, sizeof(d2fc->hdr.reserved));
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*data = d2fc;
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*data_free_ptr = d2fc;
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*size = d2fc->hdr.len + sizeof(struct dbfs_d2fc_hdr);
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return 0;
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}
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static struct hypfs_dbfs_file dbfs_file_2fc = {
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.name = "diag_2fc",
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.data_create = dbfs_diag2fc_create,
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.data_free = diag2fc_free,
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};
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int hypfs_vm_init(void)
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{
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if (!MACHINE_IS_VM)
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return 0;
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if (diag2fc(0, all_guests, NULL) > 0)
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diag2fc_guest_query = all_guests;
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else if (diag2fc(0, local_guest, NULL) > 0)
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diag2fc_guest_query = local_guest;
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else
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return -EACCES;
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hypfs_dbfs_create_file(&dbfs_file_2fc);
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return 0;
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}
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void hypfs_vm_exit(void)
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{
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if (!MACHINE_IS_VM)
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return;
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hypfs_dbfs_remove_file(&dbfs_file_2fc);
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}
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