linux/drivers/misc/sgi-gru/grulib.h
Gustavo A. R. Silva f490e8aea3 misc: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Link: https://lore.kernel.org/r/20200226222240.GA14474@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-18 12:24:19 +01:00

154 lines
3.9 KiB
C

/*
* Copyright (c) 2008 Silicon Graphics, Inc. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __GRULIB_H__
#define __GRULIB_H__
#define GRU_BASENAME "gru"
#define GRU_FULLNAME "/dev/gru"
#define GRU_IOCTL_NUM 'G'
/*
* Maximum number of GRU segments that a user can have open
* ZZZ temp - set high for testing. Revisit.
*/
#define GRU_MAX_OPEN_CONTEXTS 32
/* Set Number of Request Blocks */
#define GRU_CREATE_CONTEXT _IOWR(GRU_IOCTL_NUM, 1, void *)
/* Set Context Options */
#define GRU_SET_CONTEXT_OPTION _IOWR(GRU_IOCTL_NUM, 4, void *)
/* Fetch exception detail */
#define GRU_USER_GET_EXCEPTION_DETAIL _IOWR(GRU_IOCTL_NUM, 6, void *)
/* For user call_os handling - normally a TLB fault */
#define GRU_USER_CALL_OS _IOWR(GRU_IOCTL_NUM, 8, void *)
/* For user unload context */
#define GRU_USER_UNLOAD_CONTEXT _IOWR(GRU_IOCTL_NUM, 9, void *)
/* For dumpping GRU chiplet state */
#define GRU_DUMP_CHIPLET_STATE _IOWR(GRU_IOCTL_NUM, 11, void *)
/* For getting gseg statistics */
#define GRU_GET_GSEG_STATISTICS _IOWR(GRU_IOCTL_NUM, 12, void *)
/* For user TLB flushing (primarily for tests) */
#define GRU_USER_FLUSH_TLB _IOWR(GRU_IOCTL_NUM, 50, void *)
/* Get some config options (primarily for tests & emulator) */
#define GRU_GET_CONFIG_INFO _IOWR(GRU_IOCTL_NUM, 51, void *)
/* Various kernel self-tests */
#define GRU_KTEST _IOWR(GRU_IOCTL_NUM, 52, void *)
#define CONTEXT_WINDOW_BYTES(th) (GRU_GSEG_PAGESIZE * (th))
#define THREAD_POINTER(p, th) (p + GRU_GSEG_PAGESIZE * (th))
#define GSEG_START(cb) ((void *)((unsigned long)(cb) & ~(GRU_GSEG_PAGESIZE - 1)))
struct gru_get_gseg_statistics_req {
unsigned long gseg;
struct gru_gseg_statistics stats;
};
/*
* Structure used to pass TLB flush parameters to the driver
*/
struct gru_create_context_req {
unsigned long gseg;
unsigned int data_segment_bytes;
unsigned int control_blocks;
unsigned int maximum_thread_count;
unsigned int options;
unsigned char tlb_preload_count;
};
/*
* Structure used to pass unload context parameters to the driver
*/
struct gru_unload_context_req {
unsigned long gseg;
};
/*
* Structure used to set context options
*/
enum {sco_gseg_owner, sco_cch_req_slice, sco_blade_chiplet};
struct gru_set_context_option_req {
unsigned long gseg;
int op;
int val0;
long val1;
};
/*
* Structure used to pass TLB flush parameters to the driver
*/
struct gru_flush_tlb_req {
unsigned long gseg;
unsigned long vaddr;
size_t len;
};
/*
* Structure used to pass TLB flush parameters to the driver
*/
enum {dcs_pid, dcs_gid};
struct gru_dump_chiplet_state_req {
unsigned int op;
unsigned int gid;
int ctxnum;
char data_opt;
char lock_cch;
char flush_cbrs;
char fill[10];
pid_t pid;
void *buf;
size_t buflen;
/* ---- output --- */
unsigned int num_contexts;
};
#define GRU_DUMP_MAGIC 0x3474ab6c
struct gru_dump_context_header {
unsigned int magic;
unsigned int gid;
unsigned char ctxnum;
unsigned char cbrcnt;
unsigned char dsrcnt;
pid_t pid;
unsigned long vaddr;
int cch_locked;
unsigned long data[];
};
/*
* GRU configuration info (temp - for testing)
*/
struct gru_config_info {
int cpus;
int blades;
int nodes;
int chiplets;
int fill[16];
};
#endif /* __GRULIB_H__ */