94dfc73e7c
There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].
This code was transformed with the help of Coccinelle:
(linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)
@@
identifier S, member, array;
type T1, T2;
@@
struct S {
...
T1 member;
T2 array[
- 0
];
};
-fstrict-flex-arrays=3 is coming and we need to land these changes
to prevent issues like these in the short future:
../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0,
but the source string has length 2 (including NUL byte) [-Wfortify-source]
strcpy(de3->name, ".");
^
Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If
this breaks anything, we can use a union with a new member name.
[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays
Link: https://github.com/KSPP/linux/issues/78
Build-tested-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/
Acked-by: Dan Williams <dan.j.williams@intel.com> # For ndctl.h
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
52 lines
1.6 KiB
C
52 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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/*
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* Copyright IBM Corp. 2021
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* Interface implementation for communication with the CPU Measurement
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* counter facility device driver.
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*
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* Author(s): Thomas Richter <tmricht@linux.ibm.com>
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*
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* Define for ioctl() commands to communicate with the CPU Measurement
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* counter facility device driver.
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*/
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#ifndef _PERF_CPUM_CF_DIAG_H
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#define _PERF_CPUM_CF_DIAG_H
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#include <linux/ioctl.h>
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#include <linux/types.h>
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#define S390_HWCTR_DEVICE "hwctr"
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#define S390_HWCTR_START_VERSION 1
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struct s390_ctrset_start { /* Set CPUs to operate on */
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__u64 version; /* Version of interface */
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__u64 data_bytes; /* # of bytes required */
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__u64 cpumask_len; /* Length of CPU mask in bytes */
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__u64 *cpumask; /* Pointer to CPU mask */
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__u64 counter_sets; /* Bit mask of counter sets to get */
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};
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struct s390_ctrset_setdata { /* Counter set data */
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__u32 set; /* Counter set number */
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__u32 no_cnts; /* # of counters stored in cv[] */
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__u64 cv[]; /* Counter values (variable length) */
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};
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struct s390_ctrset_cpudata { /* Counter set data per CPU */
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__u32 cpu_nr; /* CPU number */
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__u32 no_sets; /* # of counters sets in data[] */
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struct s390_ctrset_setdata data[];
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};
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struct s390_ctrset_read { /* Structure to get all ctr sets */
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__u64 no_cpus; /* Total # of CPUs data taken from */
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struct s390_ctrset_cpudata data[];
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};
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#define S390_HWCTR_MAGIC 'C' /* Random magic # for ioctls */
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#define S390_HWCTR_START _IOWR(S390_HWCTR_MAGIC, 1, struct s390_ctrset_start)
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#define S390_HWCTR_STOP _IO(S390_HWCTR_MAGIC, 2)
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#define S390_HWCTR_READ _IOWR(S390_HWCTR_MAGIC, 3, struct s390_ctrset_read)
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#endif
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