Revision 5e98e916f95bdc50e90f3199d7f3d74b94fa5976 authored by Linus Torvalds on 12 February 2023, 21:52:17 UTC, committed by Linus Torvalds on 12 February 2023, 21:52:17 UTC
Pull tracing fix from Steven Rostedt:
"Fix showing of TASK_COMM_LEN instead of its value
The TASK_COMM_LEN was converted from a macro into an enum so that BTF
would have access to it. But this unfortunately caused TASK_COMM_LEN
to display in the format fields of trace events, as they are created
by the TRACE_EVENT() macro and such, macros convert to their values,
where as enums do not.
To handle this, instead of using the field itself to be display, save
the value of the array size as another field in the trace_event_fields
structure, and use that instead.
Not only does this fix the issue, but also converts the other trace
events that have this same problem (but were not breaking tooling).
With this change, the original work around b3bc8547d3be6 ("tracing:
Have TRACE_DEFINE_ENUM affect trace event types as well") could be
reverted (but that should be done in the merge window)"
* tag 'trace-v6.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix TASK_COMM_LEN in trace event format file
crc4.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* crc4.c - simple crc-4 calculations.
*/
#include <linux/crc4.h>
#include <linux/module.h>
static const uint8_t crc4_tab[] = {
0x0, 0x7, 0xe, 0x9, 0xb, 0xc, 0x5, 0x2,
0x1, 0x6, 0xf, 0x8, 0xa, 0xd, 0x4, 0x3,
};
/**
* crc4 - calculate the 4-bit crc of a value.
* @c: starting crc4
* @x: value to checksum
* @bits: number of bits in @x to checksum
*
* Returns the crc4 value of @x, using polynomial 0b10111.
*
* The @x value is treated as left-aligned, and bits above @bits are ignored
* in the crc calculations.
*/
uint8_t crc4(uint8_t c, uint64_t x, int bits)
{
int i;
/* mask off anything above the top bit */
x &= (1ull << bits) - 1;
/* Align to 4-bits */
bits = (bits + 3) & ~0x3;
/* Calculate crc4 over four-bit nibbles, starting at the MSbit */
for (i = bits - 4; i >= 0; i -= 4)
c = crc4_tab[c ^ ((x >> i) & 0xf)];
return c;
}
EXPORT_SYMBOL_GPL(crc4);
MODULE_DESCRIPTION("CRC4 calculations");
MODULE_LICENSE("GPL");
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