91 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			91 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0
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#include <asm/byteorder.h>
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#include <asm/lppaca.h>
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/*
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 * The associativity domain numbers are returned from the hypervisor as a
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 * stream of mixed 16-bit and 32-bit fields. The stream is terminated by the
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 * special value of "all ones" (aka. 0xffff) and its size may not exceed 48
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 * bytes.
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 *
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 *    --- 16-bit fields -->
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 *  _________________________
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 *  |  0  |  1  |  2  |  3  |   be_packed[0]
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 *  ------+-----+-----+------
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 *  _________________________
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 *  |  4  |  5  |  6  |  7  |   be_packed[1]
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 *  -------------------------
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 *            ...
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 *  _________________________
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 *  | 20  | 21  | 22  | 23  |   be_packed[5]
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 *  -------------------------
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 *
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 * Convert to the sequence they would appear in the ibm,associativity property.
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 */
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static int vphn_unpack_associativity(const long *packed, __be32 *unpacked)
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{
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	__be64 be_packed[VPHN_REGISTER_COUNT];
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	int i, nr_assoc_doms = 0;
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	const __be16 *field = (const __be16 *) be_packed;
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	u16 last = 0;
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	bool is_32bit = false;
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#define VPHN_FIELD_UNUSED	(0xffff)
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#define VPHN_FIELD_MSB		(0x8000)
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#define VPHN_FIELD_MASK		(~VPHN_FIELD_MSB)
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	/* Let's fix the values returned by plpar_hcall9() */
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	for (i = 0; i < VPHN_REGISTER_COUNT; i++)
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		be_packed[i] = cpu_to_be64(packed[i]);
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	for (i = 1; i < VPHN_ASSOC_BUFSIZE; i++) {
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		u16 new = be16_to_cpup(field++);
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		if (is_32bit) {
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			/*
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			 * Let's concatenate the 16 bits of this field to the
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			 * 15 lower bits of the previous field
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			 */
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			unpacked[++nr_assoc_doms] =
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				cpu_to_be32(last << 16 | new);
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			is_32bit = false;
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		} else if (new == VPHN_FIELD_UNUSED)
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			/* This is the list terminator */
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			break;
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		else if (new & VPHN_FIELD_MSB) {
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			/* Data is in the lower 15 bits of this field */
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			unpacked[++nr_assoc_doms] =
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				cpu_to_be32(new & VPHN_FIELD_MASK);
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		} else {
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			/*
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			 * Data is in the lower 15 bits of this field
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			 * concatenated with the next 16 bit field
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			 */
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			last = new;
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			is_32bit = true;
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		}
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	}
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	/* The first cell contains the length of the property */
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	unpacked[0] = cpu_to_be32(nr_assoc_doms);
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	return nr_assoc_doms;
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}
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/* NOTE: This file is included by a selftest and built in userspace. */
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#ifdef __KERNEL__
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#include <asm/hvcall.h>
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long hcall_vphn(unsigned long cpu, u64 flags, __be32 *associativity)
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{
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	long rc;
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	long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
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	rc = plpar_hcall9(H_HOME_NODE_ASSOCIATIVITY, retbuf, flags, cpu);
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	if (rc == H_SUCCESS)
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		vphn_unpack_associativity(retbuf, associativity);
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	return rc;
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}
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#endif
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