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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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3338a65bad
The current VPHN parsing logic has some flaws that this patch aims to fix: 1) when the value 0xffff is read, the value 0xffffffff gets added to the the output list and its element count isn't incremented. This is wrong. According to PAPR+ the domain identifiers are packed into a sequence terminated by the "reserved value of all ones". This means that 0xffff is a stream terminator. 2) the combination of byteswaps and casts make the code hardly readable. Let's parse the stream one 16-bit field at a time instead. 3) it is assumed that the hypercall returns 12 32-bit values packed into 6 64-bit registers. According to PAPR+, the domain identifiers may be streamed as 16-bit values. Let's increase the number of expected numbers to 24. Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
#include <asm/byteorder.h>
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#include "vphn.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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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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/* 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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/* 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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