mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 03:10:12 +00:00
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>
70 lines
2 KiB
C
70 lines
2 KiB
C
#include <asm/byteorder.h>
|
|
#include "vphn.h"
|
|
|
|
/*
|
|
* The associativity domain numbers are returned from the hypervisor as a
|
|
* stream of mixed 16-bit and 32-bit fields. The stream is terminated by the
|
|
* special value of "all ones" (aka. 0xffff) and its size may not exceed 48
|
|
* bytes.
|
|
*
|
|
* --- 16-bit fields -->
|
|
* _________________________
|
|
* | 0 | 1 | 2 | 3 | be_packed[0]
|
|
* ------+-----+-----+------
|
|
* _________________________
|
|
* | 4 | 5 | 6 | 7 | be_packed[1]
|
|
* -------------------------
|
|
* ...
|
|
* _________________________
|
|
* | 20 | 21 | 22 | 23 | be_packed[5]
|
|
* -------------------------
|
|
*
|
|
* Convert to the sequence they would appear in the ibm,associativity property.
|
|
*/
|
|
int vphn_unpack_associativity(const long *packed, __be32 *unpacked)
|
|
{
|
|
__be64 be_packed[VPHN_REGISTER_COUNT];
|
|
int i, nr_assoc_doms = 0;
|
|
const __be16 *field = (const __be16 *) be_packed;
|
|
u16 last = 0;
|
|
bool is_32bit = false;
|
|
|
|
#define VPHN_FIELD_UNUSED (0xffff)
|
|
#define VPHN_FIELD_MSB (0x8000)
|
|
#define VPHN_FIELD_MASK (~VPHN_FIELD_MSB)
|
|
|
|
/* Let's fix the values returned by plpar_hcall9() */
|
|
for (i = 0; i < VPHN_REGISTER_COUNT; i++)
|
|
be_packed[i] = cpu_to_be64(packed[i]);
|
|
|
|
for (i = 1; i < VPHN_ASSOC_BUFSIZE; i++) {
|
|
u16 new = be16_to_cpup(field++);
|
|
|
|
if (is_32bit) {
|
|
/* Let's concatenate the 16 bits of this field to the
|
|
* 15 lower bits of the previous field
|
|
*/
|
|
unpacked[++nr_assoc_doms] =
|
|
cpu_to_be32(last << 16 | new);
|
|
is_32bit = false;
|
|
} else if (new == VPHN_FIELD_UNUSED)
|
|
/* This is the list terminator */
|
|
break;
|
|
else if (new & VPHN_FIELD_MSB) {
|
|
/* Data is in the lower 15 bits of this field */
|
|
unpacked[++nr_assoc_doms] =
|
|
cpu_to_be32(new & VPHN_FIELD_MASK);
|
|
} else {
|
|
/* Data is in the lower 15 bits of this field
|
|
* concatenated with the next 16 bit field
|
|
*/
|
|
last = new;
|
|
is_32bit = true;
|
|
}
|
|
}
|
|
|
|
/* The first cell contains the length of the property */
|
|
unpacked[0] = cpu_to_be32(nr_assoc_doms);
|
|
|
|
return nr_assoc_doms;
|
|
}
|