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[PowerPC64] fix crash when using machdep.moea64_bpvo_pool_size tunable

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Summary:
This fixes kernel crashing when tunable "machdep.moea64_bpvo_pool_size" is
set to a value higher then 327680 (default value).  Function
moea64_mid_bootstrap() relies on moea64_bpvo_pool_size, but at time of the
use the variable wan't yet updated with the new value provided by user.

Problem was detected after trying to use a VM with 64GB of RAM, and default
moea64_bpvo_pool_size is insufficient (kernel boot used more than 470000) .
I think default value must be discussed to address this use case, or find a
way to calculate pool size automatically based on amount of memory detected.

Test Plan: Tested on QEMU VM with 64GB of RAM using "set
machdep.moea64_bpvo_pool_size=655360" on loader prompt

Submitted by:	Alfredo Dal'Ava Júnior (alfredo.junior_eldorado.org.br)
Differential Revision:	https://reviews.freebsd.org/D23233
This commit is contained in:
jhibbits 2020-01-19 21:17:57 +00:00
parent a3d0132770
commit 83894458ee
1 changed files with 6 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
sys/powerpc/aim/mmu_oea64.c
View File

@ -185,7 +185,6 @@ uma_zone_t moea64_pvo_zone; /* zone for pvo entries */
static struct pvo_entry *moea64_bpvo_pool;
static int moea64_bpvo_pool_index = 0;
static int moea64_bpvo_pool_size = 327680;
TUNABLE_INT("machdep.moea64_bpvo_pool_size", &moea64_bpvo_pool_size);
SYSCTL_INT(_machdep, OID_AUTO, moea64_allocated_bpvo_entries, CTLFLAG_RD,
&moea64_bpvo_pool_index, 0, "");
@ -390,9 +389,11 @@ alloc_pvo_entry(int bootstrap)
if (!moea64_initialized || bootstrap) {
if (moea64_bpvo_pool_index >= moea64_bpvo_pool_size) {
panic("moea64_enter: bpvo pool exhausted, %d, %d, %zd",
moea64_bpvo_pool_index, moea64_bpvo_pool_size,
moea64_bpvo_pool_size * sizeof(struct pvo_entry));
panic("%s: bpvo pool exhausted, index=%d, size=%d, bytes=%zd."
"Try setting machdep.moea64_bpvo_pool_size tunable",
__func__, moea64_bpvo_pool_index,
moea64_bpvo_pool_size,
moea64_bpvo_pool_size * sizeof(struct pvo_entry));
}
pvo = &moea64_bpvo_pool[
atomic_fetchadd_int(&moea64_bpvo_pool_index, 1)];
@ -914,6 +915,7 @@ moea64_mid_bootstrap(mmu_t mmup, vm_offset_t kernelstart, vm_offset_t kernelend)
/*
* Initialise the bootstrap pvo pool.
*/
TUNABLE_INT_FETCH("machdep.moea64_bpvo_pool_size", &moea64_bpvo_pool_size);
moea64_bpvo_pool = (struct pvo_entry *)moea64_bootstrap_alloc(
moea64_bpvo_pool_size*sizeof(struct pvo_entry), PAGE_SIZE);
moea64_bpvo_pool_index = 0;