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arm64: disable the physical timer for now if HCR_EL2.E2H is set

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On some hardware, we can't clear HCR_EL2.E2H so accesses to the physical
timer hopelessly trap to EL2.  Stash off the value of HCR_EL2 and use it
in has_hyp() to avoid this.

Reviewed by:	andrew
Differential Revision:	https://reviews.freebsd.org/D38884
This commit is contained in:
Kyle Evans 2023-03-03 11:02:19 -06:00
parent 577b62c2ba
commit d2ae03bae2
4 changed files with 13 additions and 3 deletions
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1
sys/arm64/arm64/genassym.c
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@ -45,6 +45,7 @@ ASSYM(BP_KERN_DELTA, offsetof(struct arm64_bootparams, kern_delta));
ASSYM(BP_KERN_STACK, offsetof(struct arm64_bootparams, kern_stack));
ASSYM(BP_KERN_TTBR0, offsetof(struct arm64_bootparams, kern_ttbr0));
ASSYM(BP_BOOT_EL, offsetof(struct arm64_bootparams, boot_el));
ASSYM(BP_HCR_EL2, offsetof(struct arm64_bootparams, hcr_el2));
ASSYM(PCPU_SIZE, sizeof(struct pcpu));
ASSYM(PC_CURPCB, offsetof(struct pcpu, pc_curpcb));

5
sys/arm64/arm64/locore.S
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@ -146,6 +146,7 @@ virtdone:
str x25, [x0, #BP_KERN_STACK]
str x27, [x0, #BP_KERN_TTBR0]
str x23, [x0, #BP_BOOT_EL]
str x4, [x0, #BP_HCR_EL2]
/* trace back starts here */
mov fp, #0
@ -286,8 +287,8 @@ LENTRY(drop_to_el1)
*/
tst x4, #HCR_E2H
mov x3, #CPTR_RES1 /* HCR_E2H == 0 */
mov x4, #CPTR_FPEN /* HCR_E2H == 1 */
csel x2, x3, x4, eq
mov x5, #CPTR_FPEN /* HCR_E2H == 1 */
csel x2, x3, x5, eq
msr cptr_el2, x2
/* Don't trap to EL2 for CP15 traps */

9
sys/arm64/arm64/machdep.c
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@ -78,6 +78,7 @@ __FBSDID("$FreeBSD$");
#include <machine/armreg.h>
#include <machine/cpu.h>
#include <machine/debug_monitor.h>
#include <machine/hypervisor.h>
#include <machine/kdb.h>
#include <machine/machdep.h>
#include <machine/metadata.h>
@ -124,6 +125,7 @@ static struct trapframe proc0_tf;
int early_boot = 1;
int cold = 1;
static int boot_el;
static uint64_t hcr_el2;
struct kva_md_info kmi;
@ -191,7 +193,11 @@ bool
has_hyp(void)
{
return (boot_el == 2);
/*
* XXX The E2H check is wrong, but it's close enough for now. Needs to
* be re-evaluated once we're running regularly in EL2.
*/
return (boot_el == 2 && (hcr_el2 & HCR_E2H) == 0);
}
static void
@ -865,6 +871,7 @@ initarm(struct arm64_bootparams *abp)
TSRAW(&thread0, TS_ENTER, __func__, NULL);
boot_el = abp->boot_el;
hcr_el2 = abp->hcr_el2;
/* Parse loader or FDT boot parametes. Determine last used address. */
lastaddr = parse_boot_param(abp);

1
sys/arm64/include/machdep.h
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@ -36,6 +36,7 @@ struct arm64_bootparams {
uint64_t kern_delta;
vm_offset_t kern_stack;
vm_paddr_t kern_ttbr0;
uint64_t hcr_el2;
int boot_el; /* EL the kernel booted from */
int pad;
};