Details

Reviewers

alc
manu
kib
markj

Group Reviewers

arm64

Commits

rG0f54e49d4b78: arm64 pmap: introduce PTE_TO_PHYS macro

Summary

Introduce macro for PTE_TO_PHYS, setting the groundwork for future
support of various Arm VMSA extensions.

For extensions such as 52-bit VA/PA (FEAT_LPA2), the representation of
an address between a PTE and PA are not equivalent. This macro will
allow converting between the different representations.

Currently going from PTE to PA is achieved by masking off the upper and
lower attributes. Retain this behaviour but replace all instances with
the new macro instead.

Diff Detail

Repository

rG FreeBSD src repository

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Event Timeline

zachary.leaf_arm.com created this revision.Apr 26 2023, 12:25 PM

Herald added a reviewer: manu. · View Herald TranscriptApr 26 2023, 12:25 PM

Herald added subscribers: emaste, andrew, imp. · View Herald Transcript

zachary.leaf_arm.com requested review of this revision.Apr 26 2023, 12:25 PM

Harbormaster completed remote builds in B51205: Diff 121073.Apr 26 2023, 12:25 PM

zachary.leaf_arm.com added a child revision: D39828: arm64 pmap: introduce PHYS_TO_PTE macro.Apr 26 2023, 12:25 PM

zachary.leaf_arm.com added reviewers: kib, markj.Apr 26 2023, 12:28 PM

zachary.leaf_arm.com added a reviewer: arm64.Apr 26 2023, 12:34 PM

This seems fine to me, just a question about naming.

setting the groundwork for future support of various Arm VMSA extensions.

Which extensions?

sys/arm64/include/pte.h
56	What exactly does "base" mean in this context? BASE_MASK and BASE_ADDR sound a bit too generic to me.

It's to help with FEAT_LPA2. This allows > 48 bit physical address space with a 4k and 16k PAGE_SIZE.

With this the shareability bits are moved to be per-ttbr and moved to tcr_el1.sh0 and tcr_el1.sh1. These bits are then used for bits 51 and 50 of the physical address.

kib added inline comments.Apr 27 2023, 4:24 AM

sys/arm64/arm64/minidump_machdep.c
309	... and in all other places

remove unnecessary brackets

Harbormaster completed remote builds in B51234: Diff 121129.Apr 27 2023, 12:14 PM

zachary.leaf_arm.com added inline comments.Apr 27 2023, 12:15 PM

sys/arm64/include/pte.h

Essentially the base VMSAv8-64 without any extensions. The idea is to use the BASE_MASK as a starting point for other extensions e.g. LPA2:

/* FEAT_LPA2: Bits 9:8 of IA are bits 51:50 of OA when TCR_ELx.DS=1 + 4KB pages */
#define LPA2_IA_BITS           UINT64_C(0x0000000000000300)
#define LPA2_IA_MASK           (BASE_MASK | LPA2_IA_BITS)
#define LPA2_OA_BITS           UINT64_C(0x000f000000000000)
#define LPA2_OA_MASK           (BASE_MASK | LPA2_OA_BITS)
#define LPA2_PTE_SHIFT(pte)    ((pte) | (((pte) & LPA2_IA_BITS) << (50-8)))
#define LPA2_PA_SHIFT(pa)      ((pa) | (((pa) & LPA2_OA_BITS) >> (50-8)))
#define LPA2_TO_PA(pte)        ((LPA2_PTE_SHIFT((pte) & LPA2_IA_MASK)) & LPA2_OA_MASK)
#define LPA2_TO_PTE(pa)        ((LPA2_PA_SHIFT((pa) & LPA2_OA_MASK)) & LPA2_IA_MASK)

zachary.leaf_arm.com edited the summary of this revision. (Show Details)Apr 27 2023, 12:19 PM

andrew added inline comments.Apr 27 2023, 1:00 PM

sys/arm64/arm64/pmap.c
4198–4199

The riscv pmap names this macro PTE_TO_PHYS, and I will argue for using the same name both here and there. Whether that happens by renaming it here, or there, I don't care. I just don't want them to use different names for doing similar things.

zachary.leaf_arm.com retitled this revision from arm64 pmap: introduce PTE_TO_PA macro to arm64 pmap: introduce PTE_TO_PHYS macro.May 2 2023, 3:10 PM

zachary.leaf_arm.com edited the summary of this revision. (Show Details)

rename PTE_TO_PA -> PTE_TO_PHYS
fix secondary indents + multi-line comments as per man style

Harbormaster completed remote builds in B51312: Diff 121389.May 2 2023, 3:13 PM

alc added inline comments.May 6 2023, 7:46 PM

sys/arm64/arm64/pmap.c
4146–4148	This is comment duplicating the last two lines of the existing comment above.
4198–4199	Here again, I would say that this comment is duplicating the comment above the loop.
4232	The indentation is incorrect.
4247	The indentation is incorrect.
7022	The indentation is incorrect.