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| author | Adrian Chadd <adrian@FreeBSD.org> | 2026-02-16 17:49:52 +0000 |
|---|---|---|
| committer | Adrian Chadd <adrian@FreeBSD.org> | 2026-02-16 17:49:52 +0000 |
| commit | 995090202cae47567cc5b0d92301692d49c1c035 (patch) | |
| tree | 48ccfa20c6c0a049425a0fe8ba1e210923ca7d4e | |
| parent | f412a5c565dedf5b6ea7cf3e43b57766ec0da63c (diff) | |
powerpc: document the magic constants for 16MB page size
After discussion with jhibbits@, we pulled out what is supported here
and how it's supported.
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D55093
| -rw-r--r-- | sys/powerpc/aim/moea64_native.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/sys/powerpc/aim/moea64_native.c b/sys/powerpc/aim/moea64_native.c index 7714187c2f4d..a3f54940ab1a 100644 --- a/sys/powerpc/aim/moea64_native.c +++ b/sys/powerpc/aim/moea64_native.c @@ -130,6 +130,19 @@ /* POWER9 only permits a 64k partition table size. */ #define PART_SIZE 0x10000 +/* + * These values are derived from the POWER8 user manual Version 1.3 + * (16-March-2016), 3.8.4 (large page support) and 3.8.16 (TLBIE Invalidate + * Entry instructions.) + * + * Notably: + * + * + POWER8 supports an MPSS (Multple Page Sizes per Segment) configuration + * of 4KB base, 16MB actual page size + * + RB[56:58] encoding for 16MB page == 100, RB[54:55] segment either 00 or 01 + * + RB[56:58] encoding for 4K page == 000, RB[54:55] segment either 00 or 01 + */ + /* Actual page sizes (to be used with tlbie, when L=0) */ #define AP_4K 0x00 #define AP_16M 0x80 |