Date: Tue, 7 May 2019 02:34:58 -0700 From: Mark Millard <marklmi@yahoo.com> To: Justin Hibbits <chmeeedalf@gmail.com>, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: PowerMac G5 context: kernel_va_to_slbv(...) and SLBV_L use vs. addresses < DMAP_BASE_ADDRESS Message-ID: <E68F567D-4F9A-46ED-B7CC-4CE8A7F1D402@yahoo.com>
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[DMAP_START below is an abbreviation of DMAP_BASE_ADDRESS.]
kernel_va_to_slbv has logic for if slbv would have
SLBV_L asserted or not:
uint64_t
kernel_va_to_slbv(vm_offset_t va)
{
uint64_t slbv;
/* Set kernel VSID to deterministic value */
slbv = (KERNEL_VSID((uintptr_t)va >> ADDR_SR_SHFT)) << SLBV_VSID_SHIFT;
/*
* Figure out if this is a large-page mapping.
*/
if (hw_direct_map && va > DMAP_BASE_ADDRESS && va < DMAP_MAX_ADDRESS) {
/*
* XXX: If we have set up a direct map, assumes
* all physical memory is mapped with large pages.
*/
if (mem_valid(DMAP_TO_PHYS(va), 0) == 0)
slbv |= SLBV_L;
}
return (slbv);
}
[Presuming hw_direct_map!=0 . . .]
By having handle_kernel_slb_spill count its usage,
broken out by address range and EXC_[DI]SE type, there
are examples of slbtrap's that use handle_kernel_slb_spill
for srr0<DMAP_START and for dar<DMAP_START.
handle_kernel_slb_spill uses kernel_va_to_slbv. (So did
my hack to -r345758 .)
Are slbv values correct for small effective addresses by
not having SLBV_L asserted? (Same memory, covered by two
different page sizes based on the style of
effective-address that happens to be used [upper bits
different].)
===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
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