On Thu, Feb 05, 2026 at 10:50:24AM -0700, Jeremy Compostella wrote: > Is there anything more I should be doing? This is a bug fix I would really > appreciate seeing merged.
It would be nice if someone else reviewed it. It's also been a day since posting. I'll put it in my list to make sure doesn't get lost for the next release, thanks. > > Regards, > Jeremy > > Jeremy Compostella <[email protected]> writes: > > > This commit updates the RAM region filtering logic in > > board_get_usable_ram_top() to skip any memory regions whose start address > > is above 4GB. Previously, only the end address was capped at 4GB, but > > regions entirely above this threshold were still considered. > > > > Typically, the following memory map entries would cause > > board_get_usable_ram_top() to return 0x100000000, which is incorrect. > > > > start=00000000, end=00001000, type=16 > > start=00001000, end=000a0000, type=1 > > start=000a0000, end=000f6000, type=2 > > start=000f6000, end=000f7000, type=16 > > start=000f7000, end=00100000, type=2 > > start=00100000, end=6f170000, type=1 > > start=6f170000, end=70000000, type=16 > > start=70000000, end=80800000, type=2 > > start=e0000000, end=f8000000, type=2 > > start=fa000000, end=fc000000, type=2 > > start=fc800000, end=fc880000, type=2 > > start=fd800000, end=fe800000, type=2 > > start=feb00000, end=feb80000, type=2 > > start=fec00000, end=fed00000, type=2 > > start=fed20000, end=fed80000, type=2 > > start=feda1000, end=feda2000, type=2 > > start=fedc0000, end=fede0000, type=2 > > start=100000000, end=102400000, type=2 > > start=102400000, end=47f800000, type=1 > > start=4000000000, end=4020000000, type=2 > > > > By adding a check to continue the loop if the region's start address > > exceeds 0xffffffffULL, the function now properly ignores regions that are > > not usable in 32-bit address space. > > > > Change-Id: I8cbe0281aeea67a2f5bb9f6669456f5c7df9b409 > > Signed-off-by: Jeremy Compostella <[email protected]> > > --- > > arch/x86/cpu/coreboot/sdram.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/arch/x86/cpu/coreboot/sdram.c b/arch/x86/cpu/coreboot/sdram.c > > index 013225f129a..cc1edd7badd 100644 > > --- a/arch/x86/cpu/coreboot/sdram.c > > +++ b/arch/x86/cpu/coreboot/sdram.c > > @@ -42,6 +42,8 @@ phys_addr_t board_get_usable_ram_top(phys_size_t > > total_size) > > continue; > > > > /* Filter memory over 4GB. */ > > + if (start > 0xffffffffULL) > > + continue; > > if (end > 0xffffffffULL) > > end = 0x100000000ULL; > > /* Skip this region if it's too small. */ > > -- > Jeremy > One Emacs to rule them all -- Tom
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