From: Michael Ellerman Date: Wed, 6 Apr 2022 14:57:59 +0000 (+1000) Subject: powerpc/85xx: Fix virt_to_phys() off-by-one in smp_85xx_start_cpu() X-Git-Tag: howlett/maple/20220722_2~414^2~169 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0d897255e79e26f471d10bbf72db9eee6f9cb723;p=users%2Fjedix%2Flinux-maple.git powerpc/85xx: Fix virt_to_phys() off-by-one in smp_85xx_start_cpu() In smp_85xx_start_cpu() we are passed an address but we're unsure if it's a real or virtual address, so there's a check to determine that. The check has an off-by-one in that it tests if the address is greater than high_memory, but high_memory is the first address of high memory, so the check should be greater-or-equal. It seems this has never been a problem in practice, but it also triggers the DEBUG_VIRTUAL checks in __pa() which we would like to avoid. We can fix both issues by converting high_memory - 1 to a physical address and testing against that. Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220406145802.538416-3-mpe@ellerman.id.au --- diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c index a1c6a7827c8f..9c43cf32f4c9 100644 --- a/arch/powerpc/platforms/85xx/smp.c +++ b/arch/powerpc/platforms/85xx/smp.c @@ -208,7 +208,7 @@ static int smp_85xx_start_cpu(int cpu) * The bootpage and highmem can be accessed via ioremap(), but * we need to directly access the spinloop if its in lowmem. */ - ioremappable = *cpu_rel_addr > virt_to_phys(high_memory); + ioremappable = *cpu_rel_addr > virt_to_phys(high_memory - 1); /* Map the spin table */ if (ioremappable)