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Unverified Commit 05d013a0 authored by Paul Burton's avatar Paul Burton
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MIPS: Detect bad _PFN_SHIFT values 



2 recent commits have fixed issues where _PFN_SHIFT grew too large due
to the introduction of too many pgprot bits in our PTEs for some MIPS32
kernel configurations. Tracking down such issues can be tricky, so add a
BUILD_BUG_ON() to help.

Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
parent d1af2ab3

arch/mips/mm/init.c

+6 −0
Original line number Diff line number Diff line
@@ -446,6 +446,12 @@ static inline void __init mem_init_free_highmem(void) 


void __init mem_init(void)

{

	/*

	 * When _PFN_SHIFT is greater than PAGE_SHIFT we won't have enough PTE

	 * bits to hold a full 32b physical address on MIPS32 systems.

	 */

	BUILD_BUG_ON(IS_ENABLED(CONFIG_32BIT) && (_PFN_SHIFT > PAGE_SHIFT));



#ifdef CONFIG_HIGHMEM

#ifdef CONFIG_DISCONTIGMEM

#error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet"