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| author | Paul Burton <paul.burton@mips.com> | 2019-09-18 22:03:30 +0000 |
|---|---|---|
| committer | Paul Burton <paul.burton@mips.com> | 2019-09-20 14:55:07 -0700 |
| commit | 05d013a0366d50f4f0dbebf8c1b22b42020bf49a (patch) | |
| tree | 69811af11e7de96a88d2aac71356031142b12ada | |
| parent | d1af2ab36d80fcdc15dcaaead68f15352778aec7 (diff) | |
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: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
| -rw-r--r-- | arch/mips/mm/init.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 6fea3b54c961..090fa653dfa9 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -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" |