From 917a0153621572e88aeb2d5df025ad2e81027287 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Wed, 6 May 2009 21:36:16 -0700 Subject: [PATCH] x86: mtrr: Fix high_width computation when phys-addr is >= 44bit found one system where cpu address line is 44bits, mtrr printout is not right: [ 0.000000] MTRR variable ranges enabled: [ 0.000000] 0 base 0 00000000 mask FF0 00000000 write-back [ 0.000000] 1 base 10 00000000 mask FFF 80000000 write-back [ 0.000000] 2 base 0 80000000 mask FFF 80000000 uncachable [ 0.000000] 3 base 0 7F800000 mask FFF FF800000 uncachable Li Zefan and Frederic pointed out the high_width could be -4 some how. It turns out when phys_addr is 44bit, size_or_mask will be ffffffff,00000000 so ffs(size_or_mask) will be 0. Try to check low 32 bit, to get correct high_width. Signed-off-by: Yinghai Lu Also-analyzed-by: Frederic Weisbecker Also-analyzed-by: Li Zefan Cc: Jeremy Fitzhardinge Cc: Zhaolei Cc: Steven Rostedt Cc: Vegard Nossum Cc: Andrew Morton LKML-Reference: <4A026540.8060504@kernel.org> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/mtrr/generic.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index 0b776c09aff3..d21d4fb161f7 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -275,7 +275,11 @@ static void __init print_mtrr_state(void) } printk(KERN_DEBUG "MTRR variable ranges %sabled:\n", mtrr_state.enabled & 2 ? "en" : "dis"); - high_width = ((size_or_mask ? ffs(size_or_mask) - 1 : 32) - (32 - PAGE_SHIFT) + 3) / 4; + if (size_or_mask & 0xffffffffUL) + high_width = ffs(size_or_mask & 0xffffffffUL) - 1; + else + high_width = ffs(size_or_mask>>32) + 32 - 1; + high_width = (high_width - (32 - PAGE_SHIFT) + 3) / 4; for (i = 0; i < num_var_ranges; ++i) { if (mtrr_state.var_ranges[i].mask_lo & (1 << 11)) printk(KERN_DEBUG " %u base %0*X%05X000 mask %0*X%05X000 %s\n",