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ARM: 7980/1: kernel: improve error message when LPAE config doesn't match CPU 

Currently, when the kernel is configured with LPAE support, but the
CPU doesn't support it, the error message is fairly cryptic:

  Error: unrecognized/unsupported processor variant (0x561f5811).

This messages is normally shown when there is an issue when comparing
the processor ID (CP15 0, c0, c0) with the values/masks described in
proc-v7.S. However, the same message is displayed when LPAE support is
enabled in the kernel configuration, but not available in the CPU,
after looking at ID_MMFR0 (CP15 0, c0, c1, 4). Having the same error
message is highly misleading.

This commit improves this by showing a different error message when
this situation occurs:

  Error: Kernel with LPAE support, but CPU does not support LPAE.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Thomas Petazzoni 2014-02-18 17:02:54 +01:00 committed by Russell King
parent c9698e5cd6
commit b363457593
2 changed files with 13 additions and 1 deletions
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12
arch/arm/kernel/head-common.S
View File

@ -177,6 +177,18 @@ __lookup_processor_type_data:
.long __proc_info_end
.size __lookup_processor_type_data, . - __lookup_processor_type_data
__error_lpae:
#ifdef CONFIG_DEBUG_LL
adr r0, str_lpae
bl printascii
b __error
str_lpae: .asciz "\nError: Kernel with LPAE support, but CPU does not support LPAE.\n"
#else
b __error
#endif
.align
ENDPROC(__error_lpae)
__error_p:
#ifdef CONFIG_DEBUG_LL
adr r0, str_p1

2
arch/arm/kernel/head.S
View File

@ -102,7 +102,7 @@ ENTRY(stext)
and r3, r3, #0xf @ extract VMSA support
cmp r3, #5 @ long-descriptor translation table format?
THUMB( it lo ) @ force fixup-able long branch encoding
blo __error_p @ only classic page table format
blo __error_lpae @ only classic page table format
#endif
#ifndef CONFIG_XIP_KERNEL