Commit b3634575 authored Feb 18, 2014 by Thomas Petazzoni Committed by Russell King Feb 21, 2014

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>

parent c9698e5c

arch/arm/kernel/head-common.S

+12 −0

Original line number	Diff line number	Diff line
		@@ -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

arch/arm/kernel/head.S

+1 −1

Original line number	Diff line number	Diff line
		@@ -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