ARM: 8786/1: Debug kernel copy by printing (f3c89992) · Commits · 戴 / test

It may happen that when we relocate the kernel we corrupt other sensible memory (e.g. the memory needed by U-Boot for dealing with bootm command) while copying the kernel. If we overwrite the content of the memory area used by U-Boot's command bootm (described by U-Boot's parameters bootm_low and bootm_size), the kernel won't be able to boot. Troubleshooting the problem then is not straightforward. This commit allows the user to easily print information on where the kernel gets copied from/to in order to help with the design of the system memory map (e.g. bootm_low and bootm_size) at boot up. Signed-off-by:

Fabrizio Castro <fabrizio.castro@bp.renesas.com> Reviewed-by:

Chris Paterson <Chris.Paterson2@renesas.com> Acked-by:

Biju Das <biju.das@bp.renesas.com> Signed-off-by:

Russell King <rmk+kernel@armlinux.org.uk>

arch/arm/boot/compressed/head.S

+43 −0

Original line number	Diff line number	Diff line
		@@ -114,6 +114,35 @@
		#endif
		.endm

		/*
		* Debug kernel copy by printing the memory addresses involved
		*/
		.macro dbgkc, begin, end, cbegin, cend
		#ifdef DEBUG
		kputc #'\n'
		kputc #'C'
		kputc #':'
		kputc #'0'
		kputc #'x'
		kphex \begin, 8 /* Start of compressed kernel */
		kputc #'-'
		kputc #'0'
		kputc #'x'
		kphex \end, 8 /* End of compressed kernel */
		kputc #'-'
		kputc #'>'
		kputc #'0'
		kputc #'x'
		kphex \cbegin, 8 /* Start of kernel copy */
		kputc #'-'
		kputc #'0'
		kputc #'x'
		kphex \cend, 8 /* End of kernel copy */
		kputc #'\n'
		kputc #'\r'
		#endif
		.endm

		.section ".start", #alloc, #execinstr
		/*
		* sort out different calling conventions
		@@ -450,6 +479,20 @@ dtb_check_done:
		add r6, r9, r5
		add r9, r9, r10

		#ifdef DEBUG
		sub r10, r6, r5
		sub r10, r9, r10
		/*
		* We are about to copy the kernel to a new memory area.
		* The boundaries of the new memory area can be found in
		* r10 and r9, whilst r5 and r6 contain the boundaries
		* of the memory we are going to copy.
		* Calling dbgkc will help with the printing of this
		* information.
		*/
		dbgkc r5, r6, r10, r9
		#endif

		1: ldmdb r6!, {r0 - r3, r10 - r12, lr}
		cmp r6, r5
		stmdb r9!, {r0 - r3, r10 - r12, lr}

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