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| author | Fabrizio Castro <fabrizio.castro@bp.renesas.com> | 2018-08-21 19:54:13 +0200 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-09-19 11:44:50 +0200 |
| commit | f3c899927e19d1be39818145efc39ea27b8efc69 (patch) | |
| tree | 907774fde22b48241e28cc379d8ebe81fc2d4279 /arch/arm/boot/compressed | |
| parent | Linux 4.19-rc1 (diff) | |
| download | linux-f3c899927e19d1be39818145efc39ea27b8efc69.tar.xz linux-f3c899927e19d1be39818145efc39ea27b8efc69.zip | |
ARM: 8786/1: Debug kernel copy by printing
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>
Diffstat (limited to 'arch/arm/boot/compressed')
| -rw-r--r-- | arch/arm/boot/compressed/head.S | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index 517e0e18f0b8..6c7ccb428c07 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -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} |