diff options
| author | Guilherme G. Piccoli <gpiccoli@igalia.com> | 2021-12-21 12:52:30 -0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-12-22 11:06:11 +0000 |
| commit | 31e833b2031232493f2c30e53401e1f5ba293f97 (patch) | |
| tree | c56b74cc4928dd8c5f13dd3827f4681ba9227ff3 /arch/arm64/kernel | |
| parent | d5624bb29f49b849ac8d1e9783dbf9c65cf33457 (diff) | |
arm64: Unhash early pointer print plus improve comment
When facing a really early issue on DT parsing we have currently
a message that shows both the physical and virtual address of the FDT.
The printk pointer modifier for the virtual address shows a hashed
address there unless the user provides "no_hash_pointers" parameter in
the command-line. The situation in which this message shows-up is a bit
more serious though: the boot process is broken, nothing can be done
(even an oops is too much for this early stage) so we have this message
as a last resort in order to help debug bootloader issues, for example.
Hence, we hereby change that to "%px" in order to make debugging easy,
there's not much information leak risk in such early boot failure.
Also, we tried to improve a bit the commenting on that function, given
that if kernel fails there, it just hangs forever in a cpu_relax() loop.
The reason we cannot BUG/panic is that is too early to do so; thanks to
Mark Brown for pointing that on IRC and thanks Robin Murphy for the good
pointer hash discussion in the mailing-list.
Cc: Mark Brown <broonie@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211221155230.1532850-1-gpiccoli@igalia.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/setup.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index be5f85b0a24d..a80430550a73 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -189,11 +189,16 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys) if (!dt_virt || !early_init_dt_scan(dt_virt)) { pr_crit("\n" - "Error: invalid device tree blob at physical address %pa (virtual address 0x%p)\n" + "Error: invalid device tree blob at physical address %pa (virtual address 0x%px)\n" "The dtb must be 8-byte aligned and must not exceed 2 MB in size\n" "\nPlease check your bootloader.", &dt_phys, dt_virt); + /* + * Note that in this _really_ early stage we cannot even BUG() + * or oops, so the least terrible thing to do is cpu_relax(), + * or else we could end-up printing non-initialized data, etc. + */ while (true) cpu_relax(); } |