Re: [PATCH v2] arm64: kaslr: Use standard early random function

From: Guenter Roeck
Date: Fri Aug 07 2020 - 14:00:55 EST

On 8/7/20 10:35 AM, Catalin Marinas wrote:
> On Fri, Aug 07, 2020 at 07:45:21AM -0700, Guenter Roeck wrote:
>> Commit 585524081ecd ("random: random.h should include archrandom.h, not
>> the other way around") tries to fix a problem with recursive inclusion
>> of linux/random.h and arch/archrandom.h for arm64. Unfortunately, this
>> results in the following compile error if ARCH_RANDOM is disabled.
>> arch/arm64/kernel/kaslr.c: In function 'kaslr_early_init':
>> arch/arm64/kernel/kaslr.c:128:6: error: implicit declaration of function
>> '__early_cpu_has_rndr'; did you mean '__early_pfn_to_nid'?
>> [-Werror=implicit-function-declaration]
>> if (__early_cpu_has_rndr()) {
>> ^~~~~~~~~~~~~~~~~~~~
>> __early_pfn_to_nid
>> arch/arm64/kernel/kaslr.c:131:7: error: implicit declaration of function
>> '__arm64_rndr' [-Werror=implicit-function-declaration]
>> if (__arm64_rndr(&raw))
>> ^~~~~~~~~~~~
>> Problem is that arch/archrandom.h is only included from linux/random.h if
>> ARCH_RANDOM is enabled. If not, __arm64_rndr() and __early_cpu_has_rndr()
>> are undeclared, causing the problem.
>> Use arch_get_random_seed_long_early() instead of arm64 specific functions
>> to solve the problem.
>> Reported-by: Qian Cai <cai@xxxxxx>
>> Fixes: 585524081ecd ("random: random.h should include archrandom.h, not the other way around")
>> Cc: Qian Cai <cai@xxxxxx>
>> Cc: Mark Brown <broonie@xxxxxxxxxx>
>> Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
>> Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
>> Tested-by: Mark Brown <broonie@xxxxxxxxxx>
>> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Linus, could you please pick this up directly? Otherwise, it will wait
> until we reach -rc1 to avoid basing a branch on a random commit.
> (at the moment I can't build Linus' tree at all, fails early with some
> device tree errors)

You either need to revert the dts changes, or you have to pull in
"dt-bindings: agilex: add NAND_X_CLK and NAND_ECC_CLK" from
linux-next to fix that problem. I did the latter to test this patch.
Hopefully the problem resolves itself after the clock tree has been
merged (though -next itself is in pretty bad shape too, so by then
we may see other problems).