arm64: kaslr: Use standard early random function

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))
         ^~~~~~~~~~~~

The 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@lca.pw>
Fixes: 585524081ecd ("random: random.h should include archrandom.h, not the other way around")
Cc: Qian Cai <cai@lca.pw>
Cc: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
index 9ded4237e1c16c14ed6eb61280a4ac3f291b40f8..b181e0544b79909b8d514e69514c57af8a8cb258 100644 (file)
--- a/arch/arm64/kernel/kaslr.c
+++ b/arch/arm64/kernel/kaslr.c
@@ -84,6 +84,7 @@ u64 __init kaslr_early_init(u64 dt_phys)
        void *fdt;
        u64 seed, offset, mask, module_range;
        const u8 *cmdline, *str;
+       unsigned long raw;
        int size;
 
        /*
@@ -122,15 +123,12 @@ u64 __init kaslr_early_init(u64 dt_phys)
        }
 
        /*
-        * Mix in any entropy obtainable architecturally, open coded
-        * since this runs extremely early.
+        * Mix in any entropy obtainable architecturally if enabled
+        * and supported.
         */
-       if (__early_cpu_has_rndr()) {
-               unsigned long raw;
 
-               if (__arm64_rndr(&raw))
-                       seed ^= raw;
-       }
+       if (arch_get_random_seed_long_early(&raw))
+               seed ^= raw;
 
        if (!seed) {
                kaslr_status = KASLR_DISABLED_NO_SEED;