From: Guenter Roeck linux@roeck-us.net
mainline inclusion from mainline-v5.8 commit 9bceb80b3cc483e6763c39a4928402fa82815d3e category:bugfix bugzilla:NA CVE:NA
-------------------
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 Signed-off-by: Chen Jun chenjun102@huawei.com Reviewed-by: Xie XiuQi xiexiuqi@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/arm64/kernel/kaslr.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c index ab629f564043..5db9228e555c 100644 --- a/arch/arm64/kernel/kaslr.c +++ b/arch/arm64/kernel/kaslr.c @@ -90,6 +90,7 @@ 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;
/* @@ -128,15 +129,12 @@ 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;