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From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
To:     linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Stephen Boyd <swboyd@chromium.org>,
        Phil Elwell <phil@raspberrypi.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Russel King <linux@armlinux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>
Subject: [PATCH] riscv: initialize jump labels before early_init_dt_scan()
Date:   Tue,  7 Jun 2022 21:57:52 +0200
Message-Id: <20220607195752.1146431-1-Jason@zx2c4.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Stephen reported that a static key warning splat appears during early
boot on arm64 systems that credit randomness from device trees that
contain an "rng-seed" property, because the dtb is parsed is called
before jump_label_init() during setup_arch(), which was fixed by
73e2d827a501 ("arm64: Initialize jump labels before
setup_machine_fdt()").

The same basic issue applies to RISC-V as well. So this commit moves the
call to jump_label_init() just before early_init_dt_scan().
jump_label_init() actually requires sbi_init() to be called first for
proper functioning, so it also moves that to the right place.

Reported-by: Stephen Boyd <swboyd@chromium.org>
Reported-by: Phil Elwell <phil@raspberrypi.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Russel King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Fixes: f5bda35fba61 ("random: use static branch for crng_ready()")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 arch/riscv/kernel/setup.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index f0f36a4a0e9b..c44c81b1cfb3 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -263,13 +263,15 @@ static void __init parse_dtb(void)
 
 void __init setup_arch(char **cmdline_p)
 {
+	early_ioremap_setup();
+	sbi_init();
+	jump_label_init();
+
 	parse_dtb();
 	setup_initial_init_mm(_stext, _etext, _edata, _end);
 
 	*cmdline_p = boot_command_line;
 
-	early_ioremap_setup();
-	jump_label_init();
 	parse_early_param();
 
 	efi_init();
@@ -285,7 +287,6 @@ void __init setup_arch(char **cmdline_p)
 	misc_mem_init();
 
 	init_resources();
-	sbi_init();
 
 #ifdef CONFIG_KASAN
 	kasan_init();
-- 
2.35.1