[PATCH v3] ARM: initialize jump labels before setup_machine_fdt()
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: 2022-06-08 02:18:34
Also in:
lkml
Subsystem:
arm port, static branch/call, the rest · Maintainers:
Russell King, Peter Zijlstra, Josh Poimboeuf, Jason Baron, Alice Ryhl, Linus Torvalds
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 setup_machine_fdt() 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 arm32 as well. So this commit adds a
call to jump_label_init() just before setup_machine_fdt(). Since the
page maps haven't been set yet, this also requires us to use the early
patching code in the jump label code.
Reported-by: Stephen Boyd <redacted>
Reported-by: Phil Elwell <redacted>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Russel King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Fixes: f5bda35fba61 ("random: use static branch for crng_ready()")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
arch/arm/kernel/jump_label.c | 3 ++-
arch/arm/kernel/setup.c | 1 +
arch/arm/mm/mmu.c | 3 +++
3 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c
index 303b3ab87f7e..8f8c5312f917 100644
--- a/arch/arm/kernel/jump_label.c
+++ b/arch/arm/kernel/jump_label.c@@ -8,6 +8,7 @@ static void __arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type, bool is_static) { + extern bool early_mm_initialized; void *addr = (void *)entry->code; unsigned int insn;
@@ -16,7 +17,7 @@ static void __arch_jump_label_transform(struct jump_entry *entry, else insn = arm_gen_nop(); - if (is_static) + if (is_static || !early_mm_initialized) __patch_text_early(addr, insn); else patch_text(addr, insn);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 1e8a50a97edf..3ff80b1ee0b5 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c@@ -1101,6 +1101,7 @@ void __init setup_arch(char **cmdline_p) atags_vaddr = FDT_VIRT_BASE(__atags_pointer); setup_processor(); + jump_label_init(); if (atags_vaddr) { mdesc = setup_machine_fdt(atags_vaddr); if (mdesc)
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 5e2be37a198e..3f63a5581966 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c@@ -1754,10 +1754,13 @@ void __init paging_init(const struct machine_desc *mdesc) __flush_dcache_page(NULL, empty_zero_page); } +bool early_mm_initialized; + void __init early_mm_init(const struct machine_desc *mdesc) { build_mem_type_table(); early_paging_init(mdesc); + early_mm_initialized = true; } void set_pte_at(struct mm_struct *mm, unsigned long addr,
--
2.35.1
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