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authorArd Biesheuvel <ardb@kernel.org>2025-05-31 14:30:05 +0200
committerWill Deacon <will@kernel.org>2025-06-02 12:53:18 +0100
commitdc0a083948040ff364d065da8bb50c29f77a39ad (patch)
treea77127a1c0ff3917258436f38cc55eeeea997c94
parente21560b7d33c4f692cc9cd5b75ff09024f5a69d2 (diff)
arm64: Work around convergence issue with LLD linker
LLD will occasionally error out with a '__init_end does not converge' error if INIT_IDMAP_DIR_SIZE is defined in terms of _end, as this results in a circular dependency. Counter this by dimensioning the initial IDMAP page tables based on a new boundary marker 'kimage_limit', and define it such that its value should not change as a result of the initdata segment being pushed over a 64k segment boundary due to changes in INIT_IDMAP_DIR_SIZE, provided that its value doesn't change by more than 2M between linker passes. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20250531123005.3866382-2-ardb+git@google.com Signed-off-by: Will Deacon <will@kernel.org>
-rw-r--r--arch/arm64/include/asm/kernel-pgtable.h2
-rw-r--r--arch/arm64/kernel/image-vars.h11
2 files changed, 12 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
index 9e93733523f6..74a4f738c5f5 100644
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -58,7 +58,7 @@
#define INIT_DIR_SIZE (PAGE_SIZE * (EARLY_PAGES(SWAPPER_PGTABLE_LEVELS, KIMAGE_VADDR, _end, EXTRA_PAGE) \
+ EARLY_SEGMENT_EXTRA_PAGES))
-#define INIT_IDMAP_DIR_PAGES (EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, KIMAGE_VADDR, _end, 1))
+#define INIT_IDMAP_DIR_PAGES (EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, KIMAGE_VADDR, kimage_limit, 1))
#define INIT_IDMAP_DIR_SIZE ((INIT_IDMAP_DIR_PAGES + EARLY_IDMAP_EXTRA_PAGES) * PAGE_SIZE)
#define INIT_IDMAP_FDT_PAGES (EARLY_PAGES(INIT_IDMAP_PGTABLE_LEVELS, 0UL, UL(MAX_FDT_SIZE), 1) - 1)
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 86f088a16147..1cee48feb309 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -146,6 +146,17 @@ KVM_NVHE_ALIAS(kvm_protected_mode_initialized);
_kernel_codesize = ABSOLUTE(__inittext_end - _text);
#endif
+/*
+ * LLD will occasionally error out with a '__init_end does not converge' error
+ * if INIT_IDMAP_DIR_SIZE is defined in terms of _end, as this results in a
+ * circular dependency. Counter this by dimensioning the initial IDMAP page
+ * tables based on kimage_limit, which is defined such that its value should
+ * not change as a result of the initdata segment being pushed over a 64k
+ * segment boundary due to changes in INIT_IDMAP_DIR_SIZE, provided that its
+ * value doesn't change by more than 2M between linker passes.
+ */
+kimage_limit = ALIGN(ABSOLUTE(_end + SZ_64K), SZ_2M);
+
#undef ASSERT
#endif /* __ARM64_KERNEL_IMAGE_VARS_H */