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patches: Add Kees' arm64 EFI fix
We need this to start booting via EFI. Signed-off-by: Nathan Chancellor <[email protected]>
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‎patches/llvm-all/linux/arm64/0001-arm64-efi-Move-variable-assignments-after-SECTIONS.patch

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From f43cc4ed67f44f22754bef5bec98bf8aad3e6e8d Mon Sep 17 00:00:00 2001
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From: Kees Cook <[email protected]>
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Date: Tue, 13 Aug 2019 16:04:50 -0700
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Subject: [PATCH] arm64/efi: Move variable assignments after SECTIONS
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It seems that LLVM's linker does not correctly handle variable assignments
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involving section positions that are updated during the SECTIONS
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parsing. Commit aa69fb62bea1 ("arm64/efi: Mark __efistub_stext_offset as
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an absolute symbol explicitly") ran into this too, but found a different
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workaround.
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However, this was not enough, as other variables were also miscalculated
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which manifested as boot failures under UEFI where __efistub__end was
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not taking the correct _end value (they should be the same):
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$ ld.lld -EL -maarch64elf --no-undefined -X -shared \
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-Bsymbolic -z notext -z norelro --no-apply-dynamic-relocs \
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-o vmlinux.lld -T poc.lds --whole-archive vmlinux.o && \
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readelf -Ws vmlinux.lld | egrep '\b(__efistub_|)_end\b'
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368272: ffff000002218000 0 NOTYPE LOCAL HIDDEN 38 __efistub__end
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368322: ffff000012318000 0 NOTYPE GLOBAL DEFAULT 38 _end
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$ aarch64-linux-gnu-ld.bfd -EL -maarch64elf --no-undefined -X -shared \
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-Bsymbolic -z notext -z norelro --no-apply-dynamic-relocs \
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-o vmlinux.bfd -T poc.lds --whole-archive vmlinux.o && \
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readelf -Ws vmlinux.bfd | egrep '\b(__efistub_|)_end\b'
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338124: ffff000012318000 0 NOTYPE LOCAL DEFAULT ABS __efistub__end
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383812: ffff000012318000 0 NOTYPE GLOBAL DEFAULT 15325 _end
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To work around this, all of the __efistub_-prefixed variable assignments
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need to be moved after the linker script's SECTIONS entry. As it turns
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out, this also solves the problem fixed in commit aa69fb62bea1, so those
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changes are reverted here.
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Link: https://github.com/ClangBuiltLinux/linux/issues/634
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Link: https://bugs.llvm.org/show_bug.cgi?id=42990
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Acked-by: Ard Biesheuvel <[email protected]>
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Signed-off-by: Kees Cook <[email protected]>
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Signed-off-by: Will Deacon <[email protected]>
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(am from https://git.kernel.org/arm64/c/90776dd1c427cbb4d381aa4b13338f1fb1d20f5e)
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Signed-off-by: Nathan Chancellor <[email protected]>
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---
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arch/arm64/kernel/image-vars.h | 51 +++++++++++++++++++++++++++++++++
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arch/arm64/kernel/image.h | 42 ---------------------------
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arch/arm64/kernel/vmlinux.lds.S | 2 ++
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3 files changed, 53 insertions(+), 42 deletions(-)
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create mode 100644 arch/arm64/kernel/image-vars.h
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diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
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new file mode 100644
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index 000000000000..25a2a9b479c2
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--- /dev/null
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+++ b/arch/arm64/kernel/image-vars.h
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@@ -0,0 +1,51 @@
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+/* SPDX-License-Identifier: GPL-2.0-only */
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+/*
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+ * Linker script variables to be set after section resolution, as
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+ * ld.lld does not like variables assigned before SECTIONS is processed.
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+ */
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+#ifndef __ARM64_KERNEL_IMAGE_VARS_H
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+#define __ARM64_KERNEL_IMAGE_VARS_H
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+
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+#ifndef LINKER_SCRIPT
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+#error This file should only be included in vmlinux.lds.S
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+#endif
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+
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+#ifdef CONFIG_EFI
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+
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+__efistub_stext_offset = stext - _text;
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+
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+/*
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+ * The EFI stub has its own symbol namespace prefixed by __efistub_, to
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+ * isolate it from the kernel proper. The following symbols are legally
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+ * accessed by the stub, so provide some aliases to make them accessible.
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+ * Only include data symbols here, or text symbols of functions that are
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+ * guaranteed to be safe when executed at another offset than they were
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+ * linked at. The routines below are all implemented in assembler in a
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+ * position independent manner
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+ */
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+__efistub_memcmp = __pi_memcmp;
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+__efistub_memchr = __pi_memchr;
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+__efistub_memcpy = __pi_memcpy;
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+__efistub_memmove = __pi_memmove;
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+__efistub_memset = __pi_memset;
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+__efistub_strlen = __pi_strlen;
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+__efistub_strnlen = __pi_strnlen;
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+__efistub_strcmp = __pi_strcmp;
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+__efistub_strncmp = __pi_strncmp;
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+__efistub_strrchr = __pi_strrchr;
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+__efistub___flush_dcache_area = __pi___flush_dcache_area;
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+
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+#ifdef CONFIG_KASAN
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+__efistub___memcpy = __pi_memcpy;
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+__efistub___memmove = __pi_memmove;
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+__efistub___memset = __pi_memset;
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+#endif
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+
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+__efistub__text = _text;
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+__efistub__end = _end;
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+__efistub__edata = _edata;
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+__efistub_screen_info = screen_info;
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+
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+#endif
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+
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+#endif /* __ARM64_KERNEL_IMAGE_VARS_H */
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diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
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index 2b85c0d6fa3d..c7d38c660372 100644
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--- a/arch/arm64/kernel/image.h
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+++ b/arch/arm64/kernel/image.h
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@@ -65,46 +65,4 @@
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DEFINE_IMAGE_LE64(_kernel_offset_le, TEXT_OFFSET); \
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DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS);
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-#ifdef CONFIG_EFI
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-
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-/*
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- * Use ABSOLUTE() to avoid ld.lld treating this as a relative symbol:
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- * https://github.com/ClangBuiltLinux/linux/issues/561
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- */
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-__efistub_stext_offset = ABSOLUTE(stext - _text);
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-
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-/*
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- * The EFI stub has its own symbol namespace prefixed by __efistub_, to
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- * isolate it from the kernel proper. The following symbols are legally
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- * accessed by the stub, so provide some aliases to make them accessible.
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- * Only include data symbols here, or text symbols of functions that are
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- * guaranteed to be safe when executed at another offset than they were
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- * linked at. The routines below are all implemented in assembler in a
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- * position independent manner
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- */
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-__efistub_memcmp = __pi_memcmp;
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-__efistub_memchr = __pi_memchr;
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-__efistub_memcpy = __pi_memcpy;
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-__efistub_memmove = __pi_memmove;
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-__efistub_memset = __pi_memset;
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-__efistub_strlen = __pi_strlen;
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-__efistub_strnlen = __pi_strnlen;
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-__efistub_strcmp = __pi_strcmp;
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-__efistub_strncmp = __pi_strncmp;
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-__efistub_strrchr = __pi_strrchr;
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-__efistub___flush_dcache_area = __pi___flush_dcache_area;
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-
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-#ifdef CONFIG_KASAN
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-__efistub___memcpy = __pi_memcpy;
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-__efistub___memmove = __pi_memmove;
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-__efistub___memset = __pi_memset;
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-#endif
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-
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-__efistub__text = _text;
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-__efistub__end = _end;
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-__efistub__edata = _edata;
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-__efistub_screen_info = screen_info;
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-
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-#endif
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-
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#endif /* __ARM64_KERNEL_IMAGE_H */
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diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
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index 7fa008374907..803b24d2464a 100644
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--- a/arch/arm64/kernel/vmlinux.lds.S
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+++ b/arch/arm64/kernel/vmlinux.lds.S
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@@ -245,6 +245,8 @@ SECTIONS
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HEAD_SYMBOLS
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}
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+#include "image-vars.h"
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+
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/*
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* The HYP init code and ID map text can't be longer than a page each,
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* and should not cross a page boundary.
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--
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2.23.0.rc2
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