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7424fc6b86
Currently ARM64 extracts which specific sanitizer has caused a trap via
encoded data in the trap instruction. Clang on x86 currently encodes the
same data in the UD1 instruction but x86 handle_bug() and
is_valid_bugaddr() currently only look at UD2.
Bring x86 to parity with ARM64, similar to commit 25b84002af ("arm64:
Support Clang UBSAN trap codes for better reporting"). See the llvm
links for information about the code generation.
Enable the reporting of UBSAN sanitizer details on x86 compiled with clang
when CONFIG_UBSAN_TRAP=y by analysing UD1 and retrieving the type immediate
which is encoded by the compiler after the UD1.
[ tglx: Simplified it by moving the printk() into handle_bug() ]
Signed-off-by: Gatlin Newhouse <gatlin.newhouse@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/all/20240724000206.451425-1-gatlin.newhouse@gmail.com
Link: https://github.com/llvm/llvm-project/commit/c5978f42ec8e9#diff-bb68d7cd885f41cfc35843998b0f9f534adb60b415f647109e597ce448e92d9f
Link: https://github.com/llvm/llvm-project/blob/main/llvm/lib/Target/X86/X86InstrSystem.td#L27
102 lines
2.6 KiB
C
102 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_BUG_H
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#define _ASM_X86_BUG_H
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#include <linux/stringify.h>
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#include <linux/instrumentation.h>
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#include <linux/objtool.h>
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/*
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* Despite that some emulators terminate on UD2, we use it for WARN().
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*/
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#define ASM_UD2 ".byte 0x0f, 0x0b"
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#define INSN_UD2 0x0b0f
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#define LEN_UD2 2
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/*
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* In clang we have UD1s reporting UBSAN failures on X86, 64 and 32bit.
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*/
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#define INSN_ASOP 0x67
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#define OPCODE_ESCAPE 0x0f
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#define SECOND_BYTE_OPCODE_UD1 0xb9
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#define SECOND_BYTE_OPCODE_UD2 0x0b
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#define BUG_NONE 0xffff
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#define BUG_UD1 0xfffe
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#define BUG_UD2 0xfffd
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#ifdef CONFIG_GENERIC_BUG
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#ifdef CONFIG_X86_32
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# define __BUG_REL(val) ".long " __stringify(val)
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#else
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# define __BUG_REL(val) ".long " __stringify(val) " - ."
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#endif
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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#define _BUG_FLAGS(ins, flags, extra) \
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do { \
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asm_inline volatile("1:\t" ins "\n" \
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".pushsection __bug_table,\"aw\"\n" \
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"2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
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"\t" __BUG_REL(%c0) "\t# bug_entry::file\n" \
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"\t.word %c1" "\t# bug_entry::line\n" \
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"\t.word %c2" "\t# bug_entry::flags\n" \
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"\t.org 2b+%c3\n" \
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".popsection\n" \
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extra \
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: : "i" (__FILE__), "i" (__LINE__), \
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"i" (flags), \
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"i" (sizeof(struct bug_entry))); \
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} while (0)
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#else /* !CONFIG_DEBUG_BUGVERBOSE */
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#define _BUG_FLAGS(ins, flags, extra) \
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do { \
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asm_inline volatile("1:\t" ins "\n" \
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".pushsection __bug_table,\"aw\"\n" \
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"2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
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"\t.word %c0" "\t# bug_entry::flags\n" \
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"\t.org 2b+%c1\n" \
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".popsection\n" \
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extra \
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: : "i" (flags), \
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"i" (sizeof(struct bug_entry))); \
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} while (0)
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#endif /* CONFIG_DEBUG_BUGVERBOSE */
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#else
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#define _BUG_FLAGS(ins, flags, extra) asm volatile(ins)
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#endif /* CONFIG_GENERIC_BUG */
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#define HAVE_ARCH_BUG
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#define BUG() \
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do { \
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instrumentation_begin(); \
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_BUG_FLAGS(ASM_UD2, 0, ""); \
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__builtin_unreachable(); \
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} while (0)
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/*
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* This instrumentation_begin() is strictly speaking incorrect; but it
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* suppresses the complaints from WARN()s in noinstr code. If such a WARN()
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* were to trigger, we'd rather wreck the machine in an attempt to get the
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* message out than not know about it.
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*/
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#define __WARN_FLAGS(flags) \
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do { \
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__auto_type __flags = BUGFLAG_WARNING|(flags); \
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instrumentation_begin(); \
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_BUG_FLAGS(ASM_UD2, __flags, ASM_REACHABLE); \
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instrumentation_end(); \
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} while (0)
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#include <asm-generic/bug.h>
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#endif /* _ASM_X86_BUG_H */
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