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![Nick Desaulniers](/assets/img/avatar_default.png)
Once upgrading the minimum supported version of GCC to 5.1, we can drop
the fallback code for !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW.
This is effectively a revert of commit f0907827a8
("compiler.h: enable
builtin overflow checkers and add fallback code")
Link: https://github.com/ClangBuiltLinux/linux/issues/1438#issuecomment-916745801
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
151 lines
4.7 KiB
C
151 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_COMPILER_TYPES_H
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#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
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#endif
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/*
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* Common definitions for all gcc versions go here.
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*/
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#define GCC_VERSION (__GNUC__ * 10000 \
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+ __GNUC_MINOR__ * 100 \
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+ __GNUC_PATCHLEVEL__)
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/*
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* This macro obfuscates arithmetic on a variable address so that gcc
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* shouldn't recognize the original var, and make assumptions about it.
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*
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* This is needed because the C standard makes it undefined to do
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* pointer arithmetic on "objects" outside their boundaries and the
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* gcc optimizers assume this is the case. In particular they
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* assume such arithmetic does not wrap.
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*
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* A miscompilation has been observed because of this on PPC.
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* To work around it we hide the relationship of the pointer and the object
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* using this macro.
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*
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* Versions of the ppc64 compiler before 4.1 had a bug where use of
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* RELOC_HIDE could trash r30. The bug can be worked around by changing
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* the inline assembly constraint from =g to =r, in this particular
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* case either is valid.
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*/
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#define RELOC_HIDE(ptr, off) \
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({ \
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unsigned long __ptr; \
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__asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
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(typeof(ptr)) (__ptr + (off)); \
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})
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#ifdef CONFIG_RETPOLINE
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#define __noretpoline __attribute__((__indirect_branch__("keep")))
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#endif
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#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
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#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
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#define __compiletime_warning(message) __attribute__((__warning__(message)))
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#define __compiletime_error(message) __attribute__((__error__(message)))
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#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
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#define __latent_entropy __attribute__((latent_entropy))
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#endif
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/*
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* calling noreturn functions, __builtin_unreachable() and __builtin_trap()
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* confuse the stack allocation in gcc, leading to overly large stack
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* frames, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
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*
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* Adding an empty inline assembly before it works around the problem
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*/
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#define barrier_before_unreachable() asm volatile("")
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/*
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* Mark a position in code as unreachable. This can be used to
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* suppress control flow warnings after asm blocks that transfer
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* control elsewhere.
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*/
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#define unreachable() \
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do { \
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annotate_unreachable(); \
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barrier_before_unreachable(); \
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__builtin_unreachable(); \
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} while (0)
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#if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
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#define __randomize_layout __attribute__((randomize_layout))
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#define __no_randomize_layout __attribute__((no_randomize_layout))
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/* This anon struct can add padding, so only enable it under randstruct. */
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#define randomized_struct_fields_start struct {
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#define randomized_struct_fields_end } __randomize_layout;
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#endif
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/*
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* GCC 'asm goto' miscompiles certain code sequences:
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*
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* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
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*
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* Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
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*
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* (asm goto is automatically volatile - the naming reflects this.)
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*/
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#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
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#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP)
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#define __HAVE_BUILTIN_BSWAP32__
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#define __HAVE_BUILTIN_BSWAP64__
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#define __HAVE_BUILTIN_BSWAP16__
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#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
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#if GCC_VERSION >= 70000
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#define KASAN_ABI_VERSION 5
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#elif GCC_VERSION >= 50000
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#define KASAN_ABI_VERSION 4
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#elif GCC_VERSION >= 40902
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#define KASAN_ABI_VERSION 3
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#endif
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#if __has_attribute(__no_sanitize_address__)
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#define __no_sanitize_address __attribute__((no_sanitize_address))
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#else
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#define __no_sanitize_address
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#endif
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#if defined(__SANITIZE_THREAD__) && __has_attribute(__no_sanitize_thread__)
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#define __no_sanitize_thread __attribute__((no_sanitize_thread))
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#else
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#define __no_sanitize_thread
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#endif
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#if __has_attribute(__no_sanitize_undefined__)
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#define __no_sanitize_undefined __attribute__((no_sanitize_undefined))
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#else
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#define __no_sanitize_undefined
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#endif
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#if defined(CONFIG_KCOV) && __has_attribute(__no_sanitize_coverage__)
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#define __no_sanitize_coverage __attribute__((no_sanitize_coverage))
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#else
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#define __no_sanitize_coverage
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#endif
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/*
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* Turn individual warnings and errors on and off locally, depending
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* on version.
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*/
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#define __diag_GCC(version, severity, s) \
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__diag_GCC_ ## version(__diag_GCC_ ## severity s)
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/* Severity used in pragma directives */
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#define __diag_GCC_ignore ignored
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#define __diag_GCC_warn warning
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#define __diag_GCC_error error
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#define __diag_str1(s) #s
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#define __diag_str(s) __diag_str1(s)
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#define __diag(s) _Pragma(__diag_str(GCC diagnostic s))
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#if GCC_VERSION >= 80000
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#define __diag_GCC_8(s) __diag(s)
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#else
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#define __diag_GCC_8(s)
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#endif
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