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![Dan Li](/assets/img/avatar_default.png)
Shadow call stacks will be available in GCC >= 12, this patch makes the corresponding kernel configuration available when compiling the kernel with the gcc. Note that the implementation in GCC is slightly different from Clang. With SCS enabled, functions will only pop x30 once in the epilogue, like: str x30, [x18], #8 stp x29, x30, [sp, #-16]! ...... - ldp x29, x30, [sp], #16 //clang + ldr x29, [sp], #16 //GCC ldr x30, [x18, #-8]! Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ce09ab17ddd21f73ff2caf6eec3b0ee9b0e1a11e Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Dan Li <ashimida@linux.alibaba.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220303074323.86282-1-ashimida@linux.alibaba.com
164 lines
4.9 KiB
C
164 lines
4.9 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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#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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#else
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#define KASAN_ABI_VERSION 4
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#endif
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#ifdef CONFIG_SHADOW_CALL_STACK
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#define __noscs __attribute__((__no_sanitize__("shadow-call-stack")))
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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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* Treat __SANITIZE_HWADDRESS__ the same as __SANITIZE_ADDRESS__ in the kernel,
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* matching the defines used by Clang.
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*/
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#ifdef __SANITIZE_HWADDRESS__
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#define __SANITIZE_ADDRESS__
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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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/*
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* Prior to 9.1, -Wno-alloc-size-larger-than (and therefore the "alloc_size"
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* attribute) do not work, and must be disabled.
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*/
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#if GCC_VERSION < 90100
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#undef __alloc_size__
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#endif
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