From: Sami Tolvanen <samitolvanen@google.com>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Joao Moreira <joao@overdrivepizza.com>,
Sedat Dilek <sedat.dilek@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
linux-hardening@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev,
Sami Tolvanen <samitolvanen@google.com>
Subject: [RFC PATCH v3 04/20] cfi: Drop __CFI_ADDRESSABLE
Date: Fri, 10 Jun 2022 16:34:57 -0700 [thread overview]
Message-ID: <20220610233513.1798771-5-samitolvanen@google.com> (raw)
In-Reply-To: <20220610233513.1798771-1-samitolvanen@google.com>
The __CFI_ADDRESSABLE macro is used for init_module and cleanup_module
to ensure we have the address of the CFI jump table, and with
CONFIG_X86_KERNEL_IBT to ensure LTO won't optimize away the symbols.
As __CFI_ADDRESSABLE is no longer necessary with -fsanitize=kcfi, add
a more flexible version of the __ADDRESSABLE macro and always ensure
these symbols won't be dropped.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
include/linux/cfi.h | 20 --------------------
include/linux/compiler.h | 6 ++++--
include/linux/module.h | 4 ++--
3 files changed, 6 insertions(+), 24 deletions(-)
diff --git a/include/linux/cfi.h b/include/linux/cfi.h
index 4ab51c067007..2cdbc0fbd0ab 100644
--- a/include/linux/cfi.h
+++ b/include/linux/cfi.h
@@ -13,26 +13,6 @@ typedef void (*cfi_check_fn)(uint64_t id, void *ptr, void *diag);
/* Compiler-generated function in each module, and the kernel */
extern void __cfi_check(uint64_t id, void *ptr, void *diag);
-/*
- * Force the compiler to generate a CFI jump table entry for a function
- * and store the jump table address to __cfi_jt_<function>.
- */
-#define __CFI_ADDRESSABLE(fn, __attr) \
- const void *__cfi_jt_ ## fn __visible __attr = (void *)&fn
-
-#else /* !CONFIG_CFI_CLANG */
-
-#ifdef CONFIG_X86_KERNEL_IBT
-
-#define __CFI_ADDRESSABLE(fn, __attr) \
- const void *__cfi_jt_ ## fn __visible __attr = (void *)&fn
-
-#endif /* CONFIG_X86_KERNEL_IBT */
-
#endif /* CONFIG_CFI_CLANG */
-#ifndef __CFI_ADDRESSABLE
-#define __CFI_ADDRESSABLE(fn, __attr)
-#endif
-
#endif /* _LINUX_CFI_H */
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 01ce94b58b42..63be1c23d676 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -221,9 +221,11 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
* otherwise, or eliminated entirely due to lack of references that are
* visible to the compiler.
*/
-#define __ADDRESSABLE(sym) \
- static void * __section(".discard.addressable") __used \
+#define ___ADDRESSABLE(sym, __attrs) \
+ static void * __used __attrs \
__UNIQUE_ID(__PASTE(__addressable_,sym)) = (void *)&sym;
+#define __ADDRESSABLE(sym) \
+ ___ADDRESSABLE(sym, __section(".discard.addressable"))
/**
* offset_to_ptr - convert a relative memory offset to an absolute pointer
diff --git a/include/linux/module.h b/include/linux/module.h
index abd9fa916b7d..efecd65a976d 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -132,7 +132,7 @@ extern void cleanup_module(void);
{ return initfn; } \
int init_module(void) __copy(initfn) \
__attribute__((alias(#initfn))); \
- __CFI_ADDRESSABLE(init_module, __initdata);
+ ___ADDRESSABLE(init_module, __initdata);
/* This is only required if you want to be unloadable. */
#define module_exit(exitfn) \
@@ -140,7 +140,7 @@ extern void cleanup_module(void);
{ return exitfn; } \
void cleanup_module(void) __copy(exitfn) \
__attribute__((alias(#exitfn))); \
- __CFI_ADDRESSABLE(cleanup_module, __exitdata);
+ ___ADDRESSABLE(cleanup_module, __exitdata);
#endif
--
2.36.1.476.g0c4daa206d-goog
next prev parent reply other threads:[~2022-06-10 23:35 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-10 23:34 [RFC PATCH v3 00/20] KCFI support Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 01/20] treewide: Filter out CC_FLAGS_CFI Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 02/20] scripts/kallsyms: Ignore __kcfi_typeid_ Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 03/20] cfi: Remove CONFIG_CFI_CLANG_SHADOW Sami Tolvanen
2022-06-10 23:34 ` Sami Tolvanen [this message]
2022-06-10 23:34 ` [RFC PATCH v3 05/20] cfi: Switch to -fsanitize=kcfi Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 06/20] cfi: Add type helper macros Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 07/20] lkdtm: Emit an indirect call for CFI tests Sami Tolvanen
2022-06-10 23:43 ` Nick Desaulniers
2022-06-11 6:01 ` Kees Cook
2022-06-10 23:35 ` [RFC PATCH v3 08/20] arm64: Add types to indirect called assembly functions Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 09/20] arm64: Add CFI error handling Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 10/20] arm64: Drop unneeded __nocfi attributes Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 11/20] init: Drop __nocfi from __init Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 12/20] treewide: Drop function_nocfi Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 13/20] treewide: Drop WARN_ON_FUNCTION_MISMATCH Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 14/20] treewide: Drop __cficanonical Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 15/20] objtool: Disable CFI warnings Sami Tolvanen
2022-06-13 16:10 ` Josh Poimboeuf
2022-06-10 23:35 ` [RFC PATCH v3 16/20] kallsyms: Drop CONFIG_CFI_CLANG workarounds Sami Tolvanen
2022-06-10 23:40 ` Nick Desaulniers
2022-06-13 19:19 ` Bill Wendling
2022-06-10 23:35 ` [RFC PATCH v3 17/20] x86/tools/relocs: Ignore __kcfi_typeid_ relocations Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 18/20] x86: Add types to indirectly called assembly functions Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 19/20] x86/purgatory: Disable CFI Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 20/20] x86: Add support for CONFIG_CFI_CLANG Sami Tolvanen
2022-07-23 11:21 ` Peter Zijlstra
2022-07-26 0:09 ` Sami Tolvanen
2022-06-13 17:04 ` [RFC PATCH v3 00/20] KCFI support Kees Cook
2022-07-18 21:46 ` Peter Zijlstra
2022-07-19 13:36 ` Will Deacon
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