From: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
To: mricon@kernel.org
Subject: [PATCH v5 04/21] cfi: Drop __CFI_ADDRESSABLE
Date: Thu, 01 Sep 2022 15:28:49 -0400 [thread overview]
Message-ID: <20220901-kcfi_support-v5-4-be2007d8da63@linuxfoundation.org> (raw)
In-Reply-To: <20220901-kcfi_support-v5-0-be2007d8da63@linuxfoundation.org>
From: Sami Tolvanen <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>
Tested-by: Kees Cook <keescook@chromium.org>
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 7713d7bcdaea..7bfafc69172a 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 518296ea7f73..8937b020ec04 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
--
b4 0.10.0-dev-03aea
next prev parent reply other threads:[~2022-09-01 19:28 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 19:28 [PATCH v5 00/21] KCFI support Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 01/21] treewide: Filter out CC_FLAGS_CFI Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 02/21] scripts/kallsyms: Ignore __kcfi_typeid_ Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 03/21] cfi: Remove CONFIG_CFI_CLANG_SHADOW Konstantin Ryabitsev
2022-09-01 19:28 ` Konstantin Ryabitsev [this message]
2022-09-01 19:28 ` [PATCH v5 05/21] cfi: Switch to -fsanitize=kcfi Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 06/21] cfi: Add type helper macros Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 07/21] lkdtm: Emit an indirect call for CFI tests Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 08/21] psci: Fix the function type for psci_initcall_t Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 09/21] arm64: Add types to indirect called assembly functions Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 10/21] arm64: Add CFI error handling Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 11/21] arm64: Drop unneeded __nocfi attributes Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 12/21] init: Drop __nocfi from __init Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 13/21] treewide: Drop function_nocfi Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 14/21] treewide: Drop WARN_ON_FUNCTION_MISMATCH Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 15/21] treewide: Drop __cficanonical Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 16/21] objtool: Disable CFI warnings Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 17/21] kallsyms: Drop CONFIG_CFI_CLANG workarounds Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 18/21] x86/tools/relocs: Ignore __kcfi_typeid_ relocations Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 19/21] x86: Add types to indirectly called assembly functions Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 20/21] x86/purgatory: Disable CFI Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 21/21] x86: Add support for CONFIG_CFI_CLANG Konstantin Ryabitsev
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