From 6a3193cdd5e5b96ac65f04ee42555c216da332af Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 22 Mar 2021 16:44:38 -0700 Subject: kbuild: lto: Merge module sections if and only if CONFIG_LTO_CLANG is enabled Merge module sections only when using Clang LTO. With ld.bfd, merging sections does not appear to update the symbol tables for the module, e.g. 'readelf -s' shows the value that a symbol would have had, if sections were not merged. ld.lld does not show this problem. The stale symbol table breaks gdb's function disassembler, and presumably other things, e.g. gdb -batch -ex "file arch/x86/kvm/kvm.ko" -ex "disassemble kvm_init" reads the wrong bytes and dumps garbage. Fixes: dd2776222abb ("kbuild: lto: merge module sections") Cc: Nick Desaulniers Signed-off-by: Sean Christopherson Reviewed-by: Sami Tolvanen Tested-by: Sami Tolvanen Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210322234438.502582-1-seanjc@google.com --- scripts/module.lds.S | 2 ++ 1 file changed, 2 insertions(+) (limited to 'scripts') diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 168cd27e6122..2c52535f9b56 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -20,6 +20,7 @@ SECTIONS { __patchable_function_entries : { *(__patchable_function_entries) } +#ifdef CONFIG_LTO_CLANG /* * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and * -ffunction-sections, which increases the size of the final module. @@ -41,6 +42,7 @@ SECTIONS { } .text : { *(.text .text.[0-9a-zA-Z_]*) } +#endif } /* bring in arch-specific sections */ -- cgit v1.2.3 From 5c595ac4c776c44b5c59de22ab43b3fe256d9fbb Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 16 Apr 2021 15:45:57 -0700 Subject: kasan: fix hwasan build for gcc gcc-11 adds support for -fsanitize=kernel-hwaddress, so it becomes possible to enable CONFIG_KASAN_SW_TAGS. Unfortunately this fails to build at the moment, because the corresponding command line arguments use llvm specific syntax. Change it to use the cc-param macro instead, which works on both clang and gcc. [elver@google.com: fixup for "kasan: fix hwasan build for gcc"] Link: https://lkml.kernel.org/r/YHQZVfVVLE/LDK2v@elver.google.com Link: https://lkml.kernel.org/r/20210323124112.1229772-1-arnd@kernel.org Signed-off-by: Arnd Bergmann Signed-off-by: Marco Elver Reviewed-by: Marco Elver Acked-by: Andrey Konovalov Cc: Masahiro Yamada Cc: Michal Marek Cc: Andrey Ryabinin Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Alexander Potapenko Cc: Dmitry Vyukov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/Makefile.kasan | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'scripts') diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan index 1e000cc2e7b4..127012f45166 100644 --- a/scripts/Makefile.kasan +++ b/scripts/Makefile.kasan @@ -2,6 +2,8 @@ CFLAGS_KASAN_NOSANITIZE := -fno-builtin KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET) +cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1))) + ifdef CONFIG_KASAN_GENERIC ifdef CONFIG_KASAN_INLINE @@ -12,8 +14,6 @@ endif CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address -cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1))) - # -fasan-shadow-offset fails without -fsanitize CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \ -fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \ @@ -36,14 +36,14 @@ endif # CONFIG_KASAN_GENERIC ifdef CONFIG_KASAN_SW_TAGS ifdef CONFIG_KASAN_INLINE - instrumentation_flags := -mllvm -hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET) + instrumentation_flags := $(call cc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)) else - instrumentation_flags := -mllvm -hwasan-instrument-with-calls=1 + instrumentation_flags := $(call cc-param,hwasan-instrument-with-calls=1) endif CFLAGS_KASAN := -fsanitize=kernel-hwaddress \ - -mllvm -hwasan-instrument-stack=$(CONFIG_KASAN_STACK) \ - -mllvm -hwasan-use-short-granules=0 \ + $(call cc-param,hwasan-instrument-stack=$(CONFIG_KASAN_STACK)) \ + $(call cc-param,hwasan-use-short-granules=0) \ $(instrumentation_flags) endif # CONFIG_KASAN_SW_TAGS -- cgit v1.2.3 From 02c587733c8161355a43e6e110c2e29bd0acff72 Mon Sep 17 00:00:00 2001 From: Walter Wu Date: Fri, 16 Apr 2021 15:46:00 -0700 Subject: kasan: remove redundant config option CONFIG_KASAN_STACK and CONFIG_KASAN_STACK_ENABLE both enable KASAN stack instrumentation, but we should only need one config, so that we remove CONFIG_KASAN_STACK_ENABLE and make CONFIG_KASAN_STACK workable. see [1]. When enable KASAN stack instrumentation, then for gcc we could do no prompt and default value y, and for clang prompt and default value n. This patch fixes the following compilation warning: include/linux/kasan.h:333:30: warning: 'CONFIG_KASAN_STACK' is not defined, evaluates to 0 [-Wundef] [akpm@linux-foundation.org: fix merge snafu] Link: https://bugzilla.kernel.org/show_bug.cgi?id=210221 [1] Link: https://lkml.kernel.org/r/20210226012531.29231-1-walter-zh.wu@mediatek.com Fixes: d9b571c885a8 ("kasan: fix KASAN_STACK dependency for HW_TAGS") Signed-off-by: Walter Wu Suggested-by: Dmitry Vyukov Reviewed-by: Nathan Chancellor Acked-by: Arnd Bergmann Reviewed-by: Andrey Konovalov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Alexander Potapenko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/Makefile.kasan | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan index 127012f45166..3d791908ed36 100644 --- a/scripts/Makefile.kasan +++ b/scripts/Makefile.kasan @@ -4,6 +4,12 @@ KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET) cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1))) +ifdef CONFIG_KASAN_STACK + stack_enable := 1 +else + stack_enable := 0 +endif + ifdef CONFIG_KASAN_GENERIC ifdef CONFIG_KASAN_INLINE @@ -27,7 +33,7 @@ else CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \ $(call cc-param,asan-globals=1) \ $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \ - $(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \ + $(call cc-param,asan-stack=$(stack_enable)) \ $(call cc-param,asan-instrument-allocas=1) endif @@ -42,7 +48,7 @@ else endif CFLAGS_KASAN := -fsanitize=kernel-hwaddress \ - $(call cc-param,hwasan-instrument-stack=$(CONFIG_KASAN_STACK)) \ + $(call cc-param,hwasan-instrument-stack=$(stack_enable)) \ $(call cc-param,hwasan-use-short-granules=0) \ $(instrumentation_flags) -- cgit v1.2.3