A recent enhancement intentionally fails the kernel build if the compiler does not support retpolines and CONFIG_RETPOLINE is set.
However, the patch that introduced it did not change RETPOLINE macro references into CONFIG_RETPOLINE ones. As a result, indirect branches that are used by init functions are not kept (i.e., they use retpolines), and modules that do not use retpolines are marked as retpoline-safe.
Fix it be changing RETPOLINE into CONFIG_RETPOLINE.
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") Cc: Peter Zijlstra peterz@infradead.org Cc: Zhenzhong Duan zhenzhong.duan@oracle.com Cc: Thomas Gleixner tglx@linutronix.de Cc: David Woodhouse dwmw@amazon.co.uk Cc: Andy Lutomirski luto@kernel.org Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit namit@vmware.com --- arch/x86/kernel/cpu/bugs.c | 2 +- include/linux/compiler-gcc.h | 2 +- include/linux/module.h | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 8654b8b0c848..1de0f4170178 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -215,7 +215,7 @@ static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init = static enum spectre_v2_user_mitigation spectre_v2_user __ro_after_init = SPECTRE_V2_USER_NONE;
-#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE static bool spectre_v2_bad_module;
bool retpoline_module_ok(bool has_retpoline) diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 2010493e1040..977ddf2774f9 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -68,7 +68,7 @@ */ #define uninitialized_var(x) x = x
-#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE #define __noretpoline __attribute__((__indirect_branch__("keep"))) #endif
diff --git a/include/linux/module.h b/include/linux/module.h index fce6b4335e36..0c575f51fe57 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -817,7 +817,7 @@ static inline void module_bug_finalize(const Elf_Ehdr *hdr, static inline void module_bug_cleanup(struct module *mod) {} #endif /* CONFIG_GENERIC_BUG */
-#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE extern bool retpoline_module_ok(bool has_retpoline); #else static inline bool retpoline_module_ok(bool has_retpoline)
On 2019/1/1 7:42, Nadav Amit wrote:
A recent enhancement intentionally fails the kernel build if the compiler does not support retpolines and CONFIG_RETPOLINE is set.
However, the patch that introduced it did not change RETPOLINE macro references into CONFIG_RETPOLINE ones. As a result, indirect branches that are used by init functions are not kept (i.e., they use retpolines), and modules that do not use retpolines are marked as retpoline-safe.
Fix it be changing RETPOLINE into CONFIG_RETPOLINE.
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") Cc: Peter Zijlstra peterz@infradead.org Cc: Zhenzhong Duan zhenzhong.duan@oracle.com Cc: Thomas Gleixner tglx@linutronix.de Cc: David Woodhouse dwmw@amazon.co.uk Cc: Andy Lutomirski luto@kernel.org Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit namit@vmware.com
arch/x86/kernel/cpu/bugs.c | 2 +- include/linux/compiler-gcc.h | 2 +- include/linux/module.h | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 8654b8b0c848..1de0f4170178 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -215,7 +215,7 @@ static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init = static enum spectre_v2_user_mitigation spectre_v2_user __ro_after_init = SPECTRE_V2_USER_NONE; -#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE static bool spectre_v2_bad_module; bool retpoline_module_ok(bool has_retpoline) diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 2010493e1040..977ddf2774f9 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -68,7 +68,7 @@ */ #define uninitialized_var(x) x = x -#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE #define __noretpoline __attribute__((__indirect_branch__("keep"))) #endif diff --git a/include/linux/module.h b/include/linux/module.h index fce6b4335e36..0c575f51fe57 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -817,7 +817,7 @@ static inline void module_bug_finalize(const Elf_Ehdr *hdr, static inline void module_bug_cleanup(struct module *mod) {} #endif /* CONFIG_GENERIC_BUG */ -#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE extern bool retpoline_module_ok(bool has_retpoline); #else static inline bool retpoline_module_ok(bool has_retpoline)
Someone sent a similar patch last month, see below link, you missed the change in scripts/mod/modpost.c
https://lkml.org/lkml/2018/12/10/540
But you patch description is more clear.
On Jan 1, 2019, at 5:17 PM, Zhenzhong Duan zhenzhong.duan@oracle.com wrote:
On 2019/1/1 7:42, Nadav Amit wrote:
A recent enhancement intentionally fails the kernel build if the compiler does not support retpolines and CONFIG_RETPOLINE is set.
However, the patch that introduced it did not change RETPOLINE macro references into CONFIG_RETPOLINE ones. As a result, indirect branches that are used by init functions are not kept (i.e., they use retpolines), and modules that do not use retpolines are marked as retpoline-safe.
Fix it be changing RETPOLINE into CONFIG_RETPOLINE.
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") Cc: Peter Zijlstra peterz@infradead.org Cc: Zhenzhong Duan zhenzhong.duan@oracle.com Cc: Thomas Gleixner tglx@linutronix.de Cc: David Woodhouse dwmw@amazon.co.uk Cc: Andy Lutomirski luto@kernel.org Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit namit@vmware.com
arch/x86/kernel/cpu/bugs.c | 2 +- include/linux/compiler-gcc.h | 2 +- include/linux/module.h | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 8654b8b0c848..1de0f4170178 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -215,7 +215,7 @@ static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init = static enum spectre_v2_user_mitigation spectre_v2_user __ro_after_init = SPECTRE_V2_USER_NONE; -#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE static bool spectre_v2_bad_module; bool retpoline_module_ok(bool has_retpoline) diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 2010493e1040..977ddf2774f9 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -68,7 +68,7 @@ */ #define uninitialized_var(x) x = x -#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE #define __noretpoline __attribute__((__indirect_branch__("keep"))) #endif diff --git a/include/linux/module.h b/include/linux/module.h index fce6b4335e36..0c575f51fe57 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -817,7 +817,7 @@ static inline void module_bug_finalize(const Elf_Ehdr *hdr, static inline void module_bug_cleanup(struct module *mod) {} #endif /* CONFIG_GENERIC_BUG */ -#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE extern bool retpoline_module_ok(bool has_retpoline); #else static inline bool retpoline_module_ok(bool has_retpoline)
Someone sent a similar patch last month, see below link, you missed the change in scripts/mod/modpost.c
Indeed. I missed this patch since it wasn’t on tip (and Google wasn’t helpful either).
I wonder why it has still not been applied.
On 2019/1/3 1:23, Nadav Amit wrote:
On Jan 1, 2019, at 5:17 PM, Zhenzhong Duan zhenzhong.duan@oracle.com wrote:
On 2019/1/1 7:42, Nadav Amit wrote:
A recent enhancement intentionally fails the kernel build if the compiler does not support retpolines and CONFIG_RETPOLINE is set.
However, the patch that introduced it did not change RETPOLINE macro references into CONFIG_RETPOLINE ones. As a result, indirect branches that are used by init functions are not kept (i.e., they use retpolines), and modules that do not use retpolines are marked as retpoline-safe.
Fix it be changing RETPOLINE into CONFIG_RETPOLINE.
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") Cc: Peter Zijlstra peterz@infradead.org Cc: Zhenzhong Duan zhenzhong.duan@oracle.com Cc: Thomas Gleixner tglx@linutronix.de Cc: David Woodhouse dwmw@amazon.co.uk Cc: Andy Lutomirski luto@kernel.org Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit namit@vmware.com
arch/x86/kernel/cpu/bugs.c | 2 +- include/linux/compiler-gcc.h | 2 +- include/linux/module.h | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 8654b8b0c848..1de0f4170178 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -215,7 +215,7 @@ static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init = static enum spectre_v2_user_mitigation spectre_v2_user __ro_after_init = SPECTRE_V2_USER_NONE; -#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE static bool spectre_v2_bad_module; bool retpoline_module_ok(bool has_retpoline) diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 2010493e1040..977ddf2774f9 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -68,7 +68,7 @@ */ #define uninitialized_var(x) x = x -#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE #define __noretpoline __attribute__((__indirect_branch__("keep"))) #endif diff --git a/include/linux/module.h b/include/linux/module.h index fce6b4335e36..0c575f51fe57 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -817,7 +817,7 @@ static inline void module_bug_finalize(const Elf_Ehdr *hdr, static inline void module_bug_cleanup(struct module *mod) {} #endif /* CONFIG_GENERIC_BUG */ -#ifdef RETPOLINE +#ifdef CONFIG_RETPOLINE extern bool retpoline_module_ok(bool has_retpoline); #else static inline bool retpoline_module_ok(bool has_retpoline)
Someone sent a similar patch last month, see below link, you missed the change in scripts/mod/modpost.c
Indeed. I missed this patch since it wasn’t on tip (and Google wasn’t helpful either).
I wonder why it has still not been applied.
See https://lkml.org/lkml/2018/12/21/244
linux-stable-mirror@lists.linaro.org
-
Nadav Amit -
Zhenzhong Duan