diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0069-x86-retpoline-entry-Convert-entry-assembler-indirect.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0069-x86-retpoline-entry-Convert-entry-assembler-indirect.patch | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0069-x86-retpoline-entry-Convert-entry-assembler-indirect.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0069-x86-retpoline-entry-Convert-entry-assembler-indirect.patch new file mode 100644 index 00000000..db94d3d8 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0069-x86-retpoline-entry-Convert-entry-assembler-indirect.patch @@ -0,0 +1,122 @@ +From a2073819181d22ec2197b919f5f5d3a7305dd5c0 Mon Sep 17 00:00:00 2001 +From: David Woodhouse <dwmw@amazon.co.uk> +Date: Thu, 11 Jan 2018 21:46:28 +0000 +Subject: [PATCH 069/103] x86/retpoline/entry: Convert entry assembler indirect + jumps + +commit 2641f08bb7fc63a636a2b18173221d7040a3512e upstream. + +Convert indirect jumps in core 32/64bit entry assembler code to use +non-speculative sequences when CONFIG_RETPOLINE is enabled. + +Don't use CALL_NOSPEC in entry_SYSCALL_64_fastpath because the return +address after the 'call' instruction must be *precisely* at the +.Lentry_SYSCALL_64_after_fastpath label for stub_ptregs_64 to work, +and the use of alternatives will mess that up unless we play horrid +games to prepend with NOPs and make the variants the same length. It's +not worth it; in the case where we ALTERNATIVE out the retpoline, the +first instruction at __x86.indirect_thunk.rax is going to be a bare +jmp *%rax anyway. + +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Acked-by: Ingo Molnar <mingo@kernel.org> +Acked-by: Arjan van de Ven <arjan@linux.intel.com> +Cc: gnomes@lxorguk.ukuu.org.uk +Cc: Rik van Riel <riel@redhat.com> +Cc: Andi Kleen <ak@linux.intel.com> +Cc: Josh Poimboeuf <jpoimboe@redhat.com> +Cc: thomas.lendacky@amd.com +Cc: Peter Zijlstra <peterz@infradead.org> +Cc: Linus Torvalds <torvalds@linux-foundation.org> +Cc: Jiri Kosina <jikos@kernel.org> +Cc: Andy Lutomirski <luto@amacapital.net> +Cc: Dave Hansen <dave.hansen@intel.com> +Cc: Kees Cook <keescook@google.com> +Cc: Tim Chen <tim.c.chen@linux.intel.com> +Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> +Cc: Paul Turner <pjt@google.com> +Link: https://lkml.kernel.org/r/1515707194-20531-7-git-send-email-dwmw@amazon.co.uk +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/entry/entry_32.S | 5 +++-- + arch/x86/entry/entry_64.S | 10 ++++++++-- + 2 files changed, 11 insertions(+), 4 deletions(-) + +diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S +index edba860..7b95f35 100644 +--- a/arch/x86/entry/entry_32.S ++++ b/arch/x86/entry/entry_32.S +@@ -45,6 +45,7 @@ + #include <asm/asm.h> + #include <asm/smap.h> + #include <asm/export.h> ++#include <asm/nospec-branch.h> + + .section .entry.text, "ax" + +@@ -260,7 +261,7 @@ ENTRY(ret_from_fork) + + /* kernel thread */ + 1: movl %edi, %eax +- call *%ebx ++ CALL_NOSPEC %ebx + /* + * A kernel thread is allowed to return here after successfully + * calling do_execve(). Exit to userspace to complete the execve() +@@ -1062,7 +1063,7 @@ error_code: + movl %ecx, %es + TRACE_IRQS_OFF + movl %esp, %eax # pt_regs pointer +- call *%edi ++ CALL_NOSPEC %edi + jmp ret_from_exception + END(page_fault) + +diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S +index 5bb9b02..f7ebaa1 100644 +--- a/arch/x86/entry/entry_64.S ++++ b/arch/x86/entry/entry_64.S +@@ -37,6 +37,7 @@ + #include <asm/pgtable_types.h> + #include <asm/export.h> + #include <asm/kaiser.h> ++#include <asm/nospec-branch.h> + #include <linux/err.h> + + /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */ +@@ -208,7 +209,12 @@ entry_SYSCALL_64_fastpath: + * It might end up jumping to the slow path. If it jumps, RAX + * and all argument registers are clobbered. + */ ++#ifdef CONFIG_RETPOLINE ++ movq sys_call_table(, %rax, 8), %rax ++ call __x86_indirect_thunk_rax ++#else + call *sys_call_table(, %rax, 8) ++#endif + .Lentry_SYSCALL_64_after_fastpath_call: + + movq %rax, RAX(%rsp) +@@ -380,7 +386,7 @@ ENTRY(stub_ptregs_64) + jmp entry_SYSCALL64_slow_path + + 1: +- jmp *%rax /* Called from C */ ++ JMP_NOSPEC %rax /* Called from C */ + END(stub_ptregs_64) + + .macro ptregs_stub func +@@ -457,7 +463,7 @@ ENTRY(ret_from_fork) + 1: + /* kernel thread */ + movq %r12, %rdi +- call *%rbx ++ CALL_NOSPEC %rbx + /* + * A kernel thread is allowed to return here after successfully + * calling do_execve(). Exit to userspace to complete the execve() +-- +2.7.4 + |