From: Andi Kleen <a...@linux.intel.com> Convert all indirect jumps in core 32/64bit entry assembler code to use non speculative sequences.
Based on code from David Woodhouse and Tim Chen Signed-off-by: Andi Kleen <a...@linux.intel.com> --- arch/x86/entry/entry_32.S | 5 +++-- arch/x86/entry/entry_64.S | 12 +++++++----- 2 files changed, 10 insertions(+), 7 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index ace8f321a5a1..a4b88260d6f7 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -44,6 +44,7 @@ #include <asm/asm.h> #include <asm/smap.h> #include <asm/frame.h> +#include <asm/jump-asm.h> .section .entry.text, "ax" @@ -290,7 +291,7 @@ ENTRY(ret_from_fork) /* kernel thread */ 1: movl %edi, %eax - call *%ebx + NOSPEC_CALL %ebx /* * A kernel thread is allowed to return here after successfully * calling do_execve(). Exit to userspace to complete the execve() @@ -919,7 +920,7 @@ common_exception: movl %ecx, %es TRACE_IRQS_OFF movl %esp, %eax # pt_regs pointer - call *%edi + NOSPEC_CALL %edi jmp ret_from_exception END(common_exception) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index f048e384ff54..486990fb3e4d 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/frame.h> +#include <asm/jump-asm.h> #include <linux/err.h> #include "calling.h" @@ -191,7 +192,7 @@ ENTRY(entry_SYSCALL_64_trampoline) */ pushq %rdi movq $entry_SYSCALL_64_stage2, %rdi - jmp *%rdi + NOSPEC_JMP %rdi END(entry_SYSCALL_64_trampoline) .popsection @@ -269,8 +270,9 @@ entry_SYSCALL_64_fastpath: * This call instruction is handled specially in stub_ptregs_64. * It might end up jumping to the slow path. If it jumps, RAX * and all argument registers are clobbered. - */ - call *sys_call_table(, %rax, 8) + */ + movq sys_call_table(, %rax, 8), %rax + NOSPEC_CALL %rax .Lentry_SYSCALL_64_after_fastpath_call: movq %rax, RAX(%rsp) @@ -442,7 +444,7 @@ ENTRY(stub_ptregs_64) jmp entry_SYSCALL64_slow_path 1: - jmp *%rax /* Called from C */ + NOSPEC_JMP %rax /* Called from C */ END(stub_ptregs_64) .macro ptregs_stub func @@ -521,7 +523,7 @@ ENTRY(ret_from_fork) 1: /* kernel thread */ movq %r12, %rdi - call *%rbx + NOSPEC_CALL %rbx /* * A kernel thread is allowed to return here after successfully * calling do_execve(). Exit to userspace to complete the execve() -- 2.14.3