From 1739f09e33d8f66bf48ddbc3eca615574da6c4f6 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 13 Nov 2013 15:20:04 -0500 Subject: [PATCH 1/2] ftrace/x86: Load ftrace_ops in parameter not the variable holding it Function tracing callbacks expect to have the ftrace_ops that registered it passed to them, not the address of the variable that holds the ftrace_ops that registered it. Use a mov instead of a lea to store the ftrace_ops into the parameter of the function tracing callback. Signed-off-by: Steven Rostedt Reviewed-by: Masami Hiramatsu Link: http://lkml.kernel.org/r/20131113152004.459787f9@gandalf.local.home Signed-off-by: H. Peter Anvin Cc: # v3.8+ --- arch/x86/kernel/entry_32.S | 4 ++-- arch/x86/kernel/entry_64.S | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 51e2988c5728..a2a4f4697889 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -1082,7 +1082,7 @@ ENTRY(ftrace_caller) pushl $0 /* Pass NULL as regs pointer */ movl 4*4(%esp), %eax movl 0x4(%ebp), %edx - leal function_trace_op, %ecx + movl function_trace_op, %ecx subl $MCOUNT_INSN_SIZE, %eax .globl ftrace_call @@ -1140,7 +1140,7 @@ ENTRY(ftrace_regs_caller) movl 12*4(%esp), %eax /* Load ip (1st parameter) */ subl $MCOUNT_INSN_SIZE, %eax /* Adjust ip */ movl 0x4(%ebp), %edx /* Load parent ip (2nd parameter) */ - leal function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */ + movl function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */ pushl %esp /* Save pt_regs as 4th parameter */ GLOBAL(ftrace_regs_call) diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index e21b0785a85b..1e96c3628bf2 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -88,7 +88,7 @@ END(function_hook) MCOUNT_SAVE_FRAME \skip /* Load the ftrace_ops into the 3rd parameter */ - leaq function_trace_op, %rdx + movq function_trace_op(%rip), %rdx /* Load ip into the first parameter */ movq RIP(%rsp), %rdi From 26bef1318adc1b3a530ecc807ef99346db2aa8b0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 11 Jan 2014 19:15:52 -0800 Subject: [PATCH 2/2] x86, fpu, amd: Clear exceptions in AMD FXSAVE workaround Before we do an EMMS in the AMD FXSAVE information leak workaround we need to clear any pending exceptions, otherwise we trap with a floating-point exception inside this code. Reported-by: halfdog Tested-by: Borislav Petkov Link: http://lkml.kernel.org/r/CA%2B55aFxQnY_PCG_n4=0w-VG=YLXL-yr7oMxyy0WU2gCBAf3ydg@mail.gmail.com Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/fpu-internal.h | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index c49a613c6452..cea1c76d49bf 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -293,12 +293,13 @@ static inline int restore_fpu_checking(struct task_struct *tsk) /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception is pending. Clear the x87 state here by setting it to fixed values. "m" is a random variable that should be in L1 */ - alternative_input( - ASM_NOP8 ASM_NOP2, - "emms\n\t" /* clear stack tags */ - "fildl %P[addr]", /* set F?P to defined value */ - X86_FEATURE_FXSAVE_LEAK, - [addr] "m" (tsk->thread.fpu.has_fpu)); + if (unlikely(static_cpu_has(X86_FEATURE_FXSAVE_LEAK))) { + asm volatile( + "fnclex\n\t" + "emms\n\t" + "fildl %P[addr]" /* set F?P to defined value */ + : : [addr] "m" (tsk->thread.fpu.has_fpu)); + } return fpu_restore_checking(&tsk->thread.fpu); }