From 1482a0825bdf82dab4074bd3c824f4c87cbdf848 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 21 Jan 2016 16:49:29 -0600 Subject: x86/kvm: Set ELF function type for fastop functions The callable functions created with the FOP* and FASTOP* macros are missing ELF function annotations, which confuses tools like stacktool. Properly annotate them. This adds some additional labels to the assembly, but the generated binary code is unchanged (with the exception of instructions which have embedded references to __LINE__). Signed-off-by: Josh Poimboeuf Acked-by: Paolo Bonzini Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Bernd Petrovitsch Cc: Borislav Petkov Cc: Brian Gerst Cc: Chris J Arges Cc: Denys Vlasenko Cc: Gleb Natapov Cc: H. Peter Anvin Cc: Jiri Slaby Cc: Linus Torvalds Cc: Michal Marek Cc: Namhyung Kim Cc: Pedro Alves Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: kvm@vger.kernel.org Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/e399651c89ace54906c203c0557f66ed6ea3ce8d.1453405861.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kvm/emulate.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 1505587d06e9..aa4d72667878 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -309,23 +309,29 @@ static void invalidate_registers(struct x86_emulate_ctxt *ctxt) static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); -#define FOP_ALIGN ".align " __stringify(FASTOP_SIZE) " \n\t" +#define FOP_FUNC(name) \ + ".align " __stringify(FASTOP_SIZE) " \n\t" \ + ".type " name ", @function \n\t" \ + name ":\n\t" + #define FOP_RET "ret \n\t" #define FOP_START(op) \ extern void em_##op(struct fastop *fake); \ asm(".pushsection .text, \"ax\" \n\t" \ ".global em_" #op " \n\t" \ - FOP_ALIGN \ - "em_" #op ": \n\t" + FOP_FUNC("em_" #op) #define FOP_END \ ".popsection") -#define FOPNOP() FOP_ALIGN FOP_RET +#define FOPNOP() \ + FOP_FUNC(__stringify(__UNIQUE_ID(nop))) \ + FOP_RET #define FOP1E(op, dst) \ - FOP_ALIGN "10: " #op " %" #dst " \n\t" FOP_RET + FOP_FUNC(#op "_" #dst) \ + "10: " #op " %" #dst " \n\t" FOP_RET #define FOP1EEX(op, dst) \ FOP1E(op, dst) _ASM_EXTABLE(10b, kvm_fastop_exception) @@ -357,7 +363,8 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); FOP_END #define FOP2E(op, dst, src) \ - FOP_ALIGN #op " %" #src ", %" #dst " \n\t" FOP_RET + FOP_FUNC(#op "_" #dst "_" #src) \ + #op " %" #src ", %" #dst " \n\t" FOP_RET #define FASTOP2(op) \ FOP_START(op) \ @@ -395,7 +402,8 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); FOP_END #define FOP3E(op, dst, src, src2) \ - FOP_ALIGN #op " %" #src2 ", %" #src ", %" #dst " \n\t" FOP_RET + FOP_FUNC(#op "_" #dst "_" #src "_" #src2) \ + #op " %" #src2 ", %" #src ", %" #dst " \n\t" FOP_RET /* 3-operand, word-only, src2=cl */ #define FASTOP3WCL(op) \ @@ -407,7 +415,12 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); FOP_END /* Special case for SETcc - 1 instruction per cc */ -#define FOP_SETCC(op) ".align 4; " #op " %al; ret \n\t" +#define FOP_SETCC(op) \ + ".align 4 \n\t" \ + ".type " #op ", @function \n\t" \ + #op ": \n\t" \ + #op " %al \n\t" \ + FOP_RET asm(".global kvm_fastop_exception \n" "kvm_fastop_exception: xor %esi, %esi; ret"); -- cgit v1.2.3 From cb7390fed4c04e609a420ac0b1c07a7a781b43bf Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Fri, 22 Jan 2016 10:16:12 -0600 Subject: x86/kvm: Make test_cc() always inline With some configs (including allyesconfig), gcc doesn't inline test_cc(). When that happens, test_cc() doesn't create a stack frame before inserting the inline asm call instruction. This breaks frame pointer convention if CONFIG_FRAME_POINTER is enabled and can result in a bad stack trace. Force it to always be inlined so that its containing function's stack frame can be used. Suggested-by: Paolo Bonzini Signed-off-by: Josh Poimboeuf Acked-by: Paolo Bonzini Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Bernd Petrovitsch Cc: Borislav Petkov Cc: Brian Gerst Cc: Chris J Arges Cc: Denys Vlasenko Cc: Gleb Natapov Cc: H. Peter Anvin Cc: Jiri Slaby Cc: Linus Torvalds Cc: Michal Marek Cc: Namhyung Kim Cc: Pedro Alves Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: kvm@vger.kernel.org Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/20160122161612.GE20502@treble.redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kvm/emulate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index aa4d72667878..80363ebfd0a6 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -969,7 +969,7 @@ static int em_bsr_c(struct x86_emulate_ctxt *ctxt) return fastop(ctxt, em_bsr); } -static u8 test_cc(unsigned int condition, unsigned long flags) +static __always_inline u8 test_cc(unsigned int condition, unsigned long flags) { u8 rc; void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf); -- cgit v1.2.3 From 3f62de5f6f369b67b7ac709e3c942c9130d2c51a Mon Sep 17 00:00:00 2001 From: Chris J Arges Date: Fri, 22 Jan 2016 15:44:38 -0600 Subject: x86/kvm: Add output operand in vmx_handle_external_intr inline asm Stacktool generates the following warning: stacktool: arch/x86/kvm/vmx.o: vmx_handle_external_intr()+0x67: call without frame pointer save/setup By adding the stackpointer as an output operand, this patch ensures that a stack frame is created when CONFIG_FRAME_POINTER is enabled for the inline assmebly statement. Signed-off-by: Chris J Arges Reviewed-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: gleb@kernel.org Cc: kvm@vger.kernel.org Cc: live-patching@vger.kernel.org Cc: pbonzini@redhat.com Link: http://lkml.kernel.org/r/1453499078-9330-3-git-send-email-chris.j.arges@canonical.com Signed-off-by: Ingo Molnar --- arch/x86/kvm/vmx.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index e2951b6edbbc..e1535225bc1d 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -8356,6 +8356,7 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx) static void vmx_handle_external_intr(struct kvm_vcpu *vcpu) { u32 exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO); + register void *__sp asm(_ASM_SP); /* * If external interrupt exists, IF bit is set in rflags/eflags on the @@ -8388,8 +8389,9 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu) "call *%[entry]\n\t" : #ifdef CONFIG_X86_64 - [sp]"=&r"(tmp) + [sp]"=&r"(tmp), #endif + "+r"(__sp) : [entry]"r"(entry), [ss]"i"(__KERNEL_DS), -- cgit v1.2.3