The following commit has been merged into the x86/core branch of tip: Commit-ID: f1a033cc6b9eb6d80322008422df3c87aa5d47a0 Gitweb: https://git.kernel.org/tip/f1a033cc6b9eb6d80322008422df3c87aa5d47a0 Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Wed, 09 Nov 2022 14:44:18 +01:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Thu, 24 Nov 2022 13:56:44 +01:00 x86/paravirt: Use common macro for creating simple asm paravirt functions There are some paravirt assembler functions which are sharing a common pattern. Introduce a macro DEFINE_PARAVIRT_ASM() for creating them. Note that this macro is including explicit alignment of the generated functions, leading to __raw_callee_save___kvm_vcpu_is_preempted(), _paravirt_nop() and paravirt_ret0() to be aligned at 4 byte boundaries now. The explicit _paravirt_nop() prototype in paravirt.c isn't needed, as it is included in paravirt_types.h already. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Srivatsa S. Bhat (VMware) <srivatsa@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20221109134418.6516-1-jgross@xxxxxxxx --- arch/x86/include/asm/paravirt.h | 12 ++++++- arch/x86/include/asm/qspinlock_paravirt.h | 47 +++++++++------------- arch/x86/kernel/kvm.c | 19 ++------- arch/x86/kernel/paravirt.c | 23 +----------- 4 files changed, 40 insertions(+), 61 deletions(-) diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 2851bc2..73e9522 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -731,6 +731,18 @@ static __always_inline unsigned long arch_local_irq_save(void) #undef PVOP_VCALL4 #undef PVOP_CALL4 +#define DEFINE_PARAVIRT_ASM(func, instr, sec) \ + asm (".pushsection " #sec ", \"ax\"\n" \ + ".global " #func "\n\t" \ + ".type " #func ", @function\n\t" \ + ASM_FUNC_ALIGN "\n" \ + #func ":\n\t" \ + ASM_ENDBR \ + instr "\n\t" \ + ASM_RET \ + ".size " #func ", . - " #func "\n\t" \ + ".popsection") + extern void default_banner(void); #else /* __ASSEMBLY__ */ diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h index d861127..42b17cf 100644 --- a/arch/x86/include/asm/qspinlock_paravirt.h +++ b/arch/x86/include/asm/qspinlock_paravirt.h @@ -14,8 +14,6 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text"); #define __pv_queued_spin_unlock __pv_queued_spin_unlock -#define PV_UNLOCK "__raw_callee_save___pv_queued_spin_unlock" -#define PV_UNLOCK_SLOWPATH "__raw_callee_save___pv_queued_spin_unlock_slowpath" /* * Optimized assembly version of __raw_callee_save___pv_queued_spin_unlock @@ -37,32 +35,27 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text"); * rsi = lockval (second argument) * rdx = internal variable (set to 0) */ -asm (".pushsection .spinlock.text, \"ax\";" - ".globl " PV_UNLOCK ";" - ".type " PV_UNLOCK ", @function;" - ASM_FUNC_ALIGN - PV_UNLOCK ": " - ASM_ENDBR - FRAME_BEGIN - "push %rdx;" - "mov $0x1,%eax;" - "xor %edx,%edx;" - LOCK_PREFIX "cmpxchg %dl,(%rdi);" - "cmp $0x1,%al;" - "jne .slowpath;" - "pop %rdx;" +#define PV_UNLOCK_ASM \ + FRAME_BEGIN \ + "push %rdx\n\t" \ + "mov $0x1,%eax\n\t" \ + "xor %edx,%edx\n\t" \ + LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t" \ + "cmp $0x1,%al\n\t" \ + "jne .slowpath\n\t" \ + "pop %rdx\n\t" \ + FRAME_END \ + ASM_RET \ + ".slowpath:\n\t" \ + "push %rsi\n\t" \ + "movzbl %al,%esi\n\t" \ + "call __raw_callee_save___pv_queued_spin_unlock_slowpath\n\t" \ + "pop %rsi\n\t" \ + "pop %rdx\n\t" \ FRAME_END - ASM_RET - ".slowpath: " - "push %rsi;" - "movzbl %al,%esi;" - "call " PV_UNLOCK_SLOWPATH ";" - "pop %rsi;" - "pop %rdx;" - FRAME_END - ASM_RET - ".size " PV_UNLOCK ", .-" PV_UNLOCK ";" - ".popsection"); + +DEFINE_PARAVIRT_ASM(__raw_callee_save___pv_queued_spin_unlock, + PV_UNLOCK_ASM, .spinlock.text); #else /* CONFIG_64BIT */ diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 95fb85b..4d053cb 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -798,20 +798,13 @@ extern bool __raw_callee_save___kvm_vcpu_is_preempted(long); * Hand-optimize version for x86-64 to avoid 8 64-bit register saving and * restoring to/from the stack. */ -asm( -".pushsection .text;" -".global __raw_callee_save___kvm_vcpu_is_preempted;" -".type __raw_callee_save___kvm_vcpu_is_preempted, @function;" -ASM_FUNC_ALIGN -"__raw_callee_save___kvm_vcpu_is_preempted:" -ASM_ENDBR -"movq __per_cpu_offset(,%rdi,8), %rax;" -"cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);" -"setne %al;" -ASM_RET -".size __raw_callee_save___kvm_vcpu_is_preempted, .-__raw_callee_save___kvm_vcpu_is_preempted;" -".popsection"); +#define PV_VCPU_PREEMPTED_ASM \ + "movq __per_cpu_offset(,%rdi,8), %rax\n\t" \ + "cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax)\n\t" \ + "setne %al\n\t" +DEFINE_PARAVIRT_ASM(__raw_callee_save___kvm_vcpu_is_preempted, + PV_VCPU_PREEMPTED_ASM, .text); #endif static void __init kvm_guest_init(void) diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index e244c49..327757a 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -37,29 +37,10 @@ * nop stub, which must not clobber anything *including the stack* to * avoid confusing the entry prologues. */ -extern void _paravirt_nop(void); -asm (".pushsection .entry.text, \"ax\"\n" - ".global _paravirt_nop\n" - ASM_FUNC_ALIGN - "_paravirt_nop:\n\t" - ASM_ENDBR - ASM_RET - ".size _paravirt_nop, . - _paravirt_nop\n\t" - ".type _paravirt_nop, @function\n\t" - ".popsection"); +DEFINE_PARAVIRT_ASM(_paravirt_nop, "", .entry.text); /* stub always returning 0. */ -asm (".pushsection .entry.text, \"ax\"\n" - ".global paravirt_ret0\n" - ASM_FUNC_ALIGN - "paravirt_ret0:\n\t" - ASM_ENDBR - "xor %" _ASM_AX ", %" _ASM_AX ";\n\t" - ASM_RET - ".size paravirt_ret0, . - paravirt_ret0\n\t" - ".type paravirt_ret0, @function\n\t" - ".popsection"); - +DEFINE_PARAVIRT_ASM(paravirt_ret0, "xor %eax,%eax", .entry.text); void __init default_banner(void) {