Commit-ID: 55aedddb6149ab71bec9f050846855113977b033 Gitweb: https://git.kernel.org/tip/55aedddb6149ab71bec9f050846855113977b033 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Thu, 11 Jul 2019 13:40:55 +0200 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Wed, 17 Jul 2019 23:17:37 +0200
x86/paravirt: Make read_cr2() CALLEE_SAVE The one paravirt read_cr2() implementation (Xen) is actually quite trivial and doesn't need to clobber anything other than the return register. Making read_cr2() CALLEE_SAVE avoids all the PUSH/POP nonsense and allows more convenient use from assembly. Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Reviewed-by: Juergen Gross <jgr...@suse.com> Cc: b...@alien8.de Cc: rost...@goodmis.org Cc: l...@kernel.org Cc: torva...@linux-foundation.org Cc: h...@zytor.com Cc: dave.han...@linux.intel.com Cc: zhe...@windriver.com Cc: j...@joelfernandes.org Cc: de...@etsukata.com Link: https://lkml.kernel.org/r/20190711114335.887392...@infradead.org --- arch/x86/entry/calling.h | 6 ++++++ arch/x86/include/asm/paravirt.h | 22 +++++++++++++--------- arch/x86/include/asm/paravirt_types.h | 2 +- arch/x86/kernel/asm-offsets.c | 1 + arch/x86/kernel/head_64.S | 4 +--- arch/x86/kernel/paravirt.c | 2 +- arch/x86/xen/enlighten_pv.c | 3 ++- arch/x86/xen/mmu_pv.c | 12 +----------- arch/x86/xen/xen-asm.S | 16 ++++++++++++++++ arch/x86/xen/xen-ops.h | 3 +++ 10 files changed, 45 insertions(+), 26 deletions(-) diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 9f1f9e3b8230..830bd984182b 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -343,3 +343,9 @@ For 32-bit we have the following conventions - kernel is built with .Lafter_call_\@: #endif .endm + +#ifdef CONFIG_PARAVIRT_XXL +#define GET_CR2_INTO(reg) GET_CR2_INTO_AX ; _ASM_MOV %_ASM_AX, reg +#else +#define GET_CR2_INTO(reg) _ASM_MOV %cr2, reg +#endif diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index c25c38a05c1c..5135282683d4 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -116,7 +116,7 @@ static inline void write_cr0(unsigned long x) static inline unsigned long read_cr2(void) { - return PVOP_CALL0(unsigned long, mmu.read_cr2); + return PVOP_CALLEE0(unsigned long, mmu.read_cr2); } static inline void write_cr2(unsigned long x) @@ -909,13 +909,7 @@ extern void default_banner(void); ANNOTATE_RETPOLINE_SAFE; \ call PARA_INDIRECT(pv_ops+PV_CPU_swapgs); \ ) -#endif - -#define GET_CR2_INTO_RAX \ - ANNOTATE_RETPOLINE_SAFE; \ - call PARA_INDIRECT(pv_ops+PV_MMU_read_cr2); -#ifdef CONFIG_PARAVIRT_XXL #define USERGS_SYSRET64 \ PARA_SITE(PARA_PATCH(PV_CPU_usergs_sysret64), \ ANNOTATE_RETPOLINE_SAFE; \ @@ -929,9 +923,19 @@ extern void default_banner(void); call PARA_INDIRECT(pv_ops+PV_IRQ_save_fl); \ PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);) #endif -#endif +#endif /* CONFIG_PARAVIRT_XXL */ +#endif /* CONFIG_X86_64 */ + +#ifdef CONFIG_PARAVIRT_XXL + +#define GET_CR2_INTO_AX \ + PARA_SITE(PARA_PATCH(PV_MMU_read_cr2), \ + ANNOTATE_RETPOLINE_SAFE; \ + call PARA_INDIRECT(pv_ops+PV_MMU_read_cr2); \ + ) + +#endif /* CONFIG_PARAVIRT_XXL */ -#endif /* CONFIG_X86_32 */ #endif /* __ASSEMBLY__ */ #else /* CONFIG_PARAVIRT */ diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 946f8f1f1efc..639b2df445ee 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -220,7 +220,7 @@ struct pv_mmu_ops { void (*exit_mmap)(struct mm_struct *mm); #ifdef CONFIG_PARAVIRT_XXL - unsigned long (*read_cr2)(void); + struct paravirt_callee_save read_cr2; void (*write_cr2)(unsigned long); unsigned long (*read_cr3)(void); diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index da64452584b0..5c7ee3df4d0b 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -76,6 +76,7 @@ static void __used common(void) BLANK(); OFFSET(XEN_vcpu_info_mask, vcpu_info, evtchn_upcall_mask); OFFSET(XEN_vcpu_info_pending, vcpu_info, evtchn_upcall_pending); + OFFSET(XEN_vcpu_info_arch_cr2, vcpu_info, arch.cr2); #endif BLANK(); diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index bcd206c8ac90..0e2d72929a8c 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -29,9 +29,7 @@ #ifdef CONFIG_PARAVIRT_XXL #include <asm/asm-offsets.h> #include <asm/paravirt.h> -#define GET_CR2_INTO(reg) GET_CR2_INTO_RAX ; movq %rax, reg #else -#define GET_CR2_INTO(reg) movq %cr2, reg #define INTERRUPT_RETURN iretq #endif @@ -323,7 +321,7 @@ early_idt_handler_common: cmpq $14,%rsi /* Page fault? */ jnz 10f - GET_CR2_INTO(%rdi) /* Can clobber any volatile register if pv */ + GET_CR2_INTO(%rdi) /* can clobber %rax if pv */ call early_make_pgtable andl %eax,%eax jz 20f /* All good */ diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 98039d7fb998..0aa6256eedd8 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -370,7 +370,7 @@ struct paravirt_patch_template pv_ops = { .mmu.exit_mmap = paravirt_nop, #ifdef CONFIG_PARAVIRT_XXL - .mmu.read_cr2 = native_read_cr2, + .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(native_read_cr2), .mmu.write_cr2 = native_write_cr2, .mmu.read_cr3 = __native_read_cr3, .mmu.write_cr3 = native_write_cr3, diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index 4722ba2966ac..26b63d051bda 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -998,7 +998,8 @@ void __init xen_setup_vcpu_info_placement(void) __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); pv_ops.irq.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); - pv_ops.mmu.read_cr2 = xen_read_cr2_direct; + pv_ops.mmu.read_cr2 = + __PV_IS_CALLEE_SAVE(xen_read_cr2_direct); } } diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index f6e5eeecfc69..26e8b326966d 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1307,16 +1307,6 @@ static void xen_write_cr2(unsigned long cr2) this_cpu_read(xen_vcpu)->arch.cr2 = cr2; } -static unsigned long xen_read_cr2(void) -{ - return this_cpu_read(xen_vcpu)->arch.cr2; -} - -unsigned long xen_read_cr2_direct(void) -{ - return this_cpu_read(xen_vcpu_info.arch.cr2); -} - static noinline void xen_flush_tlb(void) { struct mmuext_op *op; @@ -2397,7 +2387,7 @@ static void xen_leave_lazy_mmu(void) } static const struct pv_mmu_ops xen_mmu_ops __initconst = { - .read_cr2 = xen_read_cr2, + .read_cr2 = __PV_IS_CALLEE_SAVE(xen_read_cr2), .write_cr2 = xen_write_cr2, .read_cr3 = xen_read_cr3, diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S index 8019edd0125c..be104eef80be 100644 --- a/arch/x86/xen/xen-asm.S +++ b/arch/x86/xen/xen-asm.S @@ -10,6 +10,7 @@ #include <asm/percpu.h> #include <asm/processor-flags.h> #include <asm/frame.h> +#include <asm/asm.h> #include <linux/linkage.h> @@ -135,3 +136,18 @@ ENTRY(check_events) FRAME_END ret ENDPROC(check_events) + +ENTRY(xen_read_cr2) + FRAME_BEGIN + _ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX + _ASM_MOV XEN_vcpu_info_arch_cr2(%_ASM_AX), %_ASM_AX + FRAME_END + ret + ENDPROC(xen_read_cr2); + +ENTRY(xen_read_cr2_direct) + FRAME_BEGIN + _ASM_MOV PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_arch_cr2, %_ASM_AX + FRAME_END + ret + ENDPROC(xen_read_cr2_direct); diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h index 2f111f47ba98..45a441c33d6d 100644 --- a/arch/x86/xen/xen-ops.h +++ b/arch/x86/xen/xen-ops.h @@ -134,6 +134,9 @@ __visible void xen_irq_disable_direct(void); __visible unsigned long xen_save_fl_direct(void); __visible void xen_restore_fl_direct(unsigned long); +__visible unsigned long xen_read_cr2(void); +__visible unsigned long xen_read_cr2_direct(void); + /* These are not functions, and cannot be called normally */ __visible void xen_iret(void); __visible void xen_sysret32(void);
