Commit-ID: 71f3944307adb0bf454ecef3a99d3e758ccd0038 Gitweb: http://git.kernel.org/tip/71f3944307adb0bf454ecef3a99d3e758ccd0038 Author: Juergen Gross <jgr...@suse.com> AuthorDate: Thu, 31 Aug 2017 19:42:49 +0200 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Thu, 31 Aug 2017 20:28:31 +0200
x86/xen: Get rid of paravirt op adjust_exception_frame When running as Xen pv-guest the exception frame on the stack contains %r11 and %rcx additional to the other data pushed by the processor. Instead of having a paravirt op being called for each exception type prepend the Xen specific code to each exception entry. When running as Xen pv-guest just use the exception entry with prepended instructions, otherwise use the entry without the Xen specific code. [ tglx: Merged through tip to avoid ugly merge conflict ] Signed-off-by: Juergen Gross <jgr...@suse.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: xen-de...@lists.xenproject.org Cc: boris.ostrov...@oracle.com Cc: l...@amacapital.net Link: http://lkml.kernel.org/r/20170831174249.26853-1...@pfupf.net --- arch/x86/entry/entry_64.S | 23 ++------ arch/x86/entry/entry_64_compat.S | 1 - arch/x86/include/asm/paravirt.h | 5 -- arch/x86/include/asm/paravirt_types.h | 3 -- arch/x86/include/asm/proto.h | 3 ++ arch/x86/include/asm/traps.h | 28 ++++++++-- arch/x86/kernel/asm-offsets_64.c | 1 - arch/x86/kernel/paravirt.c | 3 -- arch/x86/xen/enlighten_pv.c | 98 +++++++++++++++++++++++------------ arch/x86/xen/irq.c | 3 -- arch/x86/xen/xen-asm_64.S | 41 +++++++++++++-- arch/x86/xen/xen-ops.h | 1 - 12 files changed, 133 insertions(+), 77 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 7a1d383..bdd024a 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -821,7 +821,6 @@ ENTRY(\sym) .endif ASM_CLAC - PARAVIRT_ADJUST_EXCEPTION_FRAME .ifeq \has_error_code pushq $-1 /* ORIG_RAX: no syscall to restart */ @@ -967,7 +966,7 @@ ENTRY(do_softirq_own_stack) ENDPROC(do_softirq_own_stack) #ifdef CONFIG_XEN -idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0 +idtentry hypervisor_callback xen_do_hypervisor_callback has_error_code=0 /* * A note on the "critical region" in our callback handler. @@ -1034,8 +1033,6 @@ ENTRY(xen_failsafe_callback) movq 8(%rsp), %r11 addq $0x30, %rsp pushq $0 /* RIP */ - pushq %r11 - pushq %rcx UNWIND_HINT_IRET_REGS offset=8 jmp general_protection 1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */ @@ -1066,9 +1063,8 @@ idtentry int3 do_int3 has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK idtentry stack_segment do_stack_segment has_error_code=1 #ifdef CONFIG_XEN -idtentry xen_debug do_debug has_error_code=0 -idtentry xen_int3 do_int3 has_error_code=0 -idtentry xen_stack_segment do_stack_segment has_error_code=1 +idtentry xendebug do_debug has_error_code=0 +idtentry xenint3 do_int3 has_error_code=0 #endif idtentry general_protection do_general_protection has_error_code=1 @@ -1232,21 +1228,10 @@ ENTRY(error_exit) END(error_exit) /* Runs on exception stack */ +/* XXX: broken on Xen PV */ ENTRY(nmi) UNWIND_HINT_IRET_REGS /* - * Fix up the exception frame if we're on Xen. - * PARAVIRT_ADJUST_EXCEPTION_FRAME is guaranteed to push at most - * one value to the stack on native, so it may clobber the rdx - * scratch slot, but it won't clobber any of the important - * slots past it. - * - * Xen is a different story, because the Xen frame itself overlaps - * the "NMI executing" variable. - */ - PARAVIRT_ADJUST_EXCEPTION_FRAME - - /* * We allow breakpoints in NMIs. If a breakpoint occurs, then * the iretq it performs will take us out of NMI context. * This means that we can have nested NMIs where the next diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 5314d7b..d8468ba 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -293,7 +293,6 @@ ENTRY(entry_INT80_compat) /* * Interrupts are off on entry. */ - PARAVIRT_ADJUST_EXCEPTION_FRAME ASM_CLAC /* Do this early to minimize exposure */ SWAPGS diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 9ccac19..c25dd22 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -960,11 +960,6 @@ extern void default_banner(void); #define GET_CR2_INTO_RAX \ call PARA_INDIRECT(pv_mmu_ops+PV_MMU_read_cr2) -#define PARAVIRT_ADJUST_EXCEPTION_FRAME \ - PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_adjust_exception_frame), \ - CLBR_NONE, \ - call PARA_INDIRECT(pv_irq_ops+PV_IRQ_adjust_exception_frame)) - #define USERGS_SYSRET64 \ PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret64), \ CLBR_NONE, \ diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 9ffc36b..6b64fc6 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -196,9 +196,6 @@ struct pv_irq_ops { void (*safe_halt)(void); void (*halt)(void); -#ifdef CONFIG_X86_64 - void (*adjust_exception_frame)(void); -#endif } __no_randomize_layout; struct pv_mmu_ops { diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h index 8d3964f..b408b18 100644 --- a/arch/x86/include/asm/proto.h +++ b/arch/x86/include/asm/proto.h @@ -24,6 +24,9 @@ void entry_SYSENTER_compat(void); void __end_entry_SYSENTER_compat(void); void entry_SYSCALL_compat(void); void entry_INT80_compat(void); +#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV) +void xen_entry_INT80_compat(void); +#endif #endif void x86_configure_nx(void); diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index cd0365e..5545f64 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -13,9 +13,6 @@ asmlinkage void divide_error(void); asmlinkage void debug(void); asmlinkage void nmi(void); asmlinkage void int3(void); -asmlinkage void xen_debug(void); -asmlinkage void xen_int3(void); -asmlinkage void xen_stack_segment(void); asmlinkage void overflow(void); asmlinkage void bounds(void); asmlinkage void invalid_op(void); @@ -38,6 +35,31 @@ asmlinkage void machine_check(void); #endif /* CONFIG_X86_MCE */ asmlinkage void simd_coprocessor_error(void); +#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV) +asmlinkage void xen_divide_error(void); +asmlinkage void xen_xendebug(void); +asmlinkage void xen_xenint3(void); +asmlinkage void xen_nmi(void); +asmlinkage void xen_overflow(void); +asmlinkage void xen_bounds(void); +asmlinkage void xen_invalid_op(void); +asmlinkage void xen_device_not_available(void); +asmlinkage void xen_double_fault(void); +asmlinkage void xen_coprocessor_segment_overrun(void); +asmlinkage void xen_invalid_TSS(void); +asmlinkage void xen_segment_not_present(void); +asmlinkage void xen_stack_segment(void); +asmlinkage void xen_general_protection(void); +asmlinkage void xen_page_fault(void); +asmlinkage void xen_spurious_interrupt_bug(void); +asmlinkage void xen_coprocessor_error(void); +asmlinkage void xen_alignment_check(void); +#ifdef CONFIG_X86_MCE +asmlinkage void xen_machine_check(void); +#endif /* CONFIG_X86_MCE */ +asmlinkage void xen_simd_coprocessor_error(void); +#endif + dotraplinkage void do_divide_error(struct pt_regs *, long); dotraplinkage void do_debug(struct pt_regs *, long); dotraplinkage void do_nmi(struct pt_regs *, long); diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c index 99332f5..cf42206 100644 --- a/arch/x86/kernel/asm-offsets_64.c +++ b/arch/x86/kernel/asm-offsets_64.c @@ -20,7 +20,6 @@ static char syscalls_ia32[] = { int main(void) { #ifdef CONFIG_PARAVIRT - OFFSET(PV_IRQ_adjust_exception_frame, pv_irq_ops, adjust_exception_frame); OFFSET(PV_CPU_usergs_sysret64, pv_cpu_ops, usergs_sysret64); OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs); BLANK(); diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index bc0a849..a14df9e 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -319,9 +319,6 @@ __visible struct pv_irq_ops pv_irq_ops = { .irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable), .safe_halt = native_safe_halt, .halt = native_halt, -#ifdef CONFIG_X86_64 - .adjust_exception_frame = paravirt_nop, -#endif }; __visible struct pv_cpu_ops pv_cpu_ops = { diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index 03fb07d..3859fc1 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -579,6 +579,70 @@ static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, preempt_enable(); } +#ifdef CONFIG_X86_64 +struct trap_array_entry { + void (*orig)(void); + void (*xen)(void); + bool ist_okay; +}; + +static struct trap_array_entry trap_array[] = { + { debug, xen_xendebug, true }, + { int3, xen_xenint3, true }, + { double_fault, xen_double_fault, true }, +#ifdef CONFIG_X86_MCE + { machine_check, xen_machine_check, true }, +#endif + { nmi, xen_nmi, true }, + { overflow, xen_overflow, false }, +#ifdef CONFIG_IA32_EMULATION + { entry_INT80_compat, xen_entry_INT80_compat, false }, +#endif + { page_fault, xen_page_fault, false }, + { divide_error, xen_divide_error, false }, + { bounds, xen_bounds, false }, + { invalid_op, xen_invalid_op, false }, + { device_not_available, xen_device_not_available, false }, + { coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false }, + { invalid_TSS, xen_invalid_TSS, false }, + { segment_not_present, xen_segment_not_present, false }, + { stack_segment, xen_stack_segment, false }, + { general_protection, xen_general_protection, false }, + { spurious_interrupt_bug, xen_spurious_interrupt_bug, false }, + { coprocessor_error, xen_coprocessor_error, false }, + { alignment_check, xen_alignment_check, false }, + { simd_coprocessor_error, xen_simd_coprocessor_error, false }, +}; + +static bool get_trap_addr(void **addr, unsigned int ist) +{ + unsigned int nr; + bool ist_okay = false; + + /* + * Replace trap handler addresses by Xen specific ones. + * Check for known traps using IST and whitelist them. + * The debugger ones are the only ones we care about. + * Xen will handle faults like double_fault, * so we should never see + * them. Warn if there's an unexpected IST-using fault handler. + */ + for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++) { + struct trap_array_entry *entry = trap_array + nr; + + if (*addr == entry->orig) { + *addr = entry->xen; + ist_okay = entry->ist_okay; + break; + } + } + + if (WARN_ON(ist != 0 && !ist_okay)) + return false; + + return true; +} +#endif + static int cvt_gate_to_trap(int vector, const gate_desc *val, struct trap_info *info) { @@ -591,40 +655,8 @@ static int cvt_gate_to_trap(int vector, const gate_desc *val, addr = gate_offset(val); #ifdef CONFIG_X86_64 - /* - * Look for known traps using IST, and substitute them - * appropriately. The debugger ones are the only ones we care - * about. Xen will handle faults like double_fault, - * so we should never see them. Warn if - * there's an unexpected IST-using fault handler. - */ - if (addr == (unsigned long)debug) - addr = (unsigned long)xen_debug; - else if (addr == (unsigned long)int3) - addr = (unsigned long)xen_int3; - else if (addr == (unsigned long)stack_segment) - addr = (unsigned long)xen_stack_segment; - else if (addr == (unsigned long)double_fault) { - /* Don't need to handle these */ + if (!get_trap_addr((void **)&addr, val->bits.ist)) return 0; -#ifdef CONFIG_X86_MCE - } else if (addr == (unsigned long)machine_check) { - /* - * when xen hypervisor inject vMCE to guest, - * use native mce handler to handle it - */ - ; -#endif - } else if (addr == (unsigned long)nmi) - /* - * Use the native version as well. - */ - ; - else { - /* Some other trap using IST? */ - if (WARN_ON(val->bits.ist != 0)) - return 0; - } #endif /* CONFIG_X86_64 */ info->address = addr; diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c index 33e9295..d4eff56 100644 --- a/arch/x86/xen/irq.c +++ b/arch/x86/xen/irq.c @@ -123,9 +123,6 @@ static const struct pv_irq_ops xen_irq_ops __initconst = { .safe_halt = xen_safe_halt, .halt = xen_halt, -#ifdef CONFIG_X86_64 - .adjust_exception_frame = xen_adjust_exception_frame, -#endif }; void __init xen_init_irq_ops(void) diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S index 3a3b6a2..dae2cc3 100644 --- a/arch/x86/xen/xen-asm_64.S +++ b/arch/x86/xen/xen-asm_64.S @@ -16,11 +16,42 @@ #include <linux/linkage.h> -ENTRY(xen_adjust_exception_frame) - mov 8+0(%rsp), %rcx - mov 8+8(%rsp), %r11 - ret $16 -ENDPROC(xen_adjust_exception_frame) +.macro xen_pv_trap name +ENTRY(xen_\name) + pop %rcx + pop %r11 + jmp \name +END(xen_\name) +.endm + +xen_pv_trap divide_error +xen_pv_trap debug +xen_pv_trap xendebug +xen_pv_trap int3 +xen_pv_trap xenint3 +xen_pv_trap nmi +xen_pv_trap overflow +xen_pv_trap bounds +xen_pv_trap invalid_op +xen_pv_trap device_not_available +xen_pv_trap double_fault +xen_pv_trap coprocessor_segment_overrun +xen_pv_trap invalid_TSS +xen_pv_trap segment_not_present +xen_pv_trap stack_segment +xen_pv_trap general_protection +xen_pv_trap page_fault +xen_pv_trap spurious_interrupt_bug +xen_pv_trap coprocessor_error +xen_pv_trap alignment_check +#ifdef CONFIG_X86_MCE +xen_pv_trap machine_check +#endif /* CONFIG_X86_MCE */ +xen_pv_trap simd_coprocessor_error +#ifdef CONFIG_IA32_EMULATION +xen_pv_trap entry_INT80_compat +#endif +xen_pv_trap hypervisor_callback hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32 /* diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h index 70301ac..c8a6d22 100644 --- a/arch/x86/xen/xen-ops.h +++ b/arch/x86/xen/xen-ops.h @@ -138,7 +138,6 @@ __visible void xen_restore_fl_direct(unsigned long); __visible void xen_iret(void); __visible void xen_sysret32(void); __visible void xen_sysret64(void); -__visible void xen_adjust_exception_frame(void); extern int xen_panic_handler_init(void);
