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([172.25.112.68]) by orsmga007.jf.intel.com with ESMTP; 01 Aug 2023 02:04:29 -0700 From: Xin Li To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org Cc: Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Andy Lutomirski , Oleg Nesterov , Tony Luck , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Sean Christopherson , Peter Zijlstra , Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , Josh Poimboeuf , "Paul E . McKenney" , Catalin Marinas , Randy Dunlap , Steven Rostedt , Kim Phillips , Xin Li , Hyeonggon Yoo <42.hyeyoo@gmail.com>, "Liam R . Howlett" , Sebastian Reichel , "Kirill A . Shutemov" , Suren Baghdasaryan , Pawan Gupta , Babu Moger , Jim Mattson , Sandipan Das , Lai Jiangshan , Hans de Goede , Reinette Chatre , Daniel Sneddon , Breno Leitao , Nikunj A Dadhania , Brian Gerst , Sami Tolvanen , Alexander Potapenko , Andrew Morton , Arnd Bergmann , "Eric W . Biederman" , Kees Cook , Masami Hiramatsu , Masahiro Yamada , Ze Gao , Fei Li , Conghui , Ashok Raj , "Jason A . Donenfeld" , Mark Rutland , Jacob Pan , Jiapeng Chong , Jane Malalane , David Woodhouse , Boris Ostrovsky , Arnaldo Carvalho de Melo , Yantengsi , Christophe Leroy , Sathvika Vasireddy Subject: [PATCH RESEND v9 29/36] x86/fred: FRED entry/exit and dispatch code Date: Tue, 1 Aug 2023 01:35:46 -0700 Message-Id: <20230801083553.8468-3-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230801083553.8468-1-xin3.li@intel.com> References: <20230801083553.8468-1-xin3.li@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: "H. Peter Anvin (Intel)" The code to actually handle kernel and event entry/exit using FRED. It is split up into two files thus: - entry_64_fred.S contains the actual entrypoints and exit code, and saves and restores registers. - entry_fred.c contains the two-level event dispatch code for FRED. The first-level dispatch is on the event type, and the second-level is on the event vector. Originally-by: Megha Dey Signed-off-by: H. Peter Anvin (Intel) Co-developed-by: Xin Li Tested-by: Shan Kang Signed-off-by: Xin Li --- Changes since v8: * Don't do syscall early out in fred_entry_from_user() before there are proper performance numbers and justifications (Thomas Gleixner). * Add the control exception handler to the FRED exception handler table (Thomas Gleixner). * Add ENDBR to the FRED_ENTER asm macro. * Reflect the FRED spec 5.0 change that ERETS and ERETU add 8 to %rsp before popping the return context from the stack. Changes since v1: * Initialize a FRED exception handler to fred_bad_event() instead of NULL if no FRED handler defined for an exception vector (Peter Zijlstra). * Push calling irqentry_{enter,exit}() and instrumentation_{begin,end}() down into individual FRED exception handlers, instead of in the dispatch framework (Peter Zijlstra). --- arch/x86/entry/Makefile | 5 +- arch/x86/entry/entry_64_fred.S | 53 +++++++ arch/x86/entry/entry_fred.c | 220 ++++++++++++++++++++++++++ arch/x86/include/asm/asm-prototypes.h | 1 + arch/x86/include/asm/fred.h | 4 + arch/x86/include/asm/idtentry.h | 4 + 6 files changed, 286 insertions(+), 1 deletion(-) create mode 100644 arch/x86/entry/entry_64_fred.S create mode 100644 arch/x86/entry/entry_fred.c diff --git a/arch/x86/entry/Makefile b/arch/x86/entry/Makefile index ca2fe186994b..c93e7f5c2a06 100644 --- a/arch/x86/entry/Makefile +++ b/arch/x86/entry/Makefile @@ -18,6 +18,9 @@ obj-y += vdso/ obj-y += vsyscall/ obj-$(CONFIG_PREEMPTION) += thunk_$(BITS).o +CFLAGS_entry_fred.o += -fno-stack-protector +CFLAGS_REMOVE_entry_fred.o += -pg $(CC_FLAGS_FTRACE) +obj-$(CONFIG_X86_FRED) += entry_64_fred.o entry_fred.o + obj-$(CONFIG_IA32_EMULATION) += entry_64_compat.o syscall_32.o obj-$(CONFIG_X86_X32_ABI) += syscall_x32.o - diff --git a/arch/x86/entry/entry_64_fred.S b/arch/x86/entry/entry_64_fred.S new file mode 100644 index 000000000000..4ae12d557db3 --- /dev/null +++ b/arch/x86/entry/entry_64_fred.S @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * The actual FRED entry points. + */ + +#include + +#include "calling.h" + + .code64 + .section ".noinstr.text", "ax" + +.macro FRED_ENTER + UNWIND_HINT_END_OF_STACK + ENDBR + PUSH_AND_CLEAR_REGS + movq %rsp, %rdi /* %rdi -> pt_regs */ +.endm + +.macro FRED_EXIT + UNWIND_HINT_REGS + POP_REGS +.endm + +/* + * The new RIP value that FRED event delivery establishes is + * IA32_FRED_CONFIG & ~FFFH for events that occur in ring 3. + * Thus the FRED ring 3 entry point must be 4K page aligned. + */ + .align 4096 + +SYM_CODE_START_NOALIGN(fred_entrypoint_user) + FRED_ENTER + call fred_entry_from_user +SYM_INNER_LABEL(fred_exit_user, SYM_L_GLOBAL) + FRED_EXIT + ERETU +SYM_CODE_END(fred_entrypoint_user) + +.fill fred_entrypoint_kernel - ., 1, 0xcc + +/* + * The new RIP value that FRED event delivery establishes is + * (IA32_FRED_CONFIG & ~FFFH) + 256 for events that occur in + * ring 0, i.e., fred_entrypoint_user + 256. + */ + .org fred_entrypoint_user+256 +SYM_CODE_START_NOALIGN(fred_entrypoint_kernel) + FRED_ENTER + call fred_entry_from_kernel + FRED_EXIT + ERETS +SYM_CODE_END(fred_entrypoint_kernel) diff --git a/arch/x86/entry/entry_fred.c b/arch/x86/entry/entry_fred.c new file mode 100644 index 000000000000..1688e7e09370 --- /dev/null +++ b/arch/x86/entry/entry_fred.c @@ -0,0 +1,220 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * This contains the dispatch functions called from the entry point + * assembly. + */ + +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +static DEFINE_FRED_HANDLER(fred_bad_event) +{ + irqentry_state_t irq_state = irqentry_nmi_enter(regs); + + instrumentation_begin(); + + /* Panic on events from a high stack level */ + if (regs->sl > 0) { + pr_emerg("PANIC: invalid or fatal FRED event; event type %u " + "vector %u error 0x%lx aux 0x%lx at %04x:%016lx\n", + regs->type, regs->vector, regs->orig_ax, + fred_event_data(regs), regs->cs, regs->ip); + die("invalid or fatal FRED event", regs, regs->orig_ax); + panic("invalid or fatal FRED event"); + } else { + unsigned long flags = oops_begin(); + int sig = SIGKILL; + + pr_alert("BUG: invalid or fatal FRED event; event type %u " + "vector %u error 0x%lx aux 0x%lx at %04x:%016lx\n", + regs->type, regs->vector, regs->orig_ax, + fred_event_data(regs), regs->cs, regs->ip); + + if (__die("Invalid or fatal FRED event", regs, regs->orig_ax)) + sig = 0; + + oops_end(flags, regs, sig); + } + + instrumentation_end(); + irqentry_nmi_exit(regs, irq_state); +} + +static DEFINE_FRED_HANDLER(fred_exception) +{ + /* + * Exceptions that cannot happen on FRED h/w are set to fred_bad_event(). + */ + static const fred_handler exception_handlers[NUM_EXCEPTION_VECTORS] = { + [0 ... NUM_EXCEPTION_VECTORS-1] = fred_bad_event, + + [X86_TRAP_DE] = exc_divide_error, + [X86_TRAP_DB] = fred_exc_debug, + [X86_TRAP_BP] = exc_int3, + [X86_TRAP_OF] = exc_overflow, + [X86_TRAP_BR] = exc_bounds, + [X86_TRAP_UD] = exc_invalid_op, + [X86_TRAP_NM] = exc_device_not_available, + [X86_TRAP_DF] = fred_exc_double_fault, + [X86_TRAP_TS] = fred_exc_invalid_tss, + [X86_TRAP_NP] = fred_exc_segment_not_present, + [X86_TRAP_SS] = fred_exc_stack_segment, + [X86_TRAP_GP] = fred_exc_general_protection, + [X86_TRAP_PF] = fred_exc_page_fault, + [X86_TRAP_MF] = exc_coprocessor_error, + [X86_TRAP_AC] = fred_exc_alignment_check, + [X86_TRAP_MC] = fred_exc_machine_check, + [X86_TRAP_XF] = exc_simd_coprocessor_error, + [X86_TRAP_CP] = fred_exc_control_protection, + }; + + exception_handlers[regs->vector](regs); +} + +static __always_inline void fred_emulate_trap(struct pt_regs *regs) +{ + regs->orig_ax = 0; + fred_exception(regs); +} + +static __always_inline void fred_emulate_fault(struct pt_regs *regs) +{ + regs->ip -= regs->instr_len; + fred_emulate_trap(regs); +} + +static DEFINE_FRED_HANDLER(fred_sw_interrupt_user) +{ + /* + * In compat mode INT $0x80 (32bit system call) is + * performance-critical. Handle it first. + */ + if (IS_ENABLED(CONFIG_IA32_EMULATION) && + likely(regs->vector == IA32_SYSCALL_VECTOR)) { + regs->orig_ax = regs->ax; + regs->ax = -ENOSYS; + return do_int80_syscall_32(regs); + } + + /* + * Some software exceptions can also be triggered as + * int instructions, for historical reasons. + */ + switch (regs->vector) { + case X86_TRAP_BP: + case X86_TRAP_OF: + fred_emulate_trap(regs); + break; + default: + regs->vector = X86_TRAP_GP; + fred_emulate_fault(regs); + break; + } +} + +static DEFINE_FRED_HANDLER(fred_other_default) +{ + regs->vector = X86_TRAP_UD; + fred_emulate_fault(regs); +} + +static DEFINE_FRED_HANDLER(fred_syscall) +{ + regs->orig_ax = regs->ax; + regs->ax = -ENOSYS; + do_syscall_64(regs, regs->orig_ax); +} + +#if IS_ENABLED(CONFIG_IA32_EMULATION) +/* + * Emulate SYSENTER if applicable. This is not the preferred system + * call in 32-bit mode under FRED, rather int $0x80 is preferred and + * exported in the vdso. + */ +static DEFINE_FRED_HANDLER(fred_sysenter) +{ + regs->orig_ax = regs->ax; + regs->ax = -ENOSYS; + do_fast_syscall_32(regs); +} +#else +#define fred_sysenter fred_other_default +#endif + +static DEFINE_FRED_HANDLER(fred_other) +{ + static const fred_handler user_other_handlers[FRED_NUM_OTHER_VECTORS] = + { + /* + * Vector 0 of the other event type is not used + * per FRED spec 5.0. + */ + [0] = fred_other_default, + [FRED_SYSCALL] = fred_syscall, + [FRED_SYSENTER] = fred_sysenter + }; + + user_other_handlers[regs->vector](regs); +} + +static DEFINE_FRED_HANDLER(fred_hw_interrupt) +{ + irqentry_state_t state = irqentry_enter(regs); + + instrumentation_begin(); + external_interrupt(regs); + instrumentation_end(); + irqentry_exit(regs, state); +} + +__visible noinstr void fred_entry_from_user(struct pt_regs *regs) +{ + static const fred_handler user_handlers[FRED_EVENT_TYPE_COUNT] = + { + [EVENT_TYPE_HWINT] = fred_hw_interrupt, + [EVENT_TYPE_RESERVED] = fred_bad_event, + [EVENT_TYPE_NMI] = fred_exc_nmi, + [EVENT_TYPE_SWINT] = fred_sw_interrupt_user, + [EVENT_TYPE_HWFAULT] = fred_exception, + [EVENT_TYPE_SWFAULT] = fred_exception, + [EVENT_TYPE_PRIVSW] = fred_exception, + [EVENT_TYPE_OTHER] = fred_other + }; + + /* + * FRED employs a two-level event dispatch mechanism, with the + * first-level on the type of an event and the second-level on + * its vector. Here is the first-level dispatch for ring 3 events. + */ + user_handlers[regs->type](regs); +} + +__visible noinstr void fred_entry_from_kernel(struct pt_regs *regs) +{ + static const fred_handler kernel_handlers[FRED_EVENT_TYPE_COUNT] = + { + [EVENT_TYPE_HWINT] = fred_hw_interrupt, + [EVENT_TYPE_RESERVED] = fred_bad_event, + [EVENT_TYPE_NMI] = fred_exc_nmi, + [EVENT_TYPE_SWINT] = fred_bad_event, + [EVENT_TYPE_HWFAULT] = fred_exception, + [EVENT_TYPE_SWFAULT] = fred_exception, + [EVENT_TYPE_PRIVSW] = fred_exception, + [EVENT_TYPE_OTHER] = fred_bad_event + }; + + /* + * FRED employs a two-level event dispatch mechanism, with the + * first-level on the type of an event and the second-level on + * its vector. Here is the first-level dispatch for ring 0 events. + */ + kernel_handlers[regs->type](regs); +} diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h index b1a98fa38828..36505b991f88 100644 --- a/arch/x86/include/asm/asm-prototypes.h +++ b/arch/x86/include/asm/asm-prototypes.h @@ -13,6 +13,7 @@ #include #include #include +#include #ifndef CONFIG_X86_CMPXCHG64 extern void cmpxchg8b_emu(void); diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h index bd701ac87528..3c91f0eae62e 100644 --- a/arch/x86/include/asm/fred.h +++ b/arch/x86/include/asm/fred.h @@ -118,6 +118,10 @@ DECLARE_FRED_HANDLER(fred_exc_page_fault); DECLARE_FRED_HANDLER(fred_exc_machine_check); DECLARE_FRED_HANDLER(fred_exc_double_fault); +/* The actual assembly entry point for ring 3 and 0 */ +extern asmlinkage __visible void fred_entrypoint_user(void); +extern asmlinkage __visible void fred_entrypoint_kernel(void); + #endif /* __ASSEMBLY__ */ #endif /* CONFIG_X86_FRED */ diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index 3b743c3fbe91..0df3a3cc7e0f 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -661,6 +661,8 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_MC, exc_machine_check); #ifdef CONFIG_XEN_PV DECLARE_IDTENTRY_RAW(X86_TRAP_MC, xenpv_exc_machine_check); #endif +#else +#define fred_exc_machine_check fred_bad_event #endif /* NMI */ @@ -699,6 +701,8 @@ DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_DF, xenpv_exc_double_fault); /* #CP */ #ifdef CONFIG_X86_KERNEL_IBT DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_CP, exc_control_protection); +#else +#define fred_exc_control_protection fred_bad_event #endif /* #VC */