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([172.25.112.68]) by fmsmga006.fm.intel.com with ESMTP; 05 Dec 2023 03:21:24 -0800 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: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, pbonzini@redhat.com, seanjc@google.com, peterz@infradead.org, jgross@suse.com, ravi.v.shankar@intel.com, mhiramat@kernel.org, andrew.cooper3@citrix.com, jiangshanlai@gmail.com, nik.borisov@suse.com, shan.kang@intel.com Subject: [PATCH v13 26/35] x86/fred: FRED entry/exit and dispatch code Date: Tue, 5 Dec 2023 02:50:15 -0800 Message-ID: <20231205105030.8698-27-xin3.li@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231205105030.8698-1-xin3.li@intel.com> References: <20231205105030.8698-1-xin3.li@intel.com> Precedence: bulk X-Mailing-List: linux-edac@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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) Suggested-by: Thomas Gleixner Tested-by: Shan Kang Co-developed-by: Xin Li Signed-off-by: Xin Li --- Changes since v10: * Replace "IS_ENABLED(CONFIG_IA32_EMULATION)" with the new ia32_enabled() API (Nikolay Borisov). Changes since v9: * Don't use jump tables, indirect jumps are expensive (Thomas Gleixner). * Except NMI/#DB/#MCE, FRED really can share the exception handlers with IDT (Thomas Gleixner). * Avoid the sysvec_* idt_entry muck, do it at a central place, reuse code instead of blindly copying it, which breaks the performance optimized sysvec entries like reschedule_ipi (Thomas Gleixner). * Add asm_ prefix to FRED asm entry points (Thomas Gleixner). 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 | 52 ++++++ arch/x86/entry/entry_fred.c | 230 ++++++++++++++++++++++++++ arch/x86/include/asm/asm-prototypes.h | 1 + arch/x86/include/asm/fred.h | 6 + 5 files changed, 293 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..37a1dd5e8ace --- /dev/null +++ b/arch/x86/entry/entry_64_fred.S @@ -0,0 +1,52 @@ +/* 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(asm_fred_entrypoint_user) + FRED_ENTER + call fred_entry_from_user + FRED_EXIT + ERETU +SYM_CODE_END(asm_fred_entrypoint_user) + +.fill asm_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., asm_fred_entrypoint_user + 256. + */ + .org asm_fred_entrypoint_user + 256 +SYM_CODE_START_NOALIGN(asm_fred_entrypoint_kernel) + FRED_ENTER + call fred_entry_from_kernel + FRED_EXIT + ERETS +SYM_CODE_END(asm_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..215883e90f94 --- /dev/null +++ b/arch/x86/entry/entry_fred.c @@ -0,0 +1,230 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * The FRED specific kernel/user entry functions which are invoked from + * assembly code and dispatch to the associated handlers. + */ +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +/* FRED EVENT_TYPE_OTHER vector numbers */ +#define FRED_SYSCALL 1 +#define FRED_SYSENTER 2 + +static noinstr void fred_bad_type(struct pt_regs *regs, unsigned long error_code) +{ + irqentry_state_t irq_state = irqentry_nmi_enter(regs); + + instrumentation_begin(); + + /* Panic on events from a high stack level */ + if (regs->fred_cs.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->fred_ss.type, regs->fred_ss.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->fred_ss.type, regs->fred_ss.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 noinstr void fred_intx(struct pt_regs *regs) +{ + switch (regs->fred_ss.vector) { + /* INT0 */ + case X86_TRAP_OF: + exc_overflow(regs); + return; + + /* INT3 */ + case X86_TRAP_BP: + exc_int3(regs); + return; + + /* INT80 */ + case IA32_SYSCALL_VECTOR: + if (ia32_enabled()) { + /* Save the syscall number */ + regs->orig_ax = regs->ax; + regs->ax = -ENOSYS; + do_int80_syscall_32(regs); + return; + } + fallthrough; + + default: + exc_general_protection(regs, 0); + return; + } +} + +static __always_inline void fred_other(struct pt_regs *regs) +{ + /* The compiler can fold these conditions into a single test */ + if (likely(regs->fred_ss.vector == FRED_SYSCALL && regs->fred_ss.lm)) { + regs->orig_ax = regs->ax; + regs->ax = -ENOSYS; + do_syscall_64(regs, regs->orig_ax); + return; + } else if (ia32_enabled() && + likely(regs->fred_ss.vector == FRED_SYSENTER && + !regs->fred_ss.lm)) { + regs->orig_ax = regs->ax; + regs->ax = -ENOSYS; + do_fast_syscall_32(regs); + return; + } else { + exc_invalid_op(regs); + return; + } +} + +#define SYSVEC(_vector, _function) [_vector - FIRST_SYSTEM_VECTOR] = fred_sysvec_##_function + +static idtentry_t sysvec_table[NR_SYSTEM_VECTORS] __ro_after_init = { + SYSVEC(ERROR_APIC_VECTOR, error_interrupt), + SYSVEC(SPURIOUS_APIC_VECTOR, spurious_apic_interrupt), + SYSVEC(LOCAL_TIMER_VECTOR, apic_timer_interrupt), + SYSVEC(X86_PLATFORM_IPI_VECTOR, x86_platform_ipi), + + SYSVEC(RESCHEDULE_VECTOR, reschedule_ipi), + SYSVEC(CALL_FUNCTION_SINGLE_VECTOR, call_function_single), + SYSVEC(CALL_FUNCTION_VECTOR, call_function), + SYSVEC(REBOOT_VECTOR, reboot), + + SYSVEC(THRESHOLD_APIC_VECTOR, threshold), + SYSVEC(DEFERRED_ERROR_VECTOR, deferred_error), + SYSVEC(THERMAL_APIC_VECTOR, thermal), + + SYSVEC(IRQ_WORK_VECTOR, irq_work), + + SYSVEC(POSTED_INTR_VECTOR, kvm_posted_intr_ipi), + SYSVEC(POSTED_INTR_WAKEUP_VECTOR, kvm_posted_intr_wakeup_ipi), + SYSVEC(POSTED_INTR_NESTED_VECTOR, kvm_posted_intr_nested_ipi), +}; + +static noinstr void fred_extint(struct pt_regs *regs) +{ + unsigned int vector = regs->fred_ss.vector; + + if (WARN_ON_ONCE(vector < FIRST_EXTERNAL_VECTOR)) + return; + + if (likely(vector >= FIRST_SYSTEM_VECTOR)) { + irqentry_state_t state = irqentry_enter(regs); + + instrumentation_begin(); + sysvec_table[vector - FIRST_SYSTEM_VECTOR](regs); + instrumentation_end(); + irqentry_exit(regs, state); + } else { + common_interrupt(regs, vector); + } +} + +static noinstr void fred_exception(struct pt_regs *regs, unsigned long error_code) +{ + /* Optimize for #PF. That's the only exception which matters performance wise */ + if (likely(regs->fred_ss.vector == X86_TRAP_PF)) { + exc_page_fault(regs, error_code); + return; + } + + switch (regs->fred_ss.vector) { + case X86_TRAP_DE: return exc_divide_error(regs); + case X86_TRAP_DB: return fred_exc_debug(regs); + case X86_TRAP_BP: return exc_int3(regs); + case X86_TRAP_OF: return exc_overflow(regs); + case X86_TRAP_BR: return exc_bounds(regs); + case X86_TRAP_UD: return exc_invalid_op(regs); + case X86_TRAP_NM: return exc_device_not_available(regs); + case X86_TRAP_DF: return exc_double_fault(regs, error_code); + case X86_TRAP_TS: return exc_invalid_tss(regs, error_code); + case X86_TRAP_NP: return exc_segment_not_present(regs, error_code); + case X86_TRAP_SS: return exc_stack_segment(regs, error_code); + case X86_TRAP_GP: return exc_general_protection(regs, error_code); + case X86_TRAP_MF: return exc_coprocessor_error(regs); + case X86_TRAP_AC: return exc_alignment_check(regs, error_code); + case X86_TRAP_XF: return exc_simd_coprocessor_error(regs); + +#ifdef CONFIG_X86_MCE + case X86_TRAP_MC: return fred_exc_machine_check(regs); +#endif +#ifdef CONFIG_INTEL_TDX_GUEST + case X86_TRAP_VE: return exc_virtualization_exception(regs); +#endif +#ifdef CONFIG_X86_KERNEL_IBT + case X86_TRAP_CP: return exc_control_protection(regs, error_code); +#endif + default: return fred_bad_type(regs, error_code); + } +} + +__visible noinstr void fred_entry_from_user(struct pt_regs *regs) +{ + unsigned long error_code = regs->orig_ax; + + /* Invalidate orig_ax so that syscall_get_nr() works correctly */ + regs->orig_ax = -1; + + switch (regs->fred_ss.type) { + case EVENT_TYPE_EXTINT: + return fred_extint(regs); + case EVENT_TYPE_NMI: + return fred_exc_nmi(regs); + case EVENT_TYPE_SWINT: + return fred_intx(regs); + case EVENT_TYPE_HWEXC: + case EVENT_TYPE_SWEXC: + case EVENT_TYPE_PRIV_SWEXC: + return fred_exception(regs, error_code); + case EVENT_TYPE_OTHER: + return fred_other(regs); + default: + return fred_bad_type(regs, error_code); + } +} + +__visible noinstr void fred_entry_from_kernel(struct pt_regs *regs) +{ + unsigned long error_code = regs->orig_ax; + + /* Invalidate orig_ax so that syscall_get_nr() works correctly */ + regs->orig_ax = -1; + + switch (regs->fred_ss.type) { + case EVENT_TYPE_EXTINT: + return fred_extint(regs); + case EVENT_TYPE_NMI: + return fred_exc_nmi(regs); + case EVENT_TYPE_HWEXC: + case EVENT_TYPE_SWEXC: + case EVENT_TYPE_PRIV_SWEXC: + return fred_exception(regs, error_code); + default: + return fred_bad_type(regs, error_code); + } +} diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h index b1a98fa38828..076bf8dee702 100644 --- a/arch/x86/include/asm/asm-prototypes.h +++ b/arch/x86/include/asm/asm-prototypes.h @@ -12,6 +12,7 @@ #include #include #include +#include #include #ifndef CONFIG_X86_CMPXCHG64 diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h index f514fdb5a39f..16a64ffecbf8 100644 --- a/arch/x86/include/asm/fred.h +++ b/arch/x86/include/asm/fred.h @@ -60,6 +60,12 @@ static __always_inline unsigned long fred_event_data(struct pt_regs *regs) return fred_info(regs)->edata; } +void asm_fred_entrypoint_user(void); +void asm_fred_entrypoint_kernel(void); + +__visible void fred_entry_from_user(struct pt_regs *regs); +__visible void fred_entry_from_kernel(struct pt_regs *regs); + #else /* CONFIG_X86_FRED */ static __always_inline unsigned long fred_event_data(struct pt_regs *regs) { return 0; } #endif /* CONFIG_X86_FRED */