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Peter Anvin (Intel)" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/fred] x86/fred: Invoke FRED initialization code to enable FRED Cc: "H. Peter Anvin (Intel)" , Xin Li , Thomas Gleixner , Shan Kang , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20231205105030.8698-36-xin3.li@intel.com> References: <20231205105030.8698-36-xin3.li@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <170620687375.398.11388384121726676497.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the x86/fred branch of tip: Commit-ID: a9f26154bf5478fc155309fc69128415f3a1be08 Gitweb: https://git.kernel.org/tip/a9f26154bf5478fc155309fc69128415f= 3a1be08 Author: H. Peter Anvin (Intel) AuthorDate: Tue, 05 Dec 2023 02:50:24 -08:00 Committer: Thomas Gleixner CommitterDate: Thu, 25 Jan 2024 19:10:33 +01:00 x86/fred: Invoke FRED initialization code to enable FRED Let cpu_init_exception_handling() call cpu_init_fred_exceptions() to initialize FRED. However if FRED is unavailable or disabled, it falls back to set up TSS IST and initialize IDT. Co-developed-by: Xin Li Signed-off-by: H. Peter Anvin (Intel) Signed-off-by: Xin Li Signed-off-by: Thomas Gleixner Tested-by: Shan Kang Link: https://lore.kernel.org/r/20231205105030.8698-36-xin3.li@intel.com --- arch/x86/kernel/cpu/common.c | 22 +++++++++++++++++----- arch/x86/kernel/irqinit.c | 7 ++++++- arch/x86/kernel/traps.c | 5 ++++- 3 files changed, 27 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 399f0d0..5ed968c 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -61,6 +61,7 @@ #include #include #include +#include #include #include #include @@ -2110,7 +2111,15 @@ void syscall_init(void) /* The default user and kernel segments */ wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); =20 - idt_syscall_init(); + /* + * Except the IA32_STAR MSR, there is NO need to setup SYSCALL and + * SYSENTER MSRs for FRED, because FRED uses the ring 3 FRED + * entrypoint for SYSCALL and SYSENTER, and ERETU is the only legit + * instruction to return to ring 3 (both sysexit and sysret cause + * #UD when FRED is enabled). + */ + if (!cpu_feature_enabled(X86_FEATURE_FRED)) + idt_syscall_init(); } =20 #else /* CONFIG_X86_64 */ @@ -2216,8 +2225,9 @@ void cpu_init_exception_handling(void) /* paranoid_entry() gets the CPU number from the GDT */ setup_getcpu(cpu); =20 - /* IST vectors need TSS to be set up. */ - tss_setup_ist(tss); + /* For IDT mode, IST vectors need to be set in TSS. */ + if (!cpu_feature_enabled(X86_FEATURE_FRED)) + tss_setup_ist(tss); tss_setup_io_bitmap(tss); set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); =20 @@ -2226,8 +2236,10 @@ void cpu_init_exception_handling(void) /* GHCB needs to be setup to handle #VC. */ setup_ghcb(); =20 - /* Finally load the IDT */ - load_current_idt(); + if (cpu_feature_enabled(X86_FEATURE_FRED)) + cpu_init_fred_exceptions(); + else + load_current_idt(); } =20 /* diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c index c683666..f79c5ed 100644 --- a/arch/x86/kernel/irqinit.c +++ b/arch/x86/kernel/irqinit.c @@ -28,6 +28,7 @@ #include #include #include +#include #include =20 /* @@ -96,7 +97,11 @@ void __init native_init_IRQ(void) /* Execute any quirks before the call gates are initialised: */ x86_init.irqs.pre_vector_init(); =20 - idt_setup_apic_and_irq_gates(); + if (cpu_feature_enabled(X86_FEATURE_FRED)) + fred_complete_exception_setup(); + else + idt_setup_apic_and_irq_gates(); + lapic_assign_system_vectors(); =20 if (!acpi_ioapic && !of_ioapic && nr_legacy_irqs()) { diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index a03c233..cf198d9 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -1412,7 +1412,10 @@ void __init trap_init(void) =20 /* Initialize TSS before setting up traps so ISTs work */ cpu_init_exception_handling(); + /* Setup traps as cpu_init() might #GP */ - idt_setup_traps(); + if (!cpu_feature_enabled(X86_FEATURE_FRED)) + idt_setup_traps(); + cpu_init(); }