kern/arch/x86/trap.h

#pragma once

#define ROS_KERN_ARCH_TRAP_H

#include <ros/arch/msr-index.h>
#include <ros/errno.h>
#include <arch/fixup.h>

#define NUM_IRQS					256

/* 0-31 are hardware traps */
#define T_DIVIDE     0		// divide error
#define T_DEBUG      1		// debug exception
#define T_NMI        2		// non-maskable interrupt
#define T_BRKPT      3		// breakpoint
#define T_OFLOW      4		// overflow
#define T_BOUND      5		// bounds check
#define T_ILLOP      6		// illegal opcode
#define T_DEVICE     7		// device not available
#define T_DBLFLT     8		// double fault
/* #define T_COPROC  9 */	// reserved (not generated by recent processors)
#define T_TSS       10		// invalid task switch segment
#define T_SEGNP     11		// segment not present
#define T_STACK     12		// stack exception
#define T_GPFLT     13		// genernal protection fault
#define T_PGFLT     14		// page fault
/* #define T_RES    15 */	// reserved
#define T_FPERR     16		// floating point error
#define T_ALIGN     17		// aligment check
#define T_MCHK      18		// machine check
#define T_SIMDERR   19		// SIMD floating point error

/* 32-47 are PIC/8259 IRQ vectors */
#define IdtPIC			32
#define IrqCLOCK		0
#define IrqKBD			1
#define IrqUART1		3
#define IrqUART0		4
#define IrqPCMCIA		5
#define IrqFLOPPY		6
#define IrqLPT			7
#define IrqAUX			12	/* PS/2 port */
#define IrqIRQ13		13	/* coprocessor on 386 */
#define IrqATA0			14
#define IrqATA1			15
#define MaxIrqPIC		15
#define MaxIdtPIC		(IdtPIC + MaxIrqPIC)

/* T_SYSCALL is defined by the following include (48) */
#include <ros/arch/syscall.h>

/* 49-223 are IOAPIC routing vectors (from IOAPIC to LAPIC) */
#define IdtIOAPIC		(T_SYSCALL + 1)
#define MaxIdtIOAPIC		223

/* 224-239 are OS IPI vectors (0xe0-0xef) */
/* smp_call_function IPIs, keep in sync with NUM_HANDLER_WRAPPERS.
 * SMP_CALL0 needs to be 16-aligned (we mask in x86/trap.c).  If you move these,
 * also change INIT_HANDLER_WRAPPER */
#define I_SMP_CALL0		224
#define I_SMP_CALL1		(I_SMP_CALL0 + 1)
#define I_SMP_CALL2		(I_SMP_CALL0 + 2)
#define I_SMP_CALL3		(I_SMP_CALL0 + 3)
#define I_SMP_CALL4		(I_SMP_CALL0 + 4)
#define I_SMP_CALL_LAST		I_SMP_CALL4
#define I_TESTING		236	/* Testing IPI (used in testing.c) */
#define I_POKE_GUEST		237
#define I_POKE_CORE		238
#define I_KERNEL_MSG		239

/* 240-255 are LAPIC vectors (0xf0-0xff), hightest priority class */
#define IdtLAPIC		240
#define IdtLAPIC_TIMER		(IdtLAPIC + 0)
#define IdtLAPIC_THERMAL	(IdtLAPIC + 1)
#define IdtLAPIC_PCINT		(IdtLAPIC + 2)
#define IdtLAPIC_LINT0		(IdtLAPIC + 3)
#define IdtLAPIC_LINT1		(IdtLAPIC + 4)
#define IdtLAPIC_ERROR		(IdtLAPIC + 5)
/* Plan 9 apic note: the spurious vector number must have bits 3-0 0x0f
 * unless the Extended Spurious Vector Enable bit is set in the
 * HyperTransport Transaction Control register.  On some intel machines, those
 * bits are hardwired to 1s (SDM 3-10.9). */
#define IdtLAPIC_SPURIOUS	(IdtLAPIC + 0xf) /* Aka 255, 0xff */
#define MaxIdtLAPIC		(IdtLAPIC + 0xf)

#define IdtMAX			255

#define T_DEFAULT   0x0000beef	// catchall

/* Floating point constants */
#define FP_EXCP_IE		(1 << 0)	/* invalid op */
#define FP_EXCP_DE		(1 << 1)	/* denormalized op */
#define FP_EXCP_ZE		(1 << 2)	/* div by zero */
#define FP_EXCP_OE		(1 << 3)	/* numeric overflow */
#define FP_EXCP_UE		(1 << 4)	/* numeric underflow */
#define FP_EXCP_PE		(1 << 5)	/* precision */

#define FP_SW_SF		(1 << 6)	/* stack fault */
#define FP_SW_ES		(1 << 7)	/* error summary status */
#define FP_SW_C0		(1 << 8)	/* condition codes */
#define FP_SW_C1		(1 << 9)
#define FP_SW_C2		(1 << 10)
#define FP_SW_C3		(1 << 14)
#define FP_CW_TOP_SHIFT		(11)
#define FP_CW_TOP_MASK		(7 << FP_CW_TOP_SHIFT)

#define FP_CW_PC_SHIFT		(8)
#define FP_CW_PC_MASK		(3 << FP_CW_PC_SHIFT)
#define FP_CW_RC_SHIFT		(10)
#define FP_CW_RC_MASK		(3 << FP_CW_RC_SHIFT)
#define FP_CW_IC		(1 << 12)

#ifndef __ASSEMBLER__

#ifndef ROS_KERN_TRAP_H
#error "Do not include include arch/trap.h directly"
#endif

#include <ros/common.h>
#include <arch/mmu.h>
#include <ros/trapframe.h>
#include <arch/pci.h>
#include <arch/pic.h>
#include <arch/topology.h>
#include <cpu_feat.h>
#include <arch/io.h>
#include <stdio.h>

struct irq_handler {
	struct irq_handler *next;
	void (*isr)(struct hw_trapframe *hw_tf, void *data);
	void *data;
	int apic_vector;

	/* all handlers in the chain need to have the same func pointers.  we
	 * only really use the first one, and the latter are to catch bugs.
	 * also, we won't be doing a lot of IRQ line sharing */
	bool (*check_spurious)(int);
	void (*eoi)(int);
	void (*mask)(struct irq_handler *irq_h, int vec);
	void (*unmask)(struct irq_handler *irq_h, int vec);
	void (*route_irq)(struct irq_handler *irq_h, int vec, int dest);

	int tbdf;
	int dev_irq;

	void *dev_private;
	char *type;
	#define IRQ_NAME_LEN 26
	char name[IRQ_NAME_LEN];
};

/* The kernel's interrupt descriptor table */
extern gatedesc_t idt[];
extern pseudodesc_t idt_pd;
extern taskstate_t ts;
int bus_irq_setup(struct irq_handler *irq_h);	/* ioapic.c */
extern const char *x86_trapname(int trapno);
extern void sysenter_handler(void);

/* Defined and set up in in arch/init.c, used for XMM initialization */
extern struct ancillary_state x86_default_fpu;

static inline void save_fp_state(struct ancillary_state *silly)
{
	uint64_t x86_default_xcr0 = __proc_global_info.x86_default_xcr0;
	uint32_t eax, edx;

	/* PLEASE NOTE:
	 * AMD CPUs ignore the FOP/FIP/FDP fields when there is
	 * no pending exception. When you are on AMD, we zero these fields in
	 * the ancillary_state argument before saving. This way, if you are on
	 * AMD and re-using an ancillary_state memory region, an old save's
	 * information won't leak into your new data. The side-effect of this is
	 * that you can't trust these fields to report accurate information on
	 * AMD unless an exception was pending. Granted, AMD says that only
	 * exception handlers should care about FOP/FIP/FDP, so that's probably
	 * okay.
	 *
	 * You should also note that on newer Intel 64 processors, while the
	 * value of the FOP is always saved and restored, it contains the opcode
	 * of the most recent x87 FPU instruction that triggered an unmasked
	 * exception, rather than simply the most recent opcode. Some older
	 * Xeons and P4s had the fopcode compatibility mode feature, which you
	 * could use to make the FOP update on every x87 non-control
	 * instruction, but that has been eliminated in newer hardware.
	 *
	 */
	if (cpu_has_feat(CPU_FEAT_X86_VENDOR_AMD)) {
		silly->fp_head_64d.fop      = 0x0;
		silly->fp_head_64d.fpu_ip   = 0x0;
		silly->fp_head_64d.cs       = 0x0;
		// padding1 is FIP or rsvd, proc dep.
		silly->fp_head_64d.padding1 = 0x0;
		silly->fp_head_64d.fpu_dp   = 0x0;
		silly->fp_head_64d.ds       = 0x0;
		// padding2 is FDP or rsvd, proc dep.
		silly->fp_head_64d.padding2 = 0x0;
	}


	if (cpu_has_feat(CPU_FEAT_X86_XSAVEOPT)) {
		edx = x86_default_xcr0 >> 32;
		eax = x86_default_xcr0;
		asm volatile("xsaveopt64 %0" : : "m"(*silly), "a"(eax),
			     "d"(edx));
	} else if (cpu_has_feat(CPU_FEAT_X86_XSAVE)) {
		edx = x86_default_xcr0 >> 32;
		eax = x86_default_xcr0;
		asm volatile("xsave64 %0" : : "m"(*silly), "a"(eax), "d"(edx));
	} else {
		asm volatile("fxsave64 %0" : : "m"(*silly));
	}
}

static inline void init_fp_state(void);
static inline void restore_fp_state(struct ancillary_state *silly)
{
	uint64_t x86_default_xcr0 = __proc_global_info.x86_default_xcr0;
	int err = 0;
	uint32_t eax, edx;

	/*
	 * Since AMD CPUs ignore the FOP/FIP/FDP fields when there is
	 * no pending exception, we clear those fields before restoring
	 * when we are both on AMD and there is no pending exception in
	 * the ancillary_state argument to restore_fp_state.
	 * If there is a pending exception in the ancillary_state,
	 * these fields will be written to the FPU upon executing
	 * a restore instruction, and there is nothing to worry about.
	 *
	 * See CVE-2006-1056 and CVE-2013-2076 on cve.mitre.org.
	 *
	 * We check for a pending exception by checking FSW.ES (bit 7)
	 *
	 * FNINIT clears FIP and FDP and, even though it is technically a
	 * control instruction, it clears FOP because it is initializing the
	 * FPU.
	 *
	 * NOTE: This might not be the most efficient way to do things, and
	 *       could be an optimization target for context switch performance
	 *       on AMD processors in the future.
	 */
	if (!(silly->fp_head_64d.fsw & 0x80)
	    && cpu_has_feat(CPU_FEAT_X86_VENDOR_AMD))
		asm volatile ("fninit;");

	if (cpu_has_feat(CPU_FEAT_X86_XSAVE)) {
		edx = x86_default_xcr0 >> 32;
		eax = x86_default_xcr0;
		asm volatile(ASM_STAC               ";"
		             "1: xrstor64 %1         ;"
		             "2: " ASM_CLAC "        ;"
		             ".section .fixup, \"ax\";"
		             "3: mov %4, %0          ;"
		             "   jmp 2b              ;"
		             ".previous              ;"
		             _ASM_EXTABLE(1b, 3b)
		             : "=r" (err)
		             : "m"(*silly), "a"(eax), "d"(edx),
		               "i" (-EINVAL), "0" (err));
	} else {
		asm volatile(ASM_STAC               ";"
		             "1: fxrstor64 %1         ;"
		             "2: " ASM_CLAC "        ;"
		             ".section .fixup, \"ax\";"
		             "3: mov %2, %0          ;"
		             "   jmp 2b              ;"
		             ".previous              ;"
		             _ASM_EXTABLE(1b, 3b)
		             : "=r" (err)
		             : "m"(*silly),
		               "i" (-EINVAL), "0" (err));
	}


	if (err) {
		printk("Error restoring fp state!\n");
		printk("Likely a bad ancillary_state argument.\n");
		printk("Re-initializing fp state to default due to error.\n");
		init_fp_state();
	}
}

/* A regular fninit only initializes the control, status, tag, ip,
 * and data pointer registers. Since it leaves the data registers,
 * MXCSR, etc. unchanged, we use init_fp_state to restore a default
 * state that we save at boot time.
 *
 * If you're looking for a workout, you could also fninit, ldmxcsr with
 * a default value, and 0 all the registers by hand.
 */
static inline void init_fp_state(void)
{
	restore_fp_state(&x86_default_fpu);
}

static inline void __attribute__((always_inline))
set_stack_pointer(uintptr_t sp)
{
	asm volatile("mov %0,%%"X86_REG_SP"" : : "r"(sp)
		     : "memory", X86_REG_SP);
}

static inline void __attribute__((always_inline))
set_frame_pointer(uintptr_t fp)
{
	/* note we can't list BP as a clobber - the compiler will flip out.
	 * makes me wonder if clobbering SP above makes a difference (probably
	 * not) */
	asm volatile("mov %0,%%"X86_REG_BP"" : : "r"(fp) : "memory");
}

extern segdesc_t *gdt;

#include <arch/trap64.h>

#endif /* !__ASSEMBLER__ */