svn commit: r306090 - head/sys/boot/efi/loader/arch/amd64
Konstantin Belousov
kib at FreeBSD.org
Wed Sep 21 10:22:47 UTC 2016
Author: kib
Date: Wed Sep 21 10:22:46 2016
New Revision: 306090
URL: https://svnweb.freebsd.org/changeset/base/306090
Log:
Simple post-mortem reporter for amd64 loader.efi.
There is no way to see anything about the faults occuring in
loader.efi. Some intel BIOSes do output a line into serial port at
115200/8/1 regardless of the current port settings with the EFI error
number, but this is too little, and not always available, esp. if the
user does not know where to look.
The patch adds a simple facility to grab exceptions and at least dump
generic registers and some exception details. Due to the relative
complexity of correctly taking over the BIOS IDT setup, only install
the facility on user request.
Two new commands, 'grab_faults' and 'ungrab_faults' are provided,
first one takes over, second undoes the first. It is supposed that
user would execute 'grab' by the developer direction of collecting the
debugging data. The 'fault' command generates exception to test the
setup.
Fault handlers use dedicated stack to improve chances of catching
stack/TSS exceptions. Due to this, BIOS IDT is duplicated into a
private copy, and debugger needs to find a free GDT slot for TSS. This
is done in somewhat complicated efi_redirect_exceptions().
Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D7935
Added:
head/sys/boot/efi/loader/arch/amd64/exc.S (contents, props changed)
head/sys/boot/efi/loader/arch/amd64/trap.c (contents, props changed)
Modified:
head/sys/boot/efi/loader/arch/amd64/Makefile.inc
Modified: head/sys/boot/efi/loader/arch/amd64/Makefile.inc
==============================================================================
--- head/sys/boot/efi/loader/arch/amd64/Makefile.inc Wed Sep 21 10:15:08 2016 (r306089)
+++ head/sys/boot/efi/loader/arch/amd64/Makefile.inc Wed Sep 21 10:22:46 2016 (r306090)
@@ -3,7 +3,9 @@
SRCS+= amd64_tramp.S \
start.S \
framebuffer.c \
- elf64_freebsd.c
+ elf64_freebsd.c \
+ trap.c \
+ exc.S
.PATH: ${.CURDIR}/../../i386/libi386
SRCS+= nullconsole.c \
Added: head/sys/boot/efi/loader/arch/amd64/exc.S
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/sys/boot/efi/loader/arch/amd64/exc.S Wed Sep 21 10:22:46 2016 (r306090)
@@ -0,0 +1,165 @@
+/*-
+ * Copyright (c) 2016 The FreeBSD Foundation
+ * All rights reserved.
+ *
+ * This software was developed by Konstantin Belousov under sponsorship
+ * from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+ .macro EH N, err=1
+ .align 8
+ .globl EXC\N\()_handler
+EXC\N\()_handler:
+ .if \err != 1
+ pushq $0
+ .endif
+ pushq %rax
+ pushq %rdx
+ pushq %rcx
+ movl $\N,%ecx
+ jmp all_handlers
+ .endm
+
+ .text
+ EH 0,0
+ EH 1,0
+ EH 2,0
+ EH 3,0
+ EH 4,0
+ EH 5,0
+ EH 6,0
+ EH 7,0
+ EH 8
+ EH 9,0
+ EH 10
+ EH 11
+ EH 12
+ EH 13
+ EH 14
+ EH 16,0
+ EH 17
+ EH 18,0
+ EH 19,0
+ EH 20,0
+
+ .globl exc_rsp
+all_handlers:
+ cmpq %rsp,exc_rsp(%rip)
+ je exception
+
+ /*
+ * Interrupt, not exception.
+ * First, copy the hardware interrupt frame to the previous stack.
+ * Our handler always has private IST stack.
+ */
+ movq (6*8)(%rsp),%rax /* saved %rsp value, AKA old stack */
+ subq (5*8),%rax
+ movq (3*8)(%rsp),%rdx /* copy %rip to old stack */
+ movq %rdx,(%rax)
+ movq (4*8)(%rsp),%rdx /* copy %cs */
+ movq %rdx,(1*8)(%rax)
+ movq (5*8)(%rsp),%rdx /* copy %rflags */
+ movq %rdx,(2*8)(%rax)
+ movq (6*8)(%rsp),%rdx /* copy %rsp */
+ movq %rdx,(3*8)(%rax)
+ movq (7*8)(%rsp),%rdx /* copy %ss */
+ movq %rdx,(4*8)(%rax)
+
+ /*
+ * Now simulate invocation of the original interrupt handler
+ * with retq. We switch stacks and execute retq from the old
+ * stack since there is no free registers at the last moment.
+ */
+ subq $16,%rax
+ leaq fw_intr_handlers(%rip),%rdx
+ movq (%rdx,%rcx,8),%rdx /* push intr handler address on old stack */
+ movq %rdx,8(%rax)
+ movq (2*8)(%rsp),%rcx /* saved %rax is put on top of old stack */
+ movq %rcx,(%rax)
+ movq (%rsp),%rcx
+ movq 8(%rsp),%rdx
+
+ movq 32(%rsp),%rsp /* switch to old stack */
+ popq %rax
+ retq
+
+exception:
+ /*
+ * Form the struct trapframe on our IST stack.
+ * Skip three words, which are currently busy with temporal
+ * saves.
+ */
+ pushq %r15
+ pushq %r14
+ pushq %r13
+ pushq %r12
+ pushq %r11
+ pushq %r10
+ pushq %rbp
+ pushq %rbx
+ pushq $0 /* %rax */
+ pushq %r9
+ pushq %r8
+ pushq $0 /* %rcx */
+ pushq $0 /* %rdx */
+ pushq %rsi
+ pushq %rdi
+
+ /*
+ * Move %rax, %rdx, %rcx values into the final location,
+ * from the three words which were skipped above.
+ */
+ movq 0x88(%rsp),%rax
+ movq %rax,0x30(%rsp) /* tf_rax */
+ movq 0x78(%rsp),%rax
+ movq %rax,0x18(%rsp) /* tf_rcx */
+ movq 0x80(%rsp),%rax
+ movq %rax,0x10(%rsp) /* tf_rdx */
+
+ /*
+ * And fill the three words themself.
+ */
+ movq %cr2,%rax
+ movq %rax,0x80(%rsp) /* tf_addr */
+ movl %ecx,0x78(%rsp) /* tf_trapno */
+ movw %ds,0x8e(%rsp)
+ movw %es,0x8c(%rsp)
+ movw %fs,0x7c(%rsp)
+ movw %gs,0x7e(%rsp)
+ movw $0,0x88(%rsp) /* tf_flags */
+
+ /*
+ * Call dump routine.
+ */
+ movq %rsp,%rdi
+ callq report_exc
+
+ /*
+ * Hang after reporting. Interrupts are already disabled.
+ */
+1:
+ hlt
+ jmp 1b
Added: head/sys/boot/efi/loader/arch/amd64/trap.c
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/sys/boot/efi/loader/arch/amd64/trap.c Wed Sep 21 10:22:46 2016 (r306090)
@@ -0,0 +1,398 @@
+/*-
+ * Copyright (c) 2016 The FreeBSD Foundation
+ * All rights reserved.
+ *
+ * This software was developed by Konstantin Belousov under sponsorship
+ * from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <stand.h>
+#include <string.h>
+#include <sys/param.h>
+#include <machine/cpufunc.h>
+#include <machine/psl.h>
+#include <machine/segments.h>
+#include <machine/frame.h>
+#include <machine/tss.h>
+
+#include <efi.h>
+#include <efilib.h>
+
+#include "bootstrap.h"
+#include "loader_efi.h"
+
+#define NUM_IST 8
+#define NUM_EXC 32
+
+/*
+ * This code catches exceptions but forwards hardware interrupts to
+ * handlers installed by firmware. It differentiates exceptions
+ * vs. interrupts by presence of the error code on the stack, which
+ * causes different stack pointer value on trap handler entry.
+ *
+ * Use kernel layout for the trapframe just to not be original.
+ *
+ * Use free IST slot in existing TSS, or create our own TSS if
+ * firmware did not configured any, to have stack switched to
+ * IST-specified one, e.g. to handle #SS. If hand-off cannot find
+ * unused IST slot, or create a new descriptor in GDT, we bail out.
+ */
+
+static struct region_descriptor fw_idt; /* Descriptor for pristine fw IDT */
+static struct region_descriptor loader_idt;/* Descriptor for loader
+ shadow IDT */
+static EFI_PHYSICAL_ADDRESS lidt_pa; /* Address of loader shadow IDT */
+static EFI_PHYSICAL_ADDRESS tss_pa; /* Address of TSS */
+static EFI_PHYSICAL_ADDRESS exc_stack_pa;/* Address of IST stack for loader */
+EFI_PHYSICAL_ADDRESS exc_rsp; /* %rsp value on our IST stack when
+ exception happens */
+EFI_PHYSICAL_ADDRESS fw_intr_handlers[NUM_EXC]; /* fw handlers for < 32 IDT
+ vectors */
+static int intercepted[NUM_EXC];
+static int ist; /* IST for exception handlers */
+static uint32_t tss_fw_seg; /* Fw TSS segment */
+static uint32_t loader_tss; /* Loader TSS segment */
+static struct region_descriptor fw_gdt; /* Descriptor of pristine GDT */
+static EFI_PHYSICAL_ADDRESS loader_gdt_pa; /* Address of loader shadow GDT */
+
+void report_exc(struct trapframe *tf);
+void
+report_exc(struct trapframe *tf)
+{
+
+ /* XXX using printf */
+ printf("===================================================="
+ "============================\n");
+ printf("Exception %u\n", tf->tf_trapno);
+ printf("ss 0x%04hx cs 0x%04hx ds 0x%04hx es 0x%04hx fs 0x%04hx "
+ "gs 0x%04hx\n",
+ (uint16_t)tf->tf_ss, (uint16_t)tf->tf_cs, (uint16_t)tf->tf_ds,
+ (uint16_t)tf->tf_es, (uint16_t)tf->tf_fs, (uint16_t)tf->tf_gs);
+ printf("err 0x%08x rfl 0x%08x addr 0x%016lx\n"
+ "rsp 0x%016lx rip 0x%016lx\n",
+ (uint32_t)tf->tf_err, (uint32_t)tf->tf_rflags, tf->tf_addr,
+ tf->tf_rsp, tf->tf_rip);
+ printf(
+ "rdi 0x%016lx rsi 0x%016lx rdx 0x%016lx\n"
+ "rcx 0x%016lx r8 0x%016lx r9 0x%016lx\n"
+ "rax 0x%016lx rbx 0x%016lx rbp 0x%016lx\n"
+ "r10 0x%016lx r11 0x%016lx r12 0x%016lx\n"
+ "r13 0x%016lx r14 0x%016lx r15 0x%016lx\n",
+ tf->tf_rdi, tf->tf_rsi, tf->tf_rdx, tf->tf_rcx, tf->tf_r8,
+ tf->tf_r9, tf->tf_rax, tf->tf_rbx, tf->tf_rbp, tf->tf_r10,
+ tf->tf_r11, tf->tf_r12, tf->tf_r13, tf->tf_r14, tf->tf_r15);
+ printf("Machine stopped.\n");
+}
+
+static void
+prepare_exception(unsigned idx, uint64_t my_handler,
+ int ist_use_table[static NUM_IST])
+{
+ struct gate_descriptor *fw_idt_e, *loader_idt_e;
+
+ fw_idt_e = &((struct gate_descriptor *)fw_idt.rd_base)[idx];
+ loader_idt_e = &((struct gate_descriptor *)loader_idt.rd_base)[idx];
+ fw_intr_handlers[idx] = fw_idt_e->gd_looffset +
+ (fw_idt_e->gd_hioffset << 16);
+ intercepted[idx] = 1;
+ ist_use_table[fw_idt_e->gd_ist]++;
+ loader_idt_e->gd_looffset = my_handler;
+ loader_idt_e->gd_hioffset = my_handler >> 16;
+ loader_idt_e->gd_selector = fw_idt_e->gd_selector; /* XXX */
+ loader_idt_e->gd_ist = 0;
+ loader_idt_e->gd_type = SDT_SYSIGT;
+ loader_idt_e->gd_dpl = 0;
+ loader_idt_e->gd_p = 1;
+ loader_idt_e->gd_xx = 0;
+ loader_idt_e->sd_xx1 = 0;
+}
+#define PREPARE_EXCEPTION(N) \
+ extern char EXC##N##_handler[]; \
+ prepare_exception(N, (uintptr_t)EXC##N##_handler, ist_use_table);
+
+static void
+free_tables(void)
+{
+
+ if (lidt_pa != 0) {
+ BS->FreePages(lidt_pa, EFI_SIZE_TO_PAGES(fw_idt.rd_limit));
+ lidt_pa = 0;
+ }
+ if (exc_stack_pa != 0) {
+ BS->FreePages(exc_stack_pa, 1);
+ exc_stack_pa = 0;
+ }
+ if (tss_pa != 0 && tss_fw_seg == 0) {
+ BS->FreePages(tss_pa, EFI_SIZE_TO_PAGES(sizeof(struct
+ amd64tss)));
+ tss_pa = 0;
+ }
+ if (loader_gdt_pa != 0) {
+ BS->FreePages(tss_pa, 2);
+ loader_gdt_pa = 0;
+ }
+ ist = 0;
+ loader_tss = 0;
+}
+
+static int
+efi_setup_tss(struct region_descriptor *gdt, uint32_t loader_tss_idx,
+ struct amd64tss **tss)
+{
+ EFI_STATUS status;
+ struct system_segment_descriptor *tss_desc;
+
+ tss_desc = (struct system_segment_descriptor *)(gdt->rd_base +
+ (loader_tss_idx << 3));
+ status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData,
+ EFI_SIZE_TO_PAGES(sizeof(struct amd64tss)), &tss_pa);
+ if (EFI_ERROR(status)) {
+ printf("efi_setup_tss: AllocatePages tss error %lu\n",
+ EFI_ERROR_CODE(status));
+ return (0);
+ }
+ *tss = (struct amd64tss *)tss_pa;
+ bzero(*tss, sizeof(**tss));
+ tss_desc->sd_lolimit = sizeof(struct amd64tss);
+ tss_desc->sd_lobase = tss_pa;
+ tss_desc->sd_type = SDT_SYSTSS;
+ tss_desc->sd_dpl = 0;
+ tss_desc->sd_p = 1;
+ tss_desc->sd_hilimit = sizeof(struct amd64tss) >> 16;
+ tss_desc->sd_gran = 0;
+ tss_desc->sd_hibase = tss_pa >> 24;
+ tss_desc->sd_xx0 = 0;
+ tss_desc->sd_xx1 = 0;
+ tss_desc->sd_mbz = 0;
+ tss_desc->sd_xx2 = 0;
+ return (1);
+}
+
+static int
+efi_redirect_exceptions(void)
+{
+ int ist_use_table[NUM_IST];
+ struct gate_descriptor *loader_idt_e;
+ struct system_segment_descriptor *tss_desc, *gdt_desc;
+ struct amd64tss *tss;
+ struct region_descriptor *gdt_rd, loader_gdt;
+ uint32_t i;
+ EFI_STATUS status;
+ register_t rfl;
+
+ sidt(&fw_idt);
+ status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData,
+ EFI_SIZE_TO_PAGES(fw_idt.rd_limit), &lidt_pa);
+ if (EFI_ERROR(status)) {
+ printf("efi_redirect_exceptions: AllocatePages IDT error %lu\n",
+ EFI_ERROR_CODE(status));
+ lidt_pa = 0;
+ return (0);
+ }
+ status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData, 1,
+ &exc_stack_pa);
+ if (EFI_ERROR(status)) {
+ printf("efi_redirect_exceptions: AllocatePages stk error %lu\n",
+ EFI_ERROR_CODE(status));
+ exc_stack_pa = 0;
+ free_tables();
+ return (0);
+ }
+ loader_idt.rd_limit = fw_idt.rd_limit;
+ bcopy((void *)fw_idt.rd_base, (void *)loader_idt.rd_base,
+ loader_idt.rd_limit);
+ bzero(ist_use_table, sizeof(ist_use_table));
+ bzero(fw_intr_handlers, sizeof(fw_intr_handlers));
+ bzero(intercepted, sizeof(intercepted));
+
+ sgdt(&fw_gdt);
+ tss_fw_seg = read_tr();
+ gdt_rd = NULL;
+ if (tss_fw_seg == 0) {
+ for (i = 2; (i << 3) + sizeof(*gdt_desc) <= fw_gdt.rd_limit;
+ i += 2) {
+ gdt_desc = (struct system_segment_descriptor *)(
+ fw_gdt.rd_base + (i << 3));
+ if (gdt_desc->sd_type == 0 && gdt_desc->sd_mbz == 0) {
+ gdt_rd = &fw_gdt;
+ break;
+ }
+ }
+ if (gdt_rd == NULL) {
+ if (i >= 8190) {
+ printf("efi_redirect_exceptions: all slots "
+ "in gdt are used\n");
+ free_tables();
+ return (0);
+ }
+ loader_gdt.rd_limit = roundup2(fw_gdt.rd_limit +
+ sizeof(struct system_segment_descriptor),
+ sizeof(struct system_segment_descriptor)) - 1;
+ i = (loader_gdt.rd_limit + 1 -
+ sizeof(struct system_segment_descriptor)) /
+ sizeof(struct system_segment_descriptor) * 2;
+ status = BS->AllocatePages(AllocateAnyPages,
+ EfiLoaderData,
+ EFI_SIZE_TO_PAGES(loader_gdt.rd_limit),
+ &loader_gdt_pa);
+ if (EFI_ERROR(status)) {
+ printf("efi_setup_tss: AllocatePages gdt error "
+ "%lu\n", EFI_ERROR_CODE(status));
+ loader_gdt_pa = 0;
+ free_tables();
+ return (0);
+ }
+ loader_gdt.rd_base = loader_gdt_pa;
+ bzero((void *)loader_gdt.rd_base, loader_gdt.rd_limit);
+ bcopy((void *)fw_gdt.rd_base,
+ (void *)loader_gdt.rd_base, fw_gdt.rd_limit);
+ gdt_rd = &loader_gdt;
+ }
+ loader_tss = i << 3;
+ if (!efi_setup_tss(gdt_rd, i, &tss)) {
+ tss_pa = 0;
+ free_tables();
+ return (0);
+ }
+ } else {
+ tss_desc = (struct system_segment_descriptor *)((char *)
+ fw_gdt.rd_base + tss_fw_seg);
+ if (tss_desc->sd_type != SDT_SYSTSS &&
+ tss_desc->sd_type != SDT_SYSBSY) {
+ printf("LTR points to non-TSS descriptor\n");
+ free_tables();
+ return (0);
+ }
+ tss_pa = tss_desc->sd_lobase + (tss_desc->sd_hibase << 16);
+ tss = (struct amd64tss *)tss_pa;
+ tss_desc->sd_type = SDT_SYSTSS; /* unbusy */
+ }
+
+ PREPARE_EXCEPTION(0);
+ PREPARE_EXCEPTION(1);
+ PREPARE_EXCEPTION(2);
+ PREPARE_EXCEPTION(3);
+ PREPARE_EXCEPTION(4);
+ PREPARE_EXCEPTION(5);
+ PREPARE_EXCEPTION(6);
+ PREPARE_EXCEPTION(7);
+ PREPARE_EXCEPTION(8);
+ PREPARE_EXCEPTION(9);
+ PREPARE_EXCEPTION(10);
+ PREPARE_EXCEPTION(11);
+ PREPARE_EXCEPTION(12);
+ PREPARE_EXCEPTION(13);
+ PREPARE_EXCEPTION(14);
+ PREPARE_EXCEPTION(16);
+ PREPARE_EXCEPTION(17);
+ PREPARE_EXCEPTION(18);
+ PREPARE_EXCEPTION(19);
+ PREPARE_EXCEPTION(20);
+
+ exc_rsp = exc_stack_pa + PAGE_SIZE -
+ (6 /* hw exception frame */ + 3 /* scratch regs */) * 8;
+
+ /* Find free IST and use it */
+ for (ist = 1; ist < NUM_IST; ist++) {
+ if (ist_use_table[ist] == 0)
+ break;
+ }
+ if (ist == NUM_IST) {
+ printf("efi_redirect_exceptions: all ISTs used\n");
+ free_tables();
+ lidt_pa = 0;
+ return (0);
+ }
+ for (i = 0; i < NUM_EXC; i++) {
+ loader_idt_e = &((struct gate_descriptor *)loader_idt.
+ rd_base)[i];
+ if (intercepted[i])
+ loader_idt_e->gd_ist = ist;
+ }
+ (&(tss->tss_ist1))[ist - 1] = exc_stack_pa + PAGE_SIZE;
+
+ /* Switch to new IDT */
+ rfl = intr_disable();
+ if (loader_gdt_pa != 0)
+ bare_lgdt(&loader_gdt);
+ if (loader_tss != 0)
+ ltr(loader_tss);
+ lidt(&loader_idt);
+ intr_restore(rfl);
+ return (1);
+}
+
+static void
+efi_unredirect_exceptions(void)
+{
+ register_t rfl;
+
+ if (lidt_pa == 0)
+ return;
+
+ rfl = intr_disable();
+ if (ist != 0)
+ (&(((struct amd64tss *)tss_pa)->tss_ist1))[ist - 1] = 0;
+ if (loader_gdt_pa != 0)
+ bare_lgdt(&fw_gdt);
+ if (loader_tss != 0)
+ ltr(tss_fw_seg);
+ lidt(&fw_idt);
+ intr_restore(rfl);
+ free_tables();
+}
+
+static int
+command_grab_faults(int argc, char *argv[])
+{
+ int res;
+
+ res = efi_redirect_exceptions();
+ if (!res)
+ printf("failed\n");
+ return (CMD_OK);
+}
+COMMAND_SET(grap_faults, "grab_faults", "grab faults", command_grab_faults);
+
+static int
+command_ungrab_faults(int argc, char *argv[])
+{
+
+ efi_unredirect_exceptions();
+ return (CMD_OK);
+}
+COMMAND_SET(ungrab_faults, "ungrab_faults", "ungrab faults",
+ command_ungrab_faults);
+
+static int
+command_fault(int argc, char *argv[])
+{
+
+ __asm("ud2");
+ return (CMD_OK);
+}
+COMMAND_SET(fault, "fault", "generate fault", command_fault);
More information about the svn-src-head
mailing list