2 * Copyright (c) 2016 The FreeBSD Foundation
5 * This software was developed by Konstantin Belousov under sponsorship
6 * from the FreeBSD Foundation.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <machine/cpufunc.h>
37 #include <machine/psl.h>
38 #include <machine/segments.h>
39 #include <machine/frame.h>
40 #include <machine/tss.h>
45 #include "bootstrap.h"
46 #include "loader_efi.h"
52 * This code catches exceptions but forwards hardware interrupts to
53 * handlers installed by firmware. It differentiates exceptions
54 * vs. interrupts by presence of the error code on the stack, which
55 * causes different stack pointer value on trap handler entry.
57 * Use kernel layout for the trapframe just to not be original.
59 * Use free IST slot in existing TSS, or create our own TSS if
60 * firmware did not configured any, to have stack switched to
61 * IST-specified one, e.g. to handle #SS. If hand-off cannot find
62 * unused IST slot, or create a new descriptor in GDT, we bail out.
65 static struct region_descriptor fw_idt; /* Descriptor for pristine fw IDT */
66 static struct region_descriptor loader_idt;/* Descriptor for loader
68 static EFI_PHYSICAL_ADDRESS lidt_pa; /* Address of loader shadow IDT */
69 static EFI_PHYSICAL_ADDRESS tss_pa; /* Address of TSS */
70 static EFI_PHYSICAL_ADDRESS exc_stack_pa;/* Address of IST stack for loader */
71 EFI_PHYSICAL_ADDRESS exc_rsp; /* %rsp value on our IST stack when
73 EFI_PHYSICAL_ADDRESS fw_intr_handlers[NUM_EXC]; /* fw handlers for < 32 IDT
75 static int intercepted[NUM_EXC];
76 static int ist; /* IST for exception handlers */
77 static uint32_t tss_fw_seg; /* Fw TSS segment */
78 static uint32_t loader_tss; /* Loader TSS segment */
79 static struct region_descriptor fw_gdt; /* Descriptor of pristine GDT */
80 static EFI_PHYSICAL_ADDRESS loader_gdt_pa; /* Address of loader shadow GDT */
82 void report_exc(struct trapframe *tf);
84 report_exc(struct trapframe *tf)
88 * printf() depends on loader runtime and UEFI firmware health
89 * to produce the console output, in case of exception, the
90 * loader or firmware runtime may fail to support the printf().
92 printf("===================================================="
93 "============================\n");
94 printf("Exception %u\n", tf->tf_trapno);
95 printf("ss 0x%04hx cs 0x%04hx ds 0x%04hx es 0x%04hx fs 0x%04hx "
97 (uint16_t)tf->tf_ss, (uint16_t)tf->tf_cs, (uint16_t)tf->tf_ds,
98 (uint16_t)tf->tf_es, (uint16_t)tf->tf_fs, (uint16_t)tf->tf_gs);
99 printf("err 0x%08x rfl 0x%08x addr 0x%016lx\n"
100 "rsp 0x%016lx rip 0x%016lx\n",
101 (uint32_t)tf->tf_err, (uint32_t)tf->tf_rflags, tf->tf_addr,
102 tf->tf_rsp, tf->tf_rip);
104 "rdi 0x%016lx rsi 0x%016lx rdx 0x%016lx\n"
105 "rcx 0x%016lx r8 0x%016lx r9 0x%016lx\n"
106 "rax 0x%016lx rbx 0x%016lx rbp 0x%016lx\n"
107 "r10 0x%016lx r11 0x%016lx r12 0x%016lx\n"
108 "r13 0x%016lx r14 0x%016lx r15 0x%016lx\n",
109 tf->tf_rdi, tf->tf_rsi, tf->tf_rdx, tf->tf_rcx, tf->tf_r8,
110 tf->tf_r9, tf->tf_rax, tf->tf_rbx, tf->tf_rbp, tf->tf_r10,
111 tf->tf_r11, tf->tf_r12, tf->tf_r13, tf->tf_r14, tf->tf_r15);
112 printf("Machine stopped.\n");
116 prepare_exception(unsigned idx, uint64_t my_handler,
117 int ist_use_table[static NUM_IST])
119 struct gate_descriptor *fw_idt_e, *loader_idt_e;
121 fw_idt_e = &((struct gate_descriptor *)fw_idt.rd_base)[idx];
122 loader_idt_e = &((struct gate_descriptor *)loader_idt.rd_base)[idx];
123 fw_intr_handlers[idx] = fw_idt_e->gd_looffset +
124 (fw_idt_e->gd_hioffset << 16);
125 intercepted[idx] = 1;
126 ist_use_table[fw_idt_e->gd_ist]++;
127 loader_idt_e->gd_looffset = my_handler;
128 loader_idt_e->gd_hioffset = my_handler >> 16;
130 * We reuse uefi selector for the code segment for the exception
131 * handler code, while the reason for the fault might be the
132 * corruption of that gdt entry. On the other hand, allocating
133 * our own descriptor might be not much better, if gdt is corrupted.
135 loader_idt_e->gd_selector = fw_idt_e->gd_selector;
136 loader_idt_e->gd_ist = 0;
137 loader_idt_e->gd_type = SDT_SYSIGT;
138 loader_idt_e->gd_dpl = 0;
139 loader_idt_e->gd_p = 1;
140 loader_idt_e->gd_xx = 0;
141 loader_idt_e->sd_xx1 = 0;
143 #define PREPARE_EXCEPTION(N) \
144 extern char EXC##N##_handler[]; \
145 prepare_exception(N, (uintptr_t)EXC##N##_handler, ist_use_table);
152 BS->FreePages(lidt_pa, EFI_SIZE_TO_PAGES(fw_idt.rd_limit));
155 if (exc_stack_pa != 0) {
156 BS->FreePages(exc_stack_pa, 1);
159 if (tss_pa != 0 && tss_fw_seg == 0) {
160 BS->FreePages(tss_pa, EFI_SIZE_TO_PAGES(sizeof(struct
164 if (loader_gdt_pa != 0) {
165 BS->FreePages(tss_pa, 2);
173 efi_setup_tss(struct region_descriptor *gdt, uint32_t loader_tss_idx,
174 struct amd64tss **tss)
177 struct system_segment_descriptor *tss_desc;
179 tss_desc = (struct system_segment_descriptor *)(gdt->rd_base +
180 (loader_tss_idx << 3));
181 status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData,
182 EFI_SIZE_TO_PAGES(sizeof(struct amd64tss)), &tss_pa);
183 if (EFI_ERROR(status)) {
184 printf("efi_setup_tss: AllocatePages tss error %lu\n",
185 EFI_ERROR_CODE(status));
188 *tss = (struct amd64tss *)tss_pa;
189 bzero(*tss, sizeof(**tss));
190 tss_desc->sd_lolimit = sizeof(struct amd64tss);
191 tss_desc->sd_lobase = tss_pa;
192 tss_desc->sd_type = SDT_SYSTSS;
193 tss_desc->sd_dpl = 0;
195 tss_desc->sd_hilimit = sizeof(struct amd64tss) >> 16;
196 tss_desc->sd_gran = 0;
197 tss_desc->sd_hibase = tss_pa >> 24;
198 tss_desc->sd_xx0 = 0;
199 tss_desc->sd_xx1 = 0;
200 tss_desc->sd_mbz = 0;
201 tss_desc->sd_xx2 = 0;
206 efi_redirect_exceptions(void)
208 int ist_use_table[NUM_IST];
209 struct gate_descriptor *loader_idt_e;
210 struct system_segment_descriptor *tss_desc, *gdt_desc;
211 struct amd64tss *tss;
212 struct region_descriptor *gdt_rd, loader_gdt;
218 status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData,
219 EFI_SIZE_TO_PAGES(fw_idt.rd_limit), &lidt_pa);
220 if (EFI_ERROR(status)) {
221 printf("efi_redirect_exceptions: AllocatePages IDT error %lu\n",
222 EFI_ERROR_CODE(status));
226 status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData, 1,
228 if (EFI_ERROR(status)) {
229 printf("efi_redirect_exceptions: AllocatePages stk error %lu\n",
230 EFI_ERROR_CODE(status));
235 loader_idt.rd_limit = fw_idt.rd_limit;
236 bcopy((void *)fw_idt.rd_base, (void *)loader_idt.rd_base,
237 loader_idt.rd_limit);
238 bzero(ist_use_table, sizeof(ist_use_table));
239 bzero(fw_intr_handlers, sizeof(fw_intr_handlers));
240 bzero(intercepted, sizeof(intercepted));
243 tss_fw_seg = read_tr();
245 if (tss_fw_seg == 0) {
246 for (i = 2; (i << 3) + sizeof(*gdt_desc) <= fw_gdt.rd_limit;
248 gdt_desc = (struct system_segment_descriptor *)(
249 fw_gdt.rd_base + (i << 3));
250 if (gdt_desc->sd_type == 0 && gdt_desc->sd_mbz == 0) {
255 if (gdt_rd == NULL) {
257 printf("efi_redirect_exceptions: all slots "
258 "in gdt are used\n");
262 loader_gdt.rd_limit = roundup2(fw_gdt.rd_limit +
263 sizeof(struct system_segment_descriptor),
264 sizeof(struct system_segment_descriptor)) - 1;
265 i = (loader_gdt.rd_limit + 1 -
266 sizeof(struct system_segment_descriptor)) /
267 sizeof(struct system_segment_descriptor) * 2;
268 status = BS->AllocatePages(AllocateAnyPages,
270 EFI_SIZE_TO_PAGES(loader_gdt.rd_limit),
272 if (EFI_ERROR(status)) {
273 printf("efi_setup_tss: AllocatePages gdt error "
274 "%lu\n", EFI_ERROR_CODE(status));
279 loader_gdt.rd_base = loader_gdt_pa;
280 bzero((void *)loader_gdt.rd_base, loader_gdt.rd_limit);
281 bcopy((void *)fw_gdt.rd_base,
282 (void *)loader_gdt.rd_base, fw_gdt.rd_limit);
283 gdt_rd = &loader_gdt;
286 if (!efi_setup_tss(gdt_rd, i, &tss)) {
292 tss_desc = (struct system_segment_descriptor *)((char *)
293 fw_gdt.rd_base + tss_fw_seg);
294 if (tss_desc->sd_type != SDT_SYSTSS &&
295 tss_desc->sd_type != SDT_SYSBSY) {
296 printf("LTR points to non-TSS descriptor\n");
300 tss_pa = tss_desc->sd_lobase + (tss_desc->sd_hibase << 16);
301 tss = (struct amd64tss *)tss_pa;
302 tss_desc->sd_type = SDT_SYSTSS; /* unbusy */
305 PREPARE_EXCEPTION(0);
306 PREPARE_EXCEPTION(1);
307 PREPARE_EXCEPTION(2);
308 PREPARE_EXCEPTION(3);
309 PREPARE_EXCEPTION(4);
310 PREPARE_EXCEPTION(5);
311 PREPARE_EXCEPTION(6);
312 PREPARE_EXCEPTION(7);
313 PREPARE_EXCEPTION(8);
314 PREPARE_EXCEPTION(9);
315 PREPARE_EXCEPTION(10);
316 PREPARE_EXCEPTION(11);
317 PREPARE_EXCEPTION(12);
318 PREPARE_EXCEPTION(13);
319 PREPARE_EXCEPTION(14);
320 PREPARE_EXCEPTION(16);
321 PREPARE_EXCEPTION(17);
322 PREPARE_EXCEPTION(18);
323 PREPARE_EXCEPTION(19);
324 PREPARE_EXCEPTION(20);
326 exc_rsp = exc_stack_pa + PAGE_SIZE -
327 (6 /* hw exception frame */ + 3 /* scratch regs */) * 8;
329 /* Find free IST and use it */
330 for (ist = 1; ist < NUM_IST; ist++) {
331 if (ist_use_table[ist] == 0)
334 if (ist == NUM_IST) {
335 printf("efi_redirect_exceptions: all ISTs used\n");
340 for (i = 0; i < NUM_EXC; i++) {
341 loader_idt_e = &((struct gate_descriptor *)loader_idt.
344 loader_idt_e->gd_ist = ist;
346 (&(tss->tss_ist1))[ist - 1] = exc_stack_pa + PAGE_SIZE;
348 /* Switch to new IDT */
349 rfl = intr_disable();
350 if (loader_gdt_pa != 0)
351 bare_lgdt(&loader_gdt);
360 efi_unredirect_exceptions(void)
367 rfl = intr_disable();
369 (&(((struct amd64tss *)tss_pa)->tss_ist1))[ist - 1] = 0;
370 if (loader_gdt_pa != 0)
380 command_grab_faults(int argc, char *argv[])
384 res = efi_redirect_exceptions();
389 COMMAND_SET(grap_faults, "grab_faults", "grab faults", command_grab_faults);
392 command_ungrab_faults(int argc, char *argv[])
395 efi_unredirect_exceptions();
398 COMMAND_SET(ungrab_faults, "ungrab_faults", "ungrab faults",
399 command_ungrab_faults);
402 command_fault(int argc, char *argv[])
408 COMMAND_SET(fault, "fault", "generate fault", command_fault);