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libpayload: Rework exception hook interface

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This patch makes some slight changes to the exception hook interface.
The old code provides a different handler hook for every exception
type... however, in practice all those hook functions often need to look
very similar, so this creates more boilerplate than it removes. The new
interface just allows for a single hook with the exception type passed
as an argument, and the consumer can signal whether the exception was
handled through the return value. (Right now this still only supports
one consumer, but it could easily be extended to walk through a list of
hooks if the need arises.)

Also move the excepton state from an argument to a global. This avoids a
lot of boilerplate since some consumers need to change the state from
many places, so they would have to pass the same pointer around many
times. It also removes the false suggestion that the exception state was
not global and you could have multiple copies of it (which the exception
core doesn't support for any architecture).

On the ARM side, the exception state is separated from the exception
stack for easier access. (This requires some assembly changes, and I
threw in a few comments and corrected the immediate sigils from '$' to
the official '#' while I'm there.) Since the exception state is now both
stored and loaded through an indirection pointer, this allows for some
very limited reentrance (you could point it to a different struct while
handling an exception, and while you still won't be able to return to
the outer-level exception from there, you could at least swap out the
pointer and return back to System Mode in one go).

BUG=chrome-os-partner:18390
TEST=Made sure normal exceptions still get dumped correctly on both
archs.

Original-Change-Id: I5d9a934fab7c14ccb2c9d7ee4b3465c825521fa2
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/202562
Original-Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
(cherry picked from commit 97542110f0b385b9b8d89675866e65db8ca32aeb)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

*** Squashed to prevent build failures. ***

libpayload: align arm64 with new exception handling model

The exception handling was previously updated, however the
arm64 changes raced with hat one. Make the arm64 align with
the new model. Without these changes compilation will fail.

BUG=None
BRANCH=None
TEST=Can build libpayload for rush.

Original-Change-Id: I320b39a57b985d1f87446ea7757955664f8dba8f
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/204402
Original-Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
(cherry picked from commit 0080df41b311ef20f9214b386fa4e38ee54aa1a1)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I9a0bb3848cf5286f9f4bb08172a9f4a15278348e
Reviewed-on: http://review.coreboot.org/8117
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
Julius Werner 2014-05-15 19:41:52 -07:00 committed by Marc Jones
parent 43e10301c0
commit 092cac58de
9 changed files with 179 additions and 185 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

66
payloads/libpayload/arch/arm/exception.c
View file

@ -33,22 +33,17 @@
#include <libpayload.h> #include <libpayload.h>
#include <stdint.h> #include <stdint.h>
uint8_t exception_stack[0x1000] __attribute__((aligned(8))); u32 exception_stack[0x400] __attribute__((aligned(8)));
extern void *exception_stack_end; struct exception_state exception_state;
struct exception_handler_info static exception_hook hook;
{ static const char *names[EXC_COUNT] = {
const char *name; [EXC_UNDEF] = "Undefined Instruction",
exception_hook hook; [EXC_SWI] = "Software Interrupt",
}; [EXC_PABORT] = "Prefetch Abort",
[EXC_DABORT] = "Data Abort",
static struct exception_handler_info exceptions[EXC_COUNT] = { [EXC_IRQ] = "Interrupt",
[EXC_UNDEF] = { "_undefined_instruction" }, [EXC_FIQ] = "Fast Interrupt",
[EXC_SWI] = { "_software_interrupt" },
[EXC_PABORT] = { "_prefetch_abort" },
[EXC_DABORT] = { "_data_abort" },
[EXC_IRQ] = { "_irq" },
[EXC_FIQ] = { "_fiq" },
}; };
static void dump_stack(uintptr_t addr, size_t bytes) static void dump_stack(uintptr_t addr, size_t bytes)
@ -66,7 +61,7 @@ static void dump_stack(uintptr_t addr, size_t bytes)
} }
} }
static void print_regs(struct exception_state *state) static void print_regs(void)
{ {
int i; int i;
@ -81,30 +76,21 @@ static void print_regs(struct exception_state *state)
printf("IP"); printf("IP");
else else
printf("R%d", i); printf("R%d", i);
printf(" = 0x%08x\n", state->regs[i]); printf(" = 0x%08x\n", exception_state.regs[i]);
} }
printf("CPSR = 0x%08x\n", state->cpsr); printf("CPSR = 0x%08x\n", exception_state.cpsr);
} }
void exception_dispatch(struct exception_state *state, int idx); void exception_dispatch(u32 idx)
void exception_dispatch(struct exception_state *state, int idx)
{ {
if (idx >= EXC_COUNT) { die_if(idx >= EXC_COUNT || !names[idx], "Bad exception index %u!", idx);
printf("Bad exception index %d.\n", idx);
} else {
struct exception_handler_info *info = &exceptions[idx];
if (info->hook) {
info->hook(idx, state);
return;
}
if (info->name) if (hook && hook(idx))
printf("exception %s\n", info->name); return;
else
printf("exception _not_used.\n"); printf("%s Exception\n", names[idx]);
} print_regs();
print_regs(state); dump_stack(exception_state.regs[13], 512);
dump_stack(state->regs[13], 512);
halt(); halt();
} }
@ -119,11 +105,13 @@ void exception_init(void)
extern uint32_t exception_table[]; extern uint32_t exception_table[];
set_vbar((uintptr_t)exception_table); set_vbar((uintptr_t)exception_table);
exception_stack_end = exception_stack + sizeof(exception_stack);
exception_stack_end = exception_stack + ARRAY_SIZE(exception_stack);
exception_state_ptr = &exception_state;
} }
void exception_install_hook(int type, exception_hook hook) void exception_install_hook(exception_hook h)
{ {
die_if(type >= EXC_COUNT, "Out of bounds exception index %d.\n", type); die_if(hook, "Implement support for a list of hooks if you need it.");
exceptions[type].hook = hook; hook = h;
} }

56
payloads/libpayload/arch/arm/exception_asm.S
View file

@ -43,72 +43,76 @@ exception_table:
b 8f b 8f
1: 1:
mov sp, $0 mov sp, #0
b exception_common b exception_common
/* Undefined Instruction (CAREFUL: the PC offset is specific to thumb mode!) */ /* Undefined Instruction (CAREFUL: the PC offset is specific to thumb mode!) */
2: 2:
sub lr, lr, $2 sub lr, lr, #2
mov sp, $1 mov sp, #1
b exception_common b exception_common
/* Software Interrupt (no PC offset necessary) */ /* Software Interrupt (no PC offset necessary) */
3: 3:
mov sp, $2 mov sp, #2
b exception_common b exception_common
/* Prefetch Abort */ /* Prefetch Abort */
4: 4:
sub lr, lr, $4 sub lr, lr, #4
mov sp, $3 mov sp, #3
b exception_common b exception_common
/* Data Abort */ /* Data Abort */
5: 5:
sub lr, lr, $8 sub lr, lr, #8
mov sp, $4 mov sp, #4
b exception_common b exception_common
/* (not used) */ /* (not used) */
6: 6:
mov sp, $5 mov sp, #5
b exception_common b exception_common
/* Interrupt */ /* Interrupt */
7: 7:
sub lr, lr, $4 sub lr, lr, #4
mov sp, $6 mov sp, #6
b exception_common b exception_common
/* Fast Interrupt */ /* Fast Interrupt */
8: 8:
sub lr, lr, $4 sub lr, lr, #4
mov sp, $7 mov sp, #7
b exception_common b exception_common
exception_common: exception_common:
str sp, exception_idx str sp, exception_idx
ldr sp, exception_stack_end ldr sp, exception_state_ptr
push { lr } stmia sp!, { r0 - r12 } /* Save regs from bottom to top */
stmfd sp, { sp, lr }^ stmia sp, { sp, lr }^ /* Save banked SP/LR (no writeback) */
sub sp, sp, $8 str lr, [sp, #(4 * 2)] /* Save PC to &regs[13] + 2 */
push { r0 - r12 }
mrs r0, SPSR mrs r0, SPSR
push { r0 } str r0, [sp, #(4 * 3)] /* Save SPSR to &regs[13] + 3 */
mov r0, sp ldr sp, exception_stack_end /* Point SP to the stack for C code */
ldr r1, exception_idx ldr r0, exception_idx
blx exception_dispatch blx exception_dispatch
pop { r0 } ldr sp, exception_state_ptr
msr SPSR_cxsf, r0 ldr r0, [sp, #(4 * 16)] /* Load SPSR from &regs[0] + 16... */
pop { r0 - r12 } msr SPSR_cxsf, r0 /* ...and get it out of the way */
add sp, sp, $8 ldmia sp!, { r0 - r12 } /* Restore regs from bottom to top */
ldmfd sp!, { pc }^ ldmia sp, { sp, lr }^ /* Restore SP/LR to banked location */
add sp, sp, #8 /* Adjust SP (no writeback allowed) */
ldmia sp!, { pc }^ /* Do exception return (mode switch) */
.align 2 .align 2
.global exception_stack_end .global exception_stack_end
exception_stack_end: exception_stack_end:
.word 0 .word 0
.global exception_state_ptr
exception_state_ptr:
.word 0
exception_idx: exception_idx:
.word 0 .word 0

15
payloads/libpayload/arch/arm64/exception.c
View file

@ -36,9 +36,10 @@ extern unsigned int test_exc;
struct exception_handler_info struct exception_handler_info
{ {
const char *name; const char *name;
exception_hook hook;
}; };
static exception_hook hook;
struct exception_state *exception_state;
static struct exception_handler_info exceptions[EXC_COUNT] = { static struct exception_handler_info exceptions[EXC_COUNT] = {
[EXC_INV] = { "_invalid_exception" }, [EXC_INV] = { "_invalid_exception" },
[EXC_SYNC] = { "_sync" }, [EXC_SYNC] = { "_sync" },
@ -61,14 +62,14 @@ static void print_regs(struct exception_state *state)
void exception_dispatch(struct exception_state *state, int idx); void exception_dispatch(struct exception_state *state, int idx);
void exception_dispatch(struct exception_state *state, int idx) void exception_dispatch(struct exception_state *state, int idx)
{ {
exception_state = state;
if (idx >= EXC_COUNT) { if (idx >= EXC_COUNT) {
printf("Bad exception index %d.\n", idx); printf("Bad exception index %d.\n", idx);
} else { } else {
struct exception_handler_info *info = &exceptions[idx]; struct exception_handler_info *info = &exceptions[idx];
if (info->hook) { if (hook && hook(idx))
info->hook(idx, state);
return; return;
}
if (info->name) if (info->name)
printf("exception %s\n", info->name); printf("exception %s\n", info->name);
@ -89,8 +90,8 @@ void exception_init(void)
set_vbar(exception_table); set_vbar(exception_table);
} }
void exception_install_hook(int type, exception_hook hook) void exception_install_hook(exception_hook h)
{ {
die_if(type >= EXC_COUNT, "Out of bounds exception index %d.\n", type); die_if(hook, "Implement support for a list of hooks if you need it.");
exceptions[type].hook = hook; hook = h;
} }

159
payloads/libpayload/arch/x86/exception.c
View file

@ -32,22 +32,29 @@
#include <libpayload.h> #include <libpayload.h>
#include <stdint.h> #include <stdint.h>
uint8_t exception_stack[0x1000] __attribute__((aligned(8))); u32 exception_stack[0x400] __attribute__((aligned(8)));
extern void *exception_stack_end;
extern struct exception_handler_state *exception_handler_state_handoff;
struct exception_handler_state static exception_hook hook;
{ static const char *names[EXC_COUNT] = {
struct exception_state regs; [EXC_DE] = "Divide by Zero",
u32 error_code; [EXC_DB] = "Debug",
u32 vector; [EXC_NMI] = "Non-Maskable-Interrupt",
} __attribute__((packed)); [EXC_BP] = "Breakpoint",
[EXC_OF] = "Overflow",
struct exception_handler_info [EXC_BR] = "Bound Range",
{ [EXC_UD] = "Invalid Opcode",
const char *name; [EXC_NM] = "Device Not Available",
void (*error_code_printer)(u32 code); [EXC_DF] = "Double Fault",
exception_hook hook; [EXC_TS] = "Invalid TSS",
[EXC_NP] = "Segment Not Present",
[EXC_SS] = "Stack Fault",
[EXC_GP] = "General Protection Fault",
[EXC_PF] = "Page Fault",
[EXC_MF] = "x87 Floating Point",
[EXC_AC] = "Alignment Check",
[EXC_MC] = "Machine Check",
[EXC_XF] = "SIMD Floating Point",
[EXC_SX] = "Security",
}; };
static void print_segment_error_code(u32 code) static void print_segment_error_code(u32 code)
@ -93,36 +100,6 @@ static void print_raw_error_code(u32 code)
printf("%#x", code); printf("%#x", code);
} }
static struct exception_handler_info exceptions[EXC_COUNT] = {
[EXC_DE] = { .name = "divide by zero" },
[EXC_DB] = { .name = "debug" },
[EXC_NMI] = { .name = "non-maskable-interrupt" },
[EXC_BP] = { .name = "breakpoint" },
[EXC_OF] = { .name = "overflow" },
[EXC_BR] = { .name = "bound range" },
[EXC_UD] = { .name = "invalid opcode" },
[EXC_NM] = { .name = "device not available" },
[EXC_DF] = { .name = "double fault",
.error_code_printer = &print_raw_error_code },
[EXC_TS] = { .name = "invalid tss",
.error_code_printer = &print_segment_error_code },
[EXC_NP] = { .name = "segment not present",
.error_code_printer = &print_segment_error_code },
[EXC_SS] = { .name = "stack",
.error_code_printer = &print_segment_error_code },
[EXC_GP] = { .name = "general protection",
.error_code_printer = &print_segment_error_code },
[EXC_PF] = { .name = "page fault",
.error_code_printer = &print_page_fault_error_code },
[EXC_MF] = { .name = "x87 floating point" },
[EXC_AC] = { .name = "alignment check",
.error_code_printer = &print_raw_error_code },
[EXC_MC] = { .name = "machine check" },
[EXC_XF] = { .name = "SIMD floating point" },
[EXC_SX] = { .name = "security",
.error_code_printer = &print_raw_error_code },
};
static void dump_stack(uintptr_t addr, size_t bytes) static void dump_stack(uintptr_t addr, size_t bytes)
{ {
int i, j; int i, j;
@ -138,64 +115,70 @@ static void dump_stack(uintptr_t addr, size_t bytes)
} }
} }
static void dump_exception_state(struct exception_handler_state *state, static void dump_exception_state(void)
struct exception_handler_info *info)
{ {
if (info) { printf("%s Exception\n", names[exception_state->vector]);
printf("Exception %d (%s)\n", state->vector, info->name);
if (info->error_code_printer) { printf("Error code: ");
printf("Error code: "); switch (exception_state->vector) {
info->error_code_printer(state->error_code); case EXC_PF:
printf("\n"); print_page_fault_error_code(exception_state->error_code);
} break;
} else { case EXC_TS:
printf("Unrecognized exception %d\n", state->vector); case EXC_NP:
case EXC_SS:
case EXC_GP:
print_segment_error_code(exception_state->error_code);
break;
case EXC_DF:
case EXC_AC:
case EXC_SX:
print_raw_error_code(exception_state->error_code);
break;
default:
printf("n/a");
break;
} }
printf("EIP: 0x%08x\n", state->regs.eip); printf("\n");
printf("CS: 0x%04x\n", state->regs.cs); printf("EIP: 0x%08x\n", exception_state->regs.eip);
printf("EFLAGS: 0x%08x\n", state->regs.eflags); printf("CS: 0x%04x\n", exception_state->regs.cs);
printf("EAX: 0x%08x\n", state->regs.eax); printf("EFLAGS: 0x%08x\n", exception_state->regs.eflags);
printf("ECX: 0x%08x\n", state->regs.ecx); printf("EAX: 0x%08x\n", exception_state->regs.eax);
printf("EDX: 0x%08x\n", state->regs.edx); printf("ECX: 0x%08x\n", exception_state->regs.ecx);
printf("EBX: 0x%08x\n", state->regs.ebx); printf("EDX: 0x%08x\n", exception_state->regs.edx);
printf("ESP: 0x%08x\n", state->regs.esp); printf("EBX: 0x%08x\n", exception_state->regs.ebx);
printf("EBP: 0x%08x\n", state->regs.ebp); printf("ESP: 0x%08x\n", exception_state->regs.esp);
printf("ESI: 0x%08x\n", state->regs.esi); printf("EBP: 0x%08x\n", exception_state->regs.ebp);
printf("EDI: 0x%08x\n", state->regs.edi); printf("ESI: 0x%08x\n", exception_state->regs.esi);
printf("DS: 0x%04x\n", state->regs.ds); printf("EDI: 0x%08x\n", exception_state->regs.edi);
printf("ES: 0x%04x\n", state->regs.es); printf("DS: 0x%04x\n", exception_state->regs.ds);
printf("SS: 0x%04x\n", state->regs.ss); printf("ES: 0x%04x\n", exception_state->regs.es);
printf("FS: 0x%04x\n", state->regs.fs); printf("SS: 0x%04x\n", exception_state->regs.ss);
printf("GS: 0x%04x\n", state->regs.gs); printf("FS: 0x%04x\n", exception_state->regs.fs);
printf("GS: 0x%04x\n", exception_state->regs.gs);
} }
void exception_dispatch(void) void exception_dispatch(void)
{ {
struct exception_handler_state *state = u32 vec = exception_state->vector;
exception_handler_state_handoff; die_if(vec >= EXC_COUNT || !names[vec], "Bad exception vector %u", vec);
struct exception_handler_info *info = NULL; if (hook && hook(vec))
if (state->vector < EXC_COUNT) return;
info = &exceptions[state->vector];
if (info && info->hook) { dump_exception_state();
info->hook(state->vector, &state->regs); dump_stack(exception_state->regs.esp, 512);
} else { halt();
dump_exception_state(state, info);
dump_stack(state->regs.esp, 512);
halt();
}
} }
void exception_init(void) void exception_init(void)
{ {
exception_stack_end = exception_stack + sizeof(exception_stack); exception_stack_end = exception_stack + ARRAY_SIZE(exception_stack);
exception_init_asm(); exception_init_asm();
} }
void exception_install_hook(int type, exception_hook hook) void exception_install_hook(exception_hook h)
{ {
die_if(type >= EXC_COUNT, "Out of bound exception type %d.\n", type); die_if(hook, "Implement support for a list of hooks if you need it.");
exceptions[type].hook = hook; hook = h;
} }

8
payloads/libpayload/arch/x86/exception_asm.S
View file

@ -31,8 +31,8 @@
.global exception_stack_end .global exception_stack_end
exception_stack_end: exception_stack_end:
.long 0 .long 0
.global exception_handler_state_handoff .global exception_state
exception_handler_state_handoff: exception_state:
.long 0 .long 0
/* Some temporary variables which are used while saving exception state. */ /* Some temporary variables which are used while saving exception state. */
@ -138,11 +138,11 @@ exception_common:
/* /*
* Call the C exception handler. It will find the exception state * Call the C exception handler. It will find the exception state
* using the exception_handler_state_handoff global pointer. Not * using the exception_state global pointer. Not
* passing parameters means we don't have to worry about what ABI * passing parameters means we don't have to worry about what ABI
* is being used. * is being used.
*/ */
mov %esp, exception_handler_state_handoff mov %esp, exception_state
call exception_dispatch call exception_dispatch
/* /*

10
payloads/libpayload/include/arm/arch/exception.h
View file

@ -32,13 +32,19 @@
#include <stdint.h> #include <stdint.h>
void exception_dispatch(u32 idx);
void set_vbar(uint32_t vbar); void set_vbar(uint32_t vbar);
struct exception_state struct exception_state
{ {
uint32_t cpsr; u32 regs[16];
uint32_t regs[16]; u32 cpsr;
} __attribute__((packed)); } __attribute__((packed));
extern struct exception_state exception_state;
extern u32 exception_stack[];
extern u32 *exception_stack_end;
extern struct exception_state *exception_state_ptr;
enum { enum {
EXC_UNDEF = 1, EXC_UNDEF = 1,

2
payloads/libpayload/include/arm64/arch/exception.h
View file

@ -41,6 +41,8 @@ struct exception_state
uint64_t regs[31]; uint64_t regs[31];
} __attribute__((packed)); } __attribute__((packed));
extern struct exception_state *exception_state;
enum { enum {
EXC_INV = 0, EXC_INV = 0,
EXC_SYNC = 1, EXC_SYNC = 1,

5
payloads/libpayload/include/exception.h
View file

@ -32,9 +32,10 @@
#include <arch/exception.h> #include <arch/exception.h>
typedef void (*exception_hook)(int type, struct exception_state *state); /* Return 1 if the exception was handled, 0 to proceed to the next handler. */
typedef int (*exception_hook)(u32 type);
void exception_init(void); void exception_init(void);
void exception_install_hook(int type, exception_hook hook); void exception_install_hook(exception_hook h);
#endif #endif

43
payloads/libpayload/include/x86/arch/exception.h
View file

@ -32,28 +32,37 @@
#include <stdint.h> #include <stdint.h>
void exception_dispatch(void);
void exception_init_asm(void); void exception_init_asm(void);
void exception_dispatch(void);
struct exception_state struct exception_state
{ {
uint32_t eax; /* Careful: x86/gdb.c currently relies on the size and order of regs. */
uint32_t ecx; struct {
uint32_t edx; u32 eax;
uint32_t ebx; u32 ecx;
uint32_t esp; u32 edx;
uint32_t ebp; u32 ebx;
uint32_t esi; u32 esp;
uint32_t edi; u32 ebp;
uint32_t eip; u32 esi;
uint32_t eflags; u32 edi;
uint32_t cs; u32 eip;
uint32_t ss; u32 eflags;
uint32_t ds; u32 cs;
uint32_t es; u32 ss;
uint32_t fs; u32 ds;
uint32_t gs; u32 es;
u32 fs;
u32 gs;
} regs;
u32 error_code;
u32 vector;
} __attribute__((packed)); } __attribute__((packed));
extern struct exception_state *exception_state;
extern u32 exception_stack[];
extern u32 *exception_stack_end;
enum { enum {
EXC_DE = 0, /* Divide by zero */ EXC_DE = 0, /* Divide by zero */