Marc Jones (marc.jones@se-eng.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/8117
-gerrit
commit 24650ed6bf036269e796e27624cc3d89b266fc25 Author: Julius Werner jwerner@chromium.org Date: Thu May 15 19:41:52 2014 -0700
libpayload: Rework exception hook interface
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 --- payloads/libpayload/arch/arm/exception.c | 66 ++++----- payloads/libpayload/arch/arm/exception_asm.S | 56 +++---- payloads/libpayload/arch/arm64/exception.c | 15 +- payloads/libpayload/arch/x86/exception.c | 163 +++++++++------------ payloads/libpayload/arch/x86/exception_asm.S | 8 +- payloads/libpayload/include/arm/arch/exception.h | 10 +- payloads/libpayload/include/arm64/arch/exception.h | 2 + payloads/libpayload/include/exception.h | 5 +- payloads/libpayload/include/x86/arch/exception.h | 43 +++--- 9 files changed, 181 insertions(+), 187 deletions(-)
diff --git a/payloads/libpayload/arch/arm/exception.c b/payloads/libpayload/arch/arm/exception.c index 45b77a7..d100937 100644 --- a/payloads/libpayload/arch/arm/exception.c +++ b/payloads/libpayload/arch/arm/exception.c @@ -33,22 +33,17 @@ #include <libpayload.h> #include <stdint.h>
-uint8_t exception_stack[0x1000] __attribute__((aligned(8))); -extern void *exception_stack_end; +u32 exception_stack[0x400] __attribute__((aligned(8))); +struct exception_state exception_state;
-struct exception_handler_info -{ - const char *name; - exception_hook hook; -}; - -static struct exception_handler_info exceptions[EXC_COUNT] = { - [EXC_UNDEF] = { "_undefined_instruction" }, - [EXC_SWI] = { "_software_interrupt" }, - [EXC_PABORT] = { "_prefetch_abort" }, - [EXC_DABORT] = { "_data_abort" }, - [EXC_IRQ] = { "_irq" }, - [EXC_FIQ] = { "_fiq" }, +static exception_hook hook; +static const char *names[EXC_COUNT] = { + [EXC_UNDEF] = "Undefined Instruction", + [EXC_SWI] = "Software Interrupt", + [EXC_PABORT] = "Prefetch Abort", + [EXC_DABORT] = "Data Abort", + [EXC_IRQ] = "Interrupt", + [EXC_FIQ] = "Fast Interrupt", };
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;
@@ -81,30 +76,21 @@ static void print_regs(struct exception_state *state) printf("IP"); else 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(struct exception_state *state, int idx) +void exception_dispatch(u32 idx) { - if (idx >= EXC_COUNT) { - printf("Bad exception index %d.\n", idx); - } else { - struct exception_handler_info *info = &exceptions[idx]; - if (info->hook) { - info->hook(idx, state); - return; - } + die_if(idx >= EXC_COUNT || !names[idx], "Bad exception index %u!", idx);
- if (info->name) - printf("exception %s\n", info->name); - else - printf("exception _not_used.\n"); - } - print_regs(state); - dump_stack(state->regs[13], 512); + if (hook && hook(idx)) + return; + + printf("%s Exception\n", names[idx]); + print_regs(); + dump_stack(exception_state.regs[13], 512); halt(); }
@@ -119,11 +105,13 @@ void exception_init(void)
extern uint32_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); - exceptions[type].hook = hook; + die_if(hook, "Implement support for a list of hooks if you need it."); + hook = h; } diff --git a/payloads/libpayload/arch/arm/exception_asm.S b/payloads/libpayload/arch/arm/exception_asm.S index 7b722cb..8715955 100644 --- a/payloads/libpayload/arch/arm/exception_asm.S +++ b/payloads/libpayload/arch/arm/exception_asm.S @@ -43,72 +43,76 @@ exception_table: b 8f
1: - mov sp, $0 + mov sp, #0 b exception_common
/* Undefined Instruction (CAREFUL: the PC offset is specific to thumb mode!) */ 2: - sub lr, lr, $2 - mov sp, $1 + sub lr, lr, #2 + mov sp, #1 b exception_common
/* Software Interrupt (no PC offset necessary) */ 3: - mov sp, $2 + mov sp, #2 b exception_common
/* Prefetch Abort */ 4: - sub lr, lr, $4 - mov sp, $3 + sub lr, lr, #4 + mov sp, #3 b exception_common
/* Data Abort */ 5: - sub lr, lr, $8 - mov sp, $4 + sub lr, lr, #8 + mov sp, #4 b exception_common
/* (not used) */ 6: - mov sp, $5 + mov sp, #5 b exception_common
/* Interrupt */ 7: - sub lr, lr, $4 - mov sp, $6 + sub lr, lr, #4 + mov sp, #6 b exception_common
/* Fast Interrupt */ 8: - sub lr, lr, $4 - mov sp, $7 + sub lr, lr, #4 + mov sp, #7 b exception_common
exception_common: str sp, exception_idx - ldr sp, exception_stack_end - push { lr } - stmfd sp, { sp, lr }^ - sub sp, sp, $8 - push { r0 - r12 } + ldr sp, exception_state_ptr + stmia sp!, { r0 - r12 } /* Save regs from bottom to top */ + stmia sp, { sp, lr }^ /* Save banked SP/LR (no writeback) */ + str lr, [sp, #(4 * 2)] /* Save PC to ®s[13] + 2 */ mrs r0, SPSR - push { r0 } - mov r0, sp - ldr r1, exception_idx + str r0, [sp, #(4 * 3)] /* Save SPSR to ®s[13] + 3 */ + ldr sp, exception_stack_end /* Point SP to the stack for C code */ + ldr r0, exception_idx blx exception_dispatch - pop { r0 } - msr SPSR_cxsf, r0 - pop { r0 - r12 } - add sp, sp, $8 - ldmfd sp!, { pc }^ + ldr sp, exception_state_ptr + ldr r0, [sp, #(4 * 16)] /* Load SPSR from ®s[0] + 16... */ + msr SPSR_cxsf, r0 /* ...and get it out of the way */ + ldmia sp!, { r0 - r12 } /* Restore regs from bottom to top */ + 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 .global exception_stack_end exception_stack_end: .word 0 + .global exception_state_ptr +exception_state_ptr: + .word 0
exception_idx: .word 0 diff --git a/payloads/libpayload/arch/arm64/exception.c b/payloads/libpayload/arch/arm64/exception.c index 988bef9..226f5ca 100644 --- a/payloads/libpayload/arch/arm64/exception.c +++ b/payloads/libpayload/arch/arm64/exception.c @@ -36,9 +36,10 @@ extern unsigned int test_exc; struct exception_handler_info { const char *name; - exception_hook hook; };
+static exception_hook hook; +struct exception_state *exception_state; static struct exception_handler_info exceptions[EXC_COUNT] = { [EXC_INV] = { "_invalid_exception" }, [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) { + exception_state = state; + if (idx >= EXC_COUNT) { printf("Bad exception index %d.\n", idx); } else { struct exception_handler_info *info = &exceptions[idx]; - if (info->hook) { - info->hook(idx, state); + if (hook && hook(idx)) return; - }
if (info->name) printf("exception %s\n", info->name); @@ -89,8 +90,8 @@ void exception_init(void) 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); - exceptions[type].hook = hook; + die_if(hook, "Implement support for a list of hooks if you need it."); + hook = h; } diff --git a/payloads/libpayload/arch/x86/exception.c b/payloads/libpayload/arch/x86/exception.c index e1ff3a5..f6bb8c9 100644 --- a/payloads/libpayload/arch/x86/exception.c +++ b/payloads/libpayload/arch/x86/exception.c @@ -32,22 +32,29 @@ #include <libpayload.h> #include <stdint.h>
-uint8_t exception_stack[0x1000] __attribute__((aligned(8))); -extern void *exception_stack_end; -extern struct exception_handler_state *exception_handler_state_handoff; - -struct exception_handler_state -{ - struct exception_state regs; - u32 error_code; - u32 vector; -} __attribute__((packed)); - -struct exception_handler_info -{ - const char *name; - void (*error_code_printer)(u32 code); - exception_hook hook; +u32 exception_stack[0x400] __attribute__((aligned(8))); + +static exception_hook hook; +static const char *names[EXC_COUNT] = { + [EXC_DE] = "Divide by Zero", + [EXC_DB] = "Debug", + [EXC_NMI] = "Non-Maskable-Interrupt", + [EXC_BP] = "Breakpoint", + [EXC_OF] = "Overflow", + [EXC_BR] = "Bound Range", + [EXC_UD] = "Invalid Opcode", + [EXC_NM] = "Device Not Available", + [EXC_DF] = "Double Fault", + [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) @@ -93,36 +100,6 @@ static void print_raw_error_code(u32 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) { 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, - struct exception_handler_info *info) +static void dump_exception_state(void) { - if (info) { - printf("Exception %d (%s)\n", state->vector, info->name); - - if (info->error_code_printer) { - printf("Error code: "); - info->error_code_printer(state->error_code); - printf("\n"); - } - } else { - printf("Unrecognized exception %d\n", state->vector); + printf("%s Exception\n", names[exception_state->vector]); + + printf("Error code: "); + switch (exception_state->vector) { + case EXC_PF: + print_page_fault_error_code(exception_state->error_code); + break; + case EXC_TS: + 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("CS: 0x%04x\n", state->regs.cs); - printf("EFLAGS: 0x%08x\n", state->regs.eflags); - printf("EAX: 0x%08x\n", state->regs.eax); - printf("ECX: 0x%08x\n", state->regs.ecx); - printf("EDX: 0x%08x\n", state->regs.edx); - printf("EBX: 0x%08x\n", state->regs.ebx); - printf("ESP: 0x%08x\n", state->regs.esp); - printf("EBP: 0x%08x\n", state->regs.ebp); - printf("ESI: 0x%08x\n", state->regs.esi); - printf("EDI: 0x%08x\n", state->regs.edi); - printf("DS: 0x%04x\n", state->regs.ds); - printf("ES: 0x%04x\n", state->regs.es); - printf("SS: 0x%04x\n", state->regs.ss); - printf("FS: 0x%04x\n", state->regs.fs); - printf("GS: 0x%04x\n", state->regs.gs); + printf("\n"); + printf("EIP: 0x%08x\n", exception_state->regs.eip); + printf("CS: 0x%04x\n", exception_state->regs.cs); + printf("EFLAGS: 0x%08x\n", exception_state->regs.eflags); + printf("EAX: 0x%08x\n", exception_state->regs.eax); + printf("ECX: 0x%08x\n", exception_state->regs.ecx); + printf("EDX: 0x%08x\n", exception_state->regs.edx); + printf("EBX: 0x%08x\n", exception_state->regs.ebx); + printf("ESP: 0x%08x\n", exception_state->regs.esp); + printf("EBP: 0x%08x\n", exception_state->regs.ebp); + printf("ESI: 0x%08x\n", exception_state->regs.esi); + printf("EDI: 0x%08x\n", exception_state->regs.edi); + printf("DS: 0x%04x\n", exception_state->regs.ds); + printf("ES: 0x%04x\n", exception_state->regs.es); + printf("SS: 0x%04x\n", exception_state->regs.ss); + printf("FS: 0x%04x\n", exception_state->regs.fs); + printf("GS: 0x%04x\n", exception_state->regs.gs); }
void exception_dispatch(void) { - struct exception_handler_state *state = - exception_handler_state_handoff; + u32 vec = exception_state->vector; + die_if(vec >= EXC_COUNT || !names[vec], "Bad exception vector %u", vec);
- struct exception_handler_info *info = NULL; - if (state->vector < EXC_COUNT) - info = &exceptions[state->vector]; + if (hook && hook(vec)) + return;
- if (info && info->hook) { - info->hook(state->vector, &state->regs); - } else { - dump_exception_state(state, info); - dump_stack(state->regs.esp, 512); - halt(); - } + dump_exception_state(); + dump_stack(exception_state->regs.esp, 512); + halt(); }
void exception_init(void) { - exception_stack_end = exception_stack + sizeof(exception_stack); + exception_stack_end = exception_stack + ARRAY_SIZE(exception_stack); 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); - exceptions[type].hook = hook; + die_if(hook, "Implement support for a list of hooks if you need it."); + hook = h; } diff --git a/payloads/libpayload/arch/x86/exception_asm.S b/payloads/libpayload/arch/x86/exception_asm.S index de612ba..a8f9a1d 100644 --- a/payloads/libpayload/arch/x86/exception_asm.S +++ b/payloads/libpayload/arch/x86/exception_asm.S @@ -31,8 +31,8 @@ .global exception_stack_end exception_stack_end: .long 0 - .global exception_handler_state_handoff -exception_handler_state_handoff: + .global exception_state +exception_state: .long 0
/* 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 - * 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 * is being used. */ - mov %esp, exception_handler_state_handoff + mov %esp, exception_state call exception_dispatch
/* diff --git a/payloads/libpayload/include/arm/arch/exception.h b/payloads/libpayload/include/arm/arch/exception.h index c6864a5..fbbce5e 100644 --- a/payloads/libpayload/include/arm/arch/exception.h +++ b/payloads/libpayload/include/arm/arch/exception.h @@ -32,13 +32,19 @@
#include <stdint.h>
+void exception_dispatch(u32 idx); void set_vbar(uint32_t vbar);
struct exception_state { - uint32_t cpsr; - uint32_t regs[16]; + u32 regs[16]; + u32 cpsr; } __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 { EXC_UNDEF = 1, diff --git a/payloads/libpayload/include/arm64/arch/exception.h b/payloads/libpayload/include/arm64/arch/exception.h index f4a7552..44a4e59 100644 --- a/payloads/libpayload/include/arm64/arch/exception.h +++ b/payloads/libpayload/include/arm64/arch/exception.h @@ -41,6 +41,8 @@ struct exception_state uint64_t regs[31]; } __attribute__((packed));
+extern struct exception_state *exception_state; + enum { EXC_INV = 0, EXC_SYNC = 1, diff --git a/payloads/libpayload/include/exception.h b/payloads/libpayload/include/exception.h index 1d9b832..67923ea 100644 --- a/payloads/libpayload/include/exception.h +++ b/payloads/libpayload/include/exception.h @@ -32,9 +32,10 @@
#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_install_hook(int type, exception_hook hook); +void exception_install_hook(exception_hook h);
#endif diff --git a/payloads/libpayload/include/x86/arch/exception.h b/payloads/libpayload/include/x86/arch/exception.h index 82f2ca0..fe222aa 100644 --- a/payloads/libpayload/include/x86/arch/exception.h +++ b/payloads/libpayload/include/x86/arch/exception.h @@ -32,28 +32,37 @@
#include <stdint.h>
-void exception_dispatch(void); void exception_init_asm(void); +void exception_dispatch(void);
struct exception_state { - uint32_t eax; - uint32_t ecx; - uint32_t edx; - uint32_t ebx; - uint32_t esp; - uint32_t ebp; - uint32_t esi; - uint32_t edi; - uint32_t eip; - uint32_t eflags; - uint32_t cs; - uint32_t ss; - uint32_t ds; - uint32_t es; - uint32_t fs; - uint32_t gs; + /* Careful: x86/gdb.c currently relies on the size and order of regs. */ + struct { + u32 eax; + u32 ecx; + u32 edx; + u32 ebx; + u32 esp; + u32 ebp; + u32 esi; + u32 edi; + u32 eip; + u32 eflags; + u32 cs; + u32 ss; + u32 ds; + u32 es; + u32 fs; + u32 gs; + } regs; + u32 error_code; + u32 vector; } __attribute__((packed)); +extern struct exception_state *exception_state; + +extern u32 exception_stack[]; +extern u32 *exception_stack_end;
enum { EXC_DE = 0, /* Divide by zero */