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alistair23-linux/arch/powerpc/kernel/kgdb.c
Christoph Lameter 69111bac42 powerpc: Replace __get_cpu_var uses 
This still has not been merged and now powerpc is the only arch that does
not have this change. Sorry about missing linuxppc-dev before.

V2->V2
  - Fix up to work against 3.18-rc1

__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
[mpe: Fix build errors caused by set/or_softirq_pending(), and rework
      assignment in __set_breakpoint() to use memcpy().]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-11-03 12:12:32 +11:00

495 lines
15 KiB
C
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/*
* PowerPC backend to the KGDB stub.
*
* 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu)
* Copyright (C) 2003 Timesys Corporation.
* Copyright (C) 2004-2006 MontaVista Software, Inc.
* PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com)
* PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and
* Sergei Shtylyov <sshtylyov@ru.mvista.com>
* Copyright (C) 2007-2008 Wind River Systems, Inc.
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program as licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#include <linux/kernel.h>
#include <linux/kgdb.h>
#include <linux/smp.h>
#include <linux/signal.h>
#include <linux/ptrace.h>
#include <linux/kdebug.h>
#include <asm/current.h>
#include <asm/processor.h>
#include <asm/machdep.h>
#include <asm/debug.h>
#include <linux/slab.h>
/*
* This table contains the mapping between PowerPC hardware trap types, and
* signals, which are primarily what GDB understands. GDB and the kernel
* don't always agree on values, so we use constants taken from gdb-6.2.
*/
static struct hard_trap_info
{
unsigned int tt; /* Trap type code for powerpc */
unsigned char signo; /* Signal that we map this trap into */
} hard_trap_info[] = {
{ 0x0100, 0x02 /* SIGINT */ }, /* system reset */
{ 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */
{ 0x0300, 0x0b /* SIGSEGV */ }, /* data access */
{ 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */
{ 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */
{ 0x0600, 0x0a /* SIGBUS */ }, /* alignment */
{ 0x0700, 0x05 /* SIGTRAP */ }, /* program check */
{ 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */
{ 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */
{ 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
{ 0x2002, 0x05 /* SIGTRAP */ }, /* debug */
#if defined(CONFIG_FSL_BOOKE)
{ 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */
{ 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */
{ 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */
{ 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */
{ 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */
{ 0x2060, 0x0e /* SIGILL */ }, /* performance monitor */
{ 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */
{ 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */
{ 0x3200, 0x02 /* SIGINT */ }, /* watchdog */
#else /* ! CONFIG_FSL_BOOKE */
{ 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */
{ 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */
{ 0x1020, 0x02 /* SIGINT */ }, /* watchdog */
{ 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */
{ 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */
#endif
#else /* ! (defined(CONFIG_40x) || defined(CONFIG_BOOKE)) */
{ 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */
#if defined(CONFIG_8xx)
{ 0x1000, 0x04 /* SIGILL */ }, /* software emulation */
#else /* ! CONFIG_8xx */
{ 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */
{ 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */
{ 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */
#if defined(CONFIG_PPC64)
{ 0x1200, 0x05 /* SIGILL */ }, /* system error */
{ 0x1500, 0x04 /* SIGILL */ }, /* soft patch */
{ 0x1600, 0x04 /* SIGILL */ }, /* maintenance */
{ 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */
{ 0x1800, 0x04 /* SIGILL */ }, /* thermal */
#else /* ! CONFIG_PPC64 */
{ 0x1400, 0x02 /* SIGINT */ }, /* SMI */
{ 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */
{ 0x1700, 0x04 /* SIGILL */ }, /* TAU */
{ 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */
#endif
#endif
#endif
{ 0x0000, 0x00 } /* Must be last */
};
static int computeSignal(unsigned int tt)
{
struct hard_trap_info *ht;
for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
if (ht->tt == tt)
return ht->signo;
return SIGHUP; /* default for things we don't know about */
}
/**
*
* kgdb_skipexception - Bail out of KGDB when we've been triggered.
* @exception: Exception vector number
* @regs: Current &struct pt_regs.
*
* On some architectures we need to skip a breakpoint exception when
* it occurs after a breakpoint has been removed.
*
*/
int kgdb_skipexception(int exception, struct pt_regs *regs)
{
return kgdb_isremovedbreak(regs->nip);
}
static int kgdb_call_nmi_hook(struct pt_regs *regs)
{
kgdb_nmicallback(raw_smp_processor_id(), regs);
return 0;
}
#ifdef CONFIG_SMP
void kgdb_roundup_cpus(unsigned long flags)
{
smp_send_debugger_break();
}
#endif
/* KGDB functions to use existing PowerPC64 hooks. */
static int kgdb_debugger(struct pt_regs *regs)
{
return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
DIE_OOPS, regs);
}
static int kgdb_handle_breakpoint(struct pt_regs *regs)
{
if (user_mode(regs))
return 0;
if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
return 0;
if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr))
regs->nip += BREAK_INSTR_SIZE;
return 1;
}
static DEFINE_PER_CPU(struct thread_info, kgdb_thread_info);
static int kgdb_singlestep(struct pt_regs *regs)
{
struct thread_info *thread_info, *exception_thread_info;
struct thread_info *backup_current_thread_info =
this_cpu_ptr(&kgdb_thread_info);
if (user_mode(regs))
return 0;
/*
* On Book E and perhaps other processors, singlestep is handled on
* the critical exception stack. This causes current_thread_info()
* to fail, since it it locates the thread_info by masking off
* the low bits of the current stack pointer. We work around
* this issue by copying the thread_info from the kernel stack
* before calling kgdb_handle_exception, and copying it back
* afterwards. On most processors the copy is avoided since
* exception_thread_info == thread_info.
*/
thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1));
exception_thread_info = current_thread_info();
if (thread_info != exception_thread_info) {
/* Save the original current_thread_info. */
memcpy(backup_current_thread_info, exception_thread_info, sizeof *thread_info);
memcpy(exception_thread_info, thread_info, sizeof *thread_info);
}
kgdb_handle_exception(0, SIGTRAP, 0, regs);
if (thread_info != exception_thread_info)
/* Restore current_thread_info lastly. */
memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info);
return 1;
}
static int kgdb_iabr_match(struct pt_regs *regs)
{
if (user_mode(regs))
return 0;
if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
return 0;
return 1;
}
static int kgdb_break_match(struct pt_regs *regs)
{
if (user_mode(regs))
return 0;
if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
return 0;
return 1;
}
#define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
#define PACK32(ptr, src) do { \
u32 *ptr32; \
ptr32 = (u32 *)ptr; \
*(ptr32++) = (src); \
ptr = (unsigned long *)ptr32; \
} while (0)
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
STACK_FRAME_OVERHEAD);
unsigned long *ptr = gdb_regs;
int reg;
memset(gdb_regs, 0, NUMREGBYTES);
/* Regs GPR0-2 */
for (reg = 0; reg < 3; reg++)
PACK64(ptr, regs->gpr[reg]);
/* Regs GPR3-13 are caller saved, not in regs->gpr[] */
ptr += 11;
/* Regs GPR14-31 */
for (reg = 14; reg < 32; reg++)
PACK64(ptr, regs->gpr[reg]);
#ifdef CONFIG_FSL_BOOKE
#ifdef CONFIG_SPE
for (reg = 0; reg < 32; reg++)
PACK64(ptr, p->thread.evr[reg]);
#else
ptr += 32;
#endif
#else
/* fp registers not used by kernel, leave zero */
ptr += 32 * 8 / sizeof(long);
#endif
PACK64(ptr, regs->nip);
PACK64(ptr, regs->msr);
PACK32(ptr, regs->ccr);
PACK64(ptr, regs->link);
PACK64(ptr, regs->ctr);
PACK32(ptr, regs->xer);
BUG_ON((unsigned long)ptr >
(unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
}
#define GDB_SIZEOF_REG sizeof(unsigned long)
#define GDB_SIZEOF_REG_U32 sizeof(u32)
#ifdef CONFIG_FSL_BOOKE
#define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
#else
#define GDB_SIZEOF_FLOAT_REG sizeof(u64)
#endif
struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
{
{ "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
{ "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
{ "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
{ "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
{ "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
{ "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
{ "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
{ "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
{ "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
{ "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
{ "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
{ "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
{ "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
{ "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
{ "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
{ "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
{ "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
{ "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
{ "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
{ "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
{ "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
{ "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
{ "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
{ "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
{ "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
{ "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
{ "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
{ "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
{ "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
{ "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
{ "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
{ "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },
{ "f0", GDB_SIZEOF_FLOAT_REG, 0 },
{ "f1", GDB_SIZEOF_FLOAT_REG, 1 },
{ "f2", GDB_SIZEOF_FLOAT_REG, 2 },
{ "f3", GDB_SIZEOF_FLOAT_REG, 3 },
{ "f4", GDB_SIZEOF_FLOAT_REG, 4 },
{ "f5", GDB_SIZEOF_FLOAT_REG, 5 },
{ "f6", GDB_SIZEOF_FLOAT_REG, 6 },
{ "f7", GDB_SIZEOF_FLOAT_REG, 7 },
{ "f8", GDB_SIZEOF_FLOAT_REG, 8 },
{ "f9", GDB_SIZEOF_FLOAT_REG, 9 },
{ "f10", GDB_SIZEOF_FLOAT_REG, 10 },
{ "f11", GDB_SIZEOF_FLOAT_REG, 11 },
{ "f12", GDB_SIZEOF_FLOAT_REG, 12 },
{ "f13", GDB_SIZEOF_FLOAT_REG, 13 },
{ "f14", GDB_SIZEOF_FLOAT_REG, 14 },
{ "f15", GDB_SIZEOF_FLOAT_REG, 15 },
{ "f16", GDB_SIZEOF_FLOAT_REG, 16 },
{ "f17", GDB_SIZEOF_FLOAT_REG, 17 },
{ "f18", GDB_SIZEOF_FLOAT_REG, 18 },
{ "f19", GDB_SIZEOF_FLOAT_REG, 19 },
{ "f20", GDB_SIZEOF_FLOAT_REG, 20 },
{ "f21", GDB_SIZEOF_FLOAT_REG, 21 },
{ "f22", GDB_SIZEOF_FLOAT_REG, 22 },
{ "f23", GDB_SIZEOF_FLOAT_REG, 23 },
{ "f24", GDB_SIZEOF_FLOAT_REG, 24 },
{ "f25", GDB_SIZEOF_FLOAT_REG, 25 },
{ "f26", GDB_SIZEOF_FLOAT_REG, 26 },
{ "f27", GDB_SIZEOF_FLOAT_REG, 27 },
{ "f28", GDB_SIZEOF_FLOAT_REG, 28 },
{ "f29", GDB_SIZEOF_FLOAT_REG, 29 },
{ "f30", GDB_SIZEOF_FLOAT_REG, 30 },
{ "f31", GDB_SIZEOF_FLOAT_REG, 31 },
{ "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
{ "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
{ "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
{ "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
{ "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
{ "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
};
char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
{
if (regno >= DBG_MAX_REG_NUM || regno < 0)
return NULL;
if (regno < 32 || regno >= 64)
/* First 0 -> 31 gpr registers*/
/* pc, msr, ls... registers 64 -> 69 */
memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
dbg_reg_def[regno].size);
if (regno >= 32 && regno < 64) {
/* FP registers 32 -> 63 */
#if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
if (current)
memcpy(mem, &current->thread.evr[regno-32],
dbg_reg_def[regno].size);
#else
/* fp registers not used by kernel, leave zero */
memset(mem, 0, dbg_reg_def[regno].size);
#endif
}
return dbg_reg_def[regno].name;
}
int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
{
if (regno >= DBG_MAX_REG_NUM || regno < 0)
return -EINVAL;
if (regno < 32 || regno >= 64)
/* First 0 -> 31 gpr registers*/
/* pc, msr, ls... registers 64 -> 69 */
memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
dbg_reg_def[regno].size);
if (regno >= 32 && regno < 64) {
/* FP registers 32 -> 63 */
#if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
memcpy(&current->thread.evr[regno-32], mem,
dbg_reg_def[regno].size);
#else
/* fp registers not used by kernel, leave zero */
return 0;
#endif
}
return 0;
}
void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
{
regs->nip = pc;
}
/*
* This function does PowerPC specific procesing for interfacing to gdb.
*/
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
char *remcom_in_buffer, char *remcom_out_buffer,
struct pt_regs *linux_regs)
{
char *ptr = &remcom_in_buffer[1];
unsigned long addr;
switch (remcom_in_buffer[0]) {
/*
* sAA..AA Step one instruction from AA..AA
* This will return an error to gdb ..
*/
case 's':
case 'c':
/* handle the optional parameter */
if (kgdb_hex2long(&ptr, &addr))
linux_regs->nip = addr;
atomic_set(&kgdb_cpu_doing_single_step, -1);
/* set the trace bit if we're stepping */
if (remcom_in_buffer[0] == 's') {
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
mtspr(SPRN_DBCR0,
mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
linux_regs->msr |= MSR_DE;
#else
linux_regs->msr |= MSR_SE;
#endif
atomic_set(&kgdb_cpu_doing_single_step,
raw_smp_processor_id());
}
return 0;
}
return -1;
}
/*
* Global data
*/
struct kgdb_arch arch_kgdb_ops = {
.gdb_bpt_instr = {0x7d, 0x82, 0x10, 0x08},
};
static int kgdb_not_implemented(struct pt_regs *regs)
{
return 0;
}
static void *old__debugger_ipi;
static void *old__debugger;
static void *old__debugger_bpt;
static void *old__debugger_sstep;
static void *old__debugger_iabr_match;
static void *old__debugger_break_match;
static void *old__debugger_fault_handler;
int kgdb_arch_init(void)
{
old__debugger_ipi = __debugger_ipi;
old__debugger = __debugger;
old__debugger_bpt = __debugger_bpt;
old__debugger_sstep = __debugger_sstep;
old__debugger_iabr_match = __debugger_iabr_match;
old__debugger_break_match = __debugger_break_match;
old__debugger_fault_handler = __debugger_fault_handler;
__debugger_ipi = kgdb_call_nmi_hook;
__debugger = kgdb_debugger;
__debugger_bpt = kgdb_handle_breakpoint;
__debugger_sstep = kgdb_singlestep;
__debugger_iabr_match = kgdb_iabr_match;
__debugger_break_match = kgdb_break_match;
__debugger_fault_handler = kgdb_not_implemented;
return 0;
}
void kgdb_arch_exit(void)
{
__debugger_ipi = old__debugger_ipi;
__debugger = old__debugger;
__debugger_bpt = old__debugger_bpt;
__debugger_sstep = old__debugger_sstep;
__debugger_iabr_match = old__debugger_iabr_match;
__debugger_break_match = old__debugger_break_match;
__debugger_fault_handler = old__debugger_fault_handler;
}
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