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linux/arch/xtensa/kernel/setup.c
Max Filippov ab45fb1450 xtensa: fix secondary core boot in SMP 
There are multiple factors adding to the issue in different
configurations:

- commit 17290231df ("xtensa: add fixup for double exception raised
  in window overflow") added function window_overflow_restore_a0_fixup to
  double exception vector overlapping reset vector location of secondary
  processor cores.
- on MMUv2 cores RESET_VECTOR1_VADDR may point to uncached kernel memory
  making code overlapping depend on cache type and size, so that without
  cache or with WT cache reset vector code overwrites double exception
  code, making issue even harder to detect.
- on MMUv3 cores RESET_VECTOR1_VADDR may point to unmapped area, as
  MMUv3 cores change virtual address map to match MMUv2 layout, but
  reset vector virtual address is given for the original MMUv3 mapping.
- physical memory region of the secondary reset vector is not reserved
  in the physical memory map, and thus may be allocated and overwritten
  at arbitrary moment.

Fix it as follows:

- move window_overflow_restore_a0_fixup code to .text section.
- define RESET_VECTOR1_VADDR so that it points to reset vector in the
  cacheable MMUv2 map for cores with MMU.
- reserve reset vector region in the physical memory map. Drop separate
  literal section and build mxhead.S with text section literals.

Cc: <stable@vger.kernel.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2015-11-03 17:19:38 +03:00

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/*
* arch/xtensa/kernel/setup.c
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1995 Linus Torvalds
* Copyright (C) 2001 - 2005 Tensilica Inc.
*
* Chris Zankel <chris@zankel.net>
* Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
* Kevin Chea
* Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
*/
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/screen_info.h>
#include <linux/bootmem.h>
#include <linux/kernel.h>
#include <linux/percpu.h>
#include <linux/clk-provider.h>
#include <linux/cpu.h>
#include <linux/of_fdt.h>
#include <linux/of_platform.h>
#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
# include <linux/console.h>
#endif
#ifdef CONFIG_RTC
# include <linux/timex.h>
#endif
#ifdef CONFIG_PROC_FS
# include <linux/seq_file.h>
#endif
#include <asm/bootparam.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/timex.h>
#include <asm/platform.h>
#include <asm/page.h>
#include <asm/setup.h>
#include <asm/param.h>
#include <asm/traps.h>
#include <asm/smp.h>
#include <asm/sysmem.h>
#include <platform/hardware.h>
#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
struct screen_info screen_info = { 0, 24, 0, 0, 0, 80, 0, 0, 0, 24, 1, 16};
#endif
#ifdef CONFIG_BLK_DEV_FD
extern struct fd_ops no_fd_ops;
struct fd_ops *fd_ops;
#endif
extern struct rtc_ops no_rtc_ops;
struct rtc_ops *rtc_ops;
#ifdef CONFIG_BLK_DEV_INITRD
extern unsigned long initrd_start;
extern unsigned long initrd_end;
int initrd_is_mapped = 0;
extern int initrd_below_start_ok;
#endif
#ifdef CONFIG_OF
void *dtb_start = __dtb_start;
#endif
unsigned char aux_device_present;
extern unsigned long loops_per_jiffy;
/* Command line specified as configuration option. */
static char __initdata command_line[COMMAND_LINE_SIZE];
#ifdef CONFIG_CMDLINE_BOOL
static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
#endif
/*
* Boot parameter parsing.
*
* The Xtensa port uses a list of variable-sized tags to pass data to
* the kernel. The first tag must be a BP_TAG_FIRST tag for the list
* to be recognised. The list is terminated with a zero-sized
* BP_TAG_LAST tag.
*/
typedef struct tagtable {
u32 tag;
int (*parse)(const bp_tag_t*);
} tagtable_t;
#define __tagtable(tag, fn) static tagtable_t __tagtable_##fn \
__attribute__((used, section(".taglist"))) = { tag, fn }
/* parse current tag */
static int __init parse_tag_mem(const bp_tag_t *tag)
{
struct bp_meminfo *mi = (struct bp_meminfo *)(tag->data);
if (mi->type != MEMORY_TYPE_CONVENTIONAL)
return -1;
return add_sysmem_bank(mi->start, mi->end);
}
__tagtable(BP_TAG_MEMORY, parse_tag_mem);
#ifdef CONFIG_BLK_DEV_INITRD
static int __init parse_tag_initrd(const bp_tag_t* tag)
{
struct bp_meminfo *mi = (struct bp_meminfo *)(tag->data);
initrd_start = (unsigned long)__va(mi->start);
initrd_end = (unsigned long)__va(mi->end);
return 0;
}
__tagtable(BP_TAG_INITRD, parse_tag_initrd);
#ifdef CONFIG_OF
static int __init parse_tag_fdt(const bp_tag_t *tag)
{
dtb_start = __va(tag->data[0]);
return 0;
}
__tagtable(BP_TAG_FDT, parse_tag_fdt);
#endif /* CONFIG_OF */
#endif /* CONFIG_BLK_DEV_INITRD */
static int __init parse_tag_cmdline(const bp_tag_t* tag)
{
strlcpy(command_line, (char *)(tag->data), COMMAND_LINE_SIZE);
return 0;
}
__tagtable(BP_TAG_COMMAND_LINE, parse_tag_cmdline);
static int __init parse_bootparam(const bp_tag_t* tag)
{
extern tagtable_t __tagtable_begin, __tagtable_end;
tagtable_t *t;
/* Boot parameters must start with a BP_TAG_FIRST tag. */
if (tag->id != BP_TAG_FIRST) {
printk(KERN_WARNING "Invalid boot parameters!\n");
return 0;
}
tag = (bp_tag_t*)((unsigned long)tag + sizeof(bp_tag_t) + tag->size);
/* Parse all tags. */
while (tag != NULL && tag->id != BP_TAG_LAST) {
for (t = &__tagtable_begin; t < &__tagtable_end; t++) {
if (tag->id == t->tag) {
t->parse(tag);
break;
}
}
if (t == &__tagtable_end)
printk(KERN_WARNING "Ignoring tag "
"0x%08x\n", tag->id);
tag = (bp_tag_t*)((unsigned long)(tag + 1) + tag->size);
}
return 0;
}
#ifdef CONFIG_OF
bool __initdata dt_memory_scan = false;
#if !XCHAL_HAVE_PTP_MMU || XCHAL_HAVE_SPANNING_WAY
unsigned long xtensa_kio_paddr = XCHAL_KIO_DEFAULT_PADDR;
EXPORT_SYMBOL(xtensa_kio_paddr);
static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
int depth, void *data)
{
const __be32 *ranges;
int len;
if (depth > 1)
return 0;
if (!of_flat_dt_is_compatible(node, "simple-bus"))
return 0;
ranges = of_get_flat_dt_prop(node, "ranges", &len);
if (!ranges)
return 1;
if (len == 0)
return 1;
xtensa_kio_paddr = of_read_ulong(ranges+1, 1);
/* round down to nearest 256MB boundary */
xtensa_kio_paddr &= 0xf0000000;
return 1;
}
#else
static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
int depth, void *data)
{
return 1;
}
#endif
void __init early_init_dt_add_memory_arch(u64 base, u64 size)
{
if (!dt_memory_scan)
return;
size &= PAGE_MASK;
add_sysmem_bank(base, base + size);
}
void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
{
return __alloc_bootmem(size, align, 0);
}
void __init early_init_devtree(void *params)
{
if (sysmem.nr_banks == 0)
dt_memory_scan = true;
early_init_dt_scan(params);
of_scan_flat_dt(xtensa_dt_io_area, NULL);
if (!command_line[0])
strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
}
static int __init xtensa_device_probe(void)
{
of_clk_init(NULL);
of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
return 0;
}
device_initcall(xtensa_device_probe);
#endif /* CONFIG_OF */
/*
* Initialize architecture. (Early stage)
*/
void __init init_arch(bp_tag_t *bp_start)
{
/* Parse boot parameters */
if (bp_start)
parse_bootparam(bp_start);
#ifdef CONFIG_OF
early_init_devtree(dtb_start);
#endif
if (sysmem.nr_banks == 0) {
add_sysmem_bank(PLATFORM_DEFAULT_MEM_START,
PLATFORM_DEFAULT_MEM_START +
PLATFORM_DEFAULT_MEM_SIZE);
}
#ifdef CONFIG_CMDLINE_BOOL
if (!command_line[0])
strlcpy(command_line, default_command_line, COMMAND_LINE_SIZE);
#endif
/* Early hook for platforms */
platform_init(bp_start);
/* Initialize MMU. */
init_mmu();
}
/*
* Initialize system. Setup memory and reserve regions.
*/
extern char _end;
extern char _stext;
extern char _WindowVectors_text_start;
extern char _WindowVectors_text_end;
extern char _DebugInterruptVector_literal_start;
extern char _DebugInterruptVector_text_end;
extern char _KernelExceptionVector_literal_start;
extern char _KernelExceptionVector_text_end;
extern char _UserExceptionVector_literal_start;
extern char _UserExceptionVector_text_end;
extern char _DoubleExceptionVector_literal_start;
extern char _DoubleExceptionVector_text_end;
#if XCHAL_EXCM_LEVEL >= 2
extern char _Level2InterruptVector_text_start;
extern char _Level2InterruptVector_text_end;
#endif
#if XCHAL_EXCM_LEVEL >= 3
extern char _Level3InterruptVector_text_start;
extern char _Level3InterruptVector_text_end;
#endif
#if XCHAL_EXCM_LEVEL >= 4
extern char _Level4InterruptVector_text_start;
extern char _Level4InterruptVector_text_end;
#endif
#if XCHAL_EXCM_LEVEL >= 5
extern char _Level5InterruptVector_text_start;
extern char _Level5InterruptVector_text_end;
#endif
#if XCHAL_EXCM_LEVEL >= 6
extern char _Level6InterruptVector_text_start;
extern char _Level6InterruptVector_text_end;
#endif
#ifdef CONFIG_SMP
extern char _SecondaryResetVector_text_start;
extern char _SecondaryResetVector_text_end;
#endif
#ifdef CONFIG_S32C1I_SELFTEST
#if XCHAL_HAVE_S32C1I
static int __initdata rcw_word, rcw_probe_pc, rcw_exc;
/*
* Basic atomic compare-and-swap, that records PC of S32C1I for probing.
*
* If *v == cmp, set *v = set. Return previous *v.
*/
static inline int probed_compare_swap(int *v, int cmp, int set)
{
int tmp;
__asm__ __volatile__(
" movi %1, 1f\n"
" s32i %1, %4, 0\n"
" wsr %2, scompare1\n"
"1: s32c1i %0, %3, 0\n"
: "=a" (set), "=&a" (tmp)
: "a" (cmp), "a" (v), "a" (&rcw_probe_pc), "0" (set)
: "memory"
);
return set;
}
/* Handle probed exception */
static void __init do_probed_exception(struct pt_regs *regs,
unsigned long exccause)
{
if (regs->pc == rcw_probe_pc) { /* exception on s32c1i ? */
regs->pc += 3; /* skip the s32c1i instruction */
rcw_exc = exccause;
} else {
do_unhandled(regs, exccause);
}
}
/* Simple test of S32C1I (soc bringup assist) */
static int __init check_s32c1i(void)
{
int n, cause1, cause2;
void *handbus, *handdata, *handaddr; /* temporarily saved handlers */
rcw_probe_pc = 0;
handbus = trap_set_handler(EXCCAUSE_LOAD_STORE_ERROR,
do_probed_exception);
handdata = trap_set_handler(EXCCAUSE_LOAD_STORE_DATA_ERROR,
do_probed_exception);
handaddr = trap_set_handler(EXCCAUSE_LOAD_STORE_ADDR_ERROR,
do_probed_exception);
/* First try an S32C1I that does not store: */
rcw_exc = 0;
rcw_word = 1;
n = probed_compare_swap(&rcw_word, 0, 2);
cause1 = rcw_exc;
/* took exception? */
if (cause1 != 0) {
/* unclean exception? */
if (n != 2 || rcw_word != 1)
panic("S32C1I exception error");
} else if (rcw_word != 1 || n != 1) {
panic("S32C1I compare error");
}
/* Then an S32C1I that stores: */
rcw_exc = 0;
rcw_word = 0x1234567;
n = probed_compare_swap(&rcw_word, 0x1234567, 0xabcde);
cause2 = rcw_exc;
if (cause2 != 0) {
/* unclean exception? */
if (n != 0xabcde || rcw_word != 0x1234567)
panic("S32C1I exception error (b)");
} else if (rcw_word != 0xabcde || n != 0x1234567) {
panic("S32C1I store error");
}
/* Verify consistency of exceptions: */
if (cause1 || cause2) {
pr_warn("S32C1I took exception %d, %d\n", cause1, cause2);
/* If emulation of S32C1I upon bus error gets implemented,
we can get rid of this panic for single core (not SMP) */
panic("S32C1I exceptions not currently supported");
}
if (cause1 != cause2)
panic("inconsistent S32C1I exceptions");
trap_set_handler(EXCCAUSE_LOAD_STORE_ERROR, handbus);
trap_set_handler(EXCCAUSE_LOAD_STORE_DATA_ERROR, handdata);
trap_set_handler(EXCCAUSE_LOAD_STORE_ADDR_ERROR, handaddr);
return 0;
}
#else /* XCHAL_HAVE_S32C1I */
/* This condition should not occur with a commercially deployed processor.
Display reminder for early engr test or demo chips / FPGA bitstreams */
static int __init check_s32c1i(void)
{
pr_warn("Processor configuration lacks atomic compare-and-swap support!\n");
return 0;
}
#endif /* XCHAL_HAVE_S32C1I */
early_initcall(check_s32c1i);
#endif /* CONFIG_S32C1I_SELFTEST */
void __init setup_arch(char **cmdline_p)
{
strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
*cmdline_p = command_line;
/* Reserve some memory regions */
#ifdef CONFIG_BLK_DEV_INITRD
if (initrd_start < initrd_end) {
initrd_is_mapped = mem_reserve(__pa(initrd_start),
__pa(initrd_end), 0) == 0;
initrd_below_start_ok = 1;
} else {
initrd_start = 0;
}
#endif
mem_reserve(__pa(&_stext),__pa(&_end), 1);
mem_reserve(__pa(&_WindowVectors_text_start),
__pa(&_WindowVectors_text_end), 0);
mem_reserve(__pa(&_DebugInterruptVector_literal_start),
__pa(&_DebugInterruptVector_text_end), 0);
mem_reserve(__pa(&_KernelExceptionVector_literal_start),
__pa(&_KernelExceptionVector_text_end), 0);
mem_reserve(__pa(&_UserExceptionVector_literal_start),
__pa(&_UserExceptionVector_text_end), 0);
mem_reserve(__pa(&_DoubleExceptionVector_literal_start),
__pa(&_DoubleExceptionVector_text_end), 0);
#if XCHAL_EXCM_LEVEL >= 2
mem_reserve(__pa(&_Level2InterruptVector_text_start),
__pa(&_Level2InterruptVector_text_end), 0);
#endif
#if XCHAL_EXCM_LEVEL >= 3
mem_reserve(__pa(&_Level3InterruptVector_text_start),
__pa(&_Level3InterruptVector_text_end), 0);
#endif
#if XCHAL_EXCM_LEVEL >= 4
mem_reserve(__pa(&_Level4InterruptVector_text_start),
__pa(&_Level4InterruptVector_text_end), 0);
#endif
#if XCHAL_EXCM_LEVEL >= 5
mem_reserve(__pa(&_Level5InterruptVector_text_start),
__pa(&_Level5InterruptVector_text_end), 0);
#endif
#if XCHAL_EXCM_LEVEL >= 6
mem_reserve(__pa(&_Level6InterruptVector_text_start),
__pa(&_Level6InterruptVector_text_end), 0);
#endif
#ifdef CONFIG_SMP
mem_reserve(__pa(&_SecondaryResetVector_text_start),
__pa(&_SecondaryResetVector_text_end), 0);
#endif
parse_early_param();
bootmem_init();
unflatten_and_copy_device_tree();
platform_setup(cmdline_p);
#ifdef CONFIG_SMP
smp_init_cpus();
#endif
paging_init();
zones_init();
#ifdef CONFIG_VT
# if defined(CONFIG_VGA_CONSOLE)
conswitchp = &vga_con;
# elif defined(CONFIG_DUMMY_CONSOLE)
conswitchp = &dummy_con;
# endif
#endif
#ifdef CONFIG_PCI
platform_pcibios_init();
#endif
}
static DEFINE_PER_CPU(struct cpu, cpu_data);
static int __init topology_init(void)
{
int i;
for_each_possible_cpu(i) {
struct cpu *cpu = &per_cpu(cpu_data, i);
cpu->hotpluggable = !!i;
register_cpu(cpu, i);
}
return 0;
}
subsys_initcall(topology_init);
void machine_restart(char * cmd)
{
platform_restart();
}
void machine_halt(void)
{
platform_halt();
while (1);
}
void machine_power_off(void)
{
platform_power_off();
while (1);
}
#ifdef CONFIG_PROC_FS
/*
* Display some core information through /proc/cpuinfo.
*/
static int
c_show(struct seq_file *f, void *slot)
{
/* high-level stuff */
seq_printf(f, "CPU count\t: %u\n"
"CPU list\t: %*pbl\n"
"vendor_id\t: Tensilica\n"
"model\t\t: Xtensa " XCHAL_HW_VERSION_NAME "\n"
"core ID\t\t: " XCHAL_CORE_ID "\n"
"build ID\t: 0x%x\n"
"byte order\t: %s\n"
"cpu MHz\t\t: %lu.%02lu\n"
"bogomips\t: %lu.%02lu\n",
num_online_cpus(),
cpumask_pr_args(cpu_online_mask),
XCHAL_BUILD_UNIQUE_ID,
XCHAL_HAVE_BE ? "big" : "little",
ccount_freq/1000000,
(ccount_freq/10000) % 100,
loops_per_jiffy/(500000/HZ),
(loops_per_jiffy/(5000/HZ)) % 100);
seq_printf(f,"flags\t\t: "
#if XCHAL_HAVE_NMI
"nmi "
#endif
#if XCHAL_HAVE_DEBUG
"debug "
# if XCHAL_HAVE_OCD
"ocd "
# endif
#endif
#if XCHAL_HAVE_DENSITY
"density "
#endif
#if XCHAL_HAVE_BOOLEANS
"boolean "
#endif
#if XCHAL_HAVE_LOOPS
"loop "
#endif
#if XCHAL_HAVE_NSA
"nsa "
#endif
#if XCHAL_HAVE_MINMAX
"minmax "
#endif
#if XCHAL_HAVE_SEXT
"sext "
#endif
#if XCHAL_HAVE_CLAMPS
"clamps "
#endif
#if XCHAL_HAVE_MAC16
"mac16 "
#endif
#if XCHAL_HAVE_MUL16
"mul16 "
#endif
#if XCHAL_HAVE_MUL32
"mul32 "
#endif
#if XCHAL_HAVE_MUL32_HIGH
"mul32h "
#endif
#if XCHAL_HAVE_FP
"fpu "
#endif
#if XCHAL_HAVE_S32C1I
"s32c1i "
#endif
"\n");
/* Registers. */
seq_printf(f,"physical aregs\t: %d\n"
"misc regs\t: %d\n"
"ibreak\t\t: %d\n"
"dbreak\t\t: %d\n",
XCHAL_NUM_AREGS,
XCHAL_NUM_MISC_REGS,
XCHAL_NUM_IBREAK,
XCHAL_NUM_DBREAK);
/* Interrupt. */
seq_printf(f,"num ints\t: %d\n"
"ext ints\t: %d\n"
"int levels\t: %d\n"
"timers\t\t: %d\n"
"debug level\t: %d\n",
XCHAL_NUM_INTERRUPTS,
XCHAL_NUM_EXTINTERRUPTS,
XCHAL_NUM_INTLEVELS,
XCHAL_NUM_TIMERS,
XCHAL_DEBUGLEVEL);
/* Cache */
seq_printf(f,"icache line size: %d\n"
"icache ways\t: %d\n"
"icache size\t: %d\n"
"icache flags\t: "
#if XCHAL_ICACHE_LINE_LOCKABLE
"lock "
#endif
"\n"
"dcache line size: %d\n"
"dcache ways\t: %d\n"
"dcache size\t: %d\n"
"dcache flags\t: "
#if XCHAL_DCACHE_IS_WRITEBACK
"writeback "
#endif
#if XCHAL_DCACHE_LINE_LOCKABLE
"lock "
#endif
"\n",
XCHAL_ICACHE_LINESIZE,
XCHAL_ICACHE_WAYS,
XCHAL_ICACHE_SIZE,
XCHAL_DCACHE_LINESIZE,
XCHAL_DCACHE_WAYS,
XCHAL_DCACHE_SIZE);
return 0;
}
/*
* We show only CPU #0 info.
*/
static void *
c_start(struct seq_file *f, loff_t *pos)
{
return (*pos == 0) ? (void *)1 : NULL;
}
static void *
c_next(struct seq_file *f, void *v, loff_t *pos)
{
return NULL;
}
static void
c_stop(struct seq_file *f, void *v)
{
}
const struct seq_operations cpuinfo_op =
{
.start = c_start,
.next = c_next,
.stop = c_stop,
.show = c_show,
};
#endif /* CONFIG_PROC_FS */
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