linux_dsm_epyc7002/arch/powerpc/kernel/setup_32.c
LEROY Christophe 400c47d81c powerpc32: memset: only use dcbz once cache is enabled
memset() uses instruction dcbz to speed up clearing by not wasting time
loading cache line with data that will be overwritten.
Some platform like mpc52xx do no have cache active at startup and
can therefore not use memset(). Allthough no part of the code
explicitly uses memset(), GCC may make calls to it.

This patch modifies memset() such that at startup, memset()
unconditionally skip the optimised bloc that uses dcbz instruction.

Once the initial MMU is set up, in machine_init() we patch memset()
by replacing this inconditional jump by a NOP

Tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-09-17 10:36:53 +10:00

330 lines
7.8 KiB
C

/*
* Common prep/pmac/chrp boot and setup code.
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/reboot.h>
#include <linux/delay.h>
#include <linux/initrd.h>
#include <linux/tty.h>
#include <linux/seq_file.h>
#include <linux/root_dev.h>
#include <linux/cpu.h>
#include <linux/console.h>
#include <linux/memblock.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/processor.h>
#include <asm/pgtable.h>
#include <asm/setup.h>
#include <asm/smp.h>
#include <asm/elf.h>
#include <asm/cputable.h>
#include <asm/bootx.h>
#include <asm/btext.h>
#include <asm/machdep.h>
#include <asm/uaccess.h>
#include <asm/pmac_feature.h>
#include <asm/sections.h>
#include <asm/nvram.h>
#include <asm/xmon.h>
#include <asm/time.h>
#include <asm/serial.h>
#include <asm/udbg.h>
#include <asm/mmu_context.h>
#include <asm/epapr_hcalls.h>
#include <asm/code-patching.h>
#define DBG(fmt...)
extern void bootx_init(unsigned long r4, unsigned long phys);
int boot_cpuid_phys;
EXPORT_SYMBOL_GPL(boot_cpuid_phys);
int smp_hw_index[NR_CPUS];
unsigned long ISA_DMA_THRESHOLD;
unsigned int DMA_MODE_READ;
unsigned int DMA_MODE_WRITE;
/*
* These are used in binfmt_elf.c to put aux entries on the stack
* for each elf executable being started.
*/
int dcache_bsize;
int icache_bsize;
int ucache_bsize;
/*
* We're called here very early in the boot. We determine the machine
* type and call the appropriate low-level setup functions.
* -- Cort <cort@fsmlabs.com>
*
* Note that the kernel may be running at an address which is different
* from the address that it was linked at, so we must use RELOC/PTRRELOC
* to access static data (including strings). -- paulus
*/
notrace unsigned long __init early_init(unsigned long dt_ptr)
{
unsigned long offset = reloc_offset();
struct cpu_spec *spec;
/* First zero the BSS -- use memset_io, some platforms don't have
* caches on yet */
memset_io((void __iomem *)PTRRELOC(&__bss_start), 0,
__bss_stop - __bss_start);
/*
* Identify the CPU type and fix up code sections
* that depend on which cpu we have.
*/
spec = identify_cpu(offset, mfspr(SPRN_PVR));
do_feature_fixups(spec->cpu_features,
PTRRELOC(&__start___ftr_fixup),
PTRRELOC(&__stop___ftr_fixup));
do_feature_fixups(spec->mmu_features,
PTRRELOC(&__start___mmu_ftr_fixup),
PTRRELOC(&__stop___mmu_ftr_fixup));
do_lwsync_fixups(spec->cpu_features,
PTRRELOC(&__start___lwsync_fixup),
PTRRELOC(&__stop___lwsync_fixup));
do_final_fixups();
return KERNELBASE + offset;
}
/*
* Find out what kind of machine we're on and save any data we need
* from the early boot process (devtree is copied on pmac by prom_init()).
* This is called very early on the boot process, after a minimal
* MMU environment has been set up but before MMU_init is called.
*/
extern unsigned int memset_nocache_branch; /* Insn to be replaced by NOP */
notrace void __init machine_init(u64 dt_ptr)
{
lockdep_init();
/* Enable early debugging if any specified (see udbg.h) */
udbg_early_init();
patch_instruction((unsigned int *)&memcpy, PPC_INST_NOP);
patch_instruction(&memset_nocache_branch, PPC_INST_NOP);
/* Do some early initialization based on the flat device tree */
early_init_devtree(__va(dt_ptr));
epapr_paravirt_early_init();
early_init_mmu();
probe_machine();
setup_kdump_trampoline();
#ifdef CONFIG_6xx
if (cpu_has_feature(CPU_FTR_CAN_DOZE) ||
cpu_has_feature(CPU_FTR_CAN_NAP))
ppc_md.power_save = ppc6xx_idle;
#endif
#ifdef CONFIG_E500
if (cpu_has_feature(CPU_FTR_CAN_DOZE) ||
cpu_has_feature(CPU_FTR_CAN_NAP))
ppc_md.power_save = e500_idle;
#endif
if (ppc_md.progress)
ppc_md.progress("id mach(): done", 0x200);
}
/* Checks "l2cr=xxxx" command-line option */
int __init ppc_setup_l2cr(char *str)
{
if (cpu_has_feature(CPU_FTR_L2CR)) {
unsigned long val = simple_strtoul(str, NULL, 0);
printk(KERN_INFO "l2cr set to %lx\n", val);
_set_L2CR(0); /* force invalidate by disable cache */
_set_L2CR(val); /* and enable it */
}
return 1;
}
__setup("l2cr=", ppc_setup_l2cr);
/* Checks "l3cr=xxxx" command-line option */
int __init ppc_setup_l3cr(char *str)
{
if (cpu_has_feature(CPU_FTR_L3CR)) {
unsigned long val = simple_strtoul(str, NULL, 0);
printk(KERN_INFO "l3cr set to %lx\n", val);
_set_L3CR(val); /* and enable it */
}
return 1;
}
__setup("l3cr=", ppc_setup_l3cr);
#ifdef CONFIG_GENERIC_NVRAM
/* Generic nvram hooks used by drivers/char/gen_nvram.c */
unsigned char nvram_read_byte(int addr)
{
if (ppc_md.nvram_read_val)
return ppc_md.nvram_read_val(addr);
return 0xff;
}
EXPORT_SYMBOL(nvram_read_byte);
void nvram_write_byte(unsigned char val, int addr)
{
if (ppc_md.nvram_write_val)
ppc_md.nvram_write_val(addr, val);
}
EXPORT_SYMBOL(nvram_write_byte);
ssize_t nvram_get_size(void)
{
if (ppc_md.nvram_size)
return ppc_md.nvram_size();
return -1;
}
EXPORT_SYMBOL(nvram_get_size);
void nvram_sync(void)
{
if (ppc_md.nvram_sync)
ppc_md.nvram_sync();
}
EXPORT_SYMBOL(nvram_sync);
#endif /* CONFIG_NVRAM */
int __init ppc_init(void)
{
/* clear the progress line */
if (ppc_md.progress)
ppc_md.progress(" ", 0xffff);
/* call platform init */
if (ppc_md.init != NULL) {
ppc_md.init();
}
return 0;
}
arch_initcall(ppc_init);
static void __init irqstack_early_init(void)
{
unsigned int i;
/* interrupt stacks must be in lowmem, we get that for free on ppc32
* as the memblock is limited to lowmem by default */
for_each_possible_cpu(i) {
softirq_ctx[i] = (struct thread_info *)
__va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
hardirq_ctx[i] = (struct thread_info *)
__va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
}
}
#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
static void __init exc_lvl_early_init(void)
{
unsigned int i, hw_cpu;
/* interrupt stacks must be in lowmem, we get that for free on ppc32
* as the memblock is limited to lowmem by MEMBLOCK_REAL_LIMIT */
for_each_possible_cpu(i) {
#ifdef CONFIG_SMP
hw_cpu = get_hard_smp_processor_id(i);
#else
hw_cpu = 0;
#endif
critirq_ctx[hw_cpu] = (struct thread_info *)
__va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
#ifdef CONFIG_BOOKE
dbgirq_ctx[hw_cpu] = (struct thread_info *)
__va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
mcheckirq_ctx[hw_cpu] = (struct thread_info *)
__va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
#endif
}
}
#else
#define exc_lvl_early_init()
#endif
/* Warning, IO base is not yet inited */
void __init setup_arch(char **cmdline_p)
{
*cmdline_p = boot_command_line;
/* so udelay does something sensible, assume <= 1000 bogomips */
loops_per_jiffy = 500000000 / HZ;
unflatten_device_tree();
check_for_initrd();
if (ppc_md.init_early)
ppc_md.init_early();
find_legacy_serial_ports();
smp_setup_cpu_maps();
/* Register early console */
register_early_udbg_console();
xmon_setup();
/*
* Set cache line size based on type of cpu as a default.
* Systems with OF can look in the properties on the cpu node(s)
* for a possibly more accurate value.
*/
dcache_bsize = cur_cpu_spec->dcache_bsize;
icache_bsize = cur_cpu_spec->icache_bsize;
ucache_bsize = 0;
if (cpu_has_feature(CPU_FTR_UNIFIED_ID_CACHE))
ucache_bsize = icache_bsize = dcache_bsize;
if (ppc_md.panic)
setup_panic();
init_mm.start_code = (unsigned long)_stext;
init_mm.end_code = (unsigned long) _etext;
init_mm.end_data = (unsigned long) _edata;
init_mm.brk = klimit;
exc_lvl_early_init();
irqstack_early_init();
initmem_init();
if ( ppc_md.progress ) ppc_md.progress("setup_arch: initmem", 0x3eab);
#ifdef CONFIG_DUMMY_CONSOLE
conswitchp = &dummy_con;
#endif
if (ppc_md.setup_arch)
ppc_md.setup_arch();
if ( ppc_md.progress ) ppc_md.progress("arch: exit", 0x3eab);
paging_init();
/* Initialize the MMU context management stuff */
mmu_context_init();
}