1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Common boot and setup code.
6 * Copyright (C) 2001 PPC64 Team, IBM Corp
9 #include <linux/export.h>
10 #include <linux/string.h>
11 #include <linux/sched.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/reboot.h>
15 #include <linux/delay.h>
16 #include <linux/initrd.h>
17 #include <linux/seq_file.h>
18 #include <linux/ioport.h>
19 #include <linux/console.h>
20 #include <linux/utsname.h>
21 #include <linux/tty.h>
22 #include <linux/root_dev.h>
23 #include <linux/notifier.h>
24 #include <linux/cpu.h>
25 #include <linux/unistd.h>
26 #include <linux/serial.h>
27 #include <linux/serial_8250.h>
28 #include <linux/memblock.h>
29 #include <linux/pci.h>
30 #include <linux/lockdep.h>
31 #include <linux/memory.h>
32 #include <linux/nmi.h>
34 #include <asm/debugfs.h>
36 #include <asm/kdump.h>
38 #include <asm/processor.h>
39 #include <asm/pgtable.h>
42 #include <asm/machdep.h>
45 #include <asm/cputable.h>
46 #include <asm/dt_cpu_ftrs.h>
47 #include <asm/sections.h>
48 #include <asm/btext.h>
49 #include <asm/nvram.h>
50 #include <asm/setup.h>
52 #include <asm/iommu.h>
53 #include <asm/serial.h>
54 #include <asm/cache.h>
57 #include <asm/firmware.h>
60 #include <asm/kexec.h>
61 #include <asm/code-patching.h>
62 #include <asm/livepatch.h>
64 #include <asm/cputhreads.h>
65 #include <asm/hw_irq.h>
66 #include <asm/feature-fixups.h>
68 #include <asm/early_ioremap.h>
72 int spinning_secondaries
;
75 struct ppc64_caches ppc64_caches
= {
85 EXPORT_SYMBOL_GPL(ppc64_caches
);
87 #if defined(CONFIG_PPC_BOOK3E) && defined(CONFIG_SMP)
88 void __init
setup_tlb_core_data(void)
92 BUILD_BUG_ON(offsetof(struct tlb_core_data
, lock
) != 0);
94 for_each_possible_cpu(cpu
) {
95 int first
= cpu_first_thread_sibling(cpu
);
98 * If we boot via kdump on a non-primary thread,
99 * make sure we point at the thread that actually
102 if (cpu_first_thread_sibling(boot_cpuid
) == first
)
105 paca_ptrs
[cpu
]->tcd_ptr
= &paca_ptrs
[first
]->tcd
;
108 * If we have threads, we need either tlbsrx.
109 * or e6500 tablewalk mode, or else TLB handlers
110 * will be racy and could produce duplicate entries.
111 * Should we panic instead?
113 WARN_ONCE(smt_enabled_at_boot
>= 2 &&
114 !mmu_has_feature(MMU_FTR_USE_TLBRSRV
) &&
115 book3e_htw_mode
!= PPC_HTW_E6500
,
116 "%s: unsupported MMU configuration\n", __func__
);
123 static char *smt_enabled_cmdline
;
125 /* Look for ibm,smt-enabled OF option */
126 void __init
check_smt_enabled(void)
128 struct device_node
*dn
;
129 const char *smt_option
;
131 /* Default to enabling all threads */
132 smt_enabled_at_boot
= threads_per_core
;
134 /* Allow the command line to overrule the OF option */
135 if (smt_enabled_cmdline
) {
136 if (!strcmp(smt_enabled_cmdline
, "on"))
137 smt_enabled_at_boot
= threads_per_core
;
138 else if (!strcmp(smt_enabled_cmdline
, "off"))
139 smt_enabled_at_boot
= 0;
144 rc
= kstrtoint(smt_enabled_cmdline
, 10, &smt
);
146 smt_enabled_at_boot
=
147 min(threads_per_core
, smt
);
150 dn
= of_find_node_by_path("/options");
152 smt_option
= of_get_property(dn
, "ibm,smt-enabled",
156 if (!strcmp(smt_option
, "on"))
157 smt_enabled_at_boot
= threads_per_core
;
158 else if (!strcmp(smt_option
, "off"))
159 smt_enabled_at_boot
= 0;
167 /* Look for smt-enabled= cmdline option */
168 static int __init
early_smt_enabled(char *p
)
170 smt_enabled_cmdline
= p
;
173 early_param("smt-enabled", early_smt_enabled
);
175 #endif /* CONFIG_SMP */
177 /** Fix up paca fields required for the boot cpu */
178 static void __init
fixup_boot_paca(void)
180 /* The boot cpu is started */
181 get_paca()->cpu_start
= 1;
182 /* Allow percpu accesses to work until we setup percpu data */
183 get_paca()->data_offset
= 0;
184 /* Mark interrupts disabled in PACA */
185 irq_soft_mask_set(IRQS_DISABLED
);
188 static void __init
configure_exceptions(void)
191 * Setup the trampolines from the lowmem exception vectors
192 * to the kdump kernel when not using a relocatable kernel.
194 setup_kdump_trampoline();
196 /* Under a PAPR hypervisor, we need hypercalls */
197 if (firmware_has_feature(FW_FEATURE_SET_MODE
)) {
198 /* Enable AIL if possible */
199 pseries_enable_reloc_on_exc();
202 * Tell the hypervisor that we want our exceptions to
203 * be taken in little endian mode.
205 * We don't call this for big endian as our calling convention
206 * makes us always enter in BE, and the call may fail under
207 * some circumstances with kdump.
209 #ifdef __LITTLE_ENDIAN__
210 pseries_little_endian_exceptions();
213 /* Set endian mode using OPAL */
214 if (firmware_has_feature(FW_FEATURE_OPAL
))
215 opal_configure_cores();
217 /* AIL on native is done in cpu_ready_for_interrupts() */
221 static void cpu_ready_for_interrupts(void)
224 * Enable AIL if supported, and we are in hypervisor mode. This
225 * is called once for every processor.
227 * If we are not in hypervisor mode the job is done once for
228 * the whole partition in configure_exceptions().
230 if (cpu_has_feature(CPU_FTR_HVMODE
) &&
231 cpu_has_feature(CPU_FTR_ARCH_207S
)) {
232 unsigned long lpcr
= mfspr(SPRN_LPCR
);
233 mtspr(SPRN_LPCR
, lpcr
| LPCR_AIL_3
);
237 * Set HFSCR:TM based on CPU features:
238 * In the special case of TM no suspend (P9N DD2.1), Linux is
239 * told TM is off via the dt-ftrs but told to (partially) use
240 * it via OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED. So HFSCR[TM]
241 * will be off from dt-ftrs but we need to turn it on for the
244 if (cpu_has_feature(CPU_FTR_HVMODE
)) {
245 if (cpu_has_feature(CPU_FTR_TM_COMP
))
246 mtspr(SPRN_HFSCR
, mfspr(SPRN_HFSCR
) | HFSCR_TM
);
248 mtspr(SPRN_HFSCR
, mfspr(SPRN_HFSCR
) & ~HFSCR_TM
);
251 /* Set IR and DR in PACA MSR */
252 get_paca()->kernel_msr
= MSR_KERNEL
;
255 unsigned long spr_default_dscr
= 0;
257 void __init
record_spr_defaults(void)
259 if (early_cpu_has_feature(CPU_FTR_DSCR
))
260 spr_default_dscr
= mfspr(SPRN_DSCR
);
264 * Early initialization entry point. This is called by head.S
265 * with MMU translation disabled. We rely on the "feature" of
266 * the CPU that ignores the top 2 bits of the address in real
267 * mode so we can access kernel globals normally provided we
268 * only toy with things in the RMO region. From here, we do
269 * some early parsing of the device-tree to setup out MEMBLOCK
270 * data structures, and allocate & initialize the hash table
271 * and segment tables so we can start running with translation
274 * It is this function which will call the probe() callback of
275 * the various platform types and copy the matching one to the
276 * global ppc_md structure. Your platform can eventually do
277 * some very early initializations from the probe() routine, but
278 * this is not recommended, be very careful as, for example, the
279 * device-tree is not accessible via normal means at this point.
282 void __init
early_setup(unsigned long dt_ptr
)
284 static __initdata
struct paca_struct boot_paca
;
286 /* -------- printk is _NOT_ safe to use here ! ------- */
288 /* Try new device tree based feature discovery ... */
289 if (!dt_cpu_ftrs_init(__va(dt_ptr
)))
290 /* Otherwise use the old style CPU table */
291 identify_cpu(0, mfspr(SPRN_PVR
));
293 /* Assume we're on cpu 0 for now. Don't write to the paca yet! */
294 initialise_paca(&boot_paca
, 0);
295 setup_paca(&boot_paca
);
298 /* -------- printk is now safe to use ------- */
300 /* Enable early debugging if any specified (see udbg.h) */
303 udbg_printf(" -> %s(), dt_ptr: 0x%lx\n", __func__
, dt_ptr
);
306 * Do early initialization using the flattened device
307 * tree, such as retrieving the physical memory map or
308 * calculating/retrieving the hash table size.
310 early_init_devtree(__va(dt_ptr
));
312 /* Now we know the logical id of our boot cpu, setup the paca. */
313 if (boot_cpuid
!= 0) {
314 /* Poison paca_ptrs[0] again if it's not the boot cpu */
315 memset(&paca_ptrs
[0], 0x88, sizeof(paca_ptrs
[0]));
317 setup_paca(paca_ptrs
[boot_cpuid
]);
321 * Configure exception handlers. This include setting up trampolines
322 * if needed, setting exception endian mode, etc...
324 configure_exceptions();
327 * Configure Kernel Userspace Protection. This needs to happen before
328 * feature fixups for platforms that implement this using features.
332 /* Apply all the dynamic patching */
333 apply_feature_fixups();
334 setup_feature_keys();
336 early_ioremap_setup();
338 /* Initialize the hash table or TLB handling */
342 * After firmware and early platform setup code has set things up,
343 * we note the SPR values for configurable control/performance
344 * registers, and use those as initial defaults.
346 record_spr_defaults();
349 * At this point, we can let interrupts switch to virtual mode
350 * (the MMU has been setup), so adjust the MSR in the PACA to
351 * have IR and DR set and enable AIL if it exists
353 cpu_ready_for_interrupts();
356 * We enable ftrace here, but since we only support DYNAMIC_FTRACE, it
357 * will only actually get enabled on the boot cpu much later once
358 * ftrace itself has been initialized.
360 this_cpu_enable_ftrace();
362 udbg_printf(" <- %s()\n", __func__
);
364 #ifdef CONFIG_PPC_EARLY_DEBUG_BOOTX
366 * This needs to be done *last* (after the above udbg_printf() even)
368 * Right after we return from this function, we turn on the MMU
369 * which means the real-mode access trick that btext does will
370 * no longer work, it needs to switch to using a real MMU
371 * mapping. This call will ensure that it does
374 #endif /* CONFIG_PPC_EARLY_DEBUG_BOOTX */
378 void early_setup_secondary(void)
380 /* Mark interrupts disabled in PACA */
381 irq_soft_mask_set(IRQS_DISABLED
);
383 /* Initialize the hash table or TLB handling */
384 early_init_mmu_secondary();
386 /* Perform any KUP setup that is per-cpu */
390 * At this point, we can let interrupts switch to virtual mode
391 * (the MMU has been setup), so adjust the MSR in the PACA to
392 * have IR and DR set.
394 cpu_ready_for_interrupts();
397 #endif /* CONFIG_SMP */
399 void panic_smp_self_stop(void)
407 #if defined(CONFIG_SMP) || defined(CONFIG_KEXEC_CORE)
408 static bool use_spinloop(void)
410 if (IS_ENABLED(CONFIG_PPC_BOOK3S
)) {
412 * See comments in head_64.S -- not all platforms insert
413 * secondaries at __secondary_hold and wait at the spin
416 if (firmware_has_feature(FW_FEATURE_OPAL
))
422 * When book3e boots from kexec, the ePAPR spin table does
425 return of_property_read_bool(of_chosen
, "linux,booted-from-kexec");
428 void smp_release_cpus(void)
436 /* All secondary cpus are spinning on a common spinloop, release them
437 * all now so they can start to spin on their individual paca
438 * spinloops. For non SMP kernels, the secondary cpus never get out
439 * of the common spinloop.
442 ptr
= (unsigned long *)((unsigned long)&__secondary_hold_spinloop
444 *ptr
= ppc_function_entry(generic_secondary_smp_init
);
446 /* And wait a bit for them to catch up */
447 for (i
= 0; i
< 100000; i
++) {
450 if (spinning_secondaries
== 0)
454 pr_debug("spinning_secondaries = %d\n", spinning_secondaries
);
456 #endif /* CONFIG_SMP || CONFIG_KEXEC_CORE */
459 * Initialize some remaining members of the ppc64_caches and systemcfg
461 * (at least until we get rid of them completely). This is mostly some
462 * cache informations about the CPU that will be used by cache flush
463 * routines and/or provided to userland
466 static void init_cache_info(struct ppc_cache_info
*info
, u32 size
, u32 lsize
,
471 info
->line_size
= lsize
;
472 info
->block_size
= bsize
;
473 info
->log_block_size
= __ilog2(bsize
);
475 info
->blocks_per_page
= PAGE_SIZE
/ bsize
;
477 info
->blocks_per_page
= 0;
480 info
->assoc
= 0xffff;
482 info
->assoc
= size
/ (sets
* lsize
);
485 static bool __init
parse_cache_info(struct device_node
*np
,
487 struct ppc_cache_info
*info
)
489 static const char *ipropnames
[] __initdata
= {
492 "i-cache-block-size",
495 static const char *dpropnames
[] __initdata
= {
498 "d-cache-block-size",
501 const char **propnames
= icache
? ipropnames
: dpropnames
;
502 const __be32
*sizep
, *lsizep
, *bsizep
, *setsp
;
503 u32 size
, lsize
, bsize
, sets
;
508 lsize
= bsize
= cur_cpu_spec
->dcache_bsize
;
509 sizep
= of_get_property(np
, propnames
[0], NULL
);
511 size
= be32_to_cpu(*sizep
);
512 setsp
= of_get_property(np
, propnames
[1], NULL
);
514 sets
= be32_to_cpu(*setsp
);
515 bsizep
= of_get_property(np
, propnames
[2], NULL
);
516 lsizep
= of_get_property(np
, propnames
[3], NULL
);
520 lsize
= be32_to_cpu(*lsizep
);
522 bsize
= be32_to_cpu(*bsizep
);
523 if (sizep
== NULL
|| bsizep
== NULL
|| lsizep
== NULL
)
527 * OF is weird .. it represents fully associative caches
528 * as "1 way" which doesn't make much sense and doesn't
529 * leave room for direct mapped. We'll assume that 0
530 * in OF means direct mapped for that reason.
537 init_cache_info(info
, size
, lsize
, bsize
, sets
);
542 void __init
initialize_cache_info(void)
544 struct device_node
*cpu
= NULL
, *l2
, *l3
= NULL
;
548 * All shipping POWER8 machines have a firmware bug that
549 * puts incorrect information in the device-tree. This will
550 * be (hopefully) fixed for future chips but for now hard
551 * code the values if we are running on one of these
553 pvr
= PVR_VER(mfspr(SPRN_PVR
));
554 if (pvr
== PVR_POWER8
|| pvr
== PVR_POWER8E
||
555 pvr
== PVR_POWER8NVL
) {
556 /* size lsize blk sets */
557 init_cache_info(&ppc64_caches
.l1i
, 0x8000, 128, 128, 32);
558 init_cache_info(&ppc64_caches
.l1d
, 0x10000, 128, 128, 64);
559 init_cache_info(&ppc64_caches
.l2
, 0x80000, 128, 0, 512);
560 init_cache_info(&ppc64_caches
.l3
, 0x800000, 128, 0, 8192);
562 cpu
= of_find_node_by_type(NULL
, "cpu");
565 * We're assuming *all* of the CPUs have the same
566 * d-cache and i-cache sizes... -Peter
569 if (!parse_cache_info(cpu
, false, &ppc64_caches
.l1d
))
570 pr_warn("Argh, can't find dcache properties !\n");
572 if (!parse_cache_info(cpu
, true, &ppc64_caches
.l1i
))
573 pr_warn("Argh, can't find icache properties !\n");
576 * Try to find the L2 and L3 if any. Assume they are
577 * unified and use the D-side properties.
579 l2
= of_find_next_cache_node(cpu
);
582 parse_cache_info(l2
, false, &ppc64_caches
.l2
);
583 l3
= of_find_next_cache_node(l2
);
587 parse_cache_info(l3
, false, &ppc64_caches
.l3
);
592 /* For use by binfmt_elf */
593 dcache_bsize
= ppc64_caches
.l1d
.block_size
;
594 icache_bsize
= ppc64_caches
.l1i
.block_size
;
596 cur_cpu_spec
->dcache_bsize
= dcache_bsize
;
597 cur_cpu_spec
->icache_bsize
= icache_bsize
;
601 * This returns the limit below which memory accesses to the linear
602 * mapping are guarnateed not to cause an architectural exception (e.g.,
603 * TLB or SLB miss fault).
605 * This is used to allocate PACAs and various interrupt stacks that
606 * that are accessed early in interrupt handlers that must not cause
607 * re-entrant interrupts.
609 __init u64
ppc64_bolted_size(void)
611 #ifdef CONFIG_PPC_BOOK3E
612 /* Freescale BookE bolts the entire linear mapping */
613 /* XXX: BookE ppc64_rma_limit setup seems to disagree? */
614 if (early_mmu_has_feature(MMU_FTR_TYPE_FSL_E
))
615 return linear_map_top
;
616 /* Other BookE, we assume the first GB is bolted */
619 /* BookS radix, does not take faults on linear mapping */
620 if (early_radix_enabled())
623 /* BookS hash, the first segment is bolted */
624 if (early_mmu_has_feature(MMU_FTR_1T_SEGMENT
))
625 return 1UL << SID_SHIFT_1T
;
626 return 1UL << SID_SHIFT
;
630 static void *__init
alloc_stack(unsigned long limit
, int cpu
)
634 BUILD_BUG_ON(STACK_INT_FRAME_SIZE
% 16);
636 ptr
= memblock_alloc_try_nid(THREAD_SIZE
, THREAD_ALIGN
,
637 MEMBLOCK_LOW_LIMIT
, limit
,
638 early_cpu_to_node(cpu
));
640 panic("cannot allocate stacks");
645 void __init
irqstack_early_init(void)
647 u64 limit
= ppc64_bolted_size();
651 * Interrupt stacks must be in the first segment since we
652 * cannot afford to take SLB misses on them. They are not
653 * accessed in realmode.
655 for_each_possible_cpu(i
) {
656 softirq_ctx
[i
] = alloc_stack(limit
, i
);
657 hardirq_ctx
[i
] = alloc_stack(limit
, i
);
661 #ifdef CONFIG_PPC_BOOK3E
662 void __init
exc_lvl_early_init(void)
666 for_each_possible_cpu(i
) {
669 sp
= alloc_stack(ULONG_MAX
, i
);
671 paca_ptrs
[i
]->crit_kstack
= sp
+ THREAD_SIZE
;
673 sp
= alloc_stack(ULONG_MAX
, i
);
675 paca_ptrs
[i
]->dbg_kstack
= sp
+ THREAD_SIZE
;
677 sp
= alloc_stack(ULONG_MAX
, i
);
678 mcheckirq_ctx
[i
] = sp
;
679 paca_ptrs
[i
]->mc_kstack
= sp
+ THREAD_SIZE
;
682 if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC
))
683 patch_exception(0x040, exc_debug_debug_book3e
);
688 * Stack space used when we detect a bad kernel stack pointer, and
689 * early in SMP boots before relocation is enabled. Exclusive emergency
690 * stack for machine checks.
692 void __init
emergency_stack_init(void)
698 * Emergency stacks must be under 256MB, we cannot afford to take
699 * SLB misses on them. The ABI also requires them to be 128-byte
702 * Since we use these as temporary stacks during secondary CPU
703 * bringup, machine check, system reset, and HMI, we need to get
704 * at them in real mode. This means they must also be within the RMO
707 * The IRQ stacks allocated elsewhere in this file are zeroed and
708 * initialized in kernel/irq.c. These are initialized here in order
709 * to have emergency stacks available as early as possible.
711 limit
= min(ppc64_bolted_size(), ppc64_rma_size
);
713 for_each_possible_cpu(i
) {
714 paca_ptrs
[i
]->emergency_sp
= alloc_stack(limit
, i
) + THREAD_SIZE
;
716 #ifdef CONFIG_PPC_BOOK3S_64
717 /* emergency stack for NMI exception handling. */
718 paca_ptrs
[i
]->nmi_emergency_sp
= alloc_stack(limit
, i
) + THREAD_SIZE
;
720 /* emergency stack for machine check exception handling. */
721 paca_ptrs
[i
]->mc_emergency_sp
= alloc_stack(limit
, i
) + THREAD_SIZE
;
727 #define PCPU_DYN_SIZE ()
729 static void * __init
pcpu_fc_alloc(unsigned int cpu
, size_t size
, size_t align
)
731 return memblock_alloc_try_nid(size
, align
, __pa(MAX_DMA_ADDRESS
),
732 MEMBLOCK_ALLOC_ACCESSIBLE
,
733 early_cpu_to_node(cpu
));
737 static void __init
pcpu_fc_free(void *ptr
, size_t size
)
739 memblock_free(__pa(ptr
), size
);
742 static int pcpu_cpu_distance(unsigned int from
, unsigned int to
)
744 if (early_cpu_to_node(from
) == early_cpu_to_node(to
))
745 return LOCAL_DISTANCE
;
747 return REMOTE_DISTANCE
;
750 unsigned long __per_cpu_offset
[NR_CPUS
] __read_mostly
;
751 EXPORT_SYMBOL(__per_cpu_offset
);
753 void __init
setup_per_cpu_areas(void)
755 const size_t dyn_size
= PERCPU_MODULE_RESERVE
+ PERCPU_DYNAMIC_RESERVE
;
762 * Linear mapping is one of 4K, 1M and 16M. For 4K, no need
763 * to group units. For larger mappings, use 1M atom which
764 * should be large enough to contain a number of units.
766 if (mmu_linear_psize
== MMU_PAGE_4K
)
767 atom_size
= PAGE_SIZE
;
771 rc
= pcpu_embed_first_chunk(0, dyn_size
, atom_size
, pcpu_cpu_distance
,
772 pcpu_fc_alloc
, pcpu_fc_free
);
774 panic("cannot initialize percpu area (err=%d)", rc
);
776 delta
= (unsigned long)pcpu_base_addr
- (unsigned long)__per_cpu_start
;
777 for_each_possible_cpu(cpu
) {
778 __per_cpu_offset
[cpu
] = delta
+ pcpu_unit_offsets
[cpu
];
779 paca_ptrs
[cpu
]->data_offset
= __per_cpu_offset
[cpu
];
784 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
785 unsigned long memory_block_size_bytes(void)
787 if (ppc_md
.memory_block_size
)
788 return ppc_md
.memory_block_size();
790 return MIN_MEMORY_BLOCK_SIZE
;
794 #if defined(CONFIG_PPC_INDIRECT_PIO) || defined(CONFIG_PPC_INDIRECT_MMIO)
795 struct ppc_pci_io ppc_pci_io
;
796 EXPORT_SYMBOL(ppc_pci_io
);
799 #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
800 u64
hw_nmi_get_sample_period(int watchdog_thresh
)
802 return ppc_proc_freq
* watchdog_thresh
;
807 * The perf based hardlockup detector breaks PMU event based branches, so
808 * disable it by default. Book3S has a soft-nmi hardlockup detector based
809 * on the decrementer interrupt, so it does not suffer from this problem.
811 * It is likely to get false positives in VM guests, so disable it there
814 static int __init
disable_hardlockup_detector(void)
816 #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
817 hardlockup_detector_disable();
819 if (firmware_has_feature(FW_FEATURE_LPAR
))
820 hardlockup_detector_disable();
825 early_initcall(disable_hardlockup_detector
);
827 #ifdef CONFIG_PPC_BOOK3S_64
828 static enum l1d_flush_type enabled_flush_types
;
829 static void *l1d_flush_fallback_area
;
830 static bool no_rfi_flush
;
833 static int __init
handle_no_rfi_flush(char *p
)
835 pr_info("rfi-flush: disabled on command line.");
839 early_param("no_rfi_flush", handle_no_rfi_flush
);
842 * The RFI flush is not KPTI, but because users will see doco that says to use
843 * nopti we hijack that option here to also disable the RFI flush.
845 static int __init
handle_no_pti(char *p
)
847 pr_info("rfi-flush: disabling due to 'nopti' on command line.\n");
848 handle_no_rfi_flush(NULL
);
851 early_param("nopti", handle_no_pti
);
853 static void do_nothing(void *unused
)
856 * We don't need to do the flush explicitly, just enter+exit kernel is
857 * sufficient, the RFI exit handlers will do the right thing.
861 void rfi_flush_enable(bool enable
)
864 do_rfi_flush_fixups(enabled_flush_types
);
865 on_each_cpu(do_nothing
, NULL
, 1);
867 do_rfi_flush_fixups(L1D_FLUSH_NONE
);
872 static void __ref
init_fallback_flush(void)
877 /* Only allocate the fallback flush area once (at boot time). */
878 if (l1d_flush_fallback_area
)
881 l1d_size
= ppc64_caches
.l1d
.size
;
884 * If there is no d-cache-size property in the device tree, l1d_size
885 * could be zero. That leads to the loop in the asm wrapping around to
886 * 2^64-1, and then walking off the end of the fallback area and
887 * eventually causing a page fault which is fatal. Just default to
888 * something vaguely sane.
891 l1d_size
= (64 * 1024);
893 limit
= min(ppc64_bolted_size(), ppc64_rma_size
);
896 * Align to L1d size, and size it at 2x L1d size, to catch possible
897 * hardware prefetch runoff. We don't have a recipe for load patterns to
898 * reliably avoid the prefetcher.
900 l1d_flush_fallback_area
= memblock_alloc_try_nid(l1d_size
* 2,
901 l1d_size
, MEMBLOCK_LOW_LIMIT
,
902 limit
, NUMA_NO_NODE
);
903 if (!l1d_flush_fallback_area
)
904 panic("%s: Failed to allocate %llu bytes align=0x%llx max_addr=%pa\n",
905 __func__
, l1d_size
* 2, l1d_size
, &limit
);
908 for_each_possible_cpu(cpu
) {
909 struct paca_struct
*paca
= paca_ptrs
[cpu
];
910 paca
->rfi_flush_fallback_area
= l1d_flush_fallback_area
;
911 paca
->l1d_flush_size
= l1d_size
;
915 void setup_rfi_flush(enum l1d_flush_type types
, bool enable
)
917 if (types
& L1D_FLUSH_FALLBACK
) {
918 pr_info("rfi-flush: fallback displacement flush available\n");
919 init_fallback_flush();
922 if (types
& L1D_FLUSH_ORI
)
923 pr_info("rfi-flush: ori type flush available\n");
925 if (types
& L1D_FLUSH_MTTRIG
)
926 pr_info("rfi-flush: mttrig type flush available\n");
928 enabled_flush_types
= types
;
930 if (!no_rfi_flush
&& !cpu_mitigations_off())
931 rfi_flush_enable(enable
);
934 #ifdef CONFIG_DEBUG_FS
935 static int rfi_flush_set(void *data
, u64 val
)
946 /* Only do anything if we're changing state */
947 if (enable
!= rfi_flush
)
948 rfi_flush_enable(enable
);
953 static int rfi_flush_get(void *data
, u64
*val
)
955 *val
= rfi_flush
? 1 : 0;
959 DEFINE_SIMPLE_ATTRIBUTE(fops_rfi_flush
, rfi_flush_get
, rfi_flush_set
, "%llu\n");
961 static __init
int rfi_flush_debugfs_init(void)
963 debugfs_create_file("rfi_flush", 0600, powerpc_debugfs_root
, NULL
, &fops_rfi_flush
);
966 device_initcall(rfi_flush_debugfs_init
);
968 #endif /* CONFIG_PPC_BOOK3S_64 */