linux_dsm_epyc7002/arch/arm/include/asm/proc-fns.h
Russell King 383fb3ee80 ARM: spectre-v2: per-CPU vtables to work around big.Little systems
In big.Little systems, some CPUs require the Spectre workarounds in
paths such as the context switch, but other CPUs do not.  In order
to handle these differences, we need per-CPU vtables.

We are unable to use the kernel's per-CPU variables to support this
as per-CPU is not initialised at times when we need access to the
vtables, so we have to use an array indexed by logical CPU number.

We use an array-of-pointers to avoid having function pointers in
the kernel's read/write .data section.

Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2018-11-12 10:51:01 +00:00

195 lines
4.8 KiB
C

/*
* arch/arm/include/asm/proc-fns.h
*
* Copyright (C) 1997-1999 Russell King
* Copyright (C) 2000 Deep Blue Solutions Ltd
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __ASM_PROCFNS_H
#define __ASM_PROCFNS_H
#ifdef __KERNEL__
#include <asm/glue-proc.h>
#include <asm/page.h>
#ifndef __ASSEMBLY__
struct mm_struct;
/*
* Don't change this structure - ASM code relies on it.
*/
struct processor {
/* MISC
* get data abort address/flags
*/
void (*_data_abort)(unsigned long pc);
/*
* Retrieve prefetch fault address
*/
unsigned long (*_prefetch_abort)(unsigned long lr);
/*
* Set up any processor specifics
*/
void (*_proc_init)(void);
/*
* Check for processor bugs
*/
void (*check_bugs)(void);
/*
* Disable any processor specifics
*/
void (*_proc_fin)(void);
/*
* Special stuff for a reset
*/
void (*reset)(unsigned long addr, bool hvc) __attribute__((noreturn));
/*
* Idle the processor
*/
int (*_do_idle)(void);
/*
* Processor architecture specific
*/
/*
* clean a virtual address range from the
* D-cache without flushing the cache.
*/
void (*dcache_clean_area)(void *addr, int size);
/*
* Set the page table
*/
void (*switch_mm)(phys_addr_t pgd_phys, struct mm_struct *mm);
/*
* Set a possibly extended PTE. Non-extended PTEs should
* ignore 'ext'.
*/
#ifdef CONFIG_ARM_LPAE
void (*set_pte_ext)(pte_t *ptep, pte_t pte);
#else
void (*set_pte_ext)(pte_t *ptep, pte_t pte, unsigned int ext);
#endif
/* Suspend/resume */
unsigned int suspend_size;
void (*do_suspend)(void *);
void (*do_resume)(void *);
};
#ifndef MULTI_CPU
static inline void init_proc_vtable(const struct processor *p)
{
}
extern void cpu_proc_init(void);
extern void cpu_proc_fin(void);
extern int cpu_do_idle(void);
extern void cpu_dcache_clean_area(void *, int);
extern void cpu_do_switch_mm(phys_addr_t pgd_phys, struct mm_struct *mm);
#ifdef CONFIG_ARM_LPAE
extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte);
#else
extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte, unsigned int ext);
#endif
extern void cpu_reset(unsigned long addr, bool hvc) __attribute__((noreturn));
/* These three are private to arch/arm/kernel/suspend.c */
extern void cpu_do_suspend(void *);
extern void cpu_do_resume(void *);
#else
extern struct processor processor;
#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
#include <linux/smp.h>
/*
* This can't be a per-cpu variable because we need to access it before
* per-cpu has been initialised. We have a couple of functions that are
* called in a pre-emptible context, and so can't use smp_processor_id()
* there, hence PROC_TABLE(). We insist in init_proc_vtable() that the
* function pointers for these are identical across all CPUs.
*/
extern struct processor *cpu_vtable[];
#define PROC_VTABLE(f) cpu_vtable[smp_processor_id()]->f
#define PROC_TABLE(f) cpu_vtable[0]->f
static inline void init_proc_vtable(const struct processor *p)
{
unsigned int cpu = smp_processor_id();
*cpu_vtable[cpu] = *p;
WARN_ON_ONCE(cpu_vtable[cpu]->dcache_clean_area !=
cpu_vtable[0]->dcache_clean_area);
WARN_ON_ONCE(cpu_vtable[cpu]->set_pte_ext !=
cpu_vtable[0]->set_pte_ext);
}
#else
#define PROC_VTABLE(f) processor.f
#define PROC_TABLE(f) processor.f
static inline void init_proc_vtable(const struct processor *p)
{
processor = *p;
}
#endif
#define cpu_proc_init PROC_VTABLE(_proc_init)
#define cpu_check_bugs PROC_VTABLE(check_bugs)
#define cpu_proc_fin PROC_VTABLE(_proc_fin)
#define cpu_reset PROC_VTABLE(reset)
#define cpu_do_idle PROC_VTABLE(_do_idle)
#define cpu_dcache_clean_area PROC_TABLE(dcache_clean_area)
#define cpu_set_pte_ext PROC_TABLE(set_pte_ext)
#define cpu_do_switch_mm PROC_VTABLE(switch_mm)
/* These two are private to arch/arm/kernel/suspend.c */
#define cpu_do_suspend PROC_VTABLE(do_suspend)
#define cpu_do_resume PROC_VTABLE(do_resume)
#endif
extern void cpu_resume(void);
#include <asm/memory.h>
#ifdef CONFIG_MMU
#define cpu_switch_mm(pgd,mm) cpu_do_switch_mm(virt_to_phys(pgd),mm)
#ifdef CONFIG_ARM_LPAE
#define cpu_get_ttbr(nr) \
({ \
u64 ttbr; \
__asm__("mrrc p15, " #nr ", %Q0, %R0, c2" \
: "=r" (ttbr)); \
ttbr; \
})
#define cpu_get_pgd() \
({ \
u64 pg = cpu_get_ttbr(0); \
pg &= ~(PTRS_PER_PGD*sizeof(pgd_t)-1); \
(pgd_t *)phys_to_virt(pg); \
})
#else
#define cpu_get_pgd() \
({ \
unsigned long pg; \
__asm__("mrc p15, 0, %0, c2, c0, 0" \
: "=r" (pg) : : "cc"); \
pg &= ~0x3fff; \
(pgd_t *)phys_to_virt(pg); \
})
#endif
#else /*!CONFIG_MMU */
#define cpu_switch_mm(pgd,mm) { }
#endif
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* __ASM_PROCFNS_H */