mirror of
https://github.com/torvalds/linux.git
synced 2024-11-02 02:01:29 +00:00
89c7e4b8bb
The ARM ARM requires branch predictor maintenance if, for a given ASID, the instructions at a specific virtual address appear to change. From the kernel's point of view, that means: - Changing the kernel's view of memory (e.g. switching to the identity map) - ASID rollover (since ASIDs will be re-allocated to new tasks) This patch adds explicit branch predictor maintenance when either of the two conditions above are met. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
155 lines
3.6 KiB
C
155 lines
3.6 KiB
C
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/slab.h>
|
|
|
|
#include <asm/cputype.h>
|
|
#include <asm/idmap.h>
|
|
#include <asm/pgalloc.h>
|
|
#include <asm/pgtable.h>
|
|
#include <asm/sections.h>
|
|
#include <asm/system_info.h>
|
|
#include <asm/virt.h>
|
|
|
|
pgd_t *idmap_pgd;
|
|
|
|
#ifdef CONFIG_ARM_LPAE
|
|
static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
|
|
unsigned long prot)
|
|
{
|
|
pmd_t *pmd;
|
|
unsigned long next;
|
|
|
|
if (pud_none_or_clear_bad(pud) || (pud_val(*pud) & L_PGD_SWAPPER)) {
|
|
pmd = pmd_alloc_one(&init_mm, addr);
|
|
if (!pmd) {
|
|
pr_warning("Failed to allocate identity pmd.\n");
|
|
return;
|
|
}
|
|
pud_populate(&init_mm, pud, pmd);
|
|
pmd += pmd_index(addr);
|
|
} else
|
|
pmd = pmd_offset(pud, addr);
|
|
|
|
do {
|
|
next = pmd_addr_end(addr, end);
|
|
*pmd = __pmd((addr & PMD_MASK) | prot);
|
|
flush_pmd_entry(pmd);
|
|
} while (pmd++, addr = next, addr != end);
|
|
}
|
|
#else /* !CONFIG_ARM_LPAE */
|
|
static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
|
|
unsigned long prot)
|
|
{
|
|
pmd_t *pmd = pmd_offset(pud, addr);
|
|
|
|
addr = (addr & PMD_MASK) | prot;
|
|
pmd[0] = __pmd(addr);
|
|
addr += SECTION_SIZE;
|
|
pmd[1] = __pmd(addr);
|
|
flush_pmd_entry(pmd);
|
|
}
|
|
#endif /* CONFIG_ARM_LPAE */
|
|
|
|
static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
|
|
unsigned long prot)
|
|
{
|
|
pud_t *pud = pud_offset(pgd, addr);
|
|
unsigned long next;
|
|
|
|
do {
|
|
next = pud_addr_end(addr, end);
|
|
idmap_add_pmd(pud, addr, next, prot);
|
|
} while (pud++, addr = next, addr != end);
|
|
}
|
|
|
|
static void identity_mapping_add(pgd_t *pgd, const char *text_start,
|
|
const char *text_end, unsigned long prot)
|
|
{
|
|
unsigned long addr, end;
|
|
unsigned long next;
|
|
|
|
addr = virt_to_phys(text_start);
|
|
end = virt_to_phys(text_end);
|
|
|
|
prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
|
|
|
|
if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
|
|
prot |= PMD_BIT4;
|
|
|
|
pgd += pgd_index(addr);
|
|
do {
|
|
next = pgd_addr_end(addr, end);
|
|
idmap_add_pud(pgd, addr, next, prot);
|
|
} while (pgd++, addr = next, addr != end);
|
|
}
|
|
|
|
#if defined(CONFIG_ARM_VIRT_EXT) && defined(CONFIG_ARM_LPAE)
|
|
pgd_t *hyp_pgd;
|
|
|
|
extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[];
|
|
|
|
static int __init init_static_idmap_hyp(void)
|
|
{
|
|
hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
|
|
if (!hyp_pgd)
|
|
return -ENOMEM;
|
|
|
|
pr_info("Setting up static HYP identity map for 0x%p - 0x%p\n",
|
|
__hyp_idmap_text_start, __hyp_idmap_text_end);
|
|
identity_mapping_add(hyp_pgd, __hyp_idmap_text_start,
|
|
__hyp_idmap_text_end, PMD_SECT_AP1);
|
|
|
|
return 0;
|
|
}
|
|
#else
|
|
static int __init init_static_idmap_hyp(void)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
extern char __idmap_text_start[], __idmap_text_end[];
|
|
|
|
static int __init init_static_idmap(void)
|
|
{
|
|
int ret;
|
|
|
|
idmap_pgd = pgd_alloc(&init_mm);
|
|
if (!idmap_pgd)
|
|
return -ENOMEM;
|
|
|
|
pr_info("Setting up static identity map for 0x%p - 0x%p\n",
|
|
__idmap_text_start, __idmap_text_end);
|
|
identity_mapping_add(idmap_pgd, __idmap_text_start,
|
|
__idmap_text_end, 0);
|
|
|
|
ret = init_static_idmap_hyp();
|
|
|
|
/* Flush L1 for the hardware to see this page table content */
|
|
flush_cache_louis();
|
|
|
|
return ret;
|
|
}
|
|
early_initcall(init_static_idmap);
|
|
|
|
/*
|
|
* In order to soft-boot, we need to switch to a 1:1 mapping for the
|
|
* cpu_reset functions. This will then ensure that we have predictable
|
|
* results when turning off the mmu.
|
|
*/
|
|
void setup_mm_for_reboot(void)
|
|
{
|
|
/* Switch to the identity mapping. */
|
|
cpu_switch_mm(idmap_pgd, &init_mm);
|
|
local_flush_bp_all();
|
|
|
|
#ifdef CONFIG_CPU_HAS_ASID
|
|
/*
|
|
* We don't have a clean ASID for the identity mapping, which
|
|
* may clash with virtual addresses of the previous page tables
|
|
* and therefore potentially in the TLB.
|
|
*/
|
|
local_flush_tlb_all();
|
|
#endif
|
|
}
|