/**
* kstrdup_const - conditionally duplicate an existing const string
* @s: the string to duplicate
* @gfp: the GFP mask used in the kmalloc() call when allocating memory
*
* Function returns source string if it is in .rodata section otherwise it
* fallbacks to kstrdup.
* Strings allocated by kstrdup_const should be freed by kfree_const.
*/
const char *kstrdup_const(const char *s, gfp_t gfp)
{
if (is_kernel_rodata((unsigned long)s))
return s;
return kstrdup(s, gfp);
}
/**
* kfree_const - conditionally free memory
* @x: pointer to the memory
*
* Function calls kfree only if @x is not in .rodata section.
*/
void kfree_const(const void *x)
{
if (!is_kernel_rodata((unsigned long)x))
kfree(x);
}
/* Boot-time pagetable setup.
* Changes here may need matching changes in head.S */
void __init setup_pagetables(unsigned long boot_phys_offset, paddr_t xen_paddr)
{
unsigned long dest_va;
lpae_t pte, *p;
int i;
/* Map the destination in the boot misc area. */
dest_va = BOOT_MISC_VIRT_START;
pte = mfn_to_xen_entry(xen_paddr >> PAGE_SHIFT);
write_pte(xen_second + second_table_offset(dest_va), pte);
flush_xen_data_tlb_range_va(dest_va, SECOND_SIZE);
/* Calculate virt-to-phys offset for the new location */
phys_offset = xen_paddr - (unsigned long) _start;
/* Copy */
memcpy((void *) dest_va, _start, _end - _start);
/* Beware! Any state we modify between now and the PT switch may be
* discarded when we switch over to the copy. */
/* Update the copy of xen_pgtable to use the new paddrs */
p = (void *) xen_pgtable + dest_va - (unsigned long) _start;
#ifdef CONFIG_ARM_64
p[0].pt.base += (phys_offset - boot_phys_offset) >> PAGE_SHIFT;
p = (void *) xen_first + dest_va - (unsigned long) _start;
#endif
for ( i = 0; i < 4; i++)
p[i].pt.base += (phys_offset - boot_phys_offset) >> PAGE_SHIFT;
p = (void *) xen_second + dest_va - (unsigned long) _start;
if ( boot_phys_offset != 0 )
{
/* Remove the old identity mapping of the boot paddr */
vaddr_t va = (vaddr_t)_start + boot_phys_offset;
p[second_linear_offset(va)].bits = 0;
}
for ( i = 0; i < 4 * LPAE_ENTRIES; i++)
if ( p[i].pt.valid )
p[i].pt.base += (phys_offset - boot_phys_offset) >> PAGE_SHIFT;
/* Change pagetables to the copy in the relocated Xen */
boot_ttbr = (uintptr_t) xen_pgtable + phys_offset;
flush_xen_dcache(boot_ttbr);
flush_xen_dcache_va_range((void*)dest_va, _end - _start);
flush_xen_text_tlb();
WRITE_SYSREG64(boot_ttbr, TTBR0_EL2);
dsb(); /* Ensure visibility of HTTBR update */
flush_xen_text_tlb();
/* Undo the temporary map */
pte.bits = 0;
write_pte(xen_second + second_table_offset(dest_va), pte);
flush_xen_text_tlb();
/* Link in the fixmap pagetable */
pte = mfn_to_xen_entry((((unsigned long) xen_fixmap) + phys_offset)
>> PAGE_SHIFT);
pte.pt.table = 1;
write_pte(xen_second + second_table_offset(FIXMAP_ADDR(0)), pte);
/*
* No flush required here. Individual flushes are done in
* set_fixmap as entries are used.
*/
/* Break up the Xen mapping into 4k pages and protect them separately. */
for ( i = 0; i < LPAE_ENTRIES; i++ )
{
unsigned long mfn = paddr_to_pfn(xen_paddr) + i;
unsigned long va = XEN_VIRT_START + (i << PAGE_SHIFT);
if ( !is_kernel(va) )
break;
pte = mfn_to_xen_entry(mfn);
pte.pt.table = 1; /* 4k mappings always have this bit set */
if ( is_kernel_text(va) || is_kernel_inittext(va) )
{
pte.pt.xn = 0;
pte.pt.ro = 1;
}
if ( is_kernel_rodata(va) )
pte.pt.ro = 1;
write_pte(xen_xenmap + i, pte);
/* No flush required here as page table is not hooked in yet. */
}
pte = mfn_to_xen_entry((((unsigned long) xen_xenmap) + phys_offset)
>> PAGE_SHIFT);
pte.pt.table = 1;
write_pte(xen_second + second_linear_offset(XEN_VIRT_START), pte);
/* TLBFLUSH and ISB would be needed here, but wait until we set WXN */
/* From now on, no mapping may be both writable and executable. */
WRITE_SYSREG32(READ_SYSREG32(SCTLR_EL2) | SCTLR_WXN, SCTLR_EL2);
/* Flush everything after setting WXN bit. */
flush_xen_text_tlb();
}