linux/arch/powerpc/mm/ioremap_64.c
Christophe Leroy 57307f1b6e powerpc/mm: Leave a gap between early allocated IO areas
Vmalloc system leaves a gap between allocated areas. It helps catching
overflows.

Do the same for IO areas which are allocated with early_ioremap_range()
until slab_is_available().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c433e358190fb5d47650463ea1ab755fc7b73e6e.1618828806.git.christophe.leroy@csgroup.eu
2021-06-25 00:07:10 +10:00

66 lines
1.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
void __iomem *__ioremap_caller(phys_addr_t addr, unsigned long size,
pgprot_t prot, void *caller)
{
phys_addr_t paligned, offset;
void __iomem *ret;
int err;
/* We don't support the 4K PFN hack with ioremap */
if (pgprot_val(prot) & H_PAGE_4K_PFN)
return NULL;
/*
* Choose an address to map it to. Once the vmalloc system is running,
* we use it. Before that, we map using addresses going up from
* ioremap_bot. vmalloc will use the addresses from IOREMAP_BASE
* through ioremap_bot.
*/
paligned = addr & PAGE_MASK;
offset = addr & ~PAGE_MASK;
size = PAGE_ALIGN(addr + size) - paligned;
if (size == 0 || paligned == 0)
return NULL;
if (slab_is_available())
return do_ioremap(paligned, offset, size, prot, caller);
pr_warn("ioremap() called early from %pS. Use early_ioremap() instead\n", caller);
err = early_ioremap_range(ioremap_bot, paligned, size, prot);
if (err)
return NULL;
ret = (void __iomem *)ioremap_bot + offset;
ioremap_bot += size + PAGE_SIZE;
return ret;
}
/*
* Unmap an IO region and remove it from vmalloc'd list.
* Access to IO memory should be serialized by driver.
*/
void iounmap(volatile void __iomem *token)
{
void *addr;
if (!slab_is_available())
return;
addr = (void *)((unsigned long __force)PCI_FIX_ADDR(token) & PAGE_MASK);
if ((unsigned long)addr < ioremap_bot) {
pr_warn("Attempt to iounmap early bolted mapping at 0x%p\n", addr);
return;
}
vunmap(addr);
}
EXPORT_SYMBOL(iounmap);