u-boot/arch/arm/lib/cache-cp15.c
Marek Vasut 221a49d5bd ARM: Fix overflow in MMU setup
The patch fixes a corner case where adding size to DRAM start resulted
in a value (1 << 32), which in turn overflew the u32 computation, which
resulted in 0 and it therefore prevented correct setup of the MMU tables.

The addition of DRAM bank start and it's size can end up right at the end
of the address space in the special case of a machine with enough memory.
To prevent this overflow, shift the start and size separately and add them
only after they were shifted.

Hopefully, we only have systems in tree which have DRAM size aligned to
1MiB boundary. If not, this patch would break such systems. On the other
hand, such system would be broken by design anyway.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
2014-08-30 07:46:39 -04:00

215 lines
4 KiB
C

/*
* (C) Copyright 2002
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/system.h>
#include <asm/cache.h>
#include <linux/compiler.h>
#if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
DECLARE_GLOBAL_DATA_PTR;
__weak void arm_init_before_mmu(void)
{
}
__weak void arm_init_domains(void)
{
}
static void cp_delay (void)
{
volatile int i;
/* copro seems to need some delay between reading and writing */
for (i = 0; i < 100; i++)
nop();
asm volatile("" : : : "memory");
}
void set_section_dcache(int section, enum dcache_option option)
{
u32 *page_table = (u32 *)gd->arch.tlb_addr;
u32 value;
value = (section << MMU_SECTION_SHIFT) | (3 << 10);
value |= option;
page_table[section] = value;
}
__weak void mmu_page_table_flush(unsigned long start, unsigned long stop)
{
debug("%s: Warning: not implemented\n", __func__);
}
void mmu_set_region_dcache_behaviour(u32 start, int size,
enum dcache_option option)
{
u32 *page_table = (u32 *)gd->arch.tlb_addr;
u32 upto, end;
end = ALIGN(start + size, MMU_SECTION_SIZE) >> MMU_SECTION_SHIFT;
start = start >> MMU_SECTION_SHIFT;
debug("%s: start=%x, size=%x, option=%d\n", __func__, start, size,
option);
for (upto = start; upto < end; upto++)
set_section_dcache(upto, option);
mmu_page_table_flush((u32)&page_table[start], (u32)&page_table[end]);
}
__weak void dram_bank_mmu_setup(int bank)
{
bd_t *bd = gd->bd;
int i;
debug("%s: bank: %d\n", __func__, bank);
for (i = bd->bi_dram[bank].start >> 20;
i < (bd->bi_dram[bank].start >> 20) + (bd->bi_dram[bank].size >> 20);
i++) {
#if defined(CONFIG_SYS_ARM_CACHE_WRITETHROUGH)
set_section_dcache(i, DCACHE_WRITETHROUGH);
#else
set_section_dcache(i, DCACHE_WRITEBACK);
#endif
}
}
/* to activate the MMU we need to set up virtual memory: use 1M areas */
static inline void mmu_setup(void)
{
int i;
u32 reg;
arm_init_before_mmu();
/* Set up an identity-mapping for all 4GB, rw for everyone */
for (i = 0; i < 4096; i++)
set_section_dcache(i, DCACHE_OFF);
for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
dram_bank_mmu_setup(i);
}
/* Copy the page table address to cp15 */
asm volatile("mcr p15, 0, %0, c2, c0, 0"
: : "r" (gd->arch.tlb_addr) : "memory");
/* Set the access control to all-supervisor */
asm volatile("mcr p15, 0, %0, c3, c0, 0"
: : "r" (~0));
arm_init_domains();
/* and enable the mmu */
reg = get_cr(); /* get control reg. */
cp_delay();
set_cr(reg | CR_M);
}
static int mmu_enabled(void)
{
return get_cr() & CR_M;
}
/* cache_bit must be either CR_I or CR_C */
static void cache_enable(uint32_t cache_bit)
{
uint32_t reg;
/* The data cache is not active unless the mmu is enabled too */
if ((cache_bit == CR_C) && !mmu_enabled())
mmu_setup();
reg = get_cr(); /* get control reg. */
cp_delay();
set_cr(reg | cache_bit);
}
/* cache_bit must be either CR_I or CR_C */
static void cache_disable(uint32_t cache_bit)
{
uint32_t reg;
reg = get_cr();
cp_delay();
if (cache_bit == CR_C) {
/* if cache isn;t enabled no need to disable */
if ((reg & CR_C) != CR_C)
return;
/* if disabling data cache, disable mmu too */
cache_bit |= CR_M;
}
reg = get_cr();
cp_delay();
if (cache_bit == (CR_C | CR_M))
flush_dcache_all();
set_cr(reg & ~cache_bit);
}
#endif
#ifdef CONFIG_SYS_ICACHE_OFF
void icache_enable (void)
{
return;
}
void icache_disable (void)
{
return;
}
int icache_status (void)
{
return 0; /* always off */
}
#else
void icache_enable(void)
{
cache_enable(CR_I);
}
void icache_disable(void)
{
cache_disable(CR_I);
}
int icache_status(void)
{
return (get_cr() & CR_I) != 0;
}
#endif
#ifdef CONFIG_SYS_DCACHE_OFF
void dcache_enable (void)
{
return;
}
void dcache_disable (void)
{
return;
}
int dcache_status (void)
{
return 0; /* always off */
}
#else
void dcache_enable(void)
{
cache_enable(CR_C);
}
void dcache_disable(void)
{
cache_disable(CR_C);
}
int dcache_status(void)
{
return (get_cr() & CR_C) != 0;
}
#endif