sandbox: Enhance map_to_sysmem() to handle foreign pointers

At present map_sysmem() maps an address into the sandbox RAM buffer,
return a pointer, while map_to_sysmem() goes the other way.

The mapping is currently just 1:1 since a case was not found where a more
flexible mapping was needed. PCI does have a separate and more complex
mapping, but uses its own mechanism.

However this arrange cannot handle one important case, which is where a
test declares a stack variable and passes a pointer to it into a U-Boot
function which uses map_to_sysmem() to turn it into a address. Since the
pointer is not inside emulated DRAM, this will fail.

Add a mapping feature which can handle any such pointer, mapping it to a
simple tag value which can be passed around in U-Boot as an address.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Simon Glass 2018-09-15 00:50:56 -06:00 committed by Alexander Graf
parent fe938fb0df
commit 428aa0ca56
3 changed files with 163 additions and 11 deletions

View File

@ -57,14 +57,104 @@ int cleanup_before_linux_select(int flags)
return 0;
}
void *phys_to_virt(phys_addr_t paddr)
/**
* is_in_sandbox_mem() - Checks if a pointer is within sandbox's emulated DRAM
*
* This provides a way to check if a pointer is owned by sandbox (and is within
* its RAM) or not. Sometimes pointers come from a test which conceptually runs
* output sandbox, potentially with direct access to the C-library malloc()
* function, or the sandbox stack (which is not actually within the emulated
* DRAM.
*
* Such pointers obviously cannot be mapped into sandbox's DRAM, so we must
* detect them an process them separately, by recording a mapping to a tag,
* which we can use to map back to the pointer later.
*
* @ptr: Pointer to check
* @return true if this is within sandbox emulated DRAM, false if not
*/
static bool is_in_sandbox_mem(const void *ptr)
{
return (void *)(gd->arch.ram_buf + paddr);
return (const uint8_t *)ptr >= gd->arch.ram_buf &&
(const uint8_t *)ptr < gd->arch.ram_buf + gd->ram_size;
}
phys_addr_t virt_to_phys(void *vaddr)
/**
* phys_to_virt() - Converts a sandbox RAM address to a pointer
*
* Sandbox uses U-Boot addresses from 0 to the size of DRAM. These index into
* the emulated DRAM buffer used by sandbox. This function converts such an
* address to a pointer into this buffer, which can be used to access the
* memory.
*
* If the address is outside this range, it is assumed to be a tag
*/
void *phys_to_virt(phys_addr_t paddr)
{
return (phys_addr_t)((uint8_t *)vaddr - gd->arch.ram_buf);
struct sandbox_mapmem_entry *mentry;
struct sandbox_state *state;
/* If the address is within emulated DRAM, calculate the value */
if (paddr < gd->ram_size)
return (void *)(gd->arch.ram_buf + paddr);
/*
* Otherwise search out list of tags for the correct pointer previously
* created by map_to_sysmem()
*/
state = state_get_current();
list_for_each_entry(mentry, &state->mapmem_head, sibling_node) {
if (mentry->tag == paddr) {
printf("%s: Used map from %lx to %p\n", __func__,
(ulong)paddr, mentry->ptr);
return mentry->ptr;
}
}
printf("%s: Cannot map sandbox address %lx (SDRAM from 0 to %lx)\n",
__func__, (ulong)paddr, (ulong)gd->ram_size);
os_abort();
/* Not reached */
return NULL;
}
struct sandbox_mapmem_entry *find_tag(const void *ptr)
{
struct sandbox_mapmem_entry *mentry;
struct sandbox_state *state = state_get_current();
list_for_each_entry(mentry, &state->mapmem_head, sibling_node) {
if (mentry->ptr == ptr) {
debug("%s: Used map from %p to %lx\n", __func__, ptr,
mentry->tag);
return mentry;
}
}
return NULL;
}
phys_addr_t virt_to_phys(void *ptr)
{
struct sandbox_mapmem_entry *mentry;
/*
* If it is in emulated RAM, don't bother looking for a tag. Just
* calculate the pointer using the provides offset into the RAM buffer.
*/
if (is_in_sandbox_mem(ptr))
return (phys_addr_t)((uint8_t *)ptr - gd->arch.ram_buf);
mentry = find_tag(ptr);
if (!mentry) {
/* Abort so that gdb can be used here */
printf("%s: Cannot map sandbox address %p (SDRAM from 0 to %lx)\n",
__func__, ptr, (ulong)gd->ram_size);
os_abort();
}
printf("%s: Used map from %p to %lx\n", __func__, ptr, mentry->tag);
return mentry->tag;
}
void *map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
@ -87,26 +177,59 @@ void *map_physmem(phys_addr_t paddr, unsigned long len, unsigned long flags)
return phys_to_virt(paddr);
}
void unmap_physmem(const void *vaddr, unsigned long flags)
void unmap_physmem(const void *ptr, unsigned long flags)
{
#ifdef CONFIG_PCI
if (map_dev) {
pci_unmap_physmem(vaddr, map_len, map_dev);
pci_unmap_physmem(ptr, map_len, map_dev);
map_dev = NULL;
}
#endif
}
phys_addr_t map_to_sysmem(const void *ptr)
{
struct sandbox_mapmem_entry *mentry;
/*
* If it is in emulated RAM, don't bother creating a tag. Just return
* the offset into the RAM buffer.
*/
if (is_in_sandbox_mem(ptr))
return (u8 *)ptr - gd->arch.ram_buf;
/*
* See if there is an existing tag with this pointer. If not, set up a
* new one.
*/
mentry = find_tag(ptr);
if (!mentry) {
struct sandbox_state *state = state_get_current();
mentry = malloc(sizeof(*mentry));
if (!mentry) {
printf("%s: Error: Out of memory\n", __func__);
os_exit(ENOMEM);
}
mentry->tag = state->next_tag++;
mentry->ptr = (void *)ptr;
list_add_tail(&mentry->sibling_node, &state->mapmem_head);
debug("%s: Added map from %p to %lx\n", __func__, ptr,
(ulong)mentry->tag);
}
/*
* Return the tag as the address to use. A later call to map_sysmem()
* will return ptr
*/
return mentry->tag;
}
void sandbox_set_enable_pci_map(int enable)
{
enable_pci_map = enable;
}
phys_addr_t map_to_sysmem(const void *ptr)
{
return (u8 *)ptr - gd->arch.ram_buf;
}
void flush_dcache_range(unsigned long start, unsigned long stop)
{
}

View File

@ -359,6 +359,14 @@ void state_reset_for_test(struct sandbox_state *state)
memset(&state->wdt, '\0', sizeof(state->wdt));
memset(state->spi, '\0', sizeof(state->spi));
/*
* Set up the memory tag list. Use the top of emulated SDRAM for the
* first tag number, since that address offset is outside the legal
* range, and can be assumed to be a tag.
*/
INIT_LIST_HEAD(&state->mapmem_head);
state->next_tag = state->ram_size;
}
int state_init(void)

View File

@ -9,6 +9,7 @@
#include <config.h>
#include <sysreset.h>
#include <stdbool.h>
#include <linux/list.h>
#include <linux/stringify.h>
/**
@ -45,6 +46,23 @@ struct sandbox_wdt_info {
bool running;
};
/**
* struct sandbox_mapmem_entry - maps pointers to/from U-Boot addresses
*
* When map_to_sysmem() is called with an address outside sandbox's emulated
* RAM, a record is created with a tag that can be used to reference that
* pointer. When map_sysmem() is called later with that tag, the pointer will
* be returned, just as it would for a normal sandbox address.
*
* @tag: Address tag (a value which U-Boot uses to refer to the address)
* @ptr: Associated pointer for that tag
*/
struct sandbox_mapmem_entry {
ulong tag;
void *ptr;
struct list_head sibling_node;
};
/* The complete state of the test system */
struct sandbox_state {
const char *cmd; /* Command to execute */
@ -78,6 +96,9 @@ struct sandbox_state {
/* Information about Watchdog */
struct sandbox_wdt_info wdt;
ulong next_tag; /* Next address tag to allocate */
struct list_head mapmem_head; /* struct sandbox_mapmem_entry */
};
/* Minimum space we guarantee in the state FDT when calling read/write*/