[U-Boot] [PATCH v5 09/10] sandbox: Enhance map_to_sysmem() to handle foreign pointers
Alexander Graf
agraf at suse.de
Fri Jun 22 12:44:17 UTC 2018
From: Simon Glass <sjg at chromium.org>
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 at chromium.org>
Signed-off-by: Alexander Graf <agraf at suse.de>
---
arch/sandbox/cpu/cpu.c | 141 ++++++++++++++++++++++++++++++++++++---
arch/sandbox/cpu/state.c | 8 +++
arch/sandbox/include/asm/state.h | 21 ++++++
3 files changed, 161 insertions(+), 9 deletions(-)
diff --git a/arch/sandbox/cpu/cpu.c b/arch/sandbox/cpu/cpu.c
index e7d3c272a4..456cfa3faa 100644
--- a/arch/sandbox/cpu/cpu.c
+++ b/arch/sandbox/cpu/cpu.c
@@ -57,14 +57,104 @@ int cleanup_before_linux_select(int flags)
return 0;
}
+/**
+ * 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 (const uint8_t *)ptr >= gd->arch.ram_buf &&
+ (const uint8_t *)ptr < gd->arch.ram_buf + gd->ram_size;
+}
+
+/**
+ * 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 thi sbuffer, 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 (void *)(gd->arch.ram_buf + paddr);
+ 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 *vaddr)
+phys_addr_t virt_to_phys(void *ptr)
{
- return (phys_addr_t)((uint8_t *)vaddr - gd->arch.ram_buf);
+ 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)
@@ -87,24 +177,57 @@ 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
}
-void sandbox_set_enable_pci_map(int enable)
+phys_addr_t map_to_sysmem(const void *ptr)
{
- enable_pci_map = enable;
+ 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;
}
-phys_addr_t map_to_sysmem(const void *ptr)
+void sandbox_set_enable_pci_map(int enable)
{
- return (u8 *)ptr - gd->arch.ram_buf;
+ enable_pci_map = enable;
}
void flush_dcache_range(unsigned long start, unsigned long stop)
diff --git a/arch/sandbox/cpu/state.c b/arch/sandbox/cpu/state.c
index cc50819ab9..04a11fed55 100644
--- a/arch/sandbox/cpu/state.c
+++ b/arch/sandbox/cpu/state.c
@@ -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)
diff --git a/arch/sandbox/include/asm/state.h b/arch/sandbox/include/asm/state.h
index 7ed4b512d2..a612ce8944 100644
--- a/arch/sandbox/include/asm/state.h
+++ b/arch/sandbox/include/asm/state.h
@@ -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*/
--
2.12.3
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