Some hardware that is supported by U-Boot can not handle DMA above 32bits. For these systems, we need to come up with a way to expose the disk interface in a safe way.
This patch implements EFI specific bounce buffers. For non-EFI cases, this apparently was no issue so far, since we can just define our environment variables conveniently.
Signed-off-by: Alexander Graf agraf@suse.de --- include/efi_loader.h | 5 ++++ lib/efi_loader/Kconfig | 9 ++++++ lib/efi_loader/efi_disk.c | 70 +++++++++++++++++++++++++++++++++++++++------ lib/efi_loader/efi_memory.c | 16 +++++++++++ 4 files changed, 91 insertions(+), 9 deletions(-)
diff --git a/include/efi_loader.h b/include/efi_loader.h index 8005454..b1ca4ba 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -139,6 +139,11 @@ uint64_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type, /* Called by board init to initialize the EFI memory map */ int efi_memory_init(void);
+#ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER +extern void *efi_bounce_buffer; +#define EFI_LOADER_BOUNCE_BUFFER_SIZE (64 * 1024 * 1024) +#endif + /* Convert strings from normal C strings to uEFI strings */ static inline void ascii2unicode(u16 *unicode, char *ascii) { diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig index 14c99ec..37a0dd6 100644 --- a/lib/efi_loader/Kconfig +++ b/lib/efi_loader/Kconfig @@ -7,3 +7,12 @@ config EFI_LOADER on top of U-Boot. If this option is enabled, U-Boot will expose EFI interfaces to a loaded EFI application, enabling it to reuse U-Boot's device drivers. + +config EFI_LOADER_BOUNCE_BUFFER + bool "EFI Applications use bounce buffers for DMA operations" + depends on EFI_LOADER && ARM64 + default n + help + Some hardware does not support DMA to full 64bit addresses. For this + hardware we can create a bounce buffer so that payloads don't have to + worry about platform details. diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c index 28e5b7f..ffce286 100644 --- a/lib/efi_loader/efi_disk.c +++ b/lib/efi_loader/efi_disk.c @@ -75,9 +75,6 @@ static efi_status_t EFIAPI efi_disk_rw_blocks(struct efi_block_io *this, int blocks; unsigned long n;
- EFI_ENTRY("%p, %x, %"PRIx64", %lx, %p", this, media_id, lba, - buffer_size, buffer); - diskobj = container_of(this, struct efi_disk_obj, ops); if (!(desc = blk_get_dev(diskobj->ifname, diskobj->dev_index))) return EFI_EXIT(EFI_DEVICE_ERROR); @@ -94,10 +91,11 @@ static efi_status_t EFIAPI efi_disk_rw_blocks(struct efi_block_io *this, if (buffer_size & (blksz - 1)) return EFI_EXIT(EFI_DEVICE_ERROR);
- if (direction == EFI_DISK_READ) + if (direction == EFI_DISK_READ) { n = desc->block_read(desc, lba, blocks, buffer); - else + } else { n = desc->block_write(desc, lba, blocks, buffer); + }
/* We don't do interrupts, so check for timers cooperatively */ efi_timer_check(); @@ -115,16 +113,70 @@ static efi_status_t efi_disk_read_blocks(struct efi_block_io *this, u32 media_id, u64 lba, unsigned long buffer_size, void *buffer) { - return efi_disk_rw_blocks(this, media_id, lba, buffer_size, buffer, - EFI_DISK_READ); + void *real_buffer = buffer; + efi_status_t r; + +#ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER + if (buffer_size > EFI_LOADER_BOUNCE_BUFFER_SIZE) { + r = efi_disk_read_blocks(this, media_id, lba, + EFI_LOADER_BOUNCE_BUFFER_SIZE, buffer); + if (r != EFI_SUCCESS) + return r; + return efi_disk_read_blocks(this, media_id, lba + + EFI_LOADER_BOUNCE_BUFFER_SIZE / this->media->block_size, + buffer_size - EFI_LOADER_BOUNCE_BUFFER_SIZE, + buffer + EFI_LOADER_BOUNCE_BUFFER_SIZE); + } + + real_buffer = efi_bounce_buffer; +#endif + + EFI_ENTRY("%p, %x, %"PRIx64", %lx, %p", this, media_id, lba, + buffer_size, buffer); + + r = efi_disk_rw_blocks(this, media_id, lba, buffer_size, real_buffer, + EFI_DISK_READ); + + /* Copy from bounce buffer to real buffer if necessary */ + if ((r == EFI_SUCCESS) && (real_buffer != buffer)) + memcpy(buffer, real_buffer, buffer_size); + + return EFI_EXIT(r); }
static efi_status_t efi_disk_write_blocks(struct efi_block_io *this, u32 media_id, u64 lba, unsigned long buffer_size, void *buffer) { - return efi_disk_rw_blocks(this, media_id, lba, buffer_size, buffer, - EFI_DISK_WRITE); + void *real_buffer = buffer; + efi_status_t r; + +#ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER + if (buffer_size > EFI_LOADER_BOUNCE_BUFFER_SIZE) { + r = efi_disk_write_blocks(this, media_id, lba, + EFI_LOADER_BOUNCE_BUFFER_SIZE, buffer); + if (r != EFI_SUCCESS) + return r; + return efi_disk_write_blocks(this, media_id, lba + + EFI_LOADER_BOUNCE_BUFFER_SIZE / this->media->block_size, + buffer_size - EFI_LOADER_BOUNCE_BUFFER_SIZE, + buffer + EFI_LOADER_BOUNCE_BUFFER_SIZE); + } + + real_buffer = efi_bounce_buffer; +#endif + + EFI_ENTRY("%p, %x, %"PRIx64", %lx, %p", this, media_id, lba, + buffer_size, buffer); + + /* Populate bounce buffer if necessary */ + if (real_buffer != buffer) + memcpy(real_buffer, buffer, buffer_size); + + r = efi_disk_rw_blocks(this, media_id, lba, buffer_size, real_buffer, + EFI_DISK_WRITE); + + return EFI_EXIT(r); }
static efi_status_t EFIAPI efi_disk_flush_blocks(struct efi_block_io *this) diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c index 71a3d19..9e669f5 100644 --- a/lib/efi_loader/efi_memory.c +++ b/lib/efi_loader/efi_memory.c @@ -27,6 +27,10 @@ struct efi_mem_list { /* This list contains all memory map items */ LIST_HEAD(efi_mem);
+#ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER +void *efi_bounce_buffer; +#endif + /* * Sorts the memory list from highest address to lowest address * @@ -349,5 +353,17 @@ int efi_memory_init(void) efi_add_memory_map(runtime_start, runtime_pages, EFI_RUNTIME_SERVICES_CODE, false);
+#ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER + /* Request a 32bit 64MB bounce buffer region */ + uint64_t efi_bounce_buffer_addr = 0xffffffff; + + if (efi_allocate_pages(1, EFI_LOADER_DATA, + (64 * 1024 * 1024) >> EFI_PAGE_SHIFT, + &efi_bounce_buffer_addr) != EFI_SUCCESS) + return -1; + + efi_bounce_buffer = (void*)(uintptr_t)efi_bounce_buffer_addr; +#endif + return 0; }