[PATCH v2 2/3] sandbox: align LMB memory

[Ilias Apalodimas]

On Sun, 8 Jun 2025 at 10:54, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> To implement the EFI_SYSTEM_TABLE_POINTER we need 4 MiB aligned
> memory.
>
> On the sandbox LMB uses addresses relative to the start of a page aligned
> RAM buffer allocated with mmap(). This leads to a mismatch of alignment
> between EFI which uses pointers and LMB which uses phys_addr_t.
>
> Ensure that the RAM buffer used for LMB is 4 MiB aligned.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>

Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>

> ---
> v2:
>         rename define CFG_SYS_SDRAM_ALIGN to SB_SDRAM_ALIGN
> ---
>  arch/sandbox/cpu/state.c         | 6 ++++--
>  arch/sandbox/include/asm/state.h | 1 +
>  include/configs/sandbox.h        | 2 ++
>  3 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/arch/sandbox/cpu/state.c b/arch/sandbox/cpu/state.c
> index 49236db99c2..6a15c8b0a18 100644
> --- a/arch/sandbox/cpu/state.c
> +++ b/arch/sandbox/cpu/state.c
> @@ -480,7 +480,9 @@ int state_init(void)
>         state = &main_state;
>
>         state->ram_size = CFG_SYS_SDRAM_SIZE;
> -       state->ram_buf = os_malloc(state->ram_size);
> +       state->mmap_addr = os_malloc(state->ram_size + SB_SDRAM_ALIGN);
> +       state->ram_buf = (uint8_t *)ALIGN((uintptr_t)state->mmap_addr,
> +                                         SB_SDRAM_ALIGN);
>         if (!state->ram_buf) {
>                 printf("Out of memory\n");
>                 os_exit(1);
> @@ -533,7 +535,7 @@ int state_uninit(void)
>                 trace_set_enabled(0);
>
>         os_free(state->state_fdt);
> -       os_free(state->ram_buf);
> +       os_free(state->mmap_addr);
>         memset(state, '\0', sizeof(*state));
>
>         return 0;
> diff --git a/arch/sandbox/include/asm/state.h b/arch/sandbox/include/asm/state.h
> index dc21a623106..9dea0980bfc 100644
> --- a/arch/sandbox/include/asm/state.h
> +++ b/arch/sandbox/include/asm/state.h
> @@ -75,6 +75,7 @@ struct sandbox_state {
>         char **argv;                    /* Command line arguments */
>         const char *jumped_fname;       /* Jumped from previous U-Boot */
>         const char *prog_fname;         /* U-Boot executable filename */
> +       uint8_t *mmap_addr;             /* Memory allocated via mmap */
>         uint8_t *ram_buf;               /* Emulated RAM buffer */
>         unsigned long ram_size;         /* Size of RAM buffer */
>         const char *ram_buf_fname;      /* Filename to use for RAM buffer */
> diff --git a/include/configs/sandbox.h b/include/configs/sandbox.h
> index db2ac7f83bb..44d4960d487 100644
> --- a/include/configs/sandbox.h
> +++ b/include/configs/sandbox.h
> @@ -14,6 +14,8 @@
>  #define CFG_SYS_SDRAM_BASE             0
>  #define CFG_SYS_SDRAM_SIZE \
>                 (SB_TO_UL(CONFIG_SANDBOX_RAM_SIZE_MB) << 20)
> +/** define SB_SDRAM_ALIGN - Alignment of emulated RAM */
> +#define SB_SDRAM_ALIGN                 0x400000
>
>  #define CFG_SYS_BAUDRATE_TABLE {4800, 9600, 19200, 38400, 57600,\
>                                         115200}
> --
> 2.48.1
>