[U-Boot] [PATCH v2 2/3] spl: add relocation support【请注意，邮件由sjg at google.com代发】

[Andre Przywara]

On Mon, 20 May 2019 14:34:01 +0800
Andy Yan <andy.yan at rock-chips.com> wrote:

Hi,

> On 2019/5/19 上午12:26, Simon Glass wrote:
> > Hi Andy,
> >
> > Instead of this could you:
> >
> > - move ATF?  
> 
> All rockchip based arm64 ATF run from the start 64KB of dram as this 
> will give convenient for kernel manage the memory.

This is just BL31 of ATF, right?
ATF recently gained PIE support for BL31 [1], so by just enabling this in platform.mk you will get a relocatable BL31 image, with a very minimal runtime linker. Worked out of the box on Allwinner for me, but YMMV.
So you could load newer ATF builds everywhere.

Does that help you?

> On the other hand, change the ATF load address will break the 
> compatibility of the exiting firmware.

I am not sure what you mean with "compatibility of existing firmware"? Surely you combine all the firmware components (SPL/TPL/ATF/U-Boot proper) into one image? And there would be no real mix and match, with older pre-compiled builds? So by changing the ATF base address and the load address in TPL at the same time you won't have issues?

Cheers,
Andre.

[1] https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/commit/?id=fc922ca87cc6af8277dc0eb710fc63a2957f0194

> > - change the SPL load address so it is not in the way (since TPL can
> > load to any address)  
> 
> The SPL is loaded by bootrom after TPL back to bootrom, so the load 
> address if fixed by bootrom code.
> 
> I know we can build mmc or other storage driver into TPL so we can use 
> tpl load spl on some platform that sram is big enough, but there are 
> also many rockchip soc has very small sram, so we tend to only do dram  
> initialization in tpl, and let bootrom load next stage .
> 
> > - (in extremis) create a function which does a memmove() and a jump,
> > copy it somewhere and run it (I think x86 does this)
> >
> > Regards,
> > Simon
> >
> > On Thu, 16 May 2019 at 06:22, Andy Yan <andy.yan at rock-chips.com> wrote:  
> >> Some times we want to relocate spl code to dram after dram
> >> initialization or relocate spl code to a high memory to avoid
> >> code overid.
> >>
> >> For example on Rockchip armv8 platform, we run with boot flow
> >> TPL->SPL->ATF->U-Boot.
> >> TPL run in sram and is responsible for dram initialization.
> >> SPL run from the start address of dram and is responsible for
> >> loading ATF and U-Boot.
> >>
> >> The case here is that the ATF load address is from 64KB of dram,
> >> which overlaps with spl code itself.
> >>
> >> So we want to relocate spl itself to high memory to aovid this.
> >>
> >> Signed-off-by: Andy Yan <andy.yan at rock-chips.com>
> >> ---
> >>
> >> Changes in v2:
> >> - Move Kconfig modification to PATCH 1/3
> >>
> >>   common/spl/spl.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++
> >>   1 file changed, 55 insertions(+)
> >>
> >> diff --git a/common/spl/spl.c b/common/spl/spl.c
> >> index 88d4b8a9bf..affb65ccbd 100644
> >> --- a/common/spl/spl.c
> >> +++ b/common/spl/spl.c
> >> @@ -12,6 +12,7 @@
> >>   #include <dm.h>
> >>   #include <handoff.h>
> >>   #include <spl.h>
> >> +#include <asm/sections.h>
> >>   #include <asm/u-boot.h>
> >>   #include <nand.h>
> >>   #include <fat.h>
> >> @@ -439,6 +440,28 @@ static int spl_common_init(bool setup_malloc)
> >>          return 0;
> >>   }
> >>
> >> +#if !defined(CONFIG_SPL_SKIP_RELOCATE) && !defined(CONFIG_TPL_BUILD)
> >> +static void spl_setup_relocate(void)
> >> +{
> >> +       gd->relocaddr = CONFIG_SPL_RELOC_TEXT_BASE;
> >> +       gd->new_gd = (gd_t *)gd;
> >> +       gd->start_addr_sp = gd->relocaddr;
> >> +       gd->fdt_size = ALIGN(fdt_totalsize(gd->fdt_blob) + 0x1000, 32);
> >> +
> >> +       gd->start_addr_sp -= gd->fdt_size;
> >> +       gd->new_fdt = (void *)gd->start_addr_sp;
> >> +       memcpy(gd->new_fdt, gd->fdt_blob, gd->fdt_size);
> >> +       gd->fdt_blob = gd->new_fdt;
> >> +
> >> +       gd->reloc_off = gd->relocaddr - (unsigned long)__image_copy_start;
> >> +}
> >> +#else
> >> +static void spl_setup_relocate(void)
> >> +{
> >> +
> >> +}
> >> +#endif
> >> +
> >>   void spl_set_bd(void)
> >>   {
> >>          /*
> >> @@ -460,6 +483,8 @@ int spl_early_init(void)
> >>                  return ret;
> >>          gd->flags |= GD_FLG_SPL_EARLY_INIT;
> >>
> >> +       spl_setup_relocate();
> >> +
> >>          return 0;
> >>   }
> >>
> >> @@ -563,6 +588,34 @@ static int boot_from_devices(struct spl_image_info *spl_image,
> >>          return -ENODEV;
> >>   }
> >>
> >> +#if defined(CONFIG_DM) && !defined(CONFIG_SPL_SKIP_RELOCATE) && !defined(CONFIG_TPL_BUILD)
> >> +static int spl_initr_dm(void)
> >> +{
> >> +       int ret;
> >> +
> >> +       /* Save the pre-reloc driver model and start a new one */
> >> +       gd->dm_root_f = gd->dm_root;
> >> +       gd->dm_root = NULL;
> >> +       bootstage_start(BOOTSTATE_ID_ACCUM_DM_R, "dm_r");
> >> +       ret = dm_init_and_scan(false);
> >> +       bootstage_accum(BOOTSTATE_ID_ACCUM_DM_R);
> >> +       if (ret)
> >> +               return ret;
> >> +
> >> +#if defined(CONFIG_TIMER)
> >> +       gd->timer = NULL;
> >> +#endif
> >> +       serial_init();
> >> +
> >> +       return 0;
> >> +}
> >> +#else
> >> +static int spl_initr_dm(void)
> >> +{
> >> +       return 0;
> >> +}
> >> +#endif
> >> +
> >>   void board_init_r(gd_t *dummy1, ulong dummy2)
> >>   {
> >>          u32 spl_boot_list[] = {
> >> @@ -577,6 +630,8 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
> >>  
> >>          debug(">>" SPL_TPL_PROMPT "board_init_r()\n");  
> >>
> >> +       spl_initr_dm();
> >> +
> >>          spl_set_bd();
> >>
> >>   #if defined(CONFIG_SYS_SPL_MALLOC_START)
> >> --
> >> 2.17.1
> >>
> >>
> >>  
> >
> >  
> 
>