| Message ID | 20210710142821.4168-1-bmeng.cn@gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [1/2] firmware: Remove the unhelpful alignment codes before fdt relocation | expand |
On Sat, Jul 10, 2021 at 7:58 PM Bin Meng <bmeng.cn@gmail.com> wrote: > > If the device tree is at an address that is not __SIZEOF_POINTER__ > aligned, the fdt relocation code tries to align both source and > destination address to __SIZEOF_POINTER__ before the memory copy. > But such alignment can lead to unexpected results if either source > or destination address is not aligned. > > In fact libfdt requires that the device tree must be at an 8-byte > aligned address. Hence remove the unhelpful alignment codes. > > Signed-off-by: Bin Meng <bmeng.cn@gmail.com> With libfdt checking alignment of FDT address, we certainly don't need any alignment check or adjustment in FDT relocation Reviewed-by: Anup Patel <anup.patel@wdc.com> Applied this patch to the riscv/opensbi repo. Thanks, Anup > --- > > firmware/fw_base.S | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/firmware/fw_base.S b/firmware/fw_base.S > index 8e40562..abf21cd 100644 > --- a/firmware/fw_base.S > +++ b/firmware/fw_base.S > @@ -349,8 +349,7 @@ _scratch_init: > * previous booting stage. > */ > beqz a1, _fdt_reloc_done > - /* Mask values in a3 and a4 */ > - li a3, ~(__SIZEOF_POINTER__ - 1) > + /* Mask values in a4 */ > li a4, 0xff > /* t1 = destination FDT start address */ > MOV_3R s0, a0, s1, a1, s2, a2 > @@ -359,10 +358,8 @@ _scratch_init: > MOV_3R a0, s0, a1, s1, a2, s2 > beqz t1, _fdt_reloc_done > beq t1, a1, _fdt_reloc_done > - and t1, t1, a3 > /* t0 = source FDT start address */ > add t0, a1, zero > - and t0, t0, a3 > /* t2 = source FDT size in big-endian */ > #if __riscv_xlen == 64 > lwu t2, 4(t0) > -- > 2.25.1 > > > -- > opensbi mailing list > opensbi@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/opensbi
diff --git a/firmware/fw_base.S b/firmware/fw_base.S index 8e40562..abf21cd 100644 --- a/firmware/fw_base.S +++ b/firmware/fw_base.S @@ -349,8 +349,7 @@ _scratch_init: * previous booting stage. */ beqz a1, _fdt_reloc_done - /* Mask values in a3 and a4 */ - li a3, ~(__SIZEOF_POINTER__ - 1) + /* Mask values in a4 */ li a4, 0xff /* t1 = destination FDT start address */ MOV_3R s0, a0, s1, a1, s2, a2 @@ -359,10 +358,8 @@ _scratch_init: MOV_3R a0, s0, a1, s1, a2, s2 beqz t1, _fdt_reloc_done beq t1, a1, _fdt_reloc_done - and t1, t1, a3 /* t0 = source FDT start address */ add t0, a1, zero - and t0, t0, a3 /* t2 = source FDT size in big-endian */ #if __riscv_xlen == 64 lwu t2, 4(t0)
If the device tree is at an address that is not __SIZEOF_POINTER__ aligned, the fdt relocation code tries to align both source and destination address to __SIZEOF_POINTER__ before the memory copy. But such alignment can lead to unexpected results if either source or destination address is not aligned. In fact libfdt requires that the device tree must be at an 8-byte aligned address. Hence remove the unhelpful alignment codes. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> --- firmware/fw_base.S | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)