On 13.10.22 11:03, Ahmad Fatoum wrote:
> We observed on ARM miscompilation because get_runtime_offset() was
> cached before relocation, while address computation of symbol happened
> after, effectively adding the base address twice to the symbol offset.
>
> New get_unrelocated() hides origin of the symbol going into the address
> calculation and thereby thwarts this optimization. Employ it in RISC-V
> code as well to avoid such issues as experienced on ARM.
>
> Signed-off-by: Ahmad Fatoum <[email protected]>
> ---
> arch/riscv/boot/uncompress.c | 4 ++--
> arch/riscv/include/asm/sections.h | 2 +-
> arch/riscv/lib/reloc.c | 6 +++---
> 3 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/riscv/boot/uncompress.c b/arch/riscv/boot/uncompress.c
> index ee24f81e0159..eab51c8d52bc 100644
> --- a/arch/riscv/boot/uncompress.c
> +++ b/arch/riscv/boot/uncompress.c
> @@ -36,8 +36,8 @@ void __noreturn barebox_pbl_start(unsigned long membase,
> unsigned long memsize,
> irq_init_vector(riscv_mode());
>
> /* piggy data is not relocated, so determine the bounds now */
> - pg_start = input_data + get_runtime_offset();
> - pg_end = input_data_end + get_runtime_offset();
> + pg_start = get_unrelocated(input_data);
> + pg_end = get_unrelocated(input_data_end);
> pg_len = pg_end - pg_start;
> uncompressed_len = input_data_len();
>
> diff --git a/arch/riscv/include/asm/sections.h
> b/arch/riscv/include/asm/sections.h
> index 6673648bcd58..b90f4d6d2ad5 100644
> --- a/arch/riscv/include/asm/sections.h
> +++ b/arch/riscv/include/asm/sections.h
> @@ -19,7 +19,7 @@ unsigned long get_runtime_offset(void);
>
> static inline unsigned int input_data_len(void)
> {
> - return get_unaligned((const u32 *)(input_data_end +
> get_runtime_offset() - 4));
> + return get_unaligned((const u32 *)get_unrelocated(input_data_end) - 1);
> }
>
> #endif
> diff --git a/arch/riscv/lib/reloc.c b/arch/riscv/lib/reloc.c
> index 13118a9ac54f..1dddf627d0b9 100644
> --- a/arch/riscv/lib/reloc.c
> +++ b/arch/riscv/lib/reloc.c
> @@ -42,9 +42,9 @@ void relocate_to_current_adr(void)
> if (!offset)
> return;
>
> - dstart = __rel_dyn_start + offset;
> - dend = __rel_dyn_end + offset;
> - dynsym = (void *)__dynsym_start + offset;
> + dstart = get_unrelocated(__rel_dyn_start);
> + dend = get_unrelocated(__rel_dyn_end);
> + dynsym = get_unrelocated(__dynsym_start) + offset;
Ouch, + offset shouldn't be here. Will fix for v2.
>
> for (rela = dstart; (void *)rela < dend; rela++) {
> unsigned long *fixup;
--
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