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Re: [PATCH v1 1/1] loongarch: add relaxation support
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From: |
Daniel Kiper |
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Subject: |
Re: [PATCH v1 1/1] loongarch: add relaxation support |
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Date: |
Tue, 6 Jun 2023 18:49:37 +0200 |
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User-agent: |
NeoMutt/20170113 (1.7.2) |
On Tue, Jun 06, 2023 at 10:34:06AM +0800, Xiaotian Wu wrote:
> Add R_LARCH_B16, R_LARCH_B21 and R_LARCH_RELAX relocation types to support
> LoongArch relaxation.
Please explain why this relaxation support is needed. I think you can
copy explanation from the cover letter.
> https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=56576f4a722b7398d35802ecf7d4185c27d6d69b
> https://github.com/loongson/la-abi-specs/blob/release/laelf.adoc#relocations
>
> Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
> ---
> grub-core/kern/loongarch64/dl.c | 21 +++++++-
> grub-core/kern/loongarch64/dl_helper.c | 72 ++++++++++++++++++++++++--
> include/grub/elf.h | 3 ++
> include/grub/loongarch64/reloc.h | 6 ++-
> util/grub-mkimagexx.c | 28 ++++++++--
> util/grub-module-verifier.c | 3 ++
> 6 files changed, 122 insertions(+), 11 deletions(-)
>
> diff --git a/grub-core/kern/loongarch64/dl.c b/grub-core/kern/loongarch64/dl.c
> index 43080e72e..c22d2bd52 100644
> --- a/grub-core/kern/loongarch64/dl.c
> +++ b/grub-core/kern/loongarch64/dl.c
> @@ -87,11 +87,28 @@ grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr,
> }
> break;
> case R_LARCH_MARK_LA:
> + case R_LARCH_RELAX:
> break;
> case R_LARCH_SOP_PUSH_PCREL:
> case R_LARCH_SOP_PUSH_PLT_PCREL:
> grub_loongarch64_sop_push (&stack, sym_addr - (grub_uint64_t)place);
> break;
> + case R_LARCH_B16:
> + {
> + grub_uint32_t *abs_place = place;
> + grub_ssize_t off = sym_addr - (grub_addr_t) place;
> +
> + grub_loongarch64_b16 (abs_place, off);
> + }
> + break;
> + case R_LARCH_B21:
> + {
> + grub_uint32_t *abs_place = place;
> + grub_ssize_t off = sym_addr - (grub_addr_t) place;
> +
> + grub_loongarch64_b21 (abs_place, off);
> + }
> + break;
> case R_LARCH_B26:
> {
> grub_uint32_t *abs_place = place;
> @@ -109,13 +126,13 @@ grub_arch_dl_relocate_symbols (grub_dl_t mod, void
> *ehdr,
> case R_LARCH_ABS64_LO20:
> {
> grub_uint32_t *abs_place = place;
> - grub_loongarch64_xxx64_lo20 (abs_place, sym_addr);
> + grub_loongarch64_abs64_lo20 (abs_place, sym_addr);
This change...
> }
> break;
> case R_LARCH_ABS64_HI12:
> {
> grub_uint32_t *abs_place = place;
> - grub_loongarch64_xxx64_hi12 (abs_place, sym_addr);
> + grub_loongarch64_abs64_hi12 (abs_place, sym_addr);
... and this one does not seem to belong to this patch. Please move
these changes to separate patch.
> }
> break;
> case R_LARCH_PCALA_HI20:
> diff --git a/grub-core/kern/loongarch64/dl_helper.c
> b/grub-core/kern/loongarch64/dl_helper.c
> index cda1a53c8..2809eeb7f 100644
> --- a/grub-core/kern/loongarch64/dl_helper.c
> +++ b/grub-core/kern/loongarch64/dl_helper.c
> @@ -24,6 +24,10 @@
> #include <grub/i18n.h>
> #include <grub/loongarch64/reloc.h>
>
> +/*
> + * LoongArch relocations documentation:
> + *
> https://github.com/loongson/la-abi-specs/blob/release/laelf.adoc#relocations
> + */
Probably not a part of this patch too...
> static void grub_loongarch64_stack_push (grub_loongarch64_stack_t stack,
> grub_uint64_t x);
> static grub_uint64_t grub_loongarch64_stack_pop (grub_loongarch64_stack_t
> stack);
>
> @@ -200,14 +204,58 @@ grub_loongarch64_sop_32_s_0_10_10_16_s2
> (grub_loongarch64_stack_t stack,
> *place =(*place) | ((a >> 18) & 0x3ff);
> }
>
> +/*
> + * B16 relocation for the 18-bit PC-relative jump
> + * (*(uint32_t *) PC) [25 ... 10] = (S+A-PC) [17 ... 2]
> + */
> +void grub_loongarch64_b16 (grub_uint32_t *place, grub_int64_t offset)
> +{
> + grub_uint32_t val;
> + const grub_uint32_t insmask = grub_cpu_to_le32_compile_time (0xfc0003ff);
> +
> + grub_dprintf ("dl", " reloc_b16 %p %c= 0x%"PRIxGRUB_INT64_T"\n",
s/"PRIxGRUB_INT64_T"/" PRIxGRUB_INT64_T "/
Simply add spaces before and after PRIxGRUB_INT64_T...
> + place, offset > 0 ? '+' : '-',
> + offset < 0 ? (grub_int64_t) -(grub_uint64_t) offset : offset);
These two casts does not make a lot of sense for me. You remove minus
sign from the offset. So, I do not expect an overflow here. Then you
can safely drop casts. Right?
> + val = ((offset >> 2) & 0xffff) << 10;
> +
> + *place &= insmask;
> + *place |= grub_cpu_to_le32 (val) & ~insmask;
> +}
> +
> +/*
> + * B21 relocation for the 23-bit PC-relative jump
> + * (*(uint32_t *) PC) [4 ... 0] = (S+A-PC) [22 ... 18]
> + * (*(uint32_t *) PC) [25 ... 10] = (S+A-PC) [17 ... 2]
> + */
> +void grub_loongarch64_b21 (grub_uint32_t *place, grub_int64_t offset)
> +{
> + grub_uint32_t val;
> + const grub_uint32_t insmask = grub_cpu_to_le32_compile_time (0xfc0003e0);
> +
> + grub_dprintf ("dl", " reloc_b21 %p %c= 0x%"PRIxGRUB_INT64_T"\n",
> + place, offset > 0 ? '+' : '-',
> + offset < 0 ? (grub_int64_t) -(grub_uint64_t) offset : offset);
Ditto and below the same things...
> +
> + val = ((offset >> 18) & 0x1f) | (((offset >> 2) & 0xffff) << 10);
> +
> + *place &= insmask;
> + *place |= grub_cpu_to_le32 (val) & ~insmask;
> +}
> +
> +/*
> + * B26 relocation for the 28-bit PC-relative jump
> + * (*(uint32_t *) PC) [9 ... 0] = (S+A-PC) [27 ... 18]
> + * (*(uint32_t *) PC) [25 ... 10] = (S+A-PC) [17 ... 2]
> + */
This...
> void grub_loongarch64_b26 (grub_uint32_t *place, grub_int64_t offset)
> {
> grub_uint32_t val;
> const grub_uint32_t insmask = grub_cpu_to_le32_compile_time (0xfc000000);
>
> - grub_dprintf ("dl", " reloc_xxxx64 %p %c= 0x%llx\n",
> + grub_dprintf ("dl", " reloc_b26 %p %c= 0x%"PRIxGRUB_INT64_T"\n",
... and...
> place, offset > 0 ? '+' : '-',
> - offset < 0 ? (long long) -(unsigned long long) offset : offset);
> + offset < 0 ? (grub_int64_t) -(grub_uint64_t) offset : offset);
... and this should go to separate patch...
> val = ((offset >> 18) & 0x3ff) | (((offset >> 2) & 0xffff) << 10);
>
> @@ -215,6 +263,10 @@ void grub_loongarch64_b26 (grub_uint32_t *place,
> grub_int64_t offset)
> *place |= grub_cpu_to_le32 (val) & ~insmask;
> }
>
> +/*
> + * ABS_HI20/PCALA_HI20 relocations for 32/64-bit absolute
> address/PC-relative offset
> + * (*(uint32_t *) PC) [24 ... 5] = (S+A) [31 ... 12]
> + */
Ditto.
> void grub_loongarch64_xxx_hi20 (grub_uint32_t *place, grub_int64_t offset)
> {
> const grub_uint32_t insmask = grub_cpu_to_le32_compile_time (0xfe00001f);
> @@ -227,6 +279,10 @@ void grub_loongarch64_xxx_hi20 (grub_uint32_t *place,
> grub_int64_t offset)
> *place |= grub_cpu_to_le32 (val) & ~insmask;
> }
>
> +/*
> + * ABS_LO12/PCALA_LO12 relocations for 32/64-bit absolute address
> + * (*(uint32_t *) PC) [21 ... 10] = (S+A) [11 ... 0]
> + */
Ditto.
> void grub_loongarch64_xxx_lo12 (grub_uint32_t *place, grub_int64_t offset)
> {
> const grub_uint32_t insmask = grub_cpu_to_le32_compile_time (0xffc003ff);
> @@ -235,7 +291,11 @@ void grub_loongarch64_xxx_lo12 (grub_uint32_t *place,
> grub_int64_t offset)
> *place |= grub_cpu_to_le32 (offset << 10) & ~insmask;
> }
>
> -void grub_loongarch64_xxx64_hi12 (grub_uint32_t *place, grub_int64_t offset)
> +/*
> + * ABS64_HI12 relocation for the 64-bit absolute address
> + * (*(uint32_t *) PC) [21 ... 10] = (S+A) [63 ... 52]
> + */
Ditto...
In general please split this patch into separate logical parts.
Daniel