|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v6 2/5] x86/boot: Reuse code to relocate trampoline
On Thu, Oct 17, 2024 at 02:31:20PM +0100, Frediano Ziglio wrote:
> Move code from efi-boot.h to a separate, new, reloc-trampoline.c file.
> Reuse this new code, compiling it for 32bit as well, to replace assembly
> code in head.S doing the same thing.
>
> Signed-off-by: Frediano Ziglio <frediano.ziglio@xxxxxxxxx>
> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
For the EFI part:
Acked-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
> ---
> Changes since v3:
> - fixed a typo in comment;
> - added Reviewed-by.
>
> Changes since v5:
> - do not add obj64 to targets, already done adding it to obj-bin-y.
> ---
> xen/arch/x86/boot/Makefile | 10 +++++---
> xen/arch/x86/boot/build32.lds.S | 5 ++++
> xen/arch/x86/boot/head.S | 23 +-----------------
> xen/arch/x86/boot/reloc-trampoline.c | 36 ++++++++++++++++++++++++++++
> xen/arch/x86/efi/efi-boot.h | 15 ++----------
> 5 files changed, 51 insertions(+), 38 deletions(-)
> create mode 100644 xen/arch/x86/boot/reloc-trampoline.c
>
> diff --git a/xen/arch/x86/boot/Makefile b/xen/arch/x86/boot/Makefile
> index 5da19501be..98ceb1983d 100644
> --- a/xen/arch/x86/boot/Makefile
> +++ b/xen/arch/x86/boot/Makefile
> @@ -1,11 +1,15 @@
> obj-bin-y += head.o
> obj-bin-y += built-in-32.o
> +obj-bin-y += $(obj64)
>
> obj32 := cmdline.32.o
> obj32 += reloc.32.o
> +obj32 += reloc-trampoline.32.o
>
> -nocov-y += $(obj32)
> -noubsan-y += $(obj32)
> +obj64 := reloc-trampoline.o
> +
> +nocov-y += $(obj32) $(obj64)
> +noubsan-y += $(obj32) $(obj64)
> targets += $(obj32)
>
> obj32 := $(addprefix $(obj)/,$(obj32))
> @@ -56,7 +60,7 @@ cmd_combine = \
> --bin1 $(obj)/built-in-32.base.bin \
> --bin2 $(obj)/built-in-32.offset.bin \
> --map $(obj)/built-in-32.offset.map \
> - --exports cmdline_parse_early,reloc \
> + --exports cmdline_parse_early,reloc,reloc_trampoline32 \
> --output $@
>
> targets += built-in-32.S
> diff --git a/xen/arch/x86/boot/build32.lds.S b/xen/arch/x86/boot/build32.lds.S
> index e3f5e55261..fa282370f4 100644
> --- a/xen/arch/x86/boot/build32.lds.S
> +++ b/xen/arch/x86/boot/build32.lds.S
> @@ -41,6 +41,11 @@ SECTIONS
> * Potentially they should be all variables. */
> DECLARE_IMPORT(__base_relocs_start);
> DECLARE_IMPORT(__base_relocs_end);
> + DECLARE_IMPORT(__trampoline_rel_start);
> + DECLARE_IMPORT(__trampoline_rel_stop);
> + DECLARE_IMPORT(__trampoline_seg_start);
> + DECLARE_IMPORT(__trampoline_seg_stop);
> + DECLARE_IMPORT(trampoline_phys);
> . = . + GAP;
> *(.text)
> *(.text.*)
> diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
> index e0776e3896..ade2c5c43d 100644
> --- a/xen/arch/x86/boot/head.S
> +++ b/xen/arch/x86/boot/head.S
> @@ -706,28 +706,7 @@ trampoline_setup:
> mov %edx, sym_offs(l1_bootmap)(%esi, %ecx, 8)
>
> /* Apply relocations to bootstrap trampoline. */
> - mov sym_esi(trampoline_phys), %edx
> - lea sym_esi(__trampoline_rel_start), %edi
> - lea sym_esi(__trampoline_rel_stop), %ecx
> -1:
> - mov (%edi), %eax
> - add %edx, (%edi, %eax)
> - add $4,%edi
> -
> - cmp %ecx, %edi
> - jb 1b
> -
> - /* Patch in the trampoline segment. */
> - shr $4,%edx
> - lea sym_esi(__trampoline_seg_start), %edi
> - lea sym_esi(__trampoline_seg_stop), %ecx
> -1:
> - mov (%edi), %eax
> - mov %dx, (%edi, %eax)
> - add $4,%edi
> -
> - cmp %ecx, %edi
> - jb 1b
> + call reloc_trampoline32
>
> /* Do not parse command line on EFI platform here. */
> cmpb $0, sym_esi(efi_platform)
> diff --git a/xen/arch/x86/boot/reloc-trampoline.c
> b/xen/arch/x86/boot/reloc-trampoline.c
> new file mode 100644
> index 0000000000..0a74c1e75a
> --- /dev/null
> +++ b/xen/arch/x86/boot/reloc-trampoline.c
> @@ -0,0 +1,36 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#include <xen/compiler.h>
> +#include <xen/stdint.h>
> +#include <asm/trampoline.h>
> +
> +extern const int32_t __trampoline_rel_start[], __trampoline_rel_stop[];
> +extern const int32_t __trampoline_seg_start[], __trampoline_seg_stop[];
> +
> +#if defined(__i386__)
> +void reloc_trampoline32(void)
> +#elif defined (__x86_64__)
> +void reloc_trampoline64(void)
> +#else
> +#error Unknown architecture
> +#endif
> +{
> + unsigned long phys = trampoline_phys;
> + const int32_t *trampoline_ptr;
> +
> + /*
> + * Apply relocations to trampoline.
> + *
> + * This modifies the trampoline in place within Xen, so that it will
> + * operate correctly when copied into place.
> + */
> + for ( trampoline_ptr = __trampoline_rel_start;
> + trampoline_ptr < __trampoline_rel_stop;
> + ++trampoline_ptr )
> + *(uint32_t *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
> +
> + for ( trampoline_ptr = __trampoline_seg_start;
> + trampoline_ptr < __trampoline_seg_stop;
> + ++trampoline_ptr )
> + *(uint16_t *)(*trampoline_ptr + (long)trampoline_ptr) = phys >> 4;
> +}
> diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
> index 94f3443364..1acceec471 100644
> --- a/xen/arch/x86/efi/efi-boot.h
> +++ b/xen/arch/x86/efi/efi-boot.h
> @@ -103,27 +103,16 @@ static void __init efi_arch_relocate_image(unsigned
> long delta)
> }
> }
>
> -extern const int32_t __trampoline_rel_start[], __trampoline_rel_stop[];
> -extern const int32_t __trampoline_seg_start[], __trampoline_seg_stop[];
> +void reloc_trampoline64(void);
>
> static void __init relocate_trampoline(unsigned long phys)
> {
> - const int32_t *trampoline_ptr;
> -
> trampoline_phys = phys;
>
> if ( !efi_enabled(EFI_LOADER) )
> return;
>
> - /* Apply relocations to trampoline. */
> - for ( trampoline_ptr = __trampoline_rel_start;
> - trampoline_ptr < __trampoline_rel_stop;
> - ++trampoline_ptr )
> - *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
> - for ( trampoline_ptr = __trampoline_seg_start;
> - trampoline_ptr < __trampoline_seg_stop;
> - ++trampoline_ptr )
> - *(u16 *)(*trampoline_ptr + (long)trampoline_ptr) = phys >> 4;
> + reloc_trampoline64();
> }
>
> static void __init place_string(u32 *addr, const char *s)
> --
> 2.34.1
>
--
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
Attachment:
signature.asc
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |