On 08.07.2012 10:28, C. Masloch wrote:
>
> Thanks for the help. The attached patch includes spaces around all
> operators, doesn't include the void cast, and doesn't mention (E)DR-DOS
> any longer. I recently learned that the dl register requirement is
> present in prior releases of the FreeDOS kernel too, still called DOS-C.
> These DOS-C releases already are under GPLv2+ so I hope it is okay to
> mention them in the comment, as the attached patch does.
>
> Regards,
> Chris
>
> improve-freedos-compatibility-2.diff
>
>
> Subject: [PATCH] Improve FreeDOS direct loading support compatibility
> Date: Sun, 08 Jul 2012 10:08:29 +0200
> From: "C. Masloch" <pus...@38.de>
>
> ChangeLog | 15 ++++++
> grub-core/lib/i386/relocator.c | 2 +
> grub-core/lib/i386/relocator16.S | 5 ++
> grub-core/loader/i386/pc/freedos.c | 82
> +++++++++++++++++++++++++++++++++++--
> include/grub/i386/relocator.h | 1 +
> 5 files changed, 100 insertions(+), 5 deletions(-)
>
> # HG changeset patch
> # User C. Masloch <pus...@38.de>
> # Date 1341734778 -7200
> # Node ID 3c587f7d6d1e80c73ec0c4a664feebb788f00ed1
> # Parent 73948d0f69334ef6b60e60c16389742c402c2f3e
> Improve FreeDOS direct loading support compatibility.
>
> diff --git a/ChangeLog b/ChangeLog
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,18 @@
> +2012-06-30 C. Masloch <pus...@38.de>
> +
> + Improve FreeDOS direct loading support compatibility.
> +
> + * include/grub/i386/relocator.h (grub_relocator16_state):
> + New member ebp.
> + * grub-core/lib/i386/relocator.c (grub_relocator16_ebp): New extern
> + variable.
> + (grub_relocator16_boot): Handle %ebp.
> + * grub-core/lib/i386/relocator16.S: Likewise.
> + * grub-core/loader/i386/pc/freedos.c:
> + Load BPB to pass kernel which partition to load from.
> + Check that kernel file is not too large.
> + Set register dl to BIOS unit number as well.
> +
> 2012-06-27 Vladimir Serbinenko <phco...@gmail.com>
>
> * configure.ac: Bump version to 2.00.
> diff --git a/grub-core/lib/i386/relocator.c b/grub-core/lib/i386/relocator.c
> --- a/grub-core/lib/i386/relocator.c
> +++ b/grub-core/lib/i386/relocator.c
> @@ -54,6 +54,7 @@
> extern grub_uint32_t grub_relocator16_edx;
> extern grub_uint32_t grub_relocator16_ebx;
> extern grub_uint32_t grub_relocator16_esi;
> +extern grub_uint32_t grub_relocator16_ebp;
>
> extern grub_uint16_t grub_relocator16_keep_a20_enabled;
>
> @@ -225,6 +226,7 @@
> grub_relocator16_ss = state.ss;
> grub_relocator16_sp = state.sp;
>
> + grub_relocator16_ebp = state.ebp;
> grub_relocator16_ebx = state.ebx;
> grub_relocator16_edx = state.edx;
> grub_relocator16_esi = state.esi;
> diff --git a/grub-core/lib/i386/relocator16.S
> b/grub-core/lib/i386/relocator16.S
> --- a/grub-core/lib/i386/relocator16.S
> +++ b/grub-core/lib/i386/relocator16.S
> @@ -259,6 +259,11 @@
> VARIABLE(grub_relocator16_ebx)
> .long 0
>
> + /* movl imm32, %ebp. */
> + .byte 0x66, 0xbd
> +VARIABLE(grub_relocator16_ebp)
> + .long 0
> +
> /* Cleared direction flag is of no problem with any current
> payload and makes this implementation easier. */
> cld
> diff --git a/grub-core/loader/i386/pc/freedos.c
> b/grub-core/loader/i386/pc/freedos.c
> --- a/grub-core/loader/i386/pc/freedos.c
> +++ b/grub-core/loader/i386/pc/freedos.c
> @@ -32,6 +32,7 @@
> #include <grub/video.h>
> #include <grub/mm.h>
> #include <grub/cpu/relocator.h>
> +#include <grub/machine/chainloader.h>
>
> GRUB_MOD_LICENSE ("GPLv3+");
>
> @@ -40,8 +41,23 @@
> static grub_uint32_t ebx = 0xffffffff;
>
> #define GRUB_FREEDOS_SEGMENT 0x60
> +#define GRUB_FREEDOS_ADDR (GRUB_FREEDOS_SEGMENT << 4)
> #define GRUB_FREEDOS_STACK_SEGMENT 0x1fe0
> -#define GRUB_FREEDOS_STACK_POINTER 0x8000
> +#define GRUB_FREEDOS_STACK_BPB_POINTER 0x7c00
> +#define GRUB_FREEDOS_BPB_ADDR ((GRUB_FREEDOS_STACK_SEGMENT << 4) \
> + + GRUB_FREEDOS_STACK_BPB_POINTER)
> +
> +/* FreeDOS boot.asm passes register sp as exactly this. Importantly,
> + it must point below the BPB (to avoid overwriting any of it). */
> +#define GRUB_FREEDOS_STACK_POINTER (GRUB_FREEDOS_STACK_BPB_POINTER \
> + - 0x60)
> +
> +/* In this, the additional 8192 bytes are the stack reservation; the
> + remaining parts trivially give the maximum allowed size. */
> +#define GRUB_FREEDOS_MAX_SIZE ((GRUB_FREEDOS_STACK_SEGMENT << 4) \
> + + GRUB_FREEDOS_STACK_POINTER \
> + - GRUB_FREEDOS_ADDR \
> + - 8192)
>
> static grub_err_t
> grub_freedos_boot (void)
> @@ -49,14 +65,29 @@
> struct grub_relocator16_state state = {
> .cs = GRUB_FREEDOS_SEGMENT,
> .ip = 0,
> - .ds = 0,
> +
> + /* This is not strictly necessary for the current FreeDOS kernel
> + but improves potential compatibility with others.
> + There is no harm in setting this. */
> + .ds = GRUB_FREEDOS_STACK_SEGMENT,
> .es = 0,
> .fs = 0,
> .gs = 0,
> .ss = GRUB_FREEDOS_STACK_SEGMENT,
> .sp = GRUB_FREEDOS_STACK_POINTER,
> + .ebp = GRUB_FREEDOS_STACK_BPB_POINTER,
> .ebx = ebx,
> - .edx = 0,
> +
> + /* This is not strictly necessary for the current FreeDOS kernel
> + but is crucial for potential compatibility with the load
> + protocols of other DOS-like kernels and loaders (including
> + the older FreeDOS kernel releases called DOS-C).
> + (Among those, FreeDOS's new load protocol must be considered
> + a special case in that it doesn't require register dl to pass
> + the unit number. Incidentally, the current FreeDOS boot.asm
> + does pass it in both registers.)
> + There is no harm in setting this. */
> + .edx = ebx,
> .a20 = 1
> };
> grub_video_set_mode ("text", 0, 0);
> @@ -79,8 +110,9 @@
> {
> grub_file_t file = 0;
> grub_err_t err;
> - void *kernelsys;
> + void *bs, *kernelsys;
> grub_size_t kernelsyssize;
> + grub_device_t dev;
>
> if (argc == 0)
> return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
> @@ -95,12 +127,52 @@
> if (! file)
> goto fail;
>
> + {
> + grub_relocator_chunk_t ch;
> + err = grub_relocator_alloc_chunk_addr (rel, &ch, GRUB_FREEDOS_BPB_ADDR,
> + GRUB_DISK_SECTOR_SIZE);I don't understand this. Shouldn't it be at 0x7c00 ? Do you plan to contribute more? If so I'd prefer to make you sign a copyright assignment, otherwise this patch can go in, once it's clear with addresses. -- Regards Vladimir 'φ-coder/phcoder' Serbinenko
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