On Wed, Jun 02, 2010 at 01:56:50AM +0200, Alexander Graf wrote:
> Commit dd4239d6574ca41c94fc0d0f77ddc728510ffc57 broke multiboot. It replaced
> the
> instruction "rep insb (%dx), %es:(%edi)" by the binary output of
> "addr32 rep insb (%dx), %es:(%di)".
>
> Linuxboot calls the respective helper function in a code16 section. So the
> original instruction was automatically translated to its "addr32" equivalent.
> For multiboot, we're running in code32 so gcc didn't add the "addr32" which
> breaks the instruction.
>
> This patch splits that helper function in one which uses addr32 and one which
> does not, so everyone's happy.
>
> The good news is that nobody probably cared so far. The bundled multiboot.bin
> binary was built before the change and is thus correct.
>
> Please also put this patch into -stable.
>
> Signed-off-by: Alexander Graf
> ---
> pc-bios/optionrom/linuxboot.S |8
> pc-bios/optionrom/optionrom.h | 32
> 2 files changed, 28 insertions(+), 12 deletions(-)
Thanks, applied.
> diff --git a/pc-bios/optionrom/linuxboot.S b/pc-bios/optionrom/linuxboot.S
> index 8aebe51..c109363 100644
> --- a/pc-bios/optionrom/linuxboot.S
> +++ b/pc-bios/optionrom/linuxboot.S
> @@ -106,10 +106,10 @@ copy_kernel:
> /* We're now running in 16-bit CS, but 32-bit ES! */
>
> /* Load kernel and initrd */
> - read_fw_blob(FW_CFG_KERNEL)
> - read_fw_blob(FW_CFG_INITRD)
> - read_fw_blob(FW_CFG_CMDLINE)
> - read_fw_blob(FW_CFG_SETUP)
> + read_fw_blob_addr32(FW_CFG_KERNEL)
> + read_fw_blob_addr32(FW_CFG_INITRD)
> + read_fw_blob_addr32(FW_CFG_CMDLINE)
> + read_fw_blob_addr32(FW_CFG_SETUP)
>
> /* And now jump into Linux! */
> mov $0, %eax
> diff --git a/pc-bios/optionrom/optionrom.h b/pc-bios/optionrom/optionrom.h
> index 4dcb906..fbdd48a 100644
> --- a/pc-bios/optionrom/optionrom.h
> +++ b/pc-bios/optionrom/optionrom.h
> @@ -50,13 +50,7 @@
> bswap %eax
> .endm
>
> -/*
> - * Read a blob from the fw_cfg device.
> - * Requires _ADDR, _SIZE and _DATA values for the parameter.
> - *
> - * Clobbers: %eax, %edx, %es, %ecx, %edi
> - */
> -#define read_fw_blob(var)\
> +#define read_fw_blob_pre(var)\
> read_fw var ## _ADDR; \
> mov %eax, %edi; \
> read_fw var ## _SIZE; \
> @@ -65,10 +59,32 @@
> mov $BIOS_CFG_IOPORT_CFG, %edx; \
> outw%ax, (%dx); \
> mov $BIOS_CFG_IOPORT_DATA, %dx; \
> - cld;\
> + cld
> +
> +/*
> + * Read a blob from the fw_cfg device.
> + * Requires _ADDR, _SIZE and _DATA values for the parameter.
> + *
> + * Clobbers: %eax, %edx, %es, %ecx, %edi
> + */
> +#define read_fw_blob(var)\
> + read_fw_blob_pre(var); \
> /* old as(1) doesn't like this insn so emit the bytes instead: \
> rep insb(%dx), %es:(%edi); \
> */ \
> + .dc.b 0xf3,0x6c
> +
> +/*
> + * Read a blob from the fw_cfg device in forced addr32 mode.
> + * Requires _ADDR, _SIZE and _DATA values for the parameter.
> + *
> + * Clobbers: %eax, %edx, %es, %ecx, %edi
> + */
> +#define read_fw_blob_addr32(var) \
> + read_fw_blob_pre(var); \
> + /* old as(1) doesn't like this insn so emit the bytes instead: \
> + addr32 rep insb (%dx), %es:(%edi); \
> + */ \
> .dc.b 0x67,0xf3,0x6c
>
> #define OPTION_ROM_START \
> --
> 1.6.0.2
>
>
>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurel...@aurel32.net http://www.aurel32.net
