Re: [PATCH 1/4] kgdb: x86: Return all segment registers also in 64-bitmode

From: Jason Wessel
Date: Fri Mar 16 2012 - 11:58:16 EST


On 03/16/2012 07:17 AM, Jan Kiszka wrote:
> Even if the content is always 0, gdb expects us to return also ds,
> es, fs, and gs while in x86-64 mode. Do this to avoid ugly errors on
> "info registers".
>
> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> ---
> arch/x86/include/asm/kgdb.h | 6 +++++-
> arch/x86/kernel/kgdb.c | 6 ++++--
> 2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/include/asm/kgdb.h b/arch/x86/include/asm/kgdb.h
> index 77e95f5..e857f1a 100644
> --- a/arch/x86/include/asm/kgdb.h
> +++ b/arch/x86/include/asm/kgdb.h
> @@ -64,9 +64,13 @@ enum regnames {
> GDB_PS, /* 17 */
> GDB_CS, /* 18 */
> GDB_SS, /* 19 */
> + GDB_DS, /* 20 */
> + GDB_ES, /* 21 */
> + GDB_FS, /* 22 */
> + GDB_GS, /* 23 */
> };
> #define GDB_ORIG_AX 57
> -#define DBG_MAX_REG_NUM 20
> +#define DBG_MAX_REG_NUM 24
> /* 17 64 bit regs and 3 32 bit regs */
> #define NUMREGBYTES ((17 * 8) + (3 * 4))

You bumped the register numbers correctly, but you also need to add the correct padding to the NUMREGBYTES or you might not get a large enough memory block for the register struct.

You added 2 32 bit regs, so it should change to:

/* 17 64 bit regs and 5 32 bit regs */
#define NUMREGBYTES ((17 * 8) + (5 * 4))


The rest should be fine. I can test this and add it to the merge queue with the NUMREGBYTES change, unless you disagree.

Cheers,
Jason.
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