On Fri, Feb 27, 2015 at 11:28:50AM +0800, Wang Nan wrote:
> As early_trap_init() doesn't use IST, replace set_intr_gate_ist(..., 0)
> and set_system_intr_gate_ist(..., 0) with their standard counterparts.
>
> set_intr_gate() requires a trace_debug symbol which we don't have and
> won't use. Use a small macro trick as a workaround.
>
> Signed-off-by: Wang Nan <wangn...@huawei.com>
> ---
>
> Hi Andy Lutomirski,
>
> This patch is a bit tricky, but I think we don't need to define another
> helper for such a small problem. What's your opinion?
>
> Thank you!
>
> ---
> arch/x86/kernel/traps.c | 23 ++++++++++++++---------
> 1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> index 4281988..c24434a 100644
> --- a/arch/x86/kernel/traps.c
> +++ b/arch/x86/kernel/traps.c
> @@ -925,17 +925,22 @@ dotraplinkage void do_iret_error(struct pt_regs *regs,
> long error_code)
> /* Set of traps needed for early debugging. */
> void __init early_trap_init(void)
> {
> +
> /*
> - * Don't set ist to DEBUG_STACK as it doesn't work until TSS is
> - * ready in cpu_init() <-- trap_init(). Before trap_init(), CPU
> - * runs at ring 0 so it is impossible to hit an invalid stack.
> - * Using the original stack works well enough at this early
> - * stage. DEBUG_STACK will be equipped after cpu_init() in
> - * trap_init().
> + * Don't use IST to set DEBUG_STACK as it doesn't work until TSS is
> + * ready in cpu_init() <-- trap_init(). Before trap_init(), CPU runs at
> + * ring 0 so it is impossible to hit an invalid stack. Using the
> + * original stack works well enough at this early stage. DEBUG_STACK
> + * will be equipped after cpu_init() in trap_init().
> + *
> + * Since set_intr_gate() needs a trace_debug but we don't have it,
> + * use the following #define as a workaround.
> */
> - set_intr_gate_ist(X86_TRAP_DB, &debug, 0);
> +#define trace_debug debug
This goes to arch/x86/include/asm/traps.h like the rest of the trace_*
defines.
> + set_intr_gate(X86_TRAP_DB, debug);
> +#undef trace_debug
> /* int3 can be called from all */
> - set_system_intr_gate_ist(X86_TRAP_BP, &int3, 0);
> + set_system_intr_gate(X86_TRAP_BP, &int3);
> #ifdef CONFIG_X86_32
> set_intr_gate(X86_TRAP_PF, page_fault);
> #endif
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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