Re: [Xen-changelog] [xen-3.4-testing] x86: Generalise BUGFRAME_dump mechanism to allow polled UART irq to

[Mark Johnson <johnson.nh@gmail.com>]

FYI, I see the following build error with this patch...

MRJ


---- new warnings/errors for xen ----
keyhandler.c: In function `__dump_execstate':
keyhandler.c:96: warning: asm operand 1 probably doesn't match constraints
gmake[5]: *** [keyhandler.o] Error 1
gmake[4]: *** [/tank/ws/xvm-3.4.3/xen.hg/xen/common/built_in.o] Error 2
gmake[3]: *** [/tank/ws/xvm-3.4.3/xen.hg/xen/xen] Error 2


static void __dump_execstate(void *unused)
{
    dump_execution_state(); <==== keyhandler.c:96


> +#define dump_execution_state() run_in_exception_handler(show_execution_state)

> +#define run_in_exception_handler(fn)               \
>     asm volatile (                                 \
> -        "ud2 ; ret $0"                             \
> -        : : "i" (BUGFRAME_dump) )
> +        "ud2 ; ret %0" BUG_STR(1)                  \
> +        : : "i" (BUGFRAME_run_fn),                 \
> +            "i" (fn) )
>




On Wed, Feb 24, 2010 at 6:20 AM, Xen patchbot-3.4-testing
<patchbot-3.4-testing@lists.xensource.com> wrote:
> # HG changeset patch
> # User Keir Fraser <keir.fraser@citrix.com>
> # Date 1267009865 0
> # Node ID 3ccf3e993d5ddc4e5dff15e464dc63d5485e984c
> # Parent  cddd503fb25401fdaabe1344fdf5e060ca158e7a
> x86: Generalise BUGFRAME_dump mechanism to allow polled UART irq to
> get proper regs argument.
>
> Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
> xen-unstable changeset:   20969:8cb6e7eff2ba
> xen-unstable date:        Wed Feb 24 10:44:30 2010 +0000
> ---
>  xen/arch/x86/traps.c                  |   32 ++++++++++++++++++--------------
>  xen/drivers/acpi/utilities/utglobal.c |    1 +
>  xen/drivers/char/ns16550.c            |   22 +++++++++++++++++-----
>  xen/include/asm-x86/bug.h             |    9 +++++----
>  xen/include/asm-x86/processor.h       |    1 +
>  5 files changed, 42 insertions(+), 23 deletions(-)
>
> diff -r cddd503fb254 -r 3ccf3e993d5d xen/arch/x86/traps.c
> --- a/xen/arch/x86/traps.c      Wed Feb 24 11:10:09 2010 +0000
> +++ b/xen/arch/x86/traps.c      Wed Feb 24 11:11:05 2010 +0000
> @@ -840,6 +840,7 @@ asmlinkage void do_invalid_op(struct cpu
>  {
>     struct bug_frame bug;
>     struct bug_frame_str bug_str;
> +    const void *p;
>     const char *filename, *predicate, *eip = (char *)regs->eip;
>     unsigned long fixup;
>     int id, lineno;
> @@ -860,26 +861,29 @@ asmlinkage void do_invalid_op(struct cpu
>         goto die;
>     eip += sizeof(bug);
>
> -    id = bug.id & 3;
> -
> -    if ( id == BUGFRAME_dump )
> -    {
> -        show_execution_state(regs);
> -        regs->eip = (unsigned long)eip;
> -        return;
> -    }
> -
> -    /* WARN, BUG or ASSERT: decode the filename pointer and line number. */
> +    /* Decode first pointer argument. */
>     if ( !is_kernel(eip) ||
>          __copy_from_user(&bug_str, eip, sizeof(bug_str)) ||
>          (bug_str.mov != 0xbc) )
>         goto die;
> -    filename = bug_str(bug_str, eip);
> +    p = bug_str(bug_str, eip);
> +    if ( !is_kernel(p) )
> +        goto die;
>     eip += sizeof(bug_str);
>
> -    if ( !is_kernel(filename) )
> -        filename = "<unknown>";
> -    lineno   = bug.id >> 2;
> +    id = bug.id & 3;
> +
> +    if ( id == BUGFRAME_run_fn )
> +    {
> +        const void (*fn)(struct cpu_user_regs *) = p;
> +        (*fn)(regs);
> +        regs->eip = (unsigned long)eip;
> +        return;
> +    }
> +
> +    /* WARN, BUG or ASSERT: decode the filename pointer and line number. */
> +    filename = p;
> +    lineno = bug.id >> 2;
>
>     if ( id == BUGFRAME_warn )
>     {
> diff -r cddd503fb254 -r 3ccf3e993d5d xen/drivers/acpi/utilities/utglobal.c
> --- a/xen/drivers/acpi/utilities/utglobal.c     Wed Feb 24 11:10:09 2010 +0000
> +++ b/xen/drivers/acpi/utilities/utglobal.c     Wed Feb 24 11:11:05 2010 +0000
> @@ -45,6 +45,7 @@
>
>  #include <xen/config.h>
>  #include <xen/lib.h>
> +#include <asm/processor.h>
>  #include <acpi/acpi.h>
>  #include <acpi/acnamesp.h>
>
> diff -r cddd503fb254 -r 3ccf3e993d5d xen/drivers/char/ns16550.c
> --- a/xen/drivers/char/ns16550.c        Wed Feb 24 11:10:09 2010 +0000
> +++ b/xen/drivers/char/ns16550.c        Wed Feb 24 11:11:05 2010 +0000
> @@ -144,11 +144,13 @@ static void ns16550_interrupt(
>     }
>  }
>
> -static void ns16550_poll(void *data)
> -{
> -    struct serial_port *port = data;
> -    struct ns16550 *uart = port->uart;
> -    struct cpu_user_regs *regs = guest_cpu_user_regs();
> +/* Safe: ns16550_poll() runs in softirq context so not reentrant on a given CPU. */
> +static DEFINE_PER_CPU(struct serial_port *, poll_port);
> +
> +static void __ns16550_poll(struct cpu_user_regs *regs)
> +{
> +    struct serial_port *port = this_cpu(poll_port);
> +    struct ns16550 *uart = port->uart;
>
>     if ( uart->intr_works )
>         return;     /* Interrupts work - no more polling */
> @@ -166,6 +168,16 @@ static void ns16550_poll(void *data)
>         serial_tx_interrupt(port, regs);
>
>     set_timer(&uart->timer, NOW() + MILLISECS(uart->timeout_ms));
> +}
> +
> +static void ns16550_poll(void *data)
> +{
> +    this_cpu(poll_port) = data;
> +#ifdef run_in_exception_handler
> +    run_in_exception_handler(__ns16550_poll);
> +#else
> +    __ns16550_poll(guest_cpu_user_regs());
> +#endif
>  }
>
>  static int ns16550_tx_empty(struct serial_port *port)
> diff -r cddd503fb254 -r 3ccf3e993d5d xen/include/asm-x86/bug.h
> --- a/xen/include/asm-x86/bug.h Wed Feb 24 11:10:09 2010 +0000
> +++ b/xen/include/asm-x86/bug.h Wed Feb 24 11:11:05 2010 +0000
> @@ -13,15 +13,16 @@ struct bug_frame {
>     unsigned short id; /* BUGFRAME_??? */
>  } __attribute__((packed));
>
> -#define BUGFRAME_dump   0
> +#define BUGFRAME_run_fn 0
>  #define BUGFRAME_warn   1
>  #define BUGFRAME_bug    2
>  #define BUGFRAME_assert 3
>
> -#define dump_execution_state()                     \
> +#define run_in_exception_handler(fn)               \
>     asm volatile (                                 \
> -        "ud2 ; ret $0"                             \
> -        : : "i" (BUGFRAME_dump) )
> +        "ud2 ; ret %0" BUG_STR(1)                  \
> +        : : "i" (BUGFRAME_run_fn),                 \
> +            "i" (fn) )
>
>  #define WARN()                                     \
>     asm volatile (                                 \
> diff -r cddd503fb254 -r 3ccf3e993d5d xen/include/asm-x86/processor.h
> --- a/xen/include/asm-x86/processor.h   Wed Feb 24 11:10:09 2010 +0000
> +++ b/xen/include/asm-x86/processor.h   Wed Feb 24 11:11:05 2010 +0000
> @@ -532,6 +532,7 @@ void show_stack_overflow(unsigned int cp
>  void show_stack_overflow(unsigned int cpu, unsigned long esp);
>  void show_registers(struct cpu_user_regs *regs);
>  void show_execution_state(struct cpu_user_regs *regs);
> +#define dump_execution_state() run_in_exception_handler(show_execution_state)
>  void show_page_walk(unsigned long addr);
>  asmlinkage void fatal_trap(int trapnr, struct cpu_user_regs *regs);
>
>
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