lkml.org 
[lkml]   [2012]   [Dec]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[v1][PATCH 6/6] kgdb/kgdbts: support ppc64
    Date
    We can't look up the address of the entry point of the function simply
    via that function symbol for all architectures.

    For PPC64 ABI, actually there is a function descriptors structure.

    A function descriptor is a three doubleword data structure that contains
    the following values:
    * The first doubleword contains the address of the entry point of
    the function.
    * The second doubleword contains the TOC base address for
    the function.
    * The third doubleword contains the environment pointer for
    languages such as Pascal and PL/1.

    So we should call a wapperred dereference_function_descriptor() to get
    the address of the entry point of the function.

    Note this is also safe for other architecture after refer to
    "include/asm-generic/sections.h" since:

    dereference_function_descriptor(p) always is (p) if without arched definition.

    Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
    ---
    drivers/misc/kgdbts.c | 2 ++
    1 file changed, 2 insertions(+)

    diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c
    index 3aa9a96..4799e1f 100644
    --- a/drivers/misc/kgdbts.c
    +++ b/drivers/misc/kgdbts.c
    @@ -103,6 +103,7 @@
    #include <linux/delay.h>
    #include <linux/kthread.h>
    #include <linux/module.h>
    +#include <asm/sections.h>

    #define v1printk(a...) do { \
    if (verbose) \
    @@ -222,6 +223,7 @@ static unsigned long lookup_addr(char *arg)
    addr = (unsigned long)do_fork;
    else if (!strcmp(arg, "hw_break_val"))
    addr = (unsigned long)&hw_break_val;
    + addr = (unsigned long )dereference_function_descriptor((void *)addr);
    return addr;
    }

    --
    1.7.9.5


    \
     
     \ /
      Last update: 2012-12-20 10:41    [W:2.777 / U:0.028 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site