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kgdb/kgdbts: support ppc64 

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>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
hifive-unleashed-5.1
Tiejun Chen 2013-02-27 11:09:27 +08:00 committed by Jason Wessel
parent f7c82d5a3c
commit e78acf67ba
1 changed files with 2 additions and 0 deletions
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2
drivers/misc/kgdbts.c
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@ -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;
}