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MIPS: Tracing: Cleanup of address space checking 

This patch adds an inline function in_module() to check which space the
instruction pointer in, kernel space or module space.

Note:  This will not work when the kernel space and module space are the
same. If they are the same, we need to modify scripts/recordmcount.pl,
ftrace_make_nop/call() and the other related parts to ensure the
enabling/disabling of the calling site to _mcount is right for both
kernel and module.

[Ralf: It also is still incorrect for some 64-bit kernels.]

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Cc: David Daney <david.s.daney@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/1232/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Wu Zhangjin 2010-05-14 19:08:34 +08:00 committed by Ralf Baechle
parent 68ccf7521d
commit c9f84873c1
1 changed files with 19 additions and 3 deletions
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22
arch/mips/kernel/ftrace.c
View File

@ -17,6 +17,22 @@
#include <asm/cacheflush.h>
#include <asm/uasm.h>
/*
* If the Instruction Pointer is in module space (0xc0000000), return true;
* otherwise, it is in kernel space (0x80000000), return false.
*
* FIXME: This will not work when the kernel space and module space are the
* same. If they are the same, we need to modify scripts/recordmcount.pl,
* ftrace_make_nop/call() and the other related parts to ensure the
* enabling/disabling of the calling site to _mcount is right for both kernel
* and module.
*/
static inline int in_module(unsigned long ip)
{
return ip & 0x40000000;
}
#ifdef CONFIG_DYNAMIC_FTRACE
#define JAL 0x0c000000 /* jump & link: ip --> ra, jump to target */
@ -78,7 +94,7 @@ int ftrace_make_nop(struct module *mod,
* We have compiled module with -mlong-calls, but compiled the kernel
* without it, we need to cope with them respectively.
*/
if (ip & 0x40000000) {
if (in_module(ip)) {
#if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
/*
* lui v1, hi_16bit_of_mcount --> b 1f (0x10000005)
@ -117,7 +133,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
unsigned long ip = rec->ip;
/* ip, module: 0xc0000000, kernel: 0x80000000 */
new = (ip & 0x40000000) ? insn_lui_v1_hi16_mcount : insn_jal_ftrace_caller;
new = in_module(ip) ? insn_lui_v1_hi16_mcount : insn_jal_ftrace_caller;
return ftrace_modify_code(ip, new);
}
@ -188,7 +204,7 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr,
* instruction "lui v1, hi_16bit_of_mcount"(offset is 20), but for
* kernel, move to the instruction "move ra, at"(offset is 12)
*/
ip = self_addr - ((self_addr & 0x40000000) ? 20 : 12);
ip = self_addr - (in_module(self_addr) ? 20 : 12);
/*
* search the text until finding the non-store instruction or "s{d,w}