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MIPS, Tracing: Substitute in_kernel_space() for in_module() 

The old in_module() may not work in some situations(e.g. when module &
kernel are in the same address space when CONFIG_MAPPED_KERNEL=y), The
in_kernel_space() is more generic and it is also easy to be implemented
via cloning the existing core_kernel_text(), so, replace the in_module()
with in_kernel_space().

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2005/
Signed-off-by: Ralf Baechle <ralf@duck.linux-mips.net>
This commit is contained in:
Wu Zhangjin 2011-01-20 03:28:29 +08:00 committed by Ralf Baechle
parent 9a620a559b
commit d9cdb2f103
1 changed files with 27 additions and 27 deletions
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54
arch/mips/kernel/ftrace.c
View File

@ -17,21 +17,7 @@
#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;
}
#include <asm-generic/sections.h>
#ifdef CONFIG_DYNAMIC_FTRACE
@ -69,6 +55,20 @@ static inline void ftrace_dyn_arch_init_insns(void)
#endif
}
/*
* Check if the address is in kernel space
*
* Clone core_kernel_text() from kernel/extable.c, but doesn't call
* init_kernel_text() for Ftrace doesn't trace functions in init sections.
*/
static inline int in_kernel_space(unsigned long ip)
{
if (ip >= (unsigned long)_stext &&
ip <= (unsigned long)_etext)
return 1;
return 0;
}
static int ftrace_modify_code(unsigned long ip, unsigned int new_code)
{
int faulted;
@ -91,10 +91,16 @@ int ftrace_make_nop(struct module *mod,
unsigned long ip = rec->ip;
/*
* We have compiled module with -mlong-calls, but compiled the kernel
* without it, we need to cope with them respectively.
* If ip is in kernel space, no long call, otherwise, long call is
* needed.
*/
if (in_module(ip)) {
if (in_kernel_space(ip)) {
/*
* move at, ra
* jal _mcount --> nop
*/
new = INSN_NOP;
} else {
#if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
/*
* lui v1, hi_16bit_of_mcount --> b 1f (0x10000005)
@ -117,12 +123,6 @@ int ftrace_make_nop(struct module *mod,
*/
new = INSN_B_1F_4;
#endif
} else {
/*
* move at, ra
* jal _mcount --> nop
*/
new = INSN_NOP;
}
return ftrace_modify_code(ip, new);
}
@ -132,8 +132,8 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
unsigned int new;
unsigned long ip = rec->ip;
/* ip, module: 0xc0000000, kernel: 0x80000000 */
new = in_module(ip) ? insn_lui_v1_hi16_mcount : insn_jal_ftrace_caller;
new = in_kernel_space(ip) ? insn_jal_ftrace_caller :
insn_lui_v1_hi16_mcount;
return ftrace_modify_code(ip, new);
}
@ -204,7 +204,7 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr,
* instruction "lui v1, hi_16bit_of_mcount"(offset is 24), but for
* kernel, move after the instruction "move ra, at"(offset is 16)
*/
ip = self_addr - (in_module(self_addr) ? 24 : 16);
ip = self_addr - (in_kernel_space(self_addr) ? 16 : 24);
/*
* search the text until finding the non-store instruction or "s{d,w}