renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-17 09:43:59 +08:00
Code

ARM: 8788/1: ftrace: remove old mcount support

Browse Source 
Commit cafa0010cd ("Raise the minimum required gcc version to 4.6")
raised the minimum GCC version to 4.6. Old mcount is only required for
GCC versions older than 4.4.0. Hence old mcount support can be dropped
too.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Stefan Agner 2018-09-11 04:31:49 +01:00 committed by Russell King
parent f3c899927e
commit d3c6161956
5 changed files with 4 additions and 133 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/arm/Kconfig.debug
View File

@ -70,11 +70,6 @@ config ARM_UNWIND
the performance is not affected. Currently, this feature
only works with EABI compilers. If unsure say Y.
config OLD_MCOUNT
bool
depends on FUNCTION_TRACER && FRAME_POINTER
default y
config DEBUG_USER
bool "Verbose user fault messages"
help

3
arch/arm/include/asm/ftrace.h
View File

@ -16,9 +16,6 @@ extern void __gnu_mcount_nc(void);
#ifdef CONFIG_DYNAMIC_FTRACE
struct dyn_arch_ftrace {
#ifdef CONFIG_OLD_MCOUNT
bool old_mcount;
#endif
};
static inline unsigned long ftrace_call_adjust(unsigned long addr)

3
arch/arm/kernel/armksyms.c
View File

@ -167,9 +167,6 @@ EXPORT_SYMBOL(_find_next_bit_be);
#endif
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_OLD_MCOUNT
EXPORT_SYMBOL(mcount);
#endif
EXPORT_SYMBOL(__gnu_mcount_nc);
#endif

75
arch/arm/kernel/entry-ftrace.S
View File

@ -15,23 +15,8 @@
* start of every function. In mcount, apart from the function's address (in
* lr), we need to get hold of the function's caller's address.
*
* Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
*
* bl mcount
*
* These versions have the limitation that in order for the mcount routine to
* be able to determine the function's caller's address, an APCS-style frame
* pointer (which is set up with something like the code below) is required.
*
* mov ip, sp
* push {fp, ip, lr, pc}
* sub fp, ip, #4
*
* With EABI, these frame pointers are not available unless -mapcs-frame is
* specified, and if building as Thumb-2, not even then.
*
* Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
* with call sites like:
* Newer GCCs (4.4+) solve this problem by using a version of mcount with call
* sites like:
*
* push {lr}
* bl __gnu_mcount_nc
@ -46,17 +31,10 @@
* allows it to be clobbered in subroutines and doesn't use it to hold
* parameters.)
*
* When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
* for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
* arch/arm/kernel/ftrace.c).
* When using dynamic ftrace, we patch out the mcount call by a "pop {lr}"
* instead of the __gnu_mcount_nc call (see arch/arm/kernel/ftrace.c).
*/
#ifndef CONFIG_OLD_MCOUNT
#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
#endif
#endif
.macro mcount_adjust_addr rd, rn
bic \rd, \rn, #1 @ clear the Thumb bit if present
sub \rd, \rd, #MCOUNT_INSN_SIZE
@ -209,51 +187,6 @@ ftrace_graph_call\suffix:
mcount_exit
.endm
#ifdef CONFIG_OLD_MCOUNT
/*
* mcount
*/
.macro mcount_enter
stmdb sp!, {r0-r3, lr}
.endm
.macro mcount_get_lr reg
ldr \reg, [fp, #-4]
.endm
.macro mcount_exit
ldr lr, [fp, #-4]
ldmia sp!, {r0-r3, pc}
.endm
ENTRY(mcount)
#ifdef CONFIG_DYNAMIC_FTRACE
stmdb sp!, {lr}
ldr lr, [fp, #-4]
ldmia sp!, {pc}
#else
__mcount _old
#endif
ENDPROC(mcount)
#ifdef CONFIG_DYNAMIC_FTRACE
ENTRY(ftrace_caller_old)
__ftrace_caller _old
ENDPROC(ftrace_caller_old)
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
ENTRY(ftrace_graph_caller_old)
__ftrace_graph_caller
ENDPROC(ftrace_graph_caller_old)
#endif
.purgem mcount_enter
.purgem mcount_get_lr
.purgem mcount_exit
#endif
/*
* __gnu_mcount_nc
*/

51
arch/arm/kernel/ftrace.c
View File

@ -47,30 +47,6 @@ void arch_ftrace_update_code(int command)
stop_machine(__ftrace_modify_code, &command, NULL);
}
#ifdef CONFIG_OLD_MCOUNT
#define OLD_MCOUNT_ADDR ((unsigned long) mcount)
#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old)
#define OLD_NOP 0xe1a00000 /* mov r0, r0 */
static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
{
return rec->arch.old_mcount ? OLD_NOP : NOP;
}
static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
{
if (!rec->arch.old_mcount)
return addr;
if (addr == MCOUNT_ADDR)
addr = OLD_MCOUNT_ADDR;
else if (addr == FTRACE_ADDR)
addr = OLD_FTRACE_ADDR;
return addr;
}
#else
static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
{
return NOP;
@ -80,7 +56,6 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
{
return addr;
}
#endif
int ftrace_arch_code_modify_prepare(void)
{
@ -150,15 +125,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
}
#endif
#ifdef CONFIG_OLD_MCOUNT
if (!ret) {
pc = (unsigned long)&ftrace_call_old;
new = ftrace_call_replace(pc, (unsigned long)func);
ret = ftrace_modify_code(pc, 0, new, false);
}
#endif
return ret;
}
@ -203,16 +169,6 @@ int ftrace_make_nop(struct module *mod,
new = ftrace_nop_replace(rec);
ret = ftrace_modify_code(ip, old, new, true);
#ifdef CONFIG_OLD_MCOUNT
if (ret == -EINVAL && addr == MCOUNT_ADDR) {
rec->arch.old_mcount = true;
old = ftrace_call_replace(ip, adjust_address(rec, addr));
new = ftrace_nop_replace(rec);
ret = ftrace_modify_code(ip, old, new, true);
}
#endif
return ret;
}
@ -290,13 +246,6 @@ static int ftrace_modify_graph_caller(bool enable)
#endif
#ifdef CONFIG_OLD_MCOUNT
if (!ret)
ret = __ftrace_modify_caller(&ftrace_graph_call_old,
ftrace_graph_caller_old,
enable);
#endif
return ret;
}