Hi Guo Ren:
I used the readelf tool to view the address of csky_cmpxchg_ldw,
and used printk("0x%x\n",csky_cmpxchg_ldw) and
printk("0x%x\n",&csky_cmpxchg_ldw) to print it out in the code.
The result is that printk("0x%x\n",&csky_cmpxchg_ldw) prints the
correct result.
include/linux/linkage.h
#define GLOBAL(name) \
.globl name ASM_NL \
name:
#endif
arch/csky/kernel/atomic.S:
GLOBAL(csky_cmpxchg_ldw)
so
.globl csky_cmpxchg_ldw --->globl symbol
csky_cmpxchg_ldw: --->label symbol
yang li <yang.li85200@xxxxxxxxx> 于2024年10月18日周五 16:33写道：
>
> Hi Guo Ren:
> I used the readelf tool to view the address of csky_cmpxchg_ldw,
> and used printk("0x%x\n",csky_cmpxchg_ldw) and
> printk("0x%x\n",&csky_cmpxchg_ldw) to print it out in the code.
> The result is that printk("0x%x\n",&csky_cmpxchg_ldw) prints the
> correct result.
>
> include/linux/linkage.h
> #define GLOBAL(name) \
> .globl name ASM_NL \
> name:
> #endif
>
> arch/csky/kernel/atomic.S:
> GLOBAL(csky_cmpxchg_ldw)
> so
> .globl csky_cmpxchg_ldw --->globl symbol
> csky_cmpxchg_ldw: --->label symbol
>
>
>
>
> Guo Ren <guoren@xxxxxxxxxx> 于2024年10月17日周四 14:05写道：
>>
>> On Wed, Oct 16, 2024 at 5:56 PM Yang Li <yang.li85200@xxxxxxxxx> wrote:
>> >
>> > In the csky_cmpxchg_fixup function, it is incorrect to use the global
>> > variable csky_cmpxchg_stw to determine the address where the exception
>> > occurred.The global variable csky_cmpxchg_stw stores the opcode at the
>> > time of the exception, while &csky_cmpxchg_stw shows the address where
>> > the exception occurred.
>> >
>> > Signed-off-by: Yang Li <yang.li85200@xxxxxxxxx>
>> > ---
>> > V1 -> V2:Eliminate compilation warnings
>> >
>> > arch/csky/mm/fault.c | 4 ++--
>> > 1 file changed, 2 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
>> > index a885518ce1dd..5226bc08c336 100644
>> > --- a/arch/csky/mm/fault.c
>> > +++ b/arch/csky/mm/fault.c
>> > @@ -45,8 +45,8 @@ static inline void csky_cmpxchg_fixup(struct pt_regs *regs)
>> > if (trap_no(regs) != VEC_TLBMODIFIED)
>> > return;
>> >
>> > - if (instruction_pointer(regs) == csky_cmpxchg_stw)
>> > - instruction_pointer_set(regs, csky_cmpxchg_ldw);
>> > + if (instruction_pointer(regs) == (unsigned long)&csky_cmpxchg_stw)
>> > + instruction_pointer_set(regs, (unsigned long)&csky_cmpxchg_ldw);
>> csky_cmpxchg_ldw(stw) is a label symbol, not a variable.
>>
>> arch/csky/kernel/atomic.S:
>> GLOBAL(csky_cmpxchg_ldw)
>> GLOBAL(csky_cmpxchg_stw)
>>
>> Your modification does not affect the ASM output.
>>
>> (gdb) p main
>> $1 = {void (void)} 0x5fa <main>
>> (gdb) p &main
>> $2 = (void (*)(void)) 0x5fa <main>
>>
>> > return;
>> > }
>> > #endif
>> > --
>> > 2.34.1
>> >
>>
>>
>> --
>> Best Regards
>> Guo Ren
