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s390/entry: use assignment to read intcode / asm to copy gprs 

arch/s390/kernel/syscall.c: In function __do_syscall:
arch/s390/kernel/syscall.c:147:9: warning: memcpy reading 64 bytes from a region of size 0 [-Wstringop-overread]
  147 |         memcpy(&regs->gprs[8], S390_lowcore.save_area_sync, 8 * sizeof(unsigned long));
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/s390/kernel/syscall.c:148:9: warning: memcpy reading 4 bytes from a region of size 0 [-Wstringop-overread]
  148 |         memcpy(&regs->int_code, &S390_lowcore.svc_ilc, sizeof(regs->int_code));
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by moving the gprs restore from C to assembly, and use a assignment
for int_code instead of memcpy.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Sven Schnelle 2021-05-05 22:01:09 +02:00 committed by Vasily Gorbik
parent d460bb6c64
commit af9ad82290
4 changed files with 3 additions and 8 deletions
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3
arch/s390/include/asm/lowcore.h
View File

@ -24,8 +24,7 @@ struct lowcore {
__u32 ext_params; /* 0x0080 */
__u16 ext_cpu_addr; /* 0x0084 */
__u16 ext_int_code; /* 0x0086 */
__u16 svc_ilc; /* 0x0088 */
__u16 svc_code; /* 0x008a */
__u32 svc_int_code; /* 0x0088 */
__u16 pgm_ilc; /* 0x008c */
__u16 pgm_code; /* 0x008e */
__u32 data_exc_code; /* 0x0090 */

2
arch/s390/kernel/asm-offsets.c
View File

@ -58,8 +58,6 @@ int main(void)
OFFSET(__LC_EXT_PARAMS, lowcore, ext_params);
OFFSET(__LC_EXT_CPU_ADDR, lowcore, ext_cpu_addr);
OFFSET(__LC_EXT_INT_CODE, lowcore, ext_int_code);
OFFSET(__LC_SVC_ILC, lowcore, svc_ilc);
OFFSET(__LC_SVC_INT_CODE, lowcore, svc_code);
OFFSET(__LC_PGM_ILC, lowcore, pgm_ilc);
OFFSET(__LC_PGM_INT_CODE, lowcore, pgm_code);
OFFSET(__LC_DATA_EXC_CODE, lowcore, data_exc_code);

1
arch/s390/kernel/entry.S
View File

@ -276,6 +276,7 @@ ENTRY(system_call)
xgr %r10,%r10
xgr %r11,%r11
la %r2,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs
mvc __PT_R8(64,%r2),__LC_SAVE_AREA_SYNC
lgr %r3,%r14
brasl %r14,__do_syscall
lctlg %c1,%c1,__LC_USER_ASCE

5
arch/s390/kernel/syscall.c
View File

@ -144,11 +144,8 @@ void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
{
add_random_kstack_offset();
enter_from_user_mode(regs);
memcpy(&regs->gprs[8], S390_lowcore.save_area_sync, 8 * sizeof(unsigned long));
memcpy(&regs->int_code, &S390_lowcore.svc_ilc, sizeof(regs->int_code));
regs->psw = S390_lowcore.svc_old_psw;
regs->int_code = S390_lowcore.svc_int_code;
update_timer_sys();
local_irq_enable();