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s390/entry: Unify save_area_sync and save_area_async

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In the past two save areas existed because interrupt handlers
and system call / program check handlers where entered with
interrupts enabled. To prevent a handler from overwriting the
save areas from the previous handler, interrupts used the async
save area, while system call and program check handler used the
sync save area.

Since the removal of critical section cleanup from entry.S, handlers are
entered with interrupts disabled. When the interrupts are re-enabled,
the save area is no longer need. Therefore merge both save areas into one.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Sven Schnelle 2024-08-28 13:50:04 +02:00 committed by Vasily Gorbik
parent 56199bb956
commit ee3daf7c05
4 changed files with 16 additions and 17 deletions
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4
arch/s390/boot/head.S
View File

@ -299,11 +299,11 @@ SYM_CODE_END(startup_normal)
# the save area and does disabled wait with a faulty address.
#
SYM_CODE_START_LOCAL(startup_pgm_check_handler)
stmg %r8,%r15,__LC_SAVE_AREA_SYNC
stmg %r8,%r15,__LC_SAVE_AREA
la %r8,4095
stctg %c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r8)
stmg %r0,%r7,__LC_GPREGS_SAVE_AREA-4095(%r8)
mvc __LC_GPREGS_SAVE_AREA-4095+64(64,%r8),__LC_SAVE_AREA_SYNC
mvc __LC_GPREGS_SAVE_AREA-4095+64(64,%r8),__LC_SAVE_AREA
mvc __LC_PSW_SAVE_AREA-4095(16,%r8),__LC_PGM_OLD_PSW
mvc __LC_RETURN_PSW(16),__LC_PGM_OLD_PSW
ni __LC_RETURN_PSW,0xfc # remove IO and EX bits

4
arch/s390/include/asm/lowcore.h
View File

@ -98,8 +98,8 @@ struct lowcore {
psw_t io_new_psw; /* 0x01f0 */
/* Save areas. */
__u64 save_area_sync[8]; /* 0x0200 */
__u64 save_area_async[8]; /* 0x0240 */
__u64 save_area[8]; /* 0x0200 */
__u8 pad_0x0240[0x0280-0x0240]; /* 0x0240 */
__u64 save_area_restart[1]; /* 0x0280 */
__u64 pcpu; /* 0x0288 */

3
arch/s390/kernel/asm-offsets.c
View File

@ -112,8 +112,7 @@ int main(void)
OFFSET(__LC_MCK_NEW_PSW, lowcore, mcck_new_psw);
OFFSET(__LC_IO_NEW_PSW, lowcore, io_new_psw);
/* software defined lowcore locations 0x200 - 0xdff*/
OFFSET(__LC_SAVE_AREA_SYNC, lowcore, save_area_sync);
OFFSET(__LC_SAVE_AREA_ASYNC, lowcore, save_area_async);
OFFSET(__LC_SAVE_AREA, lowcore, save_area);
OFFSET(__LC_SAVE_AREA_RESTART, lowcore, save_area_restart);
OFFSET(__LC_PCPU, lowcore, pcpu);
OFFSET(__LC_RETURN_PSW, lowcore, return_psw);

22
arch/s390/kernel/entry.S
View File

@ -264,7 +264,7 @@ EXPORT_SYMBOL(sie_exit)
*/
SYM_CODE_START(system_call)
STMG_LC %r8,%r15,__LC_SAVE_AREA_SYNC
STMG_LC %r8,%r15,__LC_SAVE_AREA
GET_LC %r13
stpt __LC_SYS_ENTER_TIMER(%r13)
BPOFF
@ -287,7 +287,7 @@ SYM_CODE_START(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(%r13)
mvc __PT_R8(64,%r2),__LC_SAVE_AREA(%r13)
MBEAR %r2,%r13
lgr %r3,%r14
brasl %r14,__do_syscall
@ -323,7 +323,7 @@ SYM_CODE_END(ret_from_fork)
*/
SYM_CODE_START(pgm_check_handler)
STMG_LC %r8,%r15,__LC_SAVE_AREA_SYNC
STMG_LC %r8,%r15,__LC_SAVE_AREA
GET_LC %r13
stpt __LC_SYS_ENTER_TIMER(%r13)
BPOFF
@ -338,16 +338,16 @@ SYM_CODE_START(pgm_check_handler)
jnz 2f # -> enabled, can't be a double fault
tm __LC_PGM_ILC+3(%r13),0x80 # check for per exception
jnz .Lpgm_svcper # -> single stepped svc
2: CHECK_STACK __LC_SAVE_AREA_SYNC,%r13
2: CHECK_STACK __LC_SAVE_AREA,%r13
aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
# CHECK_VMAP_STACK branches to stack_overflow or 4f
CHECK_VMAP_STACK __LC_SAVE_AREA_SYNC,%r13,4f
CHECK_VMAP_STACK __LC_SAVE_AREA,%r13,4f
3: lg %r15,__LC_KERNEL_STACK(%r13)
4: la %r11,STACK_FRAME_OVERHEAD(%r15)
xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC(%r13)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA(%r13)
mvc __PT_LAST_BREAK(8,%r11),__LC_PGM_LAST_BREAK(%r13)
stctg %c1,%c1,__PT_CR1(%r11)
#if IS_ENABLED(CONFIG_KVM)
@ -398,7 +398,7 @@ SYM_CODE_END(pgm_check_handler)
*/
.macro INT_HANDLER name,lc_old_psw,handler
SYM_CODE_START(\name)
STMG_LC %r8,%r15,__LC_SAVE_AREA_ASYNC
STMG_LC %r8,%r15,__LC_SAVE_AREA
GET_LC %r13
stckf __LC_INT_CLOCK(%r13)
stpt __LC_SYS_ENTER_TIMER(%r13)
@ -414,7 +414,7 @@ SYM_CODE_START(\name)
BPENTER __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
SIEEXIT __SF_SIE_CONTROL(%r15),%r13
#endif
0: CHECK_STACK __LC_SAVE_AREA_ASYNC,%r13
0: CHECK_STACK __LC_SAVE_AREA,%r13
aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
j 2f
1: lctlg %c1,%c1,__LC_KERNEL_ASCE(%r13)
@ -432,7 +432,7 @@ SYM_CODE_START(\name)
xgr %r7,%r7
xgr %r10,%r10
xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC(%r13)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA(%r13)
MBEAR %r11,%r13
stmg %r8,%r9,__PT_PSW(%r11)
lgr %r2,%r11 # pass pointer to pt_regs
@ -601,14 +601,14 @@ SYM_CODE_END(restart_int_handler)
__INIT
SYM_CODE_START(early_pgm_check_handler)
STMG_LC %r8,%r15,__LC_SAVE_AREA_SYNC
STMG_LC %r8,%r15,__LC_SAVE_AREA
GET_LC %r13
aghi %r15,-(STACK_FRAME_OVERHEAD+__PT_SIZE)
la %r11,STACK_FRAME_OVERHEAD(%r15)
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_PSW(16,%r11),__LC_PGM_OLD_PSW(%r13)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC(%r13)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA(%r13)
lgr %r2,%r11
brasl %r14,__do_early_pgm_check
mvc __LC_RETURN_PSW(16,%r13),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)