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author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2013-05-17 14:41:37 +0200 |
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committer | Gleb Natapov <gleb@redhat.com> | 2013-05-21 11:55:26 +0300 |
commit | 7c470539c95630c1f2a10f109e96f249730b75eb (patch) | |
tree | b3d518e9d6d92eb157ace9aa864dd3515c4e216b /arch/s390/kernel | |
parent | 2c70fe4416d5f6d092b20ebf7d7654835e09c109 (diff) | |
download | op-kernel-dev-7c470539c95630c1f2a10f109e96f249730b75eb.zip op-kernel-dev-7c470539c95630c1f2a10f109e96f249730b75eb.tar.gz |
s390/kvm: avoid automatic sie reentry
Do not automatically restart the sie instruction in entry64.S after an
interrupt, return to the caller with a reason code instead. That allows
to deal with RCU and other conditions in C code.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/s390/kernel')
-rw-r--r-- | arch/s390/kernel/entry64.S | 76 |
1 files changed, 33 insertions, 43 deletions
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S index c7daeef..51d99ac 100644 --- a/arch/s390/kernel/entry64.S +++ b/arch/s390/kernel/entry64.S @@ -47,7 +47,6 @@ _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \ _TIF_MCCK_PENDING) _TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \ _TIF_SYSCALL_TRACEPOINT) -_TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING) #define BASED(name) name-system_call(%r13) @@ -81,25 +80,27 @@ _TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING) #endif .endm - .macro HANDLE_SIE_INTERCEPT scratch,pgmcheck + .macro HANDLE_SIE_INTERCEPT scratch,reason #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE) tmhh %r8,0x0001 # interrupting from user ? - jnz .+52 + jnz .+62 lgr \scratch,%r9 - slg \scratch,BASED(.Lsie_loop) - clg \scratch,BASED(.Lsie_length) - .if \pgmcheck + slg \scratch,BASED(.Lsie_critical) + clg \scratch,BASED(.Lsie_critical_length) + .if \reason==1 # Some program interrupts are suppressing (e.g. protection). # We must also check the instruction after SIE in that case. # do_protection_exception will rewind to rewind_pad - jh .+32 + jh .+42 .else - jhe .+32 + jhe .+42 .endif - lg %r9,BASED(.Lsie_loop) - LPP BASED(.Lhost_id) # set host id - lg %r14,__SF_EMPTY(%r15) # get control block pointer + lg %r14,__SF_EMPTY(%r15) # get control block pointer + LPP __SF_EMPTY+16(%r15) # set host id ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE + lctlg %c1,%c1,__LC_USER_ASCE # load primary asce + larl %r9,sie_exit # skip forward to sie_exit + mvi __SF_EMPTY+31(%r15),\reason # set exit reason #endif .endm @@ -452,7 +453,7 @@ ENTRY(io_int_handler) lg %r12,__LC_THREAD_INFO larl %r13,system_call lmg %r8,%r9,__LC_IO_OLD_PSW - HANDLE_SIE_INTERCEPT %r14,0 + HANDLE_SIE_INTERCEPT %r14,2 SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT tmhh %r8,0x0001 # interrupting from user? jz io_skip @@ -597,7 +598,7 @@ ENTRY(ext_int_handler) lg %r12,__LC_THREAD_INFO larl %r13,system_call lmg %r8,%r9,__LC_EXT_OLD_PSW - HANDLE_SIE_INTERCEPT %r14,0 + HANDLE_SIE_INTERCEPT %r14,3 SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT tmhh %r8,0x0001 # interrupting from user ? jz ext_skip @@ -645,7 +646,7 @@ ENTRY(mcck_int_handler) lg %r12,__LC_THREAD_INFO larl %r13,system_call lmg %r8,%r9,__LC_MCK_OLD_PSW - HANDLE_SIE_INTERCEPT %r14,0 + HANDLE_SIE_INTERCEPT %r14,4 tm __LC_MCCK_CODE,0x80 # system damage? jo mcck_panic # yes -> rest of mcck code invalid lghi %r14,__LC_CPU_TIMER_SAVE_AREA @@ -939,19 +940,8 @@ ENTRY(sie64a) stmg %r6,%r14,__SF_GPRS(%r15) # save kernel registers stg %r2,__SF_EMPTY(%r15) # save control block pointer stg %r3,__SF_EMPTY+8(%r15) # save guest register save area - xc __SF_EMPTY+16(8,%r15),__SF_EMPTY+16(%r15) # host id == 0 + xc __SF_EMPTY+16(16,%r15),__SF_EMPTY+16(%r15) # host id & reason lmg %r0,%r13,0(%r3) # load guest gprs 0-13 -# some program checks are suppressing. C code (e.g. do_protection_exception) -# will rewind the PSW by the ILC, which is 4 bytes in case of SIE. Other -# instructions in the sie_loop should not cause program interrupts. So -# lets use a nop (47 00 00 00) as a landing pad. -# See also HANDLE_SIE_INTERCEPT -rewind_pad: - nop 0 -sie_loop: - lg %r14,__LC_THREAD_INFO # pointer thread_info struct - tm __TI_flags+7(%r14),_TIF_EXIT_SIE - jnz sie_exit lg %r14,__LC_GMAP # get gmap pointer ltgr %r14,%r14 jz sie_gmap @@ -966,33 +956,33 @@ sie_gmap: sie_done: LPP __SF_EMPTY+16(%r15) # set host id ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE - lg %r14,__LC_THREAD_INFO # pointer thread_info struct -sie_exit: lctlg %c1,%c1,__LC_USER_ASCE # load primary asce +# some program checks are suppressing. C code (e.g. do_protection_exception) +# will rewind the PSW by the ILC, which is 4 bytes in case of SIE. Other +# instructions beween sie64a and sie_done should not cause program +# interrupts. So lets use a nop (47 00 00 00) as a landing pad. +# See also HANDLE_SIE_INTERCEPT +rewind_pad: + nop 0 +sie_exit: lg %r14,__SF_EMPTY+8(%r15) # load guest register save area stmg %r0,%r13,0(%r14) # save guest gprs 0-13 lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers - lghi %r2,0 + lg %r2,__SF_EMPTY+24(%r15) # return exit reason code br %r14 sie_fault: - lctlg %c1,%c1,__LC_USER_ASCE # load primary asce - lg %r14,__LC_THREAD_INFO # pointer thread_info struct - lg %r14,__SF_EMPTY+8(%r15) # load guest register save area - stmg %r0,%r13,0(%r14) # save guest gprs 0-13 - lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers - lghi %r2,-EFAULT - br %r14 + lghi %r14,-EFAULT + stg %r14,__SF_EMPTY+24(%r15) # set exit reason code + j sie_exit .align 8 -.Lsie_loop: - .quad sie_loop -.Lsie_length: - .quad sie_done - sie_loop -.Lhost_id: - .quad 0 +.Lsie_critical: + .quad sie_gmap +.Lsie_critical_length: + .quad sie_done - sie_gmap EX_TABLE(rewind_pad,sie_fault) - EX_TABLE(sie_loop,sie_fault) + EX_TABLE(sie_exit,sie_fault) #endif .section .rodata, "a" |