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Diffstat (limited to 'arch/s390/kernel/entry.S')
| -rw-r--r-- | arch/s390/kernel/entry.S | 715 |
1 files changed, 715 insertions, 0 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S new file mode 100644 index 000000000..d2a1f2f4f --- /dev/null +++ b/arch/s390/kernel/entry.S @@ -0,0 +1,715 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * S390 low-level entry points. + * + * Copyright IBM Corp. 1999, 2012 + * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), + * Hartmut Penner (hp@de.ibm.com), + * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com), + */ + +#include <linux/init.h> +#include <linux/linkage.h> +#include <asm/asm-extable.h> +#include <asm/alternative-asm.h> +#include <asm/processor.h> +#include <asm/cache.h> +#include <asm/dwarf.h> +#include <asm/errno.h> +#include <asm/ptrace.h> +#include <asm/thread_info.h> +#include <asm/asm-offsets.h> +#include <asm/unistd.h> +#include <asm/page.h> +#include <asm/sigp.h> +#include <asm/irq.h> +#include <asm/vx-insn.h> +#include <asm/setup.h> +#include <asm/nmi.h> +#include <asm/export.h> +#include <asm/nospec-insn.h> + +STACK_SHIFT = PAGE_SHIFT + THREAD_SIZE_ORDER +STACK_SIZE = 1 << STACK_SHIFT +STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE + +_LPP_OFFSET = __LC_LPP + + .macro STBEAR address + ALTERNATIVE "nop", ".insn s,0xb2010000,\address", 193 + .endm + + .macro LBEAR address + ALTERNATIVE "nop", ".insn s,0xb2000000,\address", 193 + .endm + + .macro LPSWEY address,lpswe + ALTERNATIVE "b \lpswe; nopr", ".insn siy,0xeb0000000071,\address,0", 193 + .endm + + .macro MBEAR reg + ALTERNATIVE "brcl 0,0", __stringify(mvc __PT_LAST_BREAK(8,\reg),__LC_LAST_BREAK), 193 + .endm + + .macro CHECK_STACK savearea +#ifdef CONFIG_CHECK_STACK + tml %r15,STACK_SIZE - CONFIG_STACK_GUARD + lghi %r14,\savearea + jz stack_overflow +#endif + .endm + + .macro CHECK_VMAP_STACK savearea,oklabel +#ifdef CONFIG_VMAP_STACK + lgr %r14,%r15 + nill %r14,0x10000 - STACK_SIZE + oill %r14,STACK_INIT + clg %r14,__LC_KERNEL_STACK + je \oklabel + clg %r14,__LC_ASYNC_STACK + je \oklabel + clg %r14,__LC_MCCK_STACK + je \oklabel + clg %r14,__LC_NODAT_STACK + je \oklabel + clg %r14,__LC_RESTART_STACK + je \oklabel + lghi %r14,\savearea + j stack_overflow +#else + j \oklabel +#endif + .endm + + /* + * The TSTMSK macro generates a test-under-mask instruction by + * calculating the memory offset for the specified mask value. + * Mask value can be any constant. The macro shifts the mask + * value to calculate the memory offset for the test-under-mask + * instruction. + */ + .macro TSTMSK addr, mask, size=8, bytepos=0 + .if (\bytepos < \size) && (\mask >> 8) + .if (\mask & 0xff) + .error "Mask exceeds byte boundary" + .endif + TSTMSK \addr, "(\mask >> 8)", \size, "(\bytepos + 1)" + .exitm + .endif + .ifeq \mask + .error "Mask must not be zero" + .endif + off = \size - \bytepos - 1 + tm off+\addr, \mask + .endm + + .macro BPOFF + ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,12,0", 82 + .endm + + .macro BPON + ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,13,0", 82 + .endm + + .macro BPENTER tif_ptr,tif_mask + ALTERNATIVE "TSTMSK \tif_ptr,\tif_mask; jz .+8; .insn rrf,0xb2e80000,0,0,13,0", \ + "j .+12; nop; nop", 82 + .endm + + .macro BPEXIT tif_ptr,tif_mask + TSTMSK \tif_ptr,\tif_mask + ALTERNATIVE "jz .+8; .insn rrf,0xb2e80000,0,0,12,0", \ + "jnz .+8; .insn rrf,0xb2e80000,0,0,13,0", 82 + .endm + + /* + * The CHKSTG macro jumps to the provided label in case the + * machine check interruption code reports one of unrecoverable + * storage errors: + * - Storage error uncorrected + * - Storage key error uncorrected + * - Storage degradation with Failing-storage-address validity + */ + .macro CHKSTG errlabel + TSTMSK __LC_MCCK_CODE,(MCCK_CODE_STG_ERROR|MCCK_CODE_STG_KEY_ERROR) + jnz \errlabel + TSTMSK __LC_MCCK_CODE,MCCK_CODE_STG_DEGRAD + jz .Loklabel\@ + TSTMSK __LC_MCCK_CODE,MCCK_CODE_STG_FAIL_ADDR + jnz \errlabel +.Loklabel\@: + .endm + +#if IS_ENABLED(CONFIG_KVM) + /* + * The OUTSIDE macro jumps to the provided label in case the value + * in the provided register is outside of the provided range. The + * macro is useful for checking whether a PSW stored in a register + * pair points inside or outside of a block of instructions. + * @reg: register to check + * @start: start of the range + * @end: end of the range + * @outside_label: jump here if @reg is outside of [@start..@end) + */ + .macro OUTSIDE reg,start,end,outside_label + lgr %r14,\reg + larl %r13,\start + slgr %r14,%r13 +#ifdef CONFIG_AS_IS_LLVM + clgfrl %r14,.Lrange_size\@ +#else + clgfi %r14,\end - \start +#endif + jhe \outside_label +#ifdef CONFIG_AS_IS_LLVM + .section .rodata, "a" + .align 4 +.Lrange_size\@: + .long \end - \start + .previous +#endif + .endm + + .macro SIEEXIT + lg %r9,__SF_SIE_CONTROL(%r15) # get control block pointer + ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE + lctlg %c1,%c1,__LC_KERNEL_ASCE # load primary asce + larl %r9,sie_exit # skip forward to sie_exit + .endm +#endif + + GEN_BR_THUNK %r14 + + .section .kprobes.text, "ax" +.Ldummy: + /* + * This nop exists only in order to avoid that __bpon starts at + * the beginning of the kprobes text section. In that case we would + * have several symbols at the same address. E.g. objdump would take + * an arbitrary symbol name when disassembling this code. + * With the added nop in between the __bpon symbol is unique + * again. + */ + nop 0 + +ENTRY(__bpon) + .globl __bpon + BPON + BR_EX %r14 +ENDPROC(__bpon) + +/* + * Scheduler resume function, called by switch_to + * gpr2 = (task_struct *) prev + * gpr3 = (task_struct *) next + * Returns: + * gpr2 = prev + */ +ENTRY(__switch_to) + stmg %r6,%r15,__SF_GPRS(%r15) # store gprs of prev task + lghi %r4,__TASK_stack + lghi %r1,__TASK_thread + llill %r5,STACK_INIT + stg %r15,__THREAD_ksp(%r1,%r2) # store kernel stack of prev + lg %r15,0(%r4,%r3) # start of kernel stack of next + agr %r15,%r5 # end of kernel stack of next + stg %r3,__LC_CURRENT # store task struct of next + stg %r15,__LC_KERNEL_STACK # store end of kernel stack + lg %r15,__THREAD_ksp(%r1,%r3) # load kernel stack of next + aghi %r3,__TASK_pid + mvc __LC_CURRENT_PID(4,%r0),0(%r3) # store pid of next + lmg %r6,%r15,__SF_GPRS(%r15) # load gprs of next task + ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40 + BR_EX %r14 +ENDPROC(__switch_to) + +#if IS_ENABLED(CONFIG_KVM) +/* + * sie64a calling convention: + * %r2 pointer to sie control block + * %r3 guest register save area + */ +ENTRY(sie64a) + stmg %r6,%r14,__SF_GPRS(%r15) # save kernel registers + lg %r12,__LC_CURRENT + stg %r2,__SF_SIE_CONTROL(%r15) # save control block pointer + stg %r3,__SF_SIE_SAVEAREA(%r15) # save guest register save area + xc __SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0 + mvc __SF_SIE_FLAGS(8,%r15),__TI_flags(%r12) # copy thread flags + lmg %r0,%r13,0(%r3) # load guest gprs 0-13 + lg %r14,__LC_GMAP # get gmap pointer + ltgr %r14,%r14 + jz .Lsie_gmap + lctlg %c1,%c1,__GMAP_ASCE(%r14) # load primary asce +.Lsie_gmap: + lg %r14,__SF_SIE_CONTROL(%r15) # get control block pointer + oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now + tm __SIE_PROG20+3(%r14),3 # last exit... + jnz .Lsie_skip + TSTMSK __LC_CPU_FLAGS,_CIF_FPU + jo .Lsie_skip # exit if fp/vx regs changed + BPEXIT __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST) +.Lsie_entry: + sie 0(%r14) +# Let the next instruction be NOP to avoid triggering a machine check +# and handling it in a guest as result of the instruction execution. + nopr 7 +.Lsie_leave: + BPOFF + BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST) +.Lsie_skip: + ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE + lctlg %c1,%c1,__LC_KERNEL_ASCE # load primary asce +.Lsie_done: +# some program checks are suppressing. C code (e.g. do_protection_exception) +# will rewind the PSW by the ILC, which is often 4 bytes in case of SIE. There +# are some corner cases (e.g. runtime instrumentation) where ILC is unpredictable. +# Other instructions between sie64a and .Lsie_done should not cause program +# interrupts. So lets use 3 nops as a landing pad for all possible rewinds. +.Lrewind_pad6: + nopr 7 +.Lrewind_pad4: + nopr 7 +.Lrewind_pad2: + nopr 7 + .globl sie_exit +sie_exit: + lg %r14,__SF_SIE_SAVEAREA(%r15) # load guest register save area + stmg %r0,%r13,0(%r14) # save guest gprs 0-13 + xgr %r0,%r0 # clear guest registers to + xgr %r1,%r1 # prevent speculative use + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 + lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers + lg %r2,__SF_SIE_REASON(%r15) # return exit reason code + BR_EX %r14 +.Lsie_fault: + lghi %r14,-EFAULT + stg %r14,__SF_SIE_REASON(%r15) # set exit reason code + j sie_exit + + EX_TABLE(.Lrewind_pad6,.Lsie_fault) + EX_TABLE(.Lrewind_pad4,.Lsie_fault) + EX_TABLE(.Lrewind_pad2,.Lsie_fault) + EX_TABLE(sie_exit,.Lsie_fault) +ENDPROC(sie64a) +EXPORT_SYMBOL(sie64a) +EXPORT_SYMBOL(sie_exit) +#endif + +/* + * SVC interrupt handler routine. System calls are synchronous events and + * are entered with interrupts disabled. + */ + +ENTRY(system_call) + stpt __LC_SYS_ENTER_TIMER + stmg %r8,%r15,__LC_SAVE_AREA_SYNC + BPOFF + lghi %r14,0 +.Lsysc_per: + STBEAR __LC_LAST_BREAK + lctlg %c1,%c1,__LC_KERNEL_ASCE + lg %r12,__LC_CURRENT + lg %r15,__LC_KERNEL_STACK + xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) + stmg %r0,%r7,STACK_FRAME_OVERHEAD+__PT_R0(%r15) + BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP + # clear user controlled register to prevent speculative use + xgr %r0,%r0 + xgr %r1,%r1 + xgr %r4,%r4 + xgr %r5,%r5 + xgr %r6,%r6 + xgr %r7,%r7 + xgr %r8,%r8 + xgr %r9,%r9 + 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 + MBEAR %r2 + lgr %r3,%r14 + brasl %r14,__do_syscall + lctlg %c1,%c1,__LC_USER_ASCE + mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15) + BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP + LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15) + lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15) + stpt __LC_EXIT_TIMER + LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE +ENDPROC(system_call) + +# +# a new process exits the kernel with ret_from_fork +# +ENTRY(ret_from_fork) + lgr %r3,%r11 + brasl %r14,__ret_from_fork + lctlg %c1,%c1,__LC_USER_ASCE + mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15) + BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP + LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15) + lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15) + stpt __LC_EXIT_TIMER + LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE +ENDPROC(ret_from_fork) + +/* + * Program check handler routine + */ + +ENTRY(pgm_check_handler) + stpt __LC_SYS_ENTER_TIMER + BPOFF + stmg %r8,%r15,__LC_SAVE_AREA_SYNC + lg %r12,__LC_CURRENT + lghi %r10,0 + lmg %r8,%r9,__LC_PGM_OLD_PSW + tmhh %r8,0x0001 # coming from user space? + jno .Lpgm_skip_asce + lctlg %c1,%c1,__LC_KERNEL_ASCE + j 3f # -> fault in user space +.Lpgm_skip_asce: +#if IS_ENABLED(CONFIG_KVM) + # cleanup critical section for program checks in sie64a + OUTSIDE %r9,.Lsie_gmap,.Lsie_done,1f + SIEEXIT + lghi %r10,_PIF_GUEST_FAULT +#endif +1: tmhh %r8,0x4000 # PER bit set in old PSW ? + jnz 2f # -> enabled, can't be a double fault + tm __LC_PGM_ILC+3,0x80 # check for per exception + jnz .Lpgm_svcper # -> single stepped svc +2: CHECK_STACK __LC_SAVE_AREA_SYNC + aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) + # CHECK_VMAP_STACK branches to stack_overflow or 4f + CHECK_VMAP_STACK __LC_SAVE_AREA_SYNC,4f +3: BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP + lg %r15,__LC_KERNEL_STACK +4: la %r11,STACK_FRAME_OVERHEAD(%r15) + stg %r10,__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 + mvc __PT_LAST_BREAK(8,%r11),__LC_PGM_LAST_BREAK + stmg %r8,%r9,__PT_PSW(%r11) + + # clear user controlled registers to prevent speculative use + xgr %r0,%r0 + xgr %r1,%r1 + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 + xgr %r6,%r6 + xgr %r7,%r7 + lgr %r2,%r11 + brasl %r14,__do_pgm_check + tmhh %r8,0x0001 # returning to user space? + jno .Lpgm_exit_kernel + lctlg %c1,%c1,__LC_USER_ASCE + BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP + stpt __LC_EXIT_TIMER +.Lpgm_exit_kernel: + mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15) + LBEAR STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15) + lmg %r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15) + LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE + +# +# single stepped system call +# +.Lpgm_svcper: + mvc __LC_RETURN_PSW(8),__LC_SVC_NEW_PSW + larl %r14,.Lsysc_per + stg %r14,__LC_RETURN_PSW+8 + lghi %r14,1 + LBEAR __LC_PGM_LAST_BREAK + LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE # branch to .Lsysc_per +ENDPROC(pgm_check_handler) + +/* + * Interrupt handler macro used for external and IO interrupts. + */ +.macro INT_HANDLER name,lc_old_psw,handler +ENTRY(\name) + stckf __LC_INT_CLOCK + stpt __LC_SYS_ENTER_TIMER + STBEAR __LC_LAST_BREAK + BPOFF + stmg %r8,%r15,__LC_SAVE_AREA_ASYNC + lg %r12,__LC_CURRENT + lmg %r8,%r9,\lc_old_psw + tmhh %r8,0x0001 # interrupting from user ? + jnz 1f +#if IS_ENABLED(CONFIG_KVM) + OUTSIDE %r9,.Lsie_gmap,.Lsie_done,0f + BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST) + SIEEXIT +#endif +0: CHECK_STACK __LC_SAVE_AREA_ASYNC + aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE) + j 2f +1: BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP + lctlg %c1,%c1,__LC_KERNEL_ASCE + lg %r15,__LC_KERNEL_STACK +2: xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) + la %r11,STACK_FRAME_OVERHEAD(%r15) + stmg %r0,%r7,__PT_R0(%r11) + # clear user controlled registers to prevent speculative use + xgr %r0,%r0 + xgr %r1,%r1 + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 + xgr %r6,%r6 + xgr %r7,%r7 + xgr %r10,%r10 + xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11) + mvc __PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC + MBEAR %r11 + stmg %r8,%r9,__PT_PSW(%r11) + lgr %r2,%r11 # pass pointer to pt_regs + brasl %r14,\handler + mvc __LC_RETURN_PSW(16),__PT_PSW(%r11) + tmhh %r8,0x0001 # returning to user ? + jno 2f + lctlg %c1,%c1,__LC_USER_ASCE + BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP + stpt __LC_EXIT_TIMER +2: LBEAR __PT_LAST_BREAK(%r11) + lmg %r0,%r15,__PT_R0(%r11) + LPSWEY __LC_RETURN_PSW,__LC_RETURN_LPSWE +ENDPROC(\name) +.endm + +INT_HANDLER ext_int_handler,__LC_EXT_OLD_PSW,do_ext_irq +INT_HANDLER io_int_handler,__LC_IO_OLD_PSW,do_io_irq + +/* + * Load idle PSW. + */ +ENTRY(psw_idle) + stg %r14,(__SF_GPRS+8*8)(%r15) + stg %r3,__SF_EMPTY(%r15) + larl %r1,psw_idle_exit + stg %r1,__SF_EMPTY+8(%r15) + larl %r1,smp_cpu_mtid + llgf %r1,0(%r1) + ltgr %r1,%r1 + jz .Lpsw_idle_stcctm + .insn rsy,0xeb0000000017,%r1,5,__MT_CYCLES_ENTER(%r2) +.Lpsw_idle_stcctm: + oi __LC_CPU_FLAGS+7,_CIF_ENABLED_WAIT + BPON + stckf __CLOCK_IDLE_ENTER(%r2) + stpt __TIMER_IDLE_ENTER(%r2) + lpswe __SF_EMPTY(%r15) +.globl psw_idle_exit +psw_idle_exit: + BR_EX %r14 +ENDPROC(psw_idle) + +/* + * Machine check handler routines + */ +ENTRY(mcck_int_handler) + stckf __LC_MCCK_CLOCK + BPOFF + la %r1,4095 # validate r1 + spt __LC_CPU_TIMER_SAVE_AREA-4095(%r1) # validate cpu timer + LBEAR __LC_LAST_BREAK_SAVE_AREA-4095(%r1) # validate bear + lmg %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# validate gprs + lg %r12,__LC_CURRENT + lmg %r8,%r9,__LC_MCK_OLD_PSW + TSTMSK __LC_MCCK_CODE,MCCK_CODE_SYSTEM_DAMAGE + jo .Lmcck_panic # yes -> rest of mcck code invalid + TSTMSK __LC_MCCK_CODE,MCCK_CODE_CR_VALID + jno .Lmcck_panic # control registers invalid -> panic + la %r14,4095 + lctlg %c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r14) # validate ctl regs + ptlb + lghi %r14,__LC_CPU_TIMER_SAVE_AREA + mvc __LC_MCCK_ENTER_TIMER(8),0(%r14) + TSTMSK __LC_MCCK_CODE,MCCK_CODE_CPU_TIMER_VALID + jo 3f + la %r14,__LC_SYS_ENTER_TIMER + clc 0(8,%r14),__LC_EXIT_TIMER + jl 1f + la %r14,__LC_EXIT_TIMER +1: clc 0(8,%r14),__LC_LAST_UPDATE_TIMER + jl 2f + la %r14,__LC_LAST_UPDATE_TIMER +2: spt 0(%r14) + mvc __LC_MCCK_ENTER_TIMER(8),0(%r14) +3: TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_MWP_VALID + jno .Lmcck_panic + tmhh %r8,0x0001 # interrupting from user ? + jnz 6f + TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_IA_VALID + jno .Lmcck_panic +#if IS_ENABLED(CONFIG_KVM) + OUTSIDE %r9,.Lsie_gmap,.Lsie_done,6f + OUTSIDE %r9,.Lsie_entry,.Lsie_leave,4f + oi __LC_CPU_FLAGS+7, _CIF_MCCK_GUEST + j 5f +4: CHKSTG .Lmcck_panic +5: larl %r14,.Lstosm_tmp + stosm 0(%r14),0x04 # turn dat on, keep irqs off + BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST) + SIEEXIT + j .Lmcck_stack +#endif +6: CHKSTG .Lmcck_panic + larl %r14,.Lstosm_tmp + stosm 0(%r14),0x04 # turn dat on, keep irqs off + tmhh %r8,0x0001 # interrupting from user ? + jz .Lmcck_stack + BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP +.Lmcck_stack: + lg %r15,__LC_MCCK_STACK + la %r11,STACK_FRAME_OVERHEAD(%r15) + stctg %c1,%c1,__PT_CR1(%r11) + lctlg %c1,%c1,__LC_KERNEL_ASCE + xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) + lghi %r14,__LC_GPREGS_SAVE_AREA+64 + stmg %r0,%r7,__PT_R0(%r11) + # clear user controlled registers to prevent speculative use + xgr %r0,%r0 + xgr %r1,%r1 + xgr %r3,%r3 + xgr %r4,%r4 + xgr %r5,%r5 + xgr %r6,%r6 + xgr %r7,%r7 + xgr %r10,%r10 + mvc __PT_R8(64,%r11),0(%r14) + stmg %r8,%r9,__PT_PSW(%r11) + xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11) + xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) + lgr %r2,%r11 # pass pointer to pt_regs + brasl %r14,s390_do_machine_check + cghi %r2,0 + je .Lmcck_return + lg %r1,__LC_KERNEL_STACK # switch to kernel stack + mvc STACK_FRAME_OVERHEAD(__PT_SIZE,%r1),0(%r11) + xc __SF_BACKCHAIN(8,%r1),__SF_BACKCHAIN(%r1) + la %r11,STACK_FRAME_OVERHEAD(%r1) + lgr %r2,%r11 + lgr %r15,%r1 + brasl %r14,s390_handle_mcck +.Lmcck_return: + lctlg %c1,%c1,__PT_CR1(%r11) + lmg %r0,%r10,__PT_R0(%r11) + mvc __LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW + tm __LC_RETURN_MCCK_PSW+1,0x01 # returning to user ? + jno 0f + BPEXIT __TI_flags(%r12),_TIF_ISOLATE_BP + stpt __LC_EXIT_TIMER +0: ALTERNATIVE "nop", __stringify(lghi %r12,__LC_LAST_BREAK_SAVE_AREA),193 + LBEAR 0(%r12) + lmg %r11,%r15,__PT_R11(%r11) + LPSWEY __LC_RETURN_MCCK_PSW,__LC_RETURN_MCCK_LPSWE + +.Lmcck_panic: + /* + * Iterate over all possible CPU addresses in the range 0..0xffff + * and stop each CPU using signal processor. Use compare and swap + * to allow just one CPU-stopper and prevent concurrent CPUs from + * stopping each other while leaving the others running. + */ + lhi %r5,0 + lhi %r6,1 + larl %r7,.Lstop_lock + cs %r5,%r6,0(%r7) # single CPU-stopper only + jnz 4f + larl %r7,.Lthis_cpu + stap 0(%r7) # this CPU address + lh %r4,0(%r7) + nilh %r4,0 + lhi %r0,1 + sll %r0,16 # CPU counter + lhi %r3,0 # next CPU address +0: cr %r3,%r4 + je 2f +1: sigp %r1,%r3,SIGP_STOP # stop next CPU + brc SIGP_CC_BUSY,1b +2: ahi %r3,1 + brct %r0,0b +3: sigp %r1,%r4,SIGP_STOP # stop this CPU + brc SIGP_CC_BUSY,3b +4: j 4b +ENDPROC(mcck_int_handler) + +ENTRY(restart_int_handler) + ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40 + stg %r15,__LC_SAVE_AREA_RESTART + TSTMSK __LC_RESTART_FLAGS,RESTART_FLAG_CTLREGS,4 + jz 0f + la %r15,4095 + lctlg %c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r15) +0: larl %r15,.Lstosm_tmp + stosm 0(%r15),0x04 # turn dat on, keep irqs off + lg %r15,__LC_RESTART_STACK + xc STACK_FRAME_OVERHEAD(__PT_SIZE,%r15),STACK_FRAME_OVERHEAD(%r15) + stmg %r0,%r14,STACK_FRAME_OVERHEAD+__PT_R0(%r15) + mvc STACK_FRAME_OVERHEAD+__PT_R15(8,%r15),__LC_SAVE_AREA_RESTART + mvc STACK_FRAME_OVERHEAD+__PT_PSW(16,%r15),__LC_RST_OLD_PSW + xc 0(STACK_FRAME_OVERHEAD,%r15),0(%r15) + lg %r1,__LC_RESTART_FN # load fn, parm & source cpu + lg %r2,__LC_RESTART_DATA + lgf %r3,__LC_RESTART_SOURCE + ltgr %r3,%r3 # test source cpu address + jm 1f # negative -> skip source stop +0: sigp %r4,%r3,SIGP_SENSE # sigp sense to source cpu + brc 10,0b # wait for status stored +1: basr %r14,%r1 # call function + stap __SF_EMPTY(%r15) # store cpu address + llgh %r3,__SF_EMPTY(%r15) +2: sigp %r4,%r3,SIGP_STOP # sigp stop to current cpu + brc 2,2b +3: j 3b +ENDPROC(restart_int_handler) + + .section .kprobes.text, "ax" + +#if defined(CONFIG_CHECK_STACK) || defined(CONFIG_VMAP_STACK) +/* + * The synchronous or the asynchronous stack overflowed. We are dead. + * No need to properly save the registers, we are going to panic anyway. + * Setup a pt_regs so that show_trace can provide a good call trace. + */ +ENTRY(stack_overflow) + lg %r15,__LC_NODAT_STACK # change to panic stack + la %r11,STACK_FRAME_OVERHEAD(%r15) + stmg %r0,%r7,__PT_R0(%r11) + stmg %r8,%r9,__PT_PSW(%r11) + mvc __PT_R8(64,%r11),0(%r14) + stg %r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2 + xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) + lgr %r2,%r11 # pass pointer to pt_regs + jg kernel_stack_overflow +ENDPROC(stack_overflow) +#endif + + .section .data, "aw" + .align 4 +.Lstop_lock: .long 0 +.Lthis_cpu: .short 0 +.Lstosm_tmp: .byte 0 + .section .rodata, "a" +#define SYSCALL(esame,emu) .quad __s390x_ ## esame + .globl sys_call_table +sys_call_table: +#include "asm/syscall_table.h" +#undef SYSCALL + +#ifdef CONFIG_COMPAT + +#define SYSCALL(esame,emu) .quad __s390_ ## emu + .globl sys_call_table_emu +sys_call_table_emu: +#include "asm/syscall_table.h" +#undef SYSCALL +#endif |