s390/alternatives: provide identical sized orginal/alternative sequences

Explicitly provide identical sized original/alternative instruction
sequences. This way there is no need for the s390 specific alternatives
infrastructure to generate padding sequences.
The code which generates such sequences will be removed with a follow on
patch.

Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20220511120532.2228616-2-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index 10a4607..37127cd 100644 (file)
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -79,7 +79,7 @@ static inline void arch_spin_unlock(arch_spinlock_t *lp)
        typecheck(int, lp->lock);
        kcsan_release();
        asm_inline volatile(
-               ALTERNATIVE("", ".insn rre,0xb2fa0000,7,0", 49) /* NIAI 7 */
+               ALTERNATIVE("nop", ".insn rre,0xb2fa0000,7,0", 49) /* NIAI 7 */
                "       sth     %1,%0\n"
                : "=R" (((unsigned short *) &lp->lock)[1])
                : "d" (0) : "cc", "memory");

diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 685ccec..a6b45ea 100644 (file)
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -53,19 +53,19 @@ STACK_INIT = STACK_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE
 _LPP_OFFSET    = __LC_LPP
 
        .macro STBEAR address
-       ALTERNATIVE "", ".insn  s,0xb2010000,\address", 193
+       ALTERNATIVE "nop", ".insn s,0xb2010000,\address", 193
        .endm
 
        .macro LBEAR address
-       ALTERNATIVE "", ".insn  s,0xb2000000,\address", 193
+       ALTERNATIVE "nop", ".insn s,0xb2000000,\address", 193
        .endm
 
        .macro LPSWEY address,lpswe
-       ALTERNATIVE "b \lpswe", ".insn siy,0xeb0000000071,\address,0", 193
+       ALTERNATIVE "b \lpswe; nopr", ".insn siy,0xeb0000000071,\address,0", 193
        .endm
 
        .macro MBEAR reg
-       ALTERNATIVE "", __stringify(mvc __PT_LAST_BREAK(8,\reg),__LC_LAST_BREAK), 193
+       ALTERNATIVE "brcl 0,0", __stringify(mvc __PT_LAST_BREAK(8,\reg),__LC_LAST_BREAK), 193
        .endm
 
        .macro  CHECK_STACK savearea
@@ -121,16 +121,16 @@ _LPP_OFFSET       = __LC_LPP
        .endm
 
        .macro BPOFF
-       ALTERNATIVE "", ".insn rrf,0xb2e80000,0,0,12,0", 82
+       ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,12,0", 82
        .endm
 
        .macro BPON
-       ALTERNATIVE "", ".insn rrf,0xb2e80000,0,0,13,0", 82
+       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", \
-                   "", 82
+                   "j .+12; nop; nop", 82
        .endm
 
        .macro BPEXIT tif_ptr,tif_mask
@@ -226,7 +226,7 @@ ENTRY(__switch_to)
        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 "", "lpp _LPP_OFFSET", 40
+       ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
        BR_EX   %r14
 ENDPROC(__switch_to)
 
@@ -610,7 +610,7 @@ ENTRY(mcck_int_handler)
        jno     0f
        BPEXIT  __TI_flags(%r12),_TIF_ISOLATE_BP
        stpt    __LC_EXIT_TIMER
-0:     ALTERNATIVE "", __stringify(lghi %r12,__LC_LAST_BREAK_SAVE_AREA),193
+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
@@ -646,7 +646,7 @@ ENTRY(mcck_int_handler)
 ENDPROC(mcck_int_handler)
 
 ENTRY(restart_int_handler)
-       ALTERNATIVE "", "lpp _LPP_OFFSET", 40
+       ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
        stg     %r15,__LC_SAVE_AREA_RESTART
        TSTMSK  __LC_RESTART_FLAGS,RESTART_FLAG_CTLREGS,4
        jz      0f

diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index 5e7ea8b..04d4c6c 100644 (file)
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -75,7 +75,7 @@ static inline int arch_load_niai4(int *lock)
        int owner;
 
        asm_inline volatile(
-               ALTERNATIVE("", ".insn rre,0xb2fa0000,4,0", 49) /* NIAI 4 */
+               ALTERNATIVE("nop", ".insn rre,0xb2fa0000,4,0", 49) /* NIAI 4 */
                "       l       %0,%1\n"
                : "=d" (owner) : "Q" (*lock) : "memory");
        return owner;
@@ -86,7 +86,7 @@ static inline int arch_cmpxchg_niai8(int *lock, int old, int new)
        int expected = old;
 
        asm_inline volatile(
-               ALTERNATIVE("", ".insn rre,0xb2fa0000,8,0", 49) /* NIAI 8 */
+               ALTERNATIVE("nop", ".insn rre,0xb2fa0000,8,0", 49) /* NIAI 8 */
                "       cs      %0,%3,%1\n"
                : "=d" (old), "=Q" (*lock)
                : "0" (old), "d" (new), "Q" (*lock)