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s390/cmpxchg: use symbolic names for inline assembly operands

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Make cmpxchg() inline assemblies more readable by using symbolic names
for operands.

Link: https://lore.kernel.org/r/Y2J7yzQYt/bjLQXY@osiris
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2022-11-02 15:16:43 +01:00
parent 247f34f7b8
commit 13f62e8438
1 changed files with 42 additions and 34 deletions
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76
arch/s390/include/asm/cmpxchg.h
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@ -96,56 +96,64 @@ static __always_inline unsigned long __cmpxchg(unsigned long address,
shift = (3 ^ (address & 3)) << 3;
address ^= address & 3;
asm volatile(
" l %0,%2\n"
"0: nr %0,%5\n"
" lr %1,%0\n"
" or %0,%3\n"
" or %1,%4\n"
" cs %0,%1,%2\n"
" jnl 1f\n"
" xr %1,%0\n"
" nr %1,%5\n"
" jnz 0b\n"
" l %[prev],%[address]\n"
"0: nr %[prev],%[mask]\n"
" lr %[tmp],%[prev]\n"
" or %[prev],%[old]\n"
" or %[tmp],%[new]\n"
" cs %[prev],%[tmp],%[address]\n"
" jnl 1f\n"
" xr %[tmp],%[prev]\n"
" nr %[tmp],%[mask]\n"
" jnz 0b\n"
"1:"
: "=&d" (prev), "=&d" (tmp), "+Q" (*(int *) address)
: "d" ((old & 0xff) << shift),
"d" ((new & 0xff) << shift),
"d" (~(0xff << shift))
: [prev] "=&d" (prev),
[tmp] "=&d" (tmp),
[address] "+Q" (*(int *)address)
: [old] "d" ((old & 0xff) << shift),
[new] "d" ((new & 0xff) << shift),
[mask] "d" (~(0xff << shift))
: "memory", "cc");
return prev >> shift;
case 2:
shift = (2 ^ (address & 2)) << 3;
address ^= address & 2;
asm volatile(
" l %0,%2\n"
"0: nr %0,%5\n"
" lr %1,%0\n"
" or %0,%3\n"
" or %1,%4\n"
" cs %0,%1,%2\n"
" jnl 1f\n"
" xr %1,%0\n"
" nr %1,%5\n"
" jnz 0b\n"
" l %[prev],%[address]\n"
"0: nr %[prev],%[mask]\n"
" lr %[tmp],%[prev]\n"
" or %[prev],%[old]\n"
" or %[tmp],%[new]\n"
" cs %[prev],%[tmp],%[address]\n"
" jnl 1f\n"
" xr %[tmp],%[prev]\n"
" nr %[tmp],%[mask]\n"
" jnz 0b\n"
"1:"
: "=&d" (prev), "=&d" (tmp), "+Q" (*(int *) address)
: "d" ((old & 0xffff) << shift),
"d" ((new & 0xffff) << shift),
"d" (~(0xffff << shift))
: [prev] "=&d" (prev),
[tmp] "=&d" (tmp),
[address] "+Q" (*(int *)address)
: [old] "d" ((old & 0xffff) << shift),
[new] "d" ((new & 0xffff) << shift),
[mask] "d" (~(0xffff << shift))
: "memory", "cc");
return prev >> shift;
case 4:
asm volatile(
" cs %0,%3,%1\n"
: "=&d" (prev), "+Q" (*(int *) address)
: "0" (old), "d" (new)
" cs %[prev],%[new],%[address]\n"
: [prev] "=&d" (prev),
[address] "+Q" (*(int *)address)
: "0" (old),
[new] "d" (new)
: "memory", "cc");
return prev;
case 8:
asm volatile(
" csg %0,%3,%1\n"
: "=&d" (prev), "+QS" (*(long *) address)
: "0" (old), "d" (new)
" csg %[prev],%[new],%[address]\n"
: [prev] "=&d" (prev),
[address] "+QS" (*(long *)address)
: "0" (old),
[new] "d" (new)
: "memory", "cc");
return prev;
}