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riscv: Implement xchg8/16() using Zabha

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This adds runtime support for Zabha in xchg8/16() operations.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20241103145153.105097-9-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Alexandre Ghiti 2024-11-03 15:51:48 +01:00 committed by Palmer Dabbelt
parent f7bd2be766
commit 97ddab7fbe
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GPG Key ID: 2E1319F35FBB1889
1 changed files with 41 additions and 24 deletions
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65
arch/riscv/include/asm/cmpxchg.h
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@ -14,29 +14,41 @@
#include <asm/insn-def.h>
#include <asm/cpufeature-macros.h>
#define __arch_xchg_masked(sc_sfx, prepend, append, r, p, n) \
({ \
u32 *__ptr32b = (u32 *)((ulong)(p) & ~0x3); \
ulong __s = ((ulong)(p) & (0x4 - sizeof(*p))) * BITS_PER_BYTE; \
ulong __mask = GENMASK(((sizeof(*p)) * BITS_PER_BYTE) - 1, 0) \
<< __s; \
ulong __newx = (ulong)(n) << __s; \
ulong __retx; \
ulong __rc; \
\
__asm__ __volatile__ ( \
prepend \
"0: lr.w %0, %2\n" \
" and %1, %0, %z4\n" \
" or %1, %1, %z3\n" \
" sc.w" sc_sfx " %1, %1, %2\n" \
" bnez %1, 0b\n" \
append \
: "=&r" (__retx), "=&r" (__rc), "+A" (*(__ptr32b)) \
: "rJ" (__newx), "rJ" (~__mask) \
: "memory"); \
\
r = (__typeof__(*(p)))((__retx & __mask) >> __s); \
#define __arch_xchg_masked(sc_sfx, swap_sfx, prepend, sc_append, \
swap_append, r, p, n) \
({ \
if (IS_ENABLED(CONFIG_RISCV_ISA_ZABHA) && \
riscv_has_extension_unlikely(RISCV_ISA_EXT_ZABHA)) { \
__asm__ __volatile__ ( \
prepend \
" amoswap" swap_sfx " %0, %z2, %1\n" \
swap_append \
: "=&r" (r), "+A" (*(p)) \
: "rJ" (n) \
: "memory"); \
} else { \
u32 *__ptr32b = (u32 *)((ulong)(p) & ~0x3); \
ulong __s = ((ulong)(p) & (0x4 - sizeof(*p))) * BITS_PER_BYTE; \
ulong __mask = GENMASK(((sizeof(*p)) * BITS_PER_BYTE) - 1, 0) \
<< __s; \
ulong __newx = (ulong)(n) << __s; \
ulong __retx; \
ulong __rc; \
\
__asm__ __volatile__ ( \
prepend \
"0: lr.w %0, %2\n" \
" and %1, %0, %z4\n" \
" or %1, %1, %z3\n" \
" sc.w" sc_sfx " %1, %1, %2\n" \
" bnez %1, 0b\n" \
sc_append \
: "=&r" (__retx), "=&r" (__rc), "+A" (*(__ptr32b)) \
: "rJ" (__newx), "rJ" (~__mask) \
: "memory"); \
\
r = (__typeof__(*(p)))((__retx & __mask) >> __s); \
} \
})
#define __arch_xchg(sfx, prepend, append, r, p, n) \
@ -59,8 +71,13 @@
\
switch (sizeof(*__ptr)) { \
case 1: \
__arch_xchg_masked(sc_sfx, ".b" swap_sfx, \
prepend, sc_append, swap_append, \
__ret, __ptr, __new); \
break; \
case 2: \
__arch_xchg_masked(sc_sfx, prepend, sc_append, \
__arch_xchg_masked(sc_sfx, ".h" swap_sfx, \
prepend, sc_append, swap_append, \
__ret, __ptr, __new); \
break; \
case 4: \