util/cpuinfo-riscv: Detect Zbkb
RISCV_HWPROBE_EXT_ZBKB was introduced in linux 6.10 with the rest of the hwprobe api. Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Richard Henderson committed
Aug 10, 2026 at 11:45 UTC
48c18cdc9c9f9beadc204895a85870bddf237f2f
2 files changed
+16
-2
host/include/riscv64/host/cpuinfo.h
+1
@@ -12,6 +12,7 @@
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#define CPUINFO_ZBS (1u << 3)
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#define CPUINFO_ZICOND (1u << 4)
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#define CPUINFO_ZVE64X (1u << 5)
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+#define CPUINFO_ZBKB (1u << 6)
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/* Initialized with a constructor. */
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extern unsigned cpuinfo;
util/cpuinfo-riscv.c
+15
-2
@@ -36,7 +36,7 @@ static void sigill_handler(int signo, siginfo_t *si, void *data)
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/* Called both as constructor and (possibly) via other constructors. */
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unsigned __attribute__((constructor)) cpuinfo_init(void)
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{
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- unsigned left = CPUINFO_ZBA | CPUINFO_ZBB | CPUINFO_ZBS
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+ unsigned left = CPUINFO_ZBA | CPUINFO_ZBB | CPUINFO_ZBS | CPUINFO_ZBKB
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| CPUINFO_ZICOND | CPUINFO_ZVE64X;
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unsigned info = cpuinfo;
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@@ -60,6 +60,9 @@ unsigned __attribute__((constructor)) cpuinfo_init(void)
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#if defined(__riscv_arch_test) && \
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(defined(__riscv_vector) || defined(__riscv_zve64x))
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info |= CPUINFO_ZVE64X;
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+#endif
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+#if defined(__riscv_arch_test) && defined(__riscv_zbkb)
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+ info |= CPUINFO_ZBKB;
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#endif
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left &= ~info;
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@@ -76,7 +79,8 @@ unsigned __attribute__((constructor)) cpuinfo_init(void)
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info |= pair.value & RISCV_HWPROBE_EXT_ZBA ? CPUINFO_ZBA : 0;
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info |= pair.value & RISCV_HWPROBE_EXT_ZBB ? CPUINFO_ZBB : 0;
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info |= pair.value & RISCV_HWPROBE_EXT_ZBS ? CPUINFO_ZBS : 0;
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- left &= ~(CPUINFO_ZBA | CPUINFO_ZBB | CPUINFO_ZBS);
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+ info |= pair.value & RISCV_HWPROBE_EXT_ZBKB ? CPUINFO_ZBKB : 0;
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+ left &= ~(CPUINFO_ZBA | CPUINFO_ZBB | CPUINFO_ZBS | CPUINFO_ZBKB);
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#ifdef RISCV_HWPROBE_EXT_ZICOND
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info |= pair.value & RISCV_HWPROBE_EXT_ZICOND ? CPUINFO_ZICOND : 0;
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left &= ~CPUINFO_ZICOND;
@@ -131,6 +135,15 @@ unsigned __attribute__((constructor)) cpuinfo_init(void)
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left &= ~CPUINFO_ZBS;
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}
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+ if (left & CPUINFO_ZBKB) {
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+ /* Probe for Zbkb: brev8 zero,zero. */
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+ got_sigill = 0;
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+ asm volatile(".insn i 0x13, 5, zero, zero, 0x687"
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+ : : : "memory");
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+ info |= got_sigill ? 0 : CPUINFO_ZBKB;
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+ left &= ~CPUINFO_ZBKB;
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+ }
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+
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if (left & CPUINFO_ZICOND) {
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/* Probe for Zicond: czero.eqz zero,zero,zero. */
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got_sigill = 0;