summaryrefslogtreecommitdiff
path: root/arch/riscv/include/asm/vdso/processor.h
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2022-08-12 18:39:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-08-12 18:39:43 -0700
commit69dac8e431af26173ca0a1ebc87054e01c585bcc (patch)
treea39774497b82ceb4fda0d5dad3e7dd56700ad312 /arch/riscv/include/asm/vdso/processor.h
parent6c833c0581f1c15db2e0344da19360cba75a3351 (diff)
parent5cef38dd03f33ef206eb792df0fb3b200d762546 (diff)
downloadlinux-69dac8e431af26173ca0a1ebc87054e01c585bcc.tar.gz
linux-69dac8e431af26173ca0a1ebc87054e01c585bcc.tar.bz2
linux-69dac8e431af26173ca0a1ebc87054e01c585bcc.zip
Merge tag 'riscv-for-linus-5.20-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull more RISC-V updates from Palmer Dabbelt: "There's still a handful of new features in here, but there are a lot of fixes/cleanups as well: - Support for the Zicbom extension for explicit cache-block management, along with the necessary bits to make the non-standard cache management ops on the Allwinner D1 function - Support for the Zihintpause extension, which codifies a go-slow instruction used for cpu_relax() - Support for the Sstc extension for supervisor-mode timer/counter management - Many device tree fixes and cleanups, including a large set for the Canaan device trees - A handful of fixes and cleanups for the PMU driver" * tag 'riscv-for-linus-5.20-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (43 commits) dt-bindings: gpio: sifive: add gpio-line-names wireguard: selftests: set CONFIG_NONPORTABLE on riscv32 RISC-V: KVM: Support sstc extension RISC-V: Improve SBI definitions RISC-V: Move counter info definition to sbi header file RISC-V: Fix SBI PMU calls for RV32 RISC-V: Update user page mapping only once during start RISC-V: Fix counter restart during overflow for RV32 RISC-V: Prefer sstc extension if available RISC-V: Enable sstc extension parsing from DT RISC-V: Add SSTC extension CSR details riscv:uprobe fix SR_SPIE set/clear handling dt-bindings: riscv: fix SiFive l2-cache's cache-sets riscv: ensure cpu_ops_sbi is declared RISC-V: cpu_ops_spinwait.c should include head.h RISC-V: Declare cpu_ops_spinwait in <asm/cpu_ops.h> riscv: dts: starfive: correct number of external interrupts riscv: dts: sifive unmatched: Add PWM controlled LEDs riscv/purgatory: Omit use of bin2c riscv/purgatory: hard-code obj-y in Makefile ...
Diffstat (limited to 'arch/riscv/include/asm/vdso/processor.h')
-rw-r--r--arch/riscv/include/asm/vdso/processor.h21
1 files changed, 18 insertions, 3 deletions
diff --git a/arch/riscv/include/asm/vdso/processor.h b/arch/riscv/include/asm/vdso/processor.h
index 134388cbaaa1..1e4f8b4aef79 100644
--- a/arch/riscv/include/asm/vdso/processor.h
+++ b/arch/riscv/include/asm/vdso/processor.h
@@ -4,15 +4,30 @@
#ifndef __ASSEMBLY__
+#include <linux/jump_label.h>
#include <asm/barrier.h>
+#include <asm/hwcap.h>
static inline void cpu_relax(void)
{
+ if (!static_branch_likely(&riscv_isa_ext_keys[RISCV_ISA_EXT_KEY_ZIHINTPAUSE])) {
#ifdef __riscv_muldiv
- int dummy;
- /* In lieu of a halt instruction, induce a long-latency stall. */
- __asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy));
+ int dummy;
+ /* In lieu of a halt instruction, induce a long-latency stall. */
+ __asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy));
#endif
+ } else {
+ /*
+ * Reduce instruction retirement.
+ * This assumes the PC changes.
+ */
+#ifdef __riscv_zihintpause
+ __asm__ __volatile__ ("pause");
+#else
+ /* Encoding of the pause instruction */
+ __asm__ __volatile__ (".4byte 0x100000F");
+#endif
+ }
barrier();
}