[PATCH v4 19/26] arm64: Add support for GICv5 GSB barriers

Lorenzo Pieralisi
2025-05-13T17:49:55Z

The GICv5 architecture introduces two barriers instructions
(GSB SYS, GSB ACK) that are used to manage interrupt effects.

Rework macro used to emit the SB barrier instruction and implement
the GSB barriers on top of it.

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/barrier.h | 3 +++
arch/arm64/include/asm/sysreg.h | 10 +++++++---
2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index 1ca947d5c93963d33fe8fb02d6037fc71bd9fd7a..f5801b0ba9e9e7e0433f16ffedf0ec7dfb3e358e 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -44,6 +44,9 @@
SB_BARRIER_INSN"nop\n", \
ARM64_HAS_SB))

+#define gsb_ack() asm volatile(GSB_ACK_BARRIER_INSN : : : "memory")
+#define gsb_sys() asm volatile(GSB_SYS_BARRIER_INSN : : : "memory")
+
#ifdef CONFIG_ARM64_PSEUDO_NMI
#define pmr_sync() \
do { \
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 2639d3633073de10f5040a7efff059021f847530..e7734f90bb723bfbd8be99f16dd6d6fdc7fa57e8 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -112,10 +112,14 @@
/* Register-based PAN access, for save/restore purposes */
#define SYS_PSTATE_PAN sys_reg(3, 0, 4, 2, 3)

-#define __SYS_BARRIER_INSN(CRm, op2, Rt) \
- __emit_inst(0xd5000000 | sys_insn(0, 3, 3, (CRm), (op2)) | ((Rt) & 0x1f))
+#define __SYS_BARRIER_INSN(op0, op1, CRn, CRm, op2, Rt) \
+ __emit_inst(0xd5000000 | \
+ sys_insn((op0), (op1), (CRn), (CRm), (op2)) | \
+ ((Rt) & 0x1f))

-#define SB_BARRIER_INSN __SYS_BARRIER_INSN(0, 7, 31)
+#define SB_BARRIER_INSN __SYS_BARRIER_INSN(0, 3, 3, 0, 7, 31)
+#define GSB_SYS_BARRIER_INSN __SYS_BARRIER_INSN(1, 0, 12, 0, 0, 31)
+#define GSB_ACK_BARRIER_INSN __SYS_BARRIER_INSN(1, 0, 12, 0, 1, 31)

#define SYS_DC_ISW sys_insn(1, 0, 7, 6, 2)
#define SYS_DC_IGSW sys_insn(1, 0, 7, 6, 4)

--
2.48.0