From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave.Martin@arm.com (Dave Martin) Date: Wed, 20 Sep 2017 13:09:48 +0100 Subject: [PATCH v2] bootwrapper: SVE: Enable SVE for EL2 and below Message-ID: <1505909388-13513-1-git-send-email-Dave.Martin@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org By default, SVE will trap to EL3. We also want to make sure that lower ELs have access to the full SVE vector length before dropping down. This patch programs CPTR_EL3 and ZCR_EL3 appropriately to enable SVE for lower exception levels and make sure that they can use the full vector length provided by the hardware. Signed-off-by: Dave Martin Cc: Mark Rutland Cc: Alex Benn?e --- This is basically the same as v1 [1], but rebased to an up-to-date bootwrapper tree. (I was previously tracking Catalin's tree, which no longer exists...) [1] [PATCH] bootwrapper: SVE: Enable SVE for EL2 and below http://lists.infradead.org/pipermail/linux-arm-kernel/2017-August/527000.html arch/aarch64/boot.S | 13 +++++++++++++ arch/aarch64/include/asm/cpu.h | 5 +++++ 2 files changed, 18 insertions(+) diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S index ceeee76..f7d795a 100644 --- a/arch/aarch64/boot.S +++ b/arch/aarch64/boot.S @@ -45,6 +45,19 @@ _start: msr cptr_el3, xzr // Disable copro. traps to EL3 + mrs x0, id_aa64pfr0_el1 + ubfx x0, x0, #32, #4 // SVE present? + cbz x0, 1f // Skip SVE init if not + + mrs x0, cptr_el3 + orr x0, x0, #CPTR_EL3_EZ // enable SVE + msr cptr_el3, x0 + isb + + mov x0, #ZCR_EL3_LEN_MASK // SVE: Enable full vector len + msr ZCR_EL3, x0 // for EL2. + +1: ldr x0, =CNTFRQ msr cntfrq_el0, x0 diff --git a/arch/aarch64/include/asm/cpu.h b/arch/aarch64/include/asm/cpu.h index 66726ef..ccb5397 100644 --- a/arch/aarch64/include/asm/cpu.h +++ b/arch/aarch64/include/asm/cpu.h @@ -27,6 +27,11 @@ #define SPSR_EL2H (9 << 0) /* EL2 Handler mode */ #define SPSR_HYP (0x1a << 0) /* M[3:0] = hyp, M[4] = AArch32 */ +#define CPTR_EL3_EZ (1 << 8) + +#define ZCR_EL3 s3_6_c1_c2_0 +#define ZCR_EL3_LEN_MASK 0x1ff + #define SCTLR_EL1_CP15BEN (1 << 5) #define SCTLR_EL1_RES1 (3 << 28 | 3 << 22 | 1 << 11) -- 2.1.4