From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Thu, 9 Feb 2017 15:19:19 +0000 Subject: [PATCH 2/4] arm64: traps: correctly handle MRS/MSR with XZR In-Reply-To: <1486653561-22357-1-git-send-email-mark.rutland@arm.com> References: <1486653561-22357-1-git-send-email-mark.rutland@arm.com> Message-ID: <1486653561-22357-3-git-send-email-mark.rutland@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Currently we hand-roll XZR-safe register handling in user_cache_maint_handler(), though we forget to do the same in ctr_read_handler(), and may erroneously write back to the user SP rather than XZR. Use the new helpers to handle these cases correctly and consistently. Signed-off-by: Mark Rutland Fixes: 116c81f427ff6c53 ("arm64: Work around systems with mismatched cache line sizes") Cc: Andre Przywara Cc: Catalin Marinas Cc: Marc Zyngier Cc: Suzuki K Poulose Cc: Will Deacon --- arch/arm64/kernel/traps.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) Note: this is dependent on patch 1, but I couldn't fill in a Cc line for stable as patch 1 doesn't (yet) have a stable commit id. Mark. diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 7c3fc06..350179be 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -466,7 +466,7 @@ static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs) int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT; int ret = 0; - address = (rt == 31) ? 0 : regs->regs[rt]; + address = pt_regs_read_reg(regs, rt); switch (crm) { case ESR_ELx_SYS64_ISS_CRM_DC_CVAU: /* DC CVAU, gets promoted */ @@ -495,8 +495,10 @@ static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs) static void ctr_read_handler(unsigned int esr, struct pt_regs *regs) { int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT; + unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0); + + pt_regs_write_reg(regs, rt, val); - regs->regs[rt] = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0); regs->pc += 4; } -- 1.9.1