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Sun, 16 Apr 2017 13:27:47 -0700 (PDT) Received: from mai.lan ([2001:41d0:fe90:b800:20c0:6248:a385:db35]) by smtp.gmail.com with ESMTPSA id 81sm7732196wmj.9.2017.04.16.13.27.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 16 Apr 2017 13:27:47 -0700 (PDT) From: Daniel Lezcano To: tglx@linutronix.de Subject: [PATCH 02/29] arm64: Add CNTVCT_EL0 trap handler Date: Sun, 16 Apr 2017 22:26:52 +0200 Message-Id: <1492374441-23336-2-git-send-email-daniel.lezcano@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1492374441-23336-1-git-send-email-daniel.lezcano@linaro.org> References: <20170416202542.GV2078@mai> <1492374441-23336-1-git-send-email-daniel.lezcano@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170416_132809_651166_459DA54A X-CRM114-Status: GOOD ( 13.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki K Poulose , Marc Zyngier , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Andre Przywara , Ingo Molnar , "moderated list:ARM64 PORT AARCH64 ARCHITECTURE" MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Marc Zyngier Since people seem to make a point in breaking the userspace visible counter, we have no choice but to trap the access. Add the required handler. Acked-by: Thomas Gleixner Acked-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/esr.h | 2 ++ arch/arm64/kernel/traps.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+) diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h index d14c478..ad42e79 100644 --- a/arch/arm64/include/asm/esr.h +++ b/arch/arm64/include/asm/esr.h @@ -175,6 +175,8 @@ #define ESR_ELx_SYS64_ISS_SYS_CTR_READ (ESR_ELx_SYS64_ISS_SYS_CTR | \ ESR_ELx_SYS64_ISS_DIR_READ) +#define ESR_ELx_SYS64_ISS_SYS_CNTVCT (ESR_ELx_SYS64_ISS_SYS_VAL(3, 3, 2, 14, 0) | \ + ESR_ELx_SYS64_ISS_DIR_READ) #ifndef __ASSEMBLY__ #include diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index e52be6a..1de444e 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -505,6 +505,14 @@ static void ctr_read_handler(unsigned int esr, struct pt_regs *regs) regs->pc += 4; } +static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs) +{ + int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT; + + pt_regs_write_reg(regs, rt, arch_counter_get_cntvct()); + regs->pc += 4; +} + struct sys64_hook { unsigned int esr_mask; unsigned int esr_val; @@ -523,6 +531,12 @@ static struct sys64_hook sys64_hooks[] = { .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ, .handler = ctr_read_handler, }, + { + /* Trap read access to CNTVCT_EL0 */ + .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK, + .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT, + .handler = cntvct_read_handler, + }, {}, };