From mboxrd@z Thu Jan 1 00:00:00 1970 From: nicolas.pitre@linaro.org (Nicolas Pitre) Date: Thu, 17 Aug 2017 03:23:40 -0400 Subject: [PATCH v2 1/8] ARM: implement get_tls syscall In-Reply-To: <20170817072347.19990-1-nicolas.pitre@linaro.org> References: <20170817072347.19990-1-nicolas.pitre@linaro.org> Message-ID: <20170817072347.19990-2-nicolas.pitre@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org When there is no dedicated register to hold the tp value and no MMU to provide a fixed address kuser helper entry point, all that is left as fallback is a syscall. Signed-off-by: Nicolas Pitre --- arch/arm/include/uapi/asm/unistd.h | 1 + arch/arm/kernel/traps.c | 3 +++ 2 files changed, 4 insertions(+) diff --git a/arch/arm/include/uapi/asm/unistd.h b/arch/arm/include/uapi/asm/unistd.h index 28bd456494..575b25fc29 100644 --- a/arch/arm/include/uapi/asm/unistd.h +++ b/arch/arm/include/uapi/asm/unistd.h @@ -35,5 +35,6 @@ #define __ARM_NR_usr26 (__ARM_NR_BASE+3) #define __ARM_NR_usr32 (__ARM_NR_BASE+4) #define __ARM_NR_set_tls (__ARM_NR_BASE+5) +#define __ARM_NR_get_tls (__ARM_NR_BASE+6) #endif /* _UAPI__ASM_ARM_UNISTD_H */ diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 948c648fea..43c0560f7b 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -647,6 +647,9 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs) set_tls(regs->ARM_r0); return 0; + case NR(get_tls): + return current_thread_info()->tp_value[0]; + default: /* Calls 9f00xx..9f07ff are defined to return -ENOSYS if not implemented, rather than raising SIGILL. This -- 2.9.5