From 8fcd6c45f5a65621ec809b7866a3623e9a01d4ed Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Fri, 28 Jul 2017 15:35:35 -0400 Subject: [PATCH] ARM: implement get_tls syscall 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 Acked-by: Mickael GUENE Tested-by: Vincent Abriou Tested-by: Andras Szemzo --- 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 28bd456494a3..575b25fc29c6 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 948c648fea00..43c0560f7b2d 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