From adf7589997927b1d84a5d003027b866bbef61ef2 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 8 Sep 2016 13:55:38 +0100 Subject: arm64: simplify sysreg manipulation A while back we added {read,write}_sysreg accessors to handle accesses to system registers, without the usual boilerplate asm volatile, temporary variable, etc. This patch makes use of these across arm64 to make code shorter and clearer. For sequences with a trailing ISB, the existing isb() macro is also used so that asm blocks can be removed entirely. A few uses of inline assembly for msr/mrs are left as-is. Those manipulating sp_el0 for the current thread_info value have special clobber requiremends. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Will Deacon --- arch/arm64/kernel/process.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'arch/arm64/kernel/process.c') diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 6cd2612236dc..a4f5f766af08 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -202,7 +202,7 @@ void show_regs(struct pt_regs * regs) static void tls_thread_flush(void) { - asm ("msr tpidr_el0, xzr"); + write_sysreg(0, tpidr_el0); if (is_compat_task()) { current->thread.tp_value = 0; @@ -213,7 +213,7 @@ static void tls_thread_flush(void) * with a stale shadow state during context switch. */ barrier(); - asm ("msr tpidrro_el0, xzr"); + write_sysreg(0, tpidrro_el0); } } @@ -253,7 +253,7 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start, * Read the current TLS pointer from tpidr_el0 as it may be * out-of-sync with the saved value. */ - asm("mrs %0, tpidr_el0" : "=r" (*task_user_tls(p))); + *task_user_tls(p) = read_sysreg(tpidr_el0); if (stack_start) { if (is_compat_thread(task_thread_info(p))) @@ -289,17 +289,15 @@ static void tls_thread_switch(struct task_struct *next) { unsigned long tpidr, tpidrro; - asm("mrs %0, tpidr_el0" : "=r" (tpidr)); + tpidr = read_sysreg(tpidr_el0); *task_user_tls(current) = tpidr; tpidr = *task_user_tls(next); tpidrro = is_compat_thread(task_thread_info(next)) ? next->thread.tp_value : 0; - asm( - " msr tpidr_el0, %0\n" - " msr tpidrro_el0, %1" - : : "r" (tpidr), "r" (tpidrro)); + write_sysreg(tpidr, tpidr_el0); + write_sysreg(tpidrro, tpidrro_el0); } /* Restore the UAO state depending on next's addr_limit */ -- cgit v1.2.3