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authorCatalin Marinas <catalin.marinas@arm.com>2012-10-05 12:31:20 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2012-10-17 14:33:31 +0100
commitc34501d21b005a6e363386a19519bd11cf92a67c (patch)
treec17d7a800d21418ef12d635a8275ebb063e2816a /arch/arm64
parentddffeb8c4d0331609ef2581d84de4d763607bd37 (diff)
downloadop-kernel-dev-c34501d21b005a6e363386a19519bd11cf92a67c.zip
op-kernel-dev-c34501d21b005a6e363386a19519bd11cf92a67c.tar.gz
arm64: Use generic kernel_thread() implementation
This patch enables CONFIG_GENERIC_KERNEL_THREAD on arm64, changes copy_threads to cope with kernel threads creation and adapts ret_from_fork accordingly. The arm64-specific kernel_thread implementation is no longer needed. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/Kconfig1
-rw-r--r--arch/arm64/include/asm/processor.h5
-rw-r--r--arch/arm64/kernel/entry.S5
-rw-r--r--arch/arm64/kernel/process.c77
4 files changed, 29 insertions, 59 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7ff68c9..4077b71 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -6,6 +6,7 @@ config ARM64
select GENERIC_IOMAP
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
+ select GENERIC_KERNEL_THREAD
select GENERIC_SMP_IDLE_THREAD
select GENERIC_TIME_VSYSCALL
select HARDIRQS_SW_RESEND
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 39a208a..d6331ac 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -136,11 +136,6 @@ unsigned long get_wchan(struct task_struct *p);
extern struct task_struct *cpu_switch_to(struct task_struct *prev,
struct task_struct *next);
-/*
- * Create a new kernel thread
- */
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
#define task_pt_regs(p) \
((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index a6f3f7d..08db897 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -611,7 +611,10 @@ ENDPROC(ret_to_user)
*/
ENTRY(ret_from_fork)
bl schedule_tail
- get_thread_info tsk
+ cbz x19, 1f // not a kernel thread
+ mov x0, x20
+ blr x19
+1: get_thread_info tsk
b ret_to_user
ENDPROC(ret_from_fork)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index f22965e..bf615e2 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -240,27 +240,35 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
struct pt_regs *childregs = task_pt_regs(p);
unsigned long tls = p->thread.tp_value;
- *childregs = *regs;
- childregs->regs[0] = 0;
+ memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
- if (is_compat_thread(task_thread_info(p)))
- childregs->compat_sp = stack_start;
- else {
+ if (likely(regs)) {
+ *childregs = *regs;
+ childregs->regs[0] = 0;
+ if (is_compat_thread(task_thread_info(p))) {
+ childregs->compat_sp = stack_start;
+ } else {
+ /*
+ * 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" (tls));
+ childregs->sp = stack_start;
+ }
/*
- * Read the current TLS pointer from tpidr_el0 as it may be
- * out-of-sync with the saved value.
+ * If a TLS pointer was passed to clone (4th argument), use it
+ * for the new thread.
*/
- asm("mrs %0, tpidr_el0" : "=r" (tls));
- childregs->sp = stack_start;
+ if (clone_flags & CLONE_SETTLS)
+ tls = regs->regs[3];
+ } else {
+ memset(childregs, 0, sizeof(struct pt_regs));
+ childregs->pstate = PSR_MODE_EL1h;
+ p->thread.cpu_context.x19 = stack_start;
+ p->thread.cpu_context.x20 = stk_sz;
}
-
- memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
- p->thread.cpu_context.sp = (unsigned long)childregs;
p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
-
- /* If a TLS pointer was passed to clone, use that for the new thread. */
- if (clone_flags & CLONE_SETTLS)
- tls = regs->regs[3];
+ p->thread.cpu_context.sp = (unsigned long)childregs;
p->thread.tp_value = tls;
ptrace_hw_copy_thread(p);
@@ -327,43 +335,6 @@ int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
}
EXPORT_SYMBOL(dump_fpu);
-/*
- * Shuffle the argument into the correct register before calling the
- * thread function. x1 is the thread argument, x2 is the pointer to
- * the thread function, and x3 points to the exit function.
- */
-extern void kernel_thread_helper(void);
-asm( ".section .text\n"
-" .align\n"
-" .type kernel_thread_helper, #function\n"
-"kernel_thread_helper:\n"
-" mov x0, x1\n"
-" mov x30, x3\n"
-" br x2\n"
-" .size kernel_thread_helper, . - kernel_thread_helper\n"
-" .previous");
-
-#define kernel_thread_exit do_exit
-
-/*
- * Create a kernel thread.
- */
-pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
- struct pt_regs regs;
-
- memset(&regs, 0, sizeof(regs));
-
- regs.regs[1] = (unsigned long)arg;
- regs.regs[2] = (unsigned long)fn;
- regs.regs[3] = (unsigned long)kernel_thread_exit;
- regs.pc = (unsigned long)kernel_thread_helper;
- regs.pstate = PSR_MODE_EL1h;
-
- return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
unsigned long get_wchan(struct task_struct *p)
{
struct stackframe frame;
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