diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 77a807a844aca6a5d7f9dfb63686dd34a982ea50..0b8227f23eed615d6d15a9322c604933fabbf07d 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -109,6 +109,7 @@ config ARM64
select POWER_SUPPLY
select SPARSE_IRQ
select SYSCTL_EXCEPTION_TRACE
+ select THREAD_INFO_IN_TASK
help
ARM 64-bit (AArch64) Linux support.
diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild
index 44e1d7f10add1f892fb839ae41bbaae4cfd76442..28196b18e3947c0d946b33bd69e5677b96c2ecd3 100644
--- a/arch/arm64/include/asm/Kbuild
+++ b/arch/arm64/include/asm/Kbuild
@@ -1,7 +1,6 @@
generic-y += bugs.h
generic-y += clkdev.h
generic-y += cputime.h
-generic-y += current.h
generic-y += delay.h
generic-y += div64.h
generic-y += dma.h
diff --git a/arch/arm64/include/asm/current.h b/arch/arm64/include/asm/current.h
new file mode 100644
index 0000000000000000000000000000000000000000..f2bcbe2d98895ea35b95b8a1e518d808738284b4
--- /dev/null
+++ b/arch/arm64/include/asm/current.h
@@ -0,0 +1,22 @@
+#ifndef __ASM_CURRENT_H
+#define __ASM_CURRENT_H
+
+#include <linux/compiler.h>
+
+#include <asm/sysreg.h>
+
+#ifndef __ASSEMBLY__
+
+struct task_struct;
+
+static __always_inline struct task_struct *get_current(void)
+{
+ return (struct task_struct *)read_sysreg(sp_el0);
+}
+
+#define current get_current()
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_CURRENT_H */
+
diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h
index 968b08de820d437c17ba4353119873cd8bcee726..a62db952ffcbbd266f3e5e1fbbd4681c4718e543 100644
--- a/arch/arm64/include/asm/smp.h
+++ b/arch/arm64/include/asm/smp.h
@@ -82,6 +82,7 @@ asmlinkage void secondary_start_kernel(void);
*/
struct secondary_data {
void *stack;
+ struct task_struct *task;
long status;
};
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index bce0f07483c10c85d4428addce812f6e4525f0ad..c17ad4d213d05d57b56495389d2e088c27334906 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -47,41 +47,17 @@ typedef unsigned long mm_segment_t;
struct thread_info {
unsigned long flags; /* low level flags */
mm_segment_t addr_limit; /* address limit */
- struct task_struct *task; /* main task structure */
int preempt_count; /* 0 => preemptable, <0 => bug */
- int cpu; /* cpu */
};
#define INIT_THREAD_INFO(tsk) \
{ \
- .task = &tsk, \
- .flags = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \
.addr_limit = KERNEL_DS, \
}
#define init_stack (init_thread_union.stack)
-/*
- * how to get the thread information struct from C
- */
-static inline struct thread_info *current_thread_info(void) __attribute_const__;
-
-/*
- * struct thread_info can be accessed directly via sp_el0.
- *
- * We don't use read_sysreg() as we want the compiler to cache the value where
- * possible.
- */
-static inline struct thread_info *current_thread_info(void)
-{
- unsigned long sp_el0;
-
- asm ("mrs %0, sp_el0" : "=r" (sp_el0));
-
- return (struct thread_info *)sp_el0;
-}
-
#define thread_saved_pc(tsk) \
((unsigned long)(tsk->thread.cpu_context.pc))
#define thread_saved_sp(tsk) \
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index d30b2321c0ee07cf6a7f6c0c2ae9a8e63db08c93..c2dc9fa4f09bef502f2582411e96cd99b5f48485 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -36,9 +36,10 @@ int main(void)
{
DEFINE(TSK_ACTIVE_MM, offsetof(struct task_struct, active_mm));
BLANK();
- DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
- DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
- DEFINE(TI_ADDR_LIMIT, offsetof(struct thread_info, addr_limit));
+ DEFINE(TSK_TI_FLAGS, offsetof(struct task_struct, thread_info.flags));
+ DEFINE(TSK_TI_PREEMPT, offsetof(struct task_struct, thread_info.preempt_count));
+ DEFINE(TSK_TI_ADDR_LIMIT, offsetof(struct task_struct, thread_info.addr_limit));
+ DEFINE(TSK_STACK, offsetof(struct task_struct, stack));
BLANK();
DEFINE(THREAD_CPU_CONTEXT, offsetof(struct task_struct, thread.cpu_context));
BLANK();
@@ -121,6 +122,7 @@ int main(void)
DEFINE(TZ_DSTTIME, offsetof(struct timezone, tz_dsttime));
BLANK();
DEFINE(CPU_BOOT_STACK, offsetof(struct secondary_data, stack));
+ DEFINE(CPU_BOOT_TASK, offsetof(struct secondary_data, task));
BLANK();
#ifdef CONFIG_KVM_ARM_HOST
DEFINE(VCPU_CONTEXT, offsetof(struct kvm_vcpu, arch.ctxt));
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 2d4c83bc1f811b030b8adebe030965c05166c04c..6349a8324b4f6be4c4599c84854e71074a972f0d 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -90,9 +90,8 @@
.if \el == 0
mrs x21, sp_el0
- mov tsk, sp
- and tsk, tsk, #~(THREAD_SIZE - 1) // Ensure MDSCR_EL1.SS is clear,
- ldr x19, [tsk, #TI_FLAGS] // since we can unmask debug
+ ldr_this_cpu tsk, __entry_task, x20 // Ensure MDSCR_EL1.SS is clear,
+ ldr x19, [tsk, #TSK_TI_FLAGS] // since we can unmask debug
disable_step_tsk x19, x20 // exceptions when scheduling.
mov x29, xzr // fp pointed to user-space
@@ -100,10 +99,10 @@
add x21, sp, #S_FRAME_SIZE
get_thread_info tsk
/* Save the task's original addr_limit and set USER_DS (TASK_SIZE_64) */
- ldr x20, [tsk, #TI_ADDR_LIMIT]
+ ldr x20, [tsk, #TSK_TI_ADDR_LIMIT]
str x20, [sp, #S_ORIG_ADDR_LIMIT]
mov x20, #TASK_SIZE_64
- str x20, [tsk, #TI_ADDR_LIMIT]
+ str x20, [tsk, #TSK_TI_ADDR_LIMIT]
/* No need to reset PSTATE.UAO, hardware's already set it to 0 for us */
.endif /* \el == 0 */
mrs x22, elr_el1
@@ -139,7 +138,7 @@
.if \el != 0
/* Restore the task's original addr_limit. */
ldr x20, [sp, #S_ORIG_ADDR_LIMIT]
- str x20, [tsk, #TI_ADDR_LIMIT]
+ str x20, [tsk, #TSK_TI_ADDR_LIMIT]
/* No need to restore UAO, it will be restored from SPSR_EL1 */
.endif
@@ -192,13 +191,14 @@ alternative_else_nop_endif
mov x19, sp // preserve the original sp
/*
- * Compare sp with the current thread_info, if the top
- * ~(THREAD_SIZE - 1) bits match, we are on a task stack, and
- * should switch to the irq stack.
+ * Compare sp with the base of the task stack.
+ * If the top ~(THREAD_SIZE - 1) bits match, we are on a task stack,
+ * and should switch to the irq stack.
*/
- and x25, x19, #~(THREAD_SIZE - 1)
- cmp x25, tsk
- b.ne 9998f
+ ldr x25, [tsk, TSK_STACK]
+ eor x25, x25, x19
+ and x25, x25, #~(THREAD_SIZE - 1)
+ cbnz x25, 9998f
adr_this_cpu x25, irq_stack, x26
mov x26, #IRQ_STACK_START_SP
@@ -427,9 +427,9 @@ el1_irq:
irq_handler
#ifdef CONFIG_PREEMPT
- ldr w24, [tsk, #TI_PREEMPT] // get preempt count
+ ldr w24, [tsk, #TSK_TI_PREEMPT] // get preempt count
cbnz w24, 1f // preempt count != 0
- ldr x0, [tsk, #TI_FLAGS] // get flags
+ ldr x0, [tsk, #TSK_TI_FLAGS] // get flags
tbz x0, #TIF_NEED_RESCHED, 1f // needs rescheduling?
bl el1_preempt
1:
@@ -444,7 +444,7 @@ ENDPROC(el1_irq)
el1_preempt:
mov x24, lr
1: bl preempt_schedule_irq // irq en/disable is done inside
- ldr x0, [tsk, #TI_FLAGS] // get new tasks TI_FLAGS
+ ldr x0, [tsk, #TSK_TI_FLAGS] // get new tasks TI_FLAGS
tbnz x0, #TIF_NEED_RESCHED, 1b // needs rescheduling?
ret x24
#endif
@@ -674,8 +674,7 @@ ENTRY(cpu_switch_to)
ldp x29, x9, [x8], #16
ldr lr, [x8]
mov sp, x9
- and x9, x9, #~(THREAD_SIZE - 1)
- msr sp_el0, x9
+ msr sp_el0, x1
ret
ENDPROC(cpu_switch_to)
@@ -686,7 +685,7 @@ ENDPROC(cpu_switch_to)
ret_fast_syscall:
disable_irq // disable interrupts
str x0, [sp, #S_X0] // returned x0
- ldr x1, [tsk, #TI_FLAGS] // re-check for syscall tracing
+ ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for syscall tracing
and x2, x1, #_TIF_SYSCALL_WORK
cbnz x2, ret_fast_syscall_trace
and x2, x1, #_TIF_WORK_MASK
@@ -706,14 +705,14 @@ work_pending:
#ifdef CONFIG_TRACE_IRQFLAGS
bl trace_hardirqs_on // enabled while in userspace
#endif
- ldr x1, [tsk, #TI_FLAGS] // re-check for single-step
+ ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for single-step
b finish_ret_to_user
/*
* "slow" syscall return path.
*/
ret_to_user:
disable_irq // disable interrupts
- ldr x1, [tsk, #TI_FLAGS]
+ ldr x1, [tsk, #TSK_TI_FLAGS]
and x2, x1, #_TIF_WORK_MASK
cbnz x2, work_pending
finish_ret_to_user:
@@ -746,7 +745,7 @@ el0_svc_naked: // compat entry point
enable_dbg_and_irq
ct_user_exit 1
- ldr x16, [tsk, #TI_FLAGS] // check for syscall hooks
+ ldr x16, [tsk, #TSK_TI_FLAGS] // check for syscall hooks
tst x16, #_TIF_SYSCALL_WORK
b.ne __sys_trace
cmp scno, sc_nr // check upper syscall limit
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 332e33193ccf1575727dfc8883644a5cfabd0e08..eaafb253bbfa58ed2fff02d636dcaed8f9c41f24 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -428,7 +428,8 @@ ENDPROC(__create_page_tables)
__primary_switched:
adrp x4, init_thread_union
add sp, x4, #THREAD_SIZE
- msr sp_el0, x4 // Save thread_info
+ adr_l x5, init_task
+ msr sp_el0, x5 // Save thread_info
adr_l x8, vectors // load VBAR_EL1 with virtual
msr vbar_el1, x8 // vector table address
@@ -699,10 +700,10 @@ __secondary_switched:
isb
adr_l x0, secondary_data
- ldr x0, [x0, #CPU_BOOT_STACK] // get secondary_data.stack
- mov sp, x0
- and x0, x0, #~(THREAD_SIZE - 1)
- msr sp_el0, x0 // save thread_info
+ ldr x1, [x0, #CPU_BOOT_STACK] // get secondary_data.stack
+ mov sp, x1
+ ldr x2, [x0, #CPU_BOOT_TASK]
+ msr sp_el0, x2
mov x29, #0
b secondary_start_kernel
ENDPROC(__secondary_switched)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index ec7b9c00effe1b3fcbb1d8cfbdc91c7f92d261ab..a98b743631c5b3e1b5df3c92e5f092353c1e71d3 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -45,6 +45,7 @@
#include <linux/personality.h>
#include <linux/notifier.h>
#include <trace/events/power.h>
+#include <linux/percpu.h>
#include <asm/alternative.h>
#include <asm/compat.h>
@@ -321,6 +322,20 @@ void uao_thread_switch(struct task_struct *next)
}
}
+/*
+ * We store our current task in sp_el0, which is clobbered by userspace. Keep a
+ * shadow copy so that we can restore this upon entry from userspace.
+ *
+ * This is *only* for exception entry from EL0, and is not valid until we
+ * __switch_to() a user task.
+ */
+DEFINE_PER_CPU(struct task_struct *, __entry_task);
+
+static void entry_task_switch(struct task_struct *next)
+{
+ __this_cpu_write(__entry_task, next);
+}
+
/*
* Thread switching.
*/
@@ -333,6 +348,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
tls_thread_switch(next);
hw_breakpoint_thread_switch(next);
contextidr_thread_switch(next);
+ entry_task_switch(next);
uao_thread_switch(next);
/*
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 6f42c68e457fcf4b461ace2c1d7f42bfcab36386..cb87234cfcf2d2b8ba75f9e83dadf78c927a3e86 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -149,6 +149,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
* We need to tell the secondary core where to find its stack and the
* page tables.
*/
+ secondary_data.task = idle;
secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
update_cpu_boot_status(CPU_MMU_OFF);
__flush_dcache_area(&secondary_data, sizeof(secondary_data));
@@ -173,6 +174,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
}
+ secondary_data.task = NULL;
secondary_data.stack = NULL;
status = READ_ONCE(secondary_data.status);
if (ret && status) {