arm64: enable context tracking

Make calls to ct_user_enter when the kernel is exited
and ct_user_exit when the kernel is entered (in el0_da,
el0_ia, el0_svc, el0_irq and all of the "error" paths).

These macros expand to function calls which will only work
properly if el0_sync and related code has been rearranged
(in a previous patch of this series).

The calls to ct_user_exit are made after hw debugging has been
enabled (enable_dbg_and_irq).

The call to ct_user_enter is made at the beginning of the
kernel_exit macro.

This patch is based on earlier work by Kevin Hilman.
Save/restore optimizations were also done by Kevin.

Acked-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Larry Bassel <larry.bassel@linaro.org>
Signed-off-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f865436096b6cacb2065e989af18253190f8c525..1cb806529393560bed4c41d094883e1c369da1bf 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -63,6 +63,7 @@ config ARM64
        select RTC_LIB
        select SPARSE_IRQ
        select SYSCTL_EXCEPTION_TRACE
+       select HAVE_CONTEXT_TRACKING
        help
          ARM 64-bit (AArch64) Linux support.
 

diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index e40b6d06d515ab9f390faf389487fdb96c7d41e8..45108d802f5e6a1a586ce519edd0375ccad65cd9 100644 (file)
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -103,6 +103,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_NEED_RESCHED       1
 #define TIF_NOTIFY_RESUME      2       /* callback before returning to user */
 #define TIF_FOREIGN_FPSTATE    3       /* CPU's FP state is not current's */
+#define TIF_NOHZ               7
 #define TIF_SYSCALL_TRACE      8
 #define TIF_SYSCALL_AUDIT      9
 #define TIF_SYSCALL_TRACEPOINT 10
@@ -118,6 +119,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_NEED_RESCHED      (1 << TIF_NEED_RESCHED)
 #define _TIF_NOTIFY_RESUME     (1 << TIF_NOTIFY_RESUME)
 #define _TIF_FOREIGN_FPSTATE   (1 << TIF_FOREIGN_FPSTATE)
+#define _TIF_NOHZ              (1 << TIF_NOHZ)
 #define _TIF_SYSCALL_TRACE     (1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT     (1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SYSCALL_TRACEPOINT        (1 << TIF_SYSCALL_TRACEPOINT)
@@ -128,7 +130,8 @@ static inline struct thread_info *current_thread_info(void)
                                 _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE)
 
 #define _TIF_SYSCALL_WORK      (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
-                                _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
+                                _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
+                                _TIF_NOHZ)
 
 #endif /* __KERNEL__ */
 #endif /* __ASM_THREAD_INFO_H */

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index d7230bf68ad155144fef43e746de89ce72969e11..93ac58dbf07cecc05173bf7ecf3aef09e0db9bd1 100644 (file)
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -29,6 +29,32 @@
 #include <asm/unistd.h>
 #include <asm/unistd32.h>
 
+/*
+ * Context tracking subsystem.  Used to instrument transitions
+ * between user and kernel mode.
+ */
+       .macro ct_user_exit, syscall = 0
+#ifdef CONFIG_CONTEXT_TRACKING
+       bl      context_tracking_user_exit
+       .if \syscall == 1
+       /*
+        * Save/restore needed during syscalls.  Restore syscall arguments from
+        * the values already saved on stack during kernel_entry.
+        */
+       ldp     x0, x1, [sp]
+       ldp     x2, x3, [sp, #S_X2]
+       ldp     x4, x5, [sp, #S_X4]
+       ldp     x6, x7, [sp, #S_X6]
+       .endif
+#endif
+       .endm
+
+       .macro ct_user_enter
+#ifdef CONFIG_CONTEXT_TRACKING
+       bl      context_tracking_user_enter
+#endif
+       .endm
+
 /*
  * Bad Abort numbers
  *-----------------
@@ -91,6 +117,7 @@
        .macro  kernel_exit, el, ret = 0
        ldp     x21, x22, [sp, #S_PC]           // load ELR, SPSR
        .if     \el == 0
+       ct_user_enter
        ldr     x23, [sp, #S_SP]                // load return stack pointer
        .endif
        .if     \ret
@@ -426,6 +453,7 @@ el0_da:
        mrs     x26, far_el1
        // enable interrupts before calling the main handler
        enable_dbg_and_irq
+       ct_user_exit
        bic     x0, x26, #(0xff << 56)
        mov     x1, x25
        mov     x2, sp
@@ -438,6 +466,7 @@ el0_ia:
        mrs     x26, far_el1
        // enable interrupts before calling the main handler
        enable_dbg_and_irq
+       ct_user_exit
        mov     x0, x26
        orr     x1, x25, #1 << 24               // use reserved ISS bit for instruction aborts
        mov     x2, sp
@@ -448,6 +477,7 @@ el0_fpsimd_acc:
         * Floating Point or Advanced SIMD access
         */
        enable_dbg
+       ct_user_exit
        mov     x0, x25
        mov     x1, sp
        adr     lr, ret_to_user
@@ -457,6 +487,7 @@ el0_fpsimd_exc:
         * Floating Point or Advanced SIMD exception
         */
        enable_dbg
+       ct_user_exit
        mov     x0, x25
        mov     x1, sp
        adr     lr, ret_to_user
@@ -479,6 +510,7 @@ el0_undef:
         */
        // enable interrupts before calling the main handler
        enable_dbg_and_irq
+       ct_user_exit
        mov     x0, sp
        adr     lr, ret_to_user
        b       do_undefinstr
@@ -492,9 +524,11 @@ el0_dbg:
        mov     x2, sp
        bl      do_debug_exception
        enable_dbg
+       ct_user_exit
        b       ret_to_user
 el0_inv:
        enable_dbg
+       ct_user_exit
        mov     x0, sp
        mov     x1, #BAD_SYNC
        mrs     x2, esr_el1
@@ -511,6 +545,7 @@ el0_irq_naked:
        bl      trace_hardirqs_off
 #endif
 
+       ct_user_exit
        irq_handler
 
 #ifdef CONFIG_TRACE_IRQFLAGS
@@ -615,6 +650,7 @@ el0_svc:
 el0_svc_naked:                                 // compat entry point
        stp     x0, scno, [sp, #S_ORIG_X0]      // save the original x0 and syscall number
        enable_dbg_and_irq
+       ct_user_exit 1
 
        ldr     x16, [tsk, #TI_FLAGS]           // check for syscall hooks
        tst     x16, #_TIF_SYSCALL_WORK