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.
Signed-off-by: Kevin Hilman <khil...@linaro.org>
Signed-off-by: Larry Bassel <larry.bas...@linaro.org>
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/thread_info.h | 4 ++++
arch/arm64/kernel/entry.S | 39 +++++++++++++++++++++++++++++++++++-
3 files changed, 43 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index e759af5..ef18ae5 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -55,6 +55,7 @@ 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 720e70b..8363f34 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -100,6 +100,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_SIGPENDING 0
#define TIF_NEED_RESCHED 1
#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
+#define TIF_NOHZ 7
#define TIF_SYSCALL_TRACE 8
#define TIF_POLLING_NRFLAG 16
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
@@ -113,9 +114,12 @@ 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_32BIT (1 << TIF_32BIT)
+#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
+#define _TIF_NOHZ (1 << TIF_NOHZ)
#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
_TIF_NOTIFY_RESUME)
+#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_NOHZ)
#endif /* __KERNEL__ */
#endif /* __ASM_THREAD_INFO_H */
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index b0101b9..3c484e2 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -30,6 +30,32 @@
#include <asm/unistd32.h>
/*
+ * Context tracking subsystem. Used to instrument transitions
+ * between user and kernel mode.
+ */
+ .macro ct_user_exit, restore = 0
+#ifdef CONFIG_CONTEXT_TRACKING
+ bl context_tracking_user_exit
+ .if \restore == 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
@@ -318,6 +345,7 @@ el1_irq:
bl trace_hardirqs_off
#endif
+ ct_user_exit
irq_handler
#ifdef CONFIG_PREEMPT
@@ -427,6 +455,7 @@ 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
@@ -439,6 +468,7 @@ 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
@@ -449,6 +479,7 @@ 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
@@ -458,6 +489,7 @@ 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
@@ -480,6 +512,7 @@ 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
@@ -493,9 +526,11 @@ 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
@@ -616,9 +651,11 @@ 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 tracing
- tbnz x16, #TIF_SYSCALL_TRACE, __sys_trace // are we tracing syscalls?
+ and x16, x16, #_TIF_SYSCALL_WORK // are we tracing syscalls?
+ cbnz x16, __sys_trace
adr lr, ret_fast_syscall // return address
cmp scno, sc_nr // check upper syscall limit
b.hs ni_sys
--
1.8.3.2
--
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