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 | 1 +
arch/arm64/kernel/entry.S | 48 ++++++++++++++++++++++++++++++++++++
3 files changed, 50 insertions(+)
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..301ea6a 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -108,6 +108,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_SINGLESTEP 21
#define TIF_32BIT 22 /* 32bit process */
#define TIF_SWITCH_MM 23 /* deferred switch_mm */
+#define TIF_NOHZ 24
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 20b336e..520da4c 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -30,6 +30,44 @@
#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, save = 0
+#ifdef CONFIG_CONTEXT_TRACKING
+ .if \save == 1
+ /*
+ * Save/restore only needed on syscall fastpath, which uses
+ * x0-x2.
+ */
+ push x2, x3
+ push x0, x1
+ .endif
+ bl context_tracking_user_enter
+ .if \save == 1
+ pop x0, x1
+ pop x2, x3
+ .endif
+#endif
+ .endm
+
+/*
* Bad Abort numbers
*-----------------
*/
@@ -91,6 +129,7 @@
.macro kernel_exit, el, ret = 0
ldp x21, x22, [sp, #S_PC] // load ELR, SPSR
.if \el == 0
+ ct_user_enter \ret
ldr x23, [sp, #S_SP] // load return stack pointer
.endif
.if \ret
@@ -318,6 +357,7 @@ el1_irq:
bl trace_hardirqs_off
#endif
+ ct_user_exit
irq_handler
#ifdef CONFIG_PREEMPT
@@ -427,6 +467,7 @@ el0_da:
mrs x26, far_el1
// enable interrupts before calling the main handler
enable_dbg_and_irq
+ ct_user_exit
mov x0, x26
bic x0, x0, #(0xff << 56)
mov x1, x25
@@ -440,6 +481,7 @@ 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
@@ -450,6 +492,7 @@ 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
@@ -459,6 +502,7 @@ 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
@@ -481,6 +525,7 @@ 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
@@ -495,10 +540,12 @@ el0_dbg:
mov x2, sp
bl do_debug_exception
enable_dbg
+ ct_user_exit
mov x0, x26
b ret_to_user
el0_inv:
enable_dbg
+ ct_user_exit
mov x0, sp
mov x1, #BAD_SYNC
mrs x2, esr_el1
@@ -619,6 +666,7 @@ 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 tracing
tbnz x16, #TIF_SYSCALL_TRACE, __sys_trace // are we tracing syscalls?
--
1.8.3.2
--
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