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 khilman@linaro.org Signed-off-by: Larry Bassel larry.bassel@linaro.org Acked-by: Will Deacon will.deacon@arm.com --- 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..39d4dc9 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, 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 @@ -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