| Message ID | 1399672310-9061-3-git-send-email-larry.bassel@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Fri, May 09, 2014 at 10:51:50PM +0100, Larry Bassel wrote: > 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). > > 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. [...] > 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 136bb7d..c839bab 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, save = 0 > +#ifdef CONFIG_CONTEXT_TRACKING > + bl context_tracking_user_exit > + .if \save == 1 It would be clearer to refer to the parameter as `restore' for the exit case, I reckon. > + /* > + * 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 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 You should check how this patch applies against my debug exception rework: 2a2830703a23 ("arm64: debug: avoid accessing mdscr_el1 on fault paths where possible") in today's next. As well as addressing the conflicts, it's worth nothing that the thread_info becomes available in tsk much earlier for exceptions from userspace with that patch applied. Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index e6e4d37..152d92b 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 136bb7d..c839bab 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, save = 0 +#ifdef CONFIG_CONTEXT_TRACKING + bl context_tracking_user_exit + .if \save == 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 *----------------- */ @@ -88,6 +126,7 @@ .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 @@ -425,6 +464,7 @@ el0_da: enable_dbg // enable interrupts before calling the main handler enable_irq + ct_user_exit mov x0, x26 bic x0, x0, #(0xff << 56) mov x1, x25 @@ -441,6 +481,7 @@ el0_ia: enable_dbg // enable interrupts before calling the main handler enable_irq + ct_user_exit mov x0, x26 orr x1, x25, #1 << 24 // use reserved ISS bit for instruction aborts mov x2, sp @@ -450,6 +491,7 @@ el0_fpsimd_acc: /* * Floating Point or Advanced SIMD access */ + ct_user_exit mov x0, x25 mov x1, sp adr lr, ret_from_exception @@ -458,6 +500,7 @@ el0_fpsimd_exc: /* * Floating Point or Advanced SIMD exception */ + ct_user_exit mov x0, x25 mov x1, sp adr lr, ret_from_exception @@ -472,6 +515,7 @@ el0_sp_pc: enable_dbg // enable interrupts before calling the main handler enable_irq + ct_user_exit mov x0, x26 mov x1, x25 mov x2, sp @@ -484,6 +528,7 @@ el0_undef: mov x26, sp // enable interrupts before calling the main handler enable_irq + ct_user_exit mov x0, x26 adr lr, ret_from_exception b do_undefinstr @@ -494,12 +539,14 @@ el0_dbg: tbnz x24, #0, el0_inv // EL0 only mrs x26, far_el1 disable_step x1 + ct_user_exit mov x0, x26 mov x1, x25 mov x2, sp adr lr, ret_from_exception b do_debug_exception el0_inv: + ct_user_exit mov x0, sp mov x1, #BAD_SYNC mrs x2, esr_el1 @@ -518,6 +565,7 @@ el0_irq_naked: bl trace_hardirqs_off #endif + ct_user_exit irq_handler get_thread_info tsk @@ -640,6 +688,7 @@ el0_svc_naked: // compat entry point isb enable_dbg enable_irq + ct_user_exit 1 get_thread_info tsk ldr x16, [tsk, #TI_FLAGS] // check for syscall tracing